pj_mcgarvey

Sounds like you are in good shape. Still trying to figure out whether I mount my PCM under the hood or under the dash... pros and cons as you see it?

Either way I need to depin stuff to fit the wires through the firewall. And I can't recall how much room I'll actually have under the dash to mount it. I have the chunkier 98 LS1 PCM. Might be more accessible under the hood (next to the relay box on pass side fo the Miata) if I need to fix wiring, etc. Looks like you deleted A/C since you ran the heater core lines through those holes... So less stuff under dash?

Did you make any add'l relay/fuse blocks, or just wire into the existing Miata stuff?

that HP tuners will come in handy though.

wcw5023

Still trying to figure out whether I mount my PCM under the hood or under the dash... pros and cons as you see it?


- Well I had attempted to do it both ways. Honestly, I was going to take the easy way out and just secure it near the fuse block. But after taking a step back, and looking at it. I really hated it. I think mine is huge, so I cant imagine putting a '98 PCM there.

So I labeled every wire, depinned it, and fished it through the factory wiring harness hole. Pulled as much cable through as possible. And there is just NO WAY you are going to mount the PCM anywhere if you have a blower motor in the car, without extending the wires.

So I pulled it all back through to the engine bay, and spotted a hole in the firewall Just to the left of this stud. ( see pic ). Chocked up my stepped bit, and opened it up to about 3/4". and pulled the ECU wires through there with a grommet.

With that said, If I were going to do it again, I would definitely drill the hole as close to the trans tunnel as you dare. I had juuuuuuust enough wire to mount the PCM where I did.



Did you make any add'l relay/fuse blocks, or just wire into the existing Miata stuff?

Nope! Everything is wired into miata fuses/relays. However I had a lot of options, since I chose to remove a lot of components such as the AC and airbags, so I had a lot of extra power sources to work with.

wcw5023

Ill just go ahead and leave this here.... Grab your headphones =)

pj_mcgarvey

got dayum!

acedeuce802

Woohoo! Nice work!

portabull

i'm gonna need a moment....

Flavaquero

Nice!

stng_96

Sorry I am a couple days behind on this thread, but I mounted my PCM in place of where my passenger airbag used to mount, worked like a charm. Also, nice startup, few feelings in the my build surpassed the thrill of my first start!

skidude

The only part I would be more excited about than the first start is the first burnout!

Castillo817

^ +1

wcw5023

Thanks for the comments everyone!

Sorry that this thread has died down, with the holidays rapidly approaching, and that first start out of the way I've really dialed back. With the nice weather still a few months away, Ive slowed down to try and give these final details the attention they deserve!

I have been doing little things though. I have all of my exhaust components on hand, and have been contemplating routing. I will save those pictures for when I have everything laid out to start tacking together!

Bought myself a little Christmas present to help my motivation through these cold months !!



The interior is a bit more together now! Not putting all the bolts in until I run the system up to operating temperature with coolant to confirm there are no leaks



Sold my Mod78 to a good friend, and picked up the new hotness =)



Fabbed up a little throttle cable bracket. Although I still need to address the cable travel issue. If you are unaware, the stock miata cable travel is not enough to bring the LS throttle plate from closed to WOT, it'll probably only get you to 85-90%, so close. but not quite enough!





I think I will end up modifying the top of the throttle pedal so that it travels a bit further on that end, rather than modifying the actual throttle body actuator.

Fan is installed on the rad. So much room for activities.... and by activities, I mean an exhaust crossover.... if ya know what i mean >=)



Thats about it for now. Ill check back in when some more exhaust stuff is done! Happy holidays everyone!

wcw5023

Just a little exhaust update. Ill let the pictures do the talking, but almost wrapped this thing up, just gotta finish up the Drivers side axle back. Im excited to see what this will sound like! Should be interesting! haha.

The start of the first leg. I decided to start with the passenger side since clearance was going to be the tightest around the starter. For some reason I forgot to grab pics, but I am very pleased with the clearance.























That about sums it up! hoping to finish up the last bit on the drivers side this week and get it all finish welded.

I took breaks from the exhaust every now and then and got to cleaning up the engine harness a bit. Ive been learning a lot as I go, and my end result has been gradually improving. My issue with that is that it makes me want to go back and redo some of my work.

pj_mcgarvey

What mufflers are you going with? Single or dual?

I hadn't thought about any flex joints for mine, though perhaps you did that for some "wiggle room" in getting it aligned.

Looks like the trans crossmember was a pain to work around.

wcw5023

I have one of these puppies. I originally bought it, thinking I might try and mount it in the trans tunnel, as a replacement for the X-pipe. But clearance was just too tight for my liking. So now its at the rear.



As far a flex joints, not so much about wiggle room, as it was just concern for cracking and thermal expansion. Not 100% necessary, but they are relatively inexpensive so why not.

The crossmember was not that much of a pain actually. It worked out better than I expected, and I really dont feel like i sacrificed much, if any, ground clearance. Looking back, would I do it differently?? Sure! This whole process has been a learning experience, but thats what makes me proud to call it "mine".

pj_mcgarvey

Yup, the pic of the muffler looked like a dual in/out. Will be curious to hear your opinion of the sound or a video of it.

acedeuce802

So you have 2 crossovers in the system?

wcw5023

Yeap! I would imagine, having more than 1 in the system offers no real performance gains. But it will be interesting to see what it does for the exhaust note!

Hoping to have some sound clips by the end of the week.

acedeuce802

Cool, I'll be curious to hear it. My first plan was to use that muffler without an X-pipe, similar to the FM exhaust. Then I was going to try the exact combination you are doing, with both crossovers. Then I settled on using an X-pipe and dual 5" diameter cylindrical mufflers.

darkblue

thanks for the great pictures. I(hope) to be at that stage in March.

wcw5023

Half a tank of Argon, 2 cutting wheels, 3 flap discs, a pile of metal dust and a burnt thumb later :







Just gotta finish weld the header--->X-pipe tubes tonight which shouldnt take long.

pj_mcgarvey

Looks good! what size pipe did you use? I'm assuming it's stainless since you're TIGing?

I like the neatness of using one muffler.

wcw5023

Thanks! 2.5" pipe, nothing crazy, should be enough for now. I'm more worried about the flow path of the muffler than anything else. Not that it wont still flow better than a baffled muffler, but more that the angle of convergence is going to be pretty steep, as that muffler was probably intended to have both inlets on one side.

And unfortunately the exhaust is steel, I just like any excuse to improve my TIG skills, even though I went through a boatload of gas doing the whole exhaust

I did pick up a couple cans of exhaust coating, So I will be spraying it to protect from rust.

pj_mcgarvey

Same here, 2.5" and plain old steel. I will be cleaning the welds up and doing exhaust paint as well. My car will be garaged, and will be a fair weather car, so it should last awhile.

wcw5023

I also did a thing this week..... As we are nearing "completion" of the miata, I need to start lining up the summertime project

pj_mcgarvey

M54, little brother of sorts to the S52 in my M3. (I cheated and saw the image filename).

What's it going into? (Please say E30).