Jason Goes VTEC Yo: Honda (Acura) J32a3 Swap (Formally "My LFX V6 Build")
 

Yes, I've decided to go with a LFX engine from a "cough" Camaro. More on that later, for now I just want to get pics of my next donor up:

It's a black 1999 with the "preferred equipment package" (means limited slip), a new top, 95K miles and fresh paint and lights on the front and rear due to an incident with a deer:

https://www.v8miata.net/members/mrm3...g1377-1102.jpg

https://www.v8miata.net/members/mrm3...g1373-1104.jpg

https://www.v8miata.net/members/mrm3...g1371-1105.jpg

https://www.v8miata.net/members/mrm3...g1375-1103.jpg

https://www.v8miata.net/members/mrm3...g1367-1106.jpg

I paid $3500 for it which is pretty awesome considering the drive line should get me $1500 to $2000 when i pull it. It has a bit of rocker rust on the driver's side but I figure I'll do to it what I did to my last one, clean it out, Por15 it to stabilize it and then put something over it. I already picked up a set of "big tupperware" side sills new-in-box with factory black paint for this purpose. I figure it will come out like this in the end:

http://carphotos.cardomain.com/ride_...0001_large.jpg

More to follow.

-Jason

I will watch this with great interest and multiple tubs of popcorn. I have a 1999 10AE that has had a rough life and needs some 'freshening up'. I've been lurking for a few months now reading up on V8 conversions. I've become quite enthralled with the LFX swap.

I'm hoping to embark on my own journey this winter. Hope to learn a lot from watching this thread.

Good Luck Jason! I'll also watch and learn, who knows one day I "may" seriously consider a LFX swap. However I'm still refining my 5.0 car, just received a Fitech fuel injection unit and am looking forward to loosing the carb issues brought on with today's gas.

Also I do like the look of a by-gone era when I raise the hood on my car. And of course it still does serve my sometimes frequent need to go medium fast.

I have always liked that black '99 on the bottom. I saved that pic to one of my old PCs years ago. I like your plan. Good luck.

it will be pretty easy to get an lfx into an nb. na, on the other hand, was tight. had to bump the hood for clearance. but it's a g-r-e-a-t engine.

Jason, is this going to be streetable? I'm curious as to how the emissions inspection hurdle can be cleared.

BTW, I'm in the process of installing your harness in my project today.

donor looks great

So, a quick update.

Although I'm pretty committed to not making any drastic changes to the car until I sell my house and buy one with a garage I did have to make a few "saftey upgrades" to the car over the last month:

The right front caliper was dragging which was a saftey concern. To fix this I could have just purchased the pin and some grease but instead replaced the entire system with sport brake components with the exception of the master cylinder itself. This includes front and rear hangers, rotors, calipers and pads. I also replaced the flex lines with new SS ones and added Hawk HPS pads. Since this would throw the front/back balance off (the rear rotors are actually larger than the front) I swapped in the 1994 Laguna's original ABS prop valve. This valve has almost the same bias as the NB sport brake one and seems to have balanced it out pretty nice. The car stops much quicker now.

Since the brakes now had more bite I found the stock suspension was not up to the task of keeping it from pitching forward. This also was a saftey concern so I added a set of used FCM Elites we had lying around with 500 pound front springs and 325 pound rears. In the name of improved fuel economy I also had to lower it about two inched from stock.

The car is now very "safe".

The brakes cost me about $400 all told and the coil overs were free (traded some V8 stuff with my dad for them). I put the original shock/springs, the four calipers with hangers and pads and the car's original 14 wheels/tires on Craiglist and recouped $350 of that back.

I also sold my early NA Laguna hard top for $1000 and picked up a black 1999 one with a defroster for $700. It's not as pretty as the Laguna one but even if I have to have it repainted (about $500) I'm still in for under $1200 on it. Considering it would have cost me $500 to have the non-defroster Laguna one painted black anyhow I think I made out OK.

The next project will be to handle the minor rust on the driver's side. My plan is to do what I did with the Laguna which is to cut it all out, paint/seal everything with Por15 and then cover it with something as opposed to welding or gluing in a new panel and then blending. This plan worked out great on the Laguna where I could use a set of Progect-G rear defusers to cover the area. On this car I'm planning on using a set of OEM large tupperware side skirts which I was able to pick up new-old-stock OEM color-matched for $225 for the set. The inspiration picture above has these on it. I don't like them with the original 2001-2005 nose piece they came with but on an NB01 with the Garage Vary front lip they look pretty nice (NB01's only came with the small tupperware). I'm hoping to get into this project before putting the car away for the winter so the rust does not spread further to the point where the skirts would not be able to cover the scar.

A roll bar will be forth coming as well but not until late fall or the spring. When it does I'll also add the DIYRoadster door bars and Hard Dog harness bar I have from the last car as well as a set of Frog Arms I acquired in a trade a while back.

I got a little pissed when I realized that the 1999-2000 "NB01" is sort of a bastard child when it comes to aftermarket parts. I like the look of the front much better than the NB02 but don't like that the eBay front lip copying people don't give it any love. For an NA you can now get a Garage Vary "style" lip for under $50 shipped and for the NB02 they are about $100. There is an eBay "GV" lip for the NB01 available but it's not the same as the actual Garage Vary NB01 lip. The Garage Vary lips have a pronounced canard type structure on the side and mount over the lower portion of the stock nose while the NA ones mount on the bottom of the bumper cover and are relatively flat around the sides. The NB01 eBay lip looks to be just a adaptation of the NA GV lip which in my opinion does not match the look of the NB at all. Figuring I can make anything fit I went and purchased a NB02 eBay GV lip and found it completely does not work. So, I'll be sending $300 to Japan (though one of the current US vendors) for an actual Garage Vary 1999-2000 front lip.

Once that's done cosmetically I'll have the inspirational car above matched. With the addition of the roll bar, my tow hooks from the Laguna (I will not put them on until it has a roll bar and can be tracked...I can't stand how many automatic Honda Civics that would not be allowed within half a mile of an actual race track have tow hooks) I'll be ready to do a few 4-cylinder track days in the spring. I figure a few track days without the 400 horse power crutch I had in the past can only help me improve my form while giving me the time to secure parts for the V6 build and an actual garage of my very own to build it in. Setting next summer or the winter after as a conversion time also gives more time for the knowledge base for both of these V6 swaps (LFX and J-series) to get a little bigger.

-Jason

I like the fact that you make the effort to keep "safety" first. I need to remember that. :)

Mike

Rust repair wise, Autoquest on RT724 just a few miles east of the RT100 interchange is who I would highly recommend now that my shop is gone.



Bill S.

This is awesome, Jason. Just found this build thread and glad I did. The black NB looks nice. Great buy.

This isn't exactly the GV lip, but it looks like a good replica of the lip on my 10AE. I've been thinking about grabbing one to replace mine as the PO banged it up on curbs pretty well and did a sorry job at repairing it..

99 00 Mazda Miata OE Style Front Bumper Lip Chin Spoiler Polyurethane PU | eBay

Maybe worth a look.

Sooooooo, I'm going with a J32a3 from a 2005 Acura TL.

I do really believe that the LFX is the best current route for the under $15K, over 300 hp build but a few factors led me to the JV6 in the end. They are:

1. I can use a Megasquirt 3
Originally I was worried that a MS3 and OBD2 compatibility were mutually exclusive of each other. When I researched deeper into how to make a parallel install work I realized it would be possible with the Acura engine to make the Mazda ecu think it's still running a 1.8 while using the MS3 to run the engine. I'll get into more detail during the build itself but in the end I'll have the Mazda ecu running everything its running now except fuel, spark and (obviously) VTEC switch over. This means no need to worry about Dakota boxes for the gauges, no issues with the check engine light and OBD2 emissions tests and ECU VIN, and no need to completely rewire the car. If it works it will be amazing.

2. I can get it done for under $6000
The LFX build is a bargain at around $12k and can get me 330hp/270tq. This can get me 270hp/245tq for half the price. The dollar:horse power gained ratio is much higher

3. I can get it done quickly
My 1999 donor has developed the dreaded 1999/2000 thrust bearing issue at 97k miles. I can get this done and rolling (maybe not programmed but no longer taking up a bay) in a few weeks. A LFX build would take longer and without my own garage I'm using the garage hospitality of my parents to get this done.

4. Knowledge base
As it turns out, my supporting knowledge base is much greater for the Honda engine than it is for the GM motor. My best friend is a service writer at a Honda dealer and will serve as an invaluable resource on this. My wife recently picked up a 2006 Honda Pilot with a J35a6 in it.

5. The car retains more "Miataness"
As I drove my stock 1999 around I realized that while I loved the brute force of the V8 Miatas I drove for over ten years, I also really like the ease of the Miata 5-speed, the rigidity of the PPF, the awesomeness of the Miata Torsen, etc. If those parts can hold up I think this car may be closer to a a properly powered Miata than a Camaro or Mustang with a Miata body kit.

I'm picking up a 2005 Acura TL J32a3 on Friday. It has only 43,000 on it and I'm getting it for $900. I'll take a few weeks to check it over and decide what will be powder coated and how to work out the integrated exhaust headers and then get my order in for a MiniTech kit. At that point 80% of the conversion is paid for. DIYAutotune has a 10% sale every black friday which should be perfect timing for picking up $700 worth of MS3x, wiring and a WB.

I'll start another thread when the build actually starts. I'm very excited about this!

-Jason

Well Dang Jason....was certainly looking forward to your LFX build. That said, this new will path be entertaining for sure. Who knows, you may pave the way for a new conversion mania.

I know, I really do think the LFX is a amaizingly well engineered kit that is compairable to the original Monster Miatas in power, accessabilty to the average weekend wrencher, and overall cost. I would have liked to go that route this time, but the overall cost and time savings of this route made it a more realistic project for where I am currently in life. That, and some minor concerns over direct injection related stories (or possibly myths) I've heard pretty much sealed the deal.

I did pick up the 2005 TL engine from Don's Automotive Mall on Friday. I'm used to u-pullit yards where picking up a part means coming out looking like you just went through a "Tough Mudder" day. This place was so clean I could have picked the engine up wearing my shirt and tie. The engine itself was so new looking it looked as though It had never been used. My father wanted to see pictures of the car it came from which they were happy to show us. Although the car had suffered a front end collusion everything looked ok on the engine so I swiped my card for the $901.00, strapped it down to the trailer and took it back to my father's garage.

Once I had it off the trailer I began to look at taking the cam belt covers off just to inspect it and see if some belt routing ideas I had may work. Once I got them off my heart sank. The relativly minor impact had his the front (passenger side) engine mount just right and cracked the waterpump. While disappointed I figured replacing the pump anyhow was not a bad idea so I looked to try to remove it. When I looked behind it my heart fell further. Not only had the waterpump been smashed but the portion of the block it mounted to was also broken off. The engine would not be usable without a new $650 block from Honda.

I called Don's back and spoke to the salesman I worked with a few hours before. He was very apologetic about the situation and is currently trying to find me another 2004-2006 Acura TL j32a3 with less than 50k on it to replace what I have. I'm not overly optimistic of his chances, most of these engines have north of 150k on them. He does have one with 99k on it but its listed for what I paid for mine. Unless he's willing to knock a few hundred off that one (or let me keep both) I don't think its a fair replacement. We'll see what next week brings.

On a positive note, I spoke to the Minitec people the other day about some last minute questions I had about their kit and got some good answers. The kit now uses ether the NA or NB steering racks and locates both in the stock locations. The fabricated side intake that several people have used to retain power steering is $300 and they can make one for that cost for the passenger or driver side. Shipping to PA from their location is $150 for the whole kit. As I'm not having them send me the clutch or exhaust components it may be cheaper. The clutch pressure plate, throwout bearing, flywheel, and pilot bearing are all from a 2000 Honda Civic Si and the clutch disk is 1.8 Miata. Using Rock Auto oem grade replacement parts this whole part of the build can come in at less than $200. Using totally awesome lightweight and heavier duty parts you're only looking at under $500. I'm pretty sure the parts in the kit are just oem stuff so this is a great place to have them leave those parts out and upgrade quality a bit.

I'm still on track for a late summer/fall build.

-Jason

Too bad you live so far away.
I sure would like to see one of these builds in person as the build progresses.
Originally my intention was to do one of these to my Miata but made the decision to go with Flyin Miata and their well engineered and proven LS swap kits. Also have to blame Tom and his LS swap videos on YouTube.

As you mentioned, the cost per HP aspect is what sells this swap.

Only other worry I had in researching the swap is retaining the factory Miata transmission and rear end components. The torque of the V6 simply looks to be right at the edge of what the Miata stuff will safely support without turning into a pile of useless trash. Particularly with respect to the transmission, it does not seem there is a reasonable transplant to a beefier unit. There is also the limited choice in rear end gearing.

I was concerned about this also at first, however, no one (to date at least) has managed to kill a Miata 5-speed or 1.8 diff with the J32 or J35 versions of this swap. I've seen it explained as having to do with the torque being delivered over the course of 6 impulses in a V6 as opposed to 4 in a high-strung 4 cylinder but that could just be a bunch of BS. Even if one does go south, Miata 5-speed transmissions are a dime a dozen. The 6-speed would be a higher capacity option if needed although their sixth gear final ratio actually comes out higher than the 5-speed's fifth,believe it or not. I'll be using an NB 5-speed which is said to be the strongest version of the trans, we'll see.

The 1.8 diff can be had as a 3.9, 4.1 or 4.3 in North America. Honestly, these are all too high for even a J32a2. The best option it seems is to go with a set of Mazda 3.636 gears that were used in Miatas in other parts of the world. A new set can be had for around $500 and installed for $200 - $400. Although I have not found a way to do so its possible an used, intact 3.636 diff could be imported from the other side of the planet, although I don't know if that would get you at the $700 to $100 it would just cost you to have one made from new parts anyhow. I have a 4.3 in my 1999 so I'll be looking into doing something with this.

-Jason

I'm pretty excited to read and watch this build come together. I like the idea of the 3.63 gear swap to make the overall ratios pretty ideal for this V6. Keep this thread going!

Update: Don's Automotive mall found me another 2005 Acura TL engine to replace the beautiful 43,000 mile boat anchor currently sitting in my father's garage. This one has 73,000 on it so they are throwing in the PS pump to sweeten the deal. I still think I'm making out alright as most I've seen online with under 100,000 are going for $1200 or so. I'm paying $850. I'll be picking it up on Wednesday.


-Jason

Update Time:

Things have been moving quickly with this as of late. Currently I'm installing a dedicated MS2 harness in the Laguna for the new owner but when that's through the 1999 goes under the knife. Here's where I'm at as of now:

Note: Please excuse the poor quality of the pictures. My complete piece of garbage HTC A9's camera died forcing me to use the selfie camera. Before starting the actual build I'll get a better camera.

Rust Repair:
The '99 had the typical rocker rust that every car here in PA has. Rather than do a full patch/repair I did the same "remediation" I did on the Laguna. I chipped/cut/ripped every bit of rust from the rocker areas until they were cut back to bare metal, treated and painted everything in the area with Por-15 and then fitted cosmetic panels over the areas. For the Laguna I used Project-G defusers, for this car I used NB2 "Large Tupperware" side skirts. To balance them out I installed a genuine Garage Vary NB1 lip which I had to have sent from Japan. Here's the result:

https://www.v8miata.net/members/mrm3...g1953-1182.jpg

https://www.v8miata.net/members/mrm3...g1927-1181.jpg

https://www.v8miata.net/members/mrm3...g1926-1180.jpg

I'm very happy with the result. I was debating between the NB1 or NB2 rear flares but actually think I'll keep it the way it is. The high back looks pretty good.

Engine Arrives:

I'm using a Gen 2 J32a3 from a 2004-06 Acura TL as opposed to the J32a2 (earlier TL) or J35a4 (Minivan) that the kit was specifically designed around. I'm doing this because (besides the fact that I can't ever just do things the easy way):

1. The J32a3 is one of only two Gen 3 J engines that use the Gen 1/2 bell housing bolt pattern the Minitec kit uses.

2. The J32a3 has the torque of the J35a4 (240 ft lbs.) and the horse power of the J32a2 (270) and can still rev to the 7K level as the J32a2 can.

3. The MS3X I'm using has a pre-configured spark trigger mode called "Honda/Acura" which is designed for the cam/crank trigger setup of the the Gen 3 motors. Using a Gen 2 would work great if I wanted to use a OEM Honda or AEM Ecu but would be a pain with a MegaSquirt. Using a MegaSquirt will allow me to run control the engine in parallel with the OBD2 Mazda ECU, hopefully keeping OBD2 functionality and eliminating any issues with the NB tach or speedometer.

4. The Gen 3 engines use a Integrated Exhaust Manifold as do the GM LFX engines. While sometimes poo-poo'ed by the "just add headers" crowd, the research I've done has shown that IEM's benefits seem to outweigh the downsides. On both the Honda and GM engines they reduce weight, give much more room for the steering shaft, and simplify exhaust routing. An added side bonus is that because the IEM's primary purpose was to make mounting a precat easier the manufactures' posted HP/Torque figures usually are done with precats in place. Replacing the precats with a "precat delete" (a straight down pipe) usually gives you 15 - 20 more horsepower right off the bat.

I picked up the second J32a3 (see the last few posts) last week and started pulling it apart to flip the intake, simplify the cooling connections, and figure out how to change the location of the PS pump. Before it goes in it's getting a new timing belt and waterpump. Here it is with the intake and fuel rails flipped:

https://www.v8miata.net/members/mrm3...g2029-1178.jpg

Engine Management:

I'm planning on running the J32a3 via a MegaSquirt MS3X in parallel with the 1999 Miata ECU. The Miata Ecu will continue to control the fuel pump, speedometer, tach and alternator (I'm keeping Miata alternator but adding a new 6-rib pulley). To keep the 1999 Miata ECU happy and thinking its still in charge of the show its going to need to keep seeing a cam and crank signal, a tps reading, a mass air reading, and readings from it's upstream and downstream narrow band o2 sensors. The Temp sensors, Mass air meter, and o2 sensors are easy...all I need to do is relocate them to the Honda block/intake/exhaust/etc. The cam and crank senders are a little more tricky. To give it a crank signal I'm planning on attaching a 1999 Miata crank trigger wheel to the front of the Honda balance and relocating the Miata sender with it. The MS3 will use the Honda wheel and sender which is much more accurate. The Honda cam sensor may actually just be able to send a signal the MS3 and Miata ECU as the pickup signal is pretty close to the Miata's. I'll try it that way and if the Mazda ecu starts throwing codes I'll mount the center of a NB Miata cam gear with the "gear" portioned machined off to the front of the Honda's rear cam (the front Honda sender uses the front cam) and mount the Miata sender over it in almost exactly the same place in it is inthe engine bay now.

The TPS signal is another issue. Since the MS3 can read the Mazda signal I figure my best bet is to just use the Mazda one and split the signal to both ecu's. From what I've read this means leaving it's ground and 5v reference voltage wires connected only to the Mazda ecu and splitting the signal out to both. Since the J32a3 uses a drive-by-wire throttle, figuring out how to replace it with a cable operated one is needed anyhow. I toyed with the idea of just using the '99 Miata throttle since it's there but decided against it due to the diameter. For this I'm going back to my Ford experience and using a 65mm Ford Explorer throttle. Adapter plates are actually made to fit Ford throttles on Honda intakes and TPS adapters are made to fit Mazda TPS sensors to Ford throttles for Miata supercharger applications. The Ford idle valve is part of the throttle and will be very easy to control via the MS3.

Here's my plan:

https://www.v8miata.net/members/mrm3...iring-1177.jpg

If everything works as it should I'll have a naturally aspirated 270 hp Miata that can actually pass a PA OBD2 inspection.

It's amazingly simple, don't you think?

-Jason

Update to the above diagram: VTEC and knock sensor added:

https://www.v8miata.net/members/mrm3...iring-1183.jpg

-Jason

Glad you think it is amazingly simple.
Sounds like a hair puller mess to me.
Hats off to you if it works correctly.

Nice!!! I'm thinking you need to start stockpiling engines. Once the beta unit is perfected this could be a very desirable and sale-able conversion.

Thanks!

The cool part about these engines is that Honda boys (and girls) have been swapping blocks/cams/cranks/rods/cams/heads between the different Honda and Acura applications for years now. This has resulted in some really awesome potential for this engine from a large bore/short stroke/oversquare/high rev 3.3 liter to a stump puller "stroker" 3.7 liter all with factory Honda parts! They refer to them as "Frankenstein" J's. Porsche tuner "Bismo" even will regrind J series cams for a reasonable price.

If I can get Minitech to look into drilling their adapter plate for the newer J bellhousing pattern it would open this build up to J engines being used today. These engines only displace 3.5 liters but make almost the power of the LFX with less weight and size.

The other cool aspect of this build is the cheapness of Honda aftermarket parts compaired to Mazda. I'm going with a flywheel/clutch/pressure plate combo that would have cost me $600 - $700 in Miata-specific parts for under $450 because they are made to fit Hondas.

The Laguna started and ran after its full nervous system transplant today which brings me one step closer to starting this build. Designing and building a full harness from scratch for that car and seeing it actually start has really boosted my confidence in building the harness for this one. I see that aspect, the engine management, as really the only unknown challenge to this build compared to what my father and I have done in the past (that and snaking a true dual exhaust around an intact PPF...but that's my exhaust guy's problem, not mine :rofl:)

-Jason

You mentioned weight of the Honda 6 cylinder powerplant.
Do you have a feel for the weight difference of the V6 & tubular subframe as opposed to the factory 4 cylinder stuff?

While looking over your wiring diagram I noticed that it appears you are using the Miata fuel pump, correct? How well does it's flow and pressure work with the requirement to feed the V6?

The Minitec site states that on their test mule the conversion increased the car's weight by about 8 pounds. They used a J32a2 which uses iron headers and a fairly heavy intake manifold. The J32a3 I'm using has a much lighter intake than the older engines and incorporates integrated exhaust manifolds which are known to save net weight. The J30 series engines lost 20 pounds when these changes were made so I figure the same must be true with the J32. I'm also using the Miata alternator which is lighter than the Honda unit. The Honda AC compressor I'll be using feels heavier just picking it up so I may be giving some weight up there. the Honda Power steering pump seems about the same weight...If I break even or come in lower it will be awesome. Even if I don't come in lower in over all weigh, the weight of the v6 engine will be somewhat lower and further back which can't be a bad thing.

I honestly hadn't even though about this until your comment. I did do a comparison between the Camaro tank pump and the Miata pump when I was still leaning toward the LFX. In that case I found there was no reason to upgrade to the $395 fuel option because in Camaro the tank pump is only a lift pump. The high pressure pump on the back of the left head ramped it up to 1500 psi for the direct injection. Just for security's sake I compared the specs of the Camaro's pump and the '99 Miata pump and found them to be almost the same...no need to upgrade.

In the case of the J32a3 the tank pump is providing the pressure to the injectors so it is very relevant. I checked the specs on the replacement grade Airtex pumps for both the 1999 Miata and the 2006 TL. Here's what I found:

1999 Miata - Airtex E2111
Maximum Free Flow Rate: 50 gph
Maximum Pressure: 90 psi
Minimum Free Flow Rate: 40 gph
Minimum Pressure: 80psi

2006 TL - Airtex E8513
Maximum Free Flow Rate: 60 gph
Maximum Pressure: 100 psi
Minimum Free Flow Rate: 50 gph
Minimum Pressure: 80 psi

So the TL pump flows 10 gph more and has 10 psi more pressure. This may be close enough to not be an issue. I was running a stock 1994 Miata pump in my last Ford V8 and that had 5.4 liters of displacement and very thirsty 38.2 pound injectors. I never experienced a pressure drop situation in that car even at full tilt on the track so I think I may be good. If not I did find this option:

1999 Miata - Spectra SP1166
Maximum Flow Rate: 50.4 gph
maximum Pressure: 109 psi
Minimum Flow Rate: 41.5 gph
Minimum Pressure: 80 psi

Price: $52.79!!!!

The Spectra pump may handle the pressure difference if needed. The flow rate may be dependent upon the Miata's line diameter so there may be nothing any pump can do about it without a full fuel system upgrade. Honestly, the 1994 Miata pump in my 331 was able to keep up on the track for 8 hours where the car was only getting 4 miles to the gallon. That's got to be a lot of flow but still below the 50 gph of the stock pump. I never saw an unexpected lean situation in the data logs. I think I'll be fine with the stock pump but its good to have options :)

-Jason

LFX Note:
Oh, one more comment for anyone reading this and still doing the LFX build: I also compared the radiator specs between a 2015 V6 Camaro and a 1999 Miata. The Miata's stock radiator is BIGGER than the stock Camaro one! There is NO reason to spend $785 on V8R's "LFX Cooling System" package unless you really need the inlet on the driver's side. If that's really an issue there are other coolant necks from different applications of the LFX that point the other direction that are a lot cheaper than $785. The Miata's stock radiator is notoriously over sized for a 4 cylinder to band aid it's very poorly designed stock cooling system.

So there you go, if you're building a LFX V6 your build just got $1180 cheaper...no need to thank me :)

And a *BIG* Thank you from me. Needed or not! :)

Update:

I've stripped down the Acura harness that came with the J32a3 in anticipation of building it into a MS3 harness. After realizing the amount of smog and transmission stuff in it I realized it would actually be easier to take what I need from it rather than try to strip it of what I don't. An hour later I had all the plugs and leads I needed for the coils, injectors, VTEC solenoid, cam and crank sensors, etc. I have all the connectors and labeled wire I'll need to build the harness which I'll start shortly.

The kit came today! I ordered the "small" kit since I figured I could source my own flywheel, clutch, etc cheaper than Minitech could. The whole package only weighed 85 pounds with the pallet. The oil pan, k frame and thermostat housing all look MUCH better than what they show on their site. They really need to update pictures. The adapter plate has been very nicely redesigned to move the starter to the side and the oil pan seems to be shallower and wider than those shown before. The welds on everything are MUCH nicer than the stuff on the site.

I've got everything purchased at this point to bolt the engine into the car and do the normal timing belt/waterpump/pulley routine maintenance on the engine. The difference in price between aftermarket parts designed for Hondas as opposed to Mazdas is amazing. I purchased an ACT stage one sfi-approved 8.8 pound billet flywheel and same series ACT clutch disk and pressure plate. Had I purchased the three as a package for a 1.8 Miata it would have cost me almost $700. Because the flywheel and pressure plate were designed for a 2000 Civic Si the whole cost came out to around $350! The disk is only Miata part in the clutch assembly.

I'm looking to start on this and have everything bolted in by the end of the summer. I'll work on the electronics and exhaust over the fall/winter. DIYAutotune usually has a pretty decent Black Friday sale (10% off everything!) so it behooves me to wait until last to drop the $660 on the actual MS3.

-Jason


Quick note on the ACT flywheel: Being machined from billet it does NOT have a removable ring gear that can be flipped. After initially flipping out about this I decided to use a file on all 220 teeth to add the small angle to each that are on the business side of the ring gear. I think it will be fine.

I once had to do the same thing for other reasons. I rigged a chain saw sharpener and was really pleased with the results.

I am still reeling from this thread and I keep coming back to a previous post: "well Dang Jason!" Didn't see the LFX to Honda thing coming!


I am also very intrigued by the relative simplicity in this but I have a 1990/1.6L. I have followed the discussions about keeping stock drivetrain but know I have a different issue.
Is it true my 1.6L locked diff won't suffice? I can always look for a 1.8 from a newer model and then there's the ratio...doesn't anybody make a gear set for these cars? Alternatively I was considering the Getrag option however it looks like V8R no longer sells the expensive kit to mount to the PPF. All kits now designed to omit the PPF.


On another front- how about my 1.6 5sp. tranny- is the 1.8 different or am I ok there?
Any thoughts would be appreciated.


Rich

Rich,
You bring up a valid point.
If I were in your shoes and considering a Honda V6 swap, rather than asking if there is the need to upgrade the rest of your drivetrain, I would look at it in a slightly different way.
How about this?
Presuming you actually decide to do the swap ..... use the transmission and differential that you already have in your car and keep the idea in the back of your mind that either (or both) might hold up or fail and be ready for that potential by having money set aside to buy the replacement pieces. If both hold up you have saved yourself a bunch of headaches and money. If one or the other fail you can decide at that time if you want to go ahead and replace both or only whatever actually fails.

The reason I mention this is that changing out the Miata 5 speed for the stronger 6 speed and changing out the differential for a limited slip unit is not really a "swap" because there are no cutting and chopping and splicing to get it done. Real simple, remove this assembly and bolt in this other replacement assembly that already fits the car with no other modifications.

My Miata had the upgraded transmission and differential that you are considering switching out for and the mental consideration mentioned above is what I would have gone with if I went the V6 route. Because I had the money available and was iffy as to how well the Miata transmission & differential & axles would hold up to the V6 long term I decided to go the V8 route so there would be no question on long term reliability. Not everybody considering a swap has the same luxury I have.

Rich and Bruce are both correct in that one of the attractive features of this swap is that only the engine, electronics and exhaust get swapped. Most other swaps require that the radiator, transmission, differential, axles, driveshaft, etc also get swapped out with non-native parts. While I was very happy with what my last car, a 331ci Ford conversion, morphed into in the end I also had a constant state of anxiety relating to the fact that most of the parts in it were never intended to be part of a Mazda Miata. One simple example of this was the differential. I went with the standard (at the time) differential for a Monster Miata, the Thunderbird-sourced Ford 7.5 with 3.27 gears and a factory limited slip. I could not understand why everytime I pushed the car (as in 2-3 hours of track time) the rear would boil over and start to leak all over the place. i posted about the issue on Mustang sites and they could not understand ether why I'd be having problems with a Ford factory Traction-loc setup over heating. Their 8.8 versions never did after all. It turned out in the end that the culprit was the lower volume of gear oil in the 7.5 vs. the 8.8. There was nothing wrong with the design of the 7.5 or even an inherent weakness in it, its just that the guy who decided on how much gear oil it should hold never thought to ask himself if just maybe he should increase the capacity because in 30 years some guy's going to be pushing 140 mph in his Miata for hours on end with it.

In planning this build so far the area I've had to work the hardest on has been researching the coolant manifold behind the block...that's it. If I choose to upgrade the trans I know a Miata 6 speed will fit right in. If I want to play with the rear gearing I can try a pullout 3.9 that I know will bolt in in 2 hours. If I'm not happy with that I can have the original rear rebuilt with 3.6 gears which I know will work. I don't even have to work out which speedometer gear to use-I have the oem part number for the sender that goes with the 6.3 gears! When I go to upgrade the radiator I won't be scouring Summit's site comparing dimensions and inlet/outlet diameters-I'll just order one of the multitude of Miata upgrade radiators that will drop right in. If you want to this kit even allow you just to keep using your factory or any upgraded bolt in Miata exhaust! If I were not set on a J engine that uses IEM's and wanting to run true duals I could just order up an off-the shelf exhaust from Flyin' Miata or Enthusa and be done with it.

I'm also very excited about the OEM-ness of the engine I'm using. Don't get me wrong, my father builds AWESOME engines and the one in the last car was no exception. At one point I said to him after a track day that building that engine for me was, short of giving me life, one of the coolest things he's ever done for me. That said, I'm looking forward to the possibly more refined feel of having an oem luxury car engine powering the car over something that could have been at home in a NASCAR stock car.

Today I dropped the car off at my parents' where I'll be doing the actual build soon. I've been working on eliminating all the extra coolant lines that the J32a3 has for the FWD automatic transmission and the throttle body. I really don't like the look of unused electrical plugs and capped lines on my builds. I've figured out how to thread and plug or reallocate all the cast holes on the coolant manifold and found a replacement coolant pipe (brings the coolant from the pump in the front of the engine to the manifold in the rear) that does not have an additional branch on it that the one I have does. I've looked through heater hose diagrams and picked a set of four that should get me from the j32's heater ports the Miata's without rerunning the lines under the dash. From researching different DIY Miata coolant reroutes I've found a nice, long radiator hose from a Escalade that may work on both sides of the engine.

I'm almost done with the rewire of my old 331 for the new owner and should hopefully start pulling the 1.8 out of the 1999 soon after.

-Jason

Jason,
One request as you are doing this swap.
PLEASE, PLEASE, PLEASE get pictures and document everything and post every little detail in this thread. Don't think that nobody is interested just because it is simple or straight forward.

One thing that put me off on the V6 Honda swap was how skimpy the Minitec instructions were to do the swap when compared to how complete the Flyin Miata instructions are to do an LS swap and how many detailed LS swap threads are on this website.
A really detailed and picture heavy swap thread would have gone a long way towards giving me a warm and fuzzy on the V6 Honda swap.
Your note about eliminating unused coolant connections is a perfect example. A few pictures showing the exact areas on the motor help a huge amount when you have somebody who does not know their way around a Honda engine.

The engine itself is almost ready to go in. I'm holding off on specifics until I can post each sub system from start to finish. The coolest thing is that I have figured out how to mount the power steering pump and the whole cost to do so was under $50. I'm currently waiting on a second oil pan. It turns out that the front and back of the Gen 3 JV6 is just different enough to not match up the front three and back two oil pan bolts. BJ at Minitec has my original J32a3 pan currently and is designing a solution. The cool part of this is that all he needs to do now is adapt the adapter plate's bolt pattern slightly and the kit will be capable of using even the most recent JV6.

Here's a teaser pic:

https://www.v8miata.net/members/mrm3...ering-1191.jpg

He should have the pan done in the next few weeks. Hopefully I'll start getting it in place by that point.

-Jason

Jason, great report. I too truly enjoy my car with it's Ford driveline. Looks great, sounds great, runs great. However I'm extremely intrigued with the path you're currently on.

My car is currently down, I've modded the extra subframe ala cvx20 (Mike) and Stien so I can run conventional Headman headers and gain a bit of ground clearance. Another benefit will be getting the drivers side exhaust pipe out from under the wife's feet since even with extensive heat mitigation efforts the passenger side is still uncomfortably hot.

That all said, I'm seriously thinking about building another car, your logic is sure interesting and I'm sorta talking myself into doing the same.

Thanks for the pioneering effort and guidance.

RonR

I just scored a lower profile, higher flow intake manifold off of a 2012 3.5 Liter TL for $125!! It's made of magnesium composite and should easily drop the total swap weight by another 10 pounds. The lower profile should help get this all under the hood. If I have extra clearance I may even be able to slightly raise the engine for some extra oil pan clearance.

Speaking of oil pans the new one has not yet arrived from Minitec.

I also have a dialog going with a guy who makes very nice stainless steel "manifold" castings for the exhaust ports. With his cooperation I may be able to use them to create a set of stainless steel down pipes I can market for this application.

Just the top part of this which he markets for TL guys:

http://www.rv6-p.com/products/tl/3rd...pcd-tl0408.jpg

Hopefully I can produce something even nicer than this with them:

https://www.rv6-p.com/v3pcd-223.html

-Jason

As a first time Miata owner and a person that always wants more out of their toys.... I am very intrigued by this build. Initially I was ls3, then 5.0 then K swap, then.... ha ha. Still reading and learning, I will eventually find the proper fit for my needs. Thank you for sharing this build, I need to do a bunch more research before diving in but this sounds like it may be the perfect fit for me.

Any idea if the oil pan will sit higher or lower in the chassis compared to the stock 1.8 set up ? I ask because I am building a bit of an unconventional Miata, it is more of a off-roadster. (don't judge, I like off the wall vehicles)

As far as I can tell the oil pan does sit a little lower than stock. The 5.0 pans do as well although being steel they do kind of stand up a little better. The JV6 pan I had was a bit more developed than some of the earlier ones I've seen and may have been a little higher.

The first pan is actually back at MiniTec currently. The particular JV6 I picked was not one of the two the kit was designed around. It fits the adapter plate but the oil pan is slightly too long. Benjamin and Norm at MiniTec are currently working with me on adapting it to the later engines which should open up the use of even 2 or 3 year old Honda/Acura V6's if it works. If not I'll be selling the 2005 TL J32a3 I prepped and picking up a 2001/02 MDX J35a3 or earlier TL/CL J32a2.

I'd really like to use a J35z6 from a 2009-2014 base TL. They are a dime a dozen at under $600 for low mile examples, weigh less than a Miata engine due to magnesium intakes/magnesium valve covers/integrated exhaust manifolds and make 280hp/254tq.

-Jason

I too am following this build closely. I hope you can get the later model j35's wOrked out with mini tech. I would really like to go that route. I'm going to mirror your build closely. I have neither the skills or time to go into this alone. Particularly with the wiring.

Im at the point I have to make some decisions. I have 2 94 miatas. One is a low mile age automatic I bought as a donor. The other is a 5 speed Torsen with a Begi turbo kit. While waiting to see how your build progresses I intend to swap the 5 speed and Torsten into the automatic, and install the turbo also. I have to make a decision whether to buy a Megasquirt which I would use for both the turbo and J swap. I could gain some needed experience working on this project and tuning with the Megasquirt while I dial in more boost and install an intercooler while waiting and watching your project.

If if I understood your intentions you were going to purchase a Megasquirt 3 on Black Friday to get the discount which I intended to do also.

Is using the Megasquirt your intention no matter the final decision as to engine choice? Or would going back to the 2001/02 J32 change that plan, i.e. not using the Megasquirt and going with a custom wiring harness and OEM ECU?

if I can use the MS3 with the whatever Acura engine I will go ahead and purchase the MS3. If not I will hold off and wait to see what you do.

My success with this project will depend on how this works out for you, and whether you will market a wiring harness that will make this pretty much a drop in plug and play wiring/ECU solution.

Oh.. almost forgot. Is your thoughts about runnning the Megasquirt along with the Mazda ECM related to emissions regulations? Or other reasons? I know Begi recommended the Megasquirt with the NA's but changed to the Exceedy(?) piggyback system for the NB's. I don't know why the difference.

So...some updates:

Minitec is continuing to work with me to develop thier kit towards using true Gen2/3 Honda/Acura J engines. They are still working on matching the oil pan to the shorter pattern of the newer engines which is a much bigger deal that the other major adaptation, matching the later bell housing bolt pattern. The only other issue that needs to be addressed is the one I spoke of in the past, the routing of the single port exhaust.

The engine is together (sans the oil pan) and ready to go in. I've found a better and lighter magnesium intake off a 2014 base Acura TL that should drop my weight by another 10 pounds or so. In addition to the weight savings it also sits about 1/2 inch lower which should help me fit the 1998 Ford Explorer 65mm throttle body I'll be using. The intake's main port is 65 mm.

I've designed and tested a circuit to run the variable intake butterfly in the TL manifold. Using a DPDT relay I'll be able to program the ECU with a rpm based on/off point and not burn out the solenoid motor that controls it. I've done the same for the VTEC control. The rest of the harness is ready to go.

I've planned out an exhaust that will consist of 90% off-the-shelf components. Starting at the rear I'll be using a Megan racing Stainless 2.5 inch system designed for a MSM which includes both the muffler and midpipe up to the cat. The cat will be Magnaflow two in/ one out unit that will double as a y-pipe. I found one with two 2" inlets and one 2.5" outlet. The downpipes will be from a eBay header/j-pipe kit for a late model Accord. The 2" bends from the down pipes to the cat inlets will be all that needs to be worked out by me or an exhaust shop. Because this is all off-the-shelf the bungs for the MS3's wide band and the Miata's two narrow band O2 sensors are already there and where they need to be.

The biggest development has been that my wife and I are again looking to buy a house. We've found ourselves in a situation where it is again looking prudent to find a new house for reasons beyond the build of this car. That said, I am not buying a home without at least a large one-car garage if not a two-car so that I am not at the mercy of other people's schedules in the build of this car or enjoyment of my hobby/business. As I near the completion of my 41st lap of the sun I'm realizing the lunacy of being someone who enjoys working with cars and not owning a garage. I'm not living the second half of my life without one.

To that end, I may have to sell the black 99 to make some quick cash to make this happen. I'm not selling the prepped engine or the kit as I'm hoping to acquire another 99/00 Miata and get working on this as soon as I purchase a house and prep the garage for it. This time around I'll likely buy myself a plane ticket to the Atlanta area, buy a rust free Georgia Miata there and drive it the 12 hours back to PA. I'm sick of PA cars. Although this one is in decent shape now after I removed its rust, sealed the affected areas and installed side skirts over the scarring, I'd really like to start with a car that does not need rust remediation done before I can start on it. I also think I want to start with a white one. Japanese cars should be white.

-Jason

I'd honestly sell both and buy a clean NB. This, and the LFX, both lend themselves better to the NB than NA. The NA's hood is shorter which is going to make position of the throttle body and issue on both. There is a fiberglass hood available with a bigger "bubble" but it really does not suit me. I'm hoping the NB hood will be able to fit over the Ford throttle I'm using without major modification if I use the later (post 2009) intakes. These intakes can be used on the earlier non-IEM engines as well.
NB's are also stiffer than NA's and require less extra bracing to make them feel "quality". While the five speed in all 1990 - 2005 Miatas is interchangeable, the NB version is thought to be the most refined and developed of the years. The NB's instrument cluster is computerized which means running it via a parallel scheme with the MS3 should work, the NA will require some type of tach adjustment.

The MS3 can run the earlier engines but its not as factory set up to do so. I would have to use a different crank wheel unless I used a J32a2 from a manual type s TL. Its possible to find one, but not easy. The MS3 has a setting in it to run the gen 2 Acura/Honda ignition as is. As far as the reason for running it in parallel, I would like it to pass emissions but don't have to. In PA I can keep it under 5000 miles a year or title it as a custom or classic vehicle to circumvent the emissions test if I have to. I know many PA drivers who keep an extra instrument cluster just to get through the first exemption. I'm doing it primarily to make the cruise and instruments work without issue. Making it OBD2 emissions compliant is more of a proof of concept kind of thing that I can market with harnesses.

Good luck with your build,

-Jason

I bought the 94 automatic before I learned of these advantages with the NB’s. So I’m probably stuck with the NA but not all bad the automatic only has 82000 miles, is from Georgia and is completely rust free. Plus I got a hardtop in excellent condition all for 2500.00. Plus in NC anything before 95 or is OBD1 is exempt from any emissions considerations.

Because it’s automatic nobody wants it, and the 5 speed is mechanically good but I would need paint to make it marketable. DK how I would come out dollarwise on this. Only have a thousand in it. I could prob part it and get more out of it. But then I wouldn’t have the 5 speed and Torsen!

The 6 speed sounds great but even with a 3.63 the gearing seems a little short for a v6 in a light Miata, esp 1st gear.

Too many variables.

For now I’m going to watch you and wait. I really like the idea of the j35z6 and to me it’s worth waiting to see if that works out. In the meantime I’ve got a lot of work to do getting a 5 speed, diff and turbo into the automatic. This will give me a lot of needed wrenching experience and render something fun to drive while continuing to monitor how things develope with the J swap.

Good luck with the house search. Being 60 years old and having owned several houses from my experience if you can find one with a basement that has a drive in garage I would give it careful consideration.

With a garage, the wife will inevitably say something like, “Honey, do you think you could ever get to a point where I can put my car in the garage during all this bad weather? It sure would be nice to unload the groceries inside when it’s raining or snowing...”. To which you reply “uhhh...”

plus the temperature is great. If enough of the structure is underground you can have a year round pleasant place to work without any extra utilities. I work in 75 degrees in the summer when it’s 100 out, and 60 in the winter when it’s 30.

Im in Winston salem, nc. 7.5 hrs from Allentown. If you wanted to check here we have good weather and cars and if you get to that point and see something you were interested I’d be happy to take pics and send them drive it whatever. I never tire of fooling with Miata’s! Hard to beat those Georgia cars though.

The wife’s sister and brother in law live in Atlanta and her Grandmother has been moved there to assisted living so we get down there too. Might even work out if you saw something down there. We were down there visiting and I was surfing CL is how I found the 94 automatic.

Allan

I really do think the J35z6 is the engine for this swap. BJ and Norm seem pretty enthusiastic about that particular engine as well. It's almost as cheap as a Oddy j35a4 but has 50% or more torque/horsepower and 20 - 30 pounds less weight. It's still under 300 hp and right at 250 pounds of torque so it should not destroy Miata transmissions "too" fast. Its magnesium intake manifold is shorter and lighter than the earlier ones and should make fitting it under the hood easier. The only real down side is that it is drive by wire, but if you're not using the Honda ECU anyhow swapping on a Mustang, Honda B, or even a bigger Miata cable throttle is not a big deal with an adapter plate.

I'm not sure yet of this but it may actually be possible to have the car come in lighter than stock with these later Honda Jv6 engines. The '93 test mule came in 8 pounds heavier with a stock J32a2 from a 2000 or so TL in it and a stock flywheel. The engines with integrated exhaust manifolds are supposedly 20 pounds less than those engines just due to the simpler pulley arrangement (one belt only) and the lack of iron exhaust manifolds. The later ones like the J35z6 also have the aluminum intakes and valve covers cast in magnesium for another 10 or so pounds of weight savings. On top of that I'm going with a modified ACT Honda B SFI flywheel that weighs a good ten pounds less than the stock one. I may be missing something (like did the original '93 have an AC pump) but mathematically its looking pretty good.

I haven't put the black '99 up for sale yet. Up here its rather pointless to try to sell a Miata between December and March. I'm planning on getting it inspected (had not done so because I thought the original engine was bad, it turned out to just be a bad clutch master...long story) and then washing it up/waxing it before the snow so that its ready to go in the spring. If I can scrape together the house money I need before that point without selling it I'll use it for the build, if not I'll sell it than and pick another up as soon as my current house sells or I can pull together another $3k to $5k for another...its really not a big deal, or a hold up for this build ether way.

In the mean time MiniTec will be getting the new pan out to me, I'll be building up the wire harness, possibly bench testing the MS3, etc.

Another possibility if I can't find a taker for the '99 is to start the build at my father's and sell the engine and rear off to collect some cash for the house. The engine and 4.3 torsen rear are worth at least $500 each. I may pull those parts at my father's, sell them off and then roll it to the new house on a spare NA rear frame when the time comes...or not.

-Jason

What year and model is the J35Z6 from?

I am trying to follow the conversation but get lost on the first line.

Looking forward to the finished product and enjoying the build ! Sounds like this will be a great track prepped / street driven j series miata. One of my favorite j series builds is the team 1320 3.7 hybrid with itb. shame about the music but listen to the motor (once the dumb music is gone haha)

Hey B Gordon here’s a link to Wikipedia a pretty good overview of the Hond / Acura V6 series. There’s a lot more details of course but good basic info here.

Jason- I had been paying close attention to this thread as I believe I am wanting to go down the same path. Having said that, it seems you've gone dark. I believe I can speak for all that your posts here have proven invaluable and we are hoping to hear all is well. I recall you were planning a move among other things, and hope that is now behind you. Just needed to convey that your words of wisdom are sorely missed here and hope that you can return to the fold soon.
Rich

Hi Rich and everyone else,
I'm still here and the project is still in progress. Since last I wrote I have:
-Completely rehabbed and staged my 1920's vintage town house in Allentown
-Sold the house in Allentown and purchased a Victorian house in Quakertown (vintage 1900) that is twice as big and has a three car, two story "carriage house"
-Had a cement floor poured in the "carriage house" to make it into a "Garage"
-Put my black '99 back on the road (now that I had a place to keep it) and drove it for the summer. During that time I put a roll bar, an old cold air intake I had lying around (Monster intake, remember those?), a rehabbed FCM coil over set and an used Project G G-string top on it.
-Utterly enjoyed driving it again for a few months after not having it avaible for over a year.
-Put a new hitch on it and used my track trailer to haul my J32a3 from my parent's house to my new garage
-Decided to start the build AFTER going back to work for the new school year. Removed the front suspension, bumper, accessories, radiator, etc one nice day in November
-Became very busy with work and requests to rehab this new home and haven't touched it much since
-Also decided to start a new business with a buddy of mine making and selling 3d printed, biodegradable plant growers/flowerpots because he talked me into it. This too has taken a lot of the time I would have used to keep building the car.

All in all the project is still on. I'm at the big step of taking the original engine out. I think once I can get that taken care of and the new engine in place the rest should be more manageable as small steps that I can slip in when I have 20 to 30 minutes. Worse case is that it goes until the third week in June when the school year is over and I get it done in two of three weeks. I'd really like to have it done before that point though.

The aforementioned 3d printer will come in very handy when it comes time to make mounts for all the Mazda senders/sensors (I'm still going to fool the original ECU into thinking the 1.8 is still in there) and when it comes to making some type of adapter to make the throttle body point downward. The printer we're using has a 300x300x400mm build area so conceivably I could actually design and 3d print a whole custom intake manifold if I need to.

Thanks for thinking of me everyone,
-Jason

The self-watering seed growers are at www.growsinhouse.com if anyone is curious.