'90 Mazdaspeed Miata Rallycross Project

cghstang is a good driver and he was driving what is arguably the most badass car at the RX Nats.

Another question! Since the MSM fuel rail doesn't have a return line should I just use a 1.8 fuel rail from 94-97? Will the MSM injectors plug into the 1.6 harness?

Now I just need to find my 3/8" drive 12mm socket to get that intake manifold off...

Get the fuel rail from a 1999-00 and mount the FPR on the end instead of the pulsation damper that's there now. You MAY need a 1994-97 FPR due to the shape of the return line, I don't remember. I already had an external FPR, so I converted a 1999-00 rail to flow-through by tapping the hole where the damper should be and installing a barb. I suspect you may be able to do the same with the MSM rail.

Yes, the injectors will plug in.

A little progress today:

VTCS butterflies removed:

Before:

After:

Then I decided to pull the dash. I need to remove the airbag wiring and A/C components. I am still debating whether I should do a half-dash or not. I probably will.

I also attempted to mount up the exhaust but the hanger on the midpipe is about 10-12" too far back, I'll have to work on that later.

If you have no HVAC, go for the half dash. It's cool. Bonus points for changing out the center support to something sexier.

A lot of aftermarket exhausts delete that first exhaust hanger.

While digging through my garage yesterday, I came across a set of plug-in injector adapters. If I'd had those,I wouldn't have had to do a bunch of splicing to my harness. Argh. I'm just trying to decide how much I want to clean up the engine bay before sticking the engine, and if I want to swap out the master, booster and brake prop valve now or do it later.

I would love to delete the HVAC but I know I am going to want heat sometimes, at least on the defrost setting.

So the aftermarket exhausts are hung only with the hangars by the muffler? That isn't too much stress on the downpipe/midpipe? I considered going with a clamp on hanger for now (I really need to get a welder) but if it isn't necessary I will just leave it off.

I'm pretty sure, I'll double-check tomorrow.

I misunderstood, I thought you were pulling the AC anyhow. You could get creative with plumbing air through the defroster without the HVAC boxes...

I am pulling the AC so the evaporator will be gone. I did see an aftermarket heater that could be used, I wonder how this would tuck under the dash.

http://www.summitracing.com/parts/SUM-991102-1/?rtype=10

Although it seems a bit silly to spend that much money to save a couple pounds and make it look cool.

Got a welder? All you need is a fan and a box to put the heater core in. Or do what I did in the Targa car and just stick a bilge pump in there for a defroster, no heater involved.

Not necessarily the most comfortable option. If you're going to keep the HVAC, then just keep the HVAC. Are you swapping in the full MSM wiring harness?

Nope, I am keeping the stock harness. I do need to run a few wires for the IAT sensor, WB O2 sensor and probably some others.

I will probably keep the HVAC for now and leave the full dash in, I can always change it later.

For anyone wondering, the MSM exhaust will not fit under the NA without running into a few obstacles.

I used to have one under the Targa car. Well, midpipe and muffler anyhow. I had an NB subframe, but that just took care of one of the rear hanger locations. The other one had a fairly stretched rubber donut. Otherwise, no problem.

When I tried to fit this up didn't look like it would work at all, unless I only used one of the existing hangers.

I'm probably going to have something made up...catless and more of a straight shot out the back.

Could you just go straight out the back after the resonator?

Or a turndown before it gets to the rear subframe?

Or are hangers the only issue(s)?

Hangers are the only issue. The exhaust will clear everything under the car once you've got it supported.

From my test fit it seemed that with the rear muffler in position, the exhaust would hit the rear diff and subframe. However, it is very possible that I didn't position it correctly.

I will try a turndown after the resonator, that should work. I would like to get rid of the cat eventually so I will have to make something custom in the future. I really need a welder.

Or I could do a dump pipe straight out the hood.

EvanB wrote: From my test fit it seemed that with the rear muffler in position, the exhaust would hit the rear diff and subframe. However, it is very possible that I didn't position it correctly. I will try a turndown after the resonator, that should work. I would like to get rid of the cat eventually so I will have to make something custom in the future. I really need a welder. Or I could do a dump pipe straight out the hood.

I prefer bumper.... Chris has seen it. It's every bit as trashy as it looks in pictures.

Keith wrote: Hangers are the only issue. The exhaust will clear everything under the car once you've got it supported.

That must have been the problem I was having. I didn't have the front of it completely in position but from lining up the hangers for the muffler it didn't seem like it would line up at all without changing the hangers.

92CelicaHalfTrac wrote:

EvanB wrote: From my test fit it seemed that with the rear muffler in position, the exhaust would hit the rear diff and subframe. However, it is very possible that I didn't position it correctly. I will try a turndown after the resonator, that should work. I would like to get rid of the cat eventually so I will have to make something custom in the future. I really need a welder. Or I could do a dump pipe straight out the hood.

I prefer bumper.... Chris has seen it. It's every bit as trashy as it looks in pictures.

Well that would make the pipe unnecessarily long, if it was FWD it would already be heading in the right direction but for mine I would have to snake it back around.

EvanB wrote:

92CelicaHalfTrac wrote:

EvanB wrote: From my test fit it seemed that with the rear muffler in position, the exhaust would hit the rear diff and subframe. However, it is very possible that I didn't position it correctly. I will try a turndown after the resonator, that should work. I would like to get rid of the cat eventually so I will have to make something custom in the future. I really need a welder. Or I could do a dump pipe straight out the hood.

I prefer bumper.... Chris has seen it. It's every bit as trashy as it looks in pictures.

Well that would make the pipe unnecessarily long, if it was FWD it would already be heading in the right direction but for mine I would have to snake it back around.

You'd also have to make a funky bend back up to clear your firewall...

Dump it behind the tire?

I could dump it behind the tire but I wouldn't want to rub the tire on it while rallycrossing.

The exhaust has to exit to the rear of the driver anyway to be legal.

EvanB wrote: Nope, I still need to get an intercooler and piping figured out.

Hey Evan, I still have the old FMII intercooler off of The Hairball if you're interested. I also went with the FM cross-flow radiator, so my old FM Twin-Cooler aluminum radiator/oil cooler is also available... And I'll make it easy on your budget, just 'cuz I would like them outta my way.

If you might be interested in either, I can run them down there for you to check them out. I'm still re-habbing the knee, so I'm off work til the 17th.

Let me know, and loving the project!!!

Will

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