New to this forum but not new to the 7. I've had 4 so far not including my recently aquired 93 fd3s mt. But all of the other ones i've had were 1st and 2nd gen.

My question is why only 4 psi, i'm guessing a boost leak. I would like some of you FD experts to guide me in the right direction. As for doing a search first I did and couldnt find any thing that realy seemed to explain my situation.

By the way I only have a PFS DP, Stock MP, PFS cat back. Other then the boost problem the car runs great, and is really smoof (yes smoof).

 

it only cost me 9000.

 

nice car man, can't help you on the boost thing though.

 

check out this site. Full of good info http://www.autosportracetech.com/RX-...leshooting.htm

 

I recently a problem similar to yours https://www.rx7club.com/showthread.p...=low+boost+804

The root cause was a clogged high-flow cat. The Bonez hi-flow was 5 years old with 74,000 miles of use. Solved the problem with a straight-through non-resonated midpipe?

Are you sure you don't mean stock "cat", because these cars came with catalytic converters, NOT midpipes. Short answer, check your catalytic converter (assuming you have one).

 

Yes I mean stock cat, so a clogged cat would cause the weird boos? I have a straight through mid pipe sitting in my garage but am scared to put it on because of all the horror stories about needing a computer upgrade first so you wont blow the motor.

 

Yes, in my experienced a clogged cat makes exactly the boost pattern you're describing.

Quote:

I have a straight through mid pipe sitting in my garage but am scared to put it on because of all the horror stories about needing a computer upgrade first so you wont blow the motor.

It's true, you need to tune your ECU for the freer flowing exhaust with a midpipe. Put the midpipe on, just to test the boost problem. Be sure to lift out of the gas when/if the boost climbs past 10 psi. At that point you'll know what your problem was If you find the clogged cat was your problem, just put your old clogged cat back on, until you can get your ECU tuned for a midpipe--assuming you have a Power FC. If you don't have a Power FC, get one. Good luck! Report back what you've found, please

 

I will do that later today, and no I dont have a power FC yet

 

I will do that later today, and no I dont have a power FC yet

 

oh man areyou serious? would this be the case for my boost problem as well possibly? mine is more like 5-0-3 roughly, and I got 68k miles on my 2nd motor.

-Gene

 

It depends on how old your catalytic converter is, and if you're also running the stock precat? Typically the cats last between 50K and 70K miles (5 years of hard use max...) before clogging or breaking up into pieces and causing a massive clog in the exhaust flow.

 

My boost was also like 10-5-7 but then I removed the pre-cat and installed Pettit DP and its fine now.

You can run midpipe on stock ECU. But you need to install a restrictor plate between DP and MP. Mine is 2+1/4" in center diameter made of stainless steel. I have no problems controlling boost with profec (so - no boost creep). But you may want to cut a smaller hole then 2+1/4" to keep the boost under/around 10psi.

Its better then running around with clogged cat.

 

So was it a clogged cat or what? I wish people would follow-up on their boost problems, so that the rest of the FD3S community would get closure to all those open thread boost problem threads dammit!

 

It wasnt a cloged cat, I replaced my cat with a mid pipe and boost was still the same. But while I was at it I checked all the hoses and found that the lower intercooler hose had a split in it so now I get 7-2-3 psi. It seems never ending but man is the car fast even with crap boost.

 

Just to clarify NOT the cat for me replacing the hose made a difference.