MRM331

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:











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:



More to follow.

-Jason

Zaphod-Beeblebrox

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.

5.0MX5

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.

crispy

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.

portabull

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.

Ford5.0

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.

stng_96

donor looks great

MRM331

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

cvx_20

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

Mike

mrmustang

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.

ToySnakePMC

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

Zaphod-Beeblebrox

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.

MRM331

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

5.0MX5

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.

MRM331

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

BGordon

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.

MRM331

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

ToySnakePMC

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!

MRM331

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

MRM331

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:







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:



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:



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

MRM331

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



-Jason

BGordon

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

5.0MX5

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.

MRM331

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 )

-Jason

BGordon

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?