Been awhile but I just picked up a mint 90 model T2. All stock. Looking to delete the pre-cat with a jdm dp i have laying around from long ago. As I recall the JDM dp does not bolt up top the usdm cat? So I plan on deleting the cats all together and installing a FCD and keep the exhaust as close to 2.5'' to help with boost control. That being said I cant remeber if this setup is safe or should I upgrade the secondary's and pump? Thanks in advance.

 

JDM downpipe will bolt right up to the main cat, and that should just work fine.

 

Gd to see another old member on here. Yea, I happened to have an old OEM JDM downpipe from a savannah and was thinking it would work, Just couldnt remember if the cats were the same size. Thanks man!

 

I'm against the FCD. It makes the engine run lean. I wouldn't feel comfortable with it

 

Some good reading material. https://www.rx7club.com/2nd-generati...stion-1000680/

 

The FCD doesn't cause a lean condition the overboost does and from what I can remember anything over 8.5psi is basically a static map in the ecu. FCD on a S5 us usually safe from what i recall. The S4 not so much. The go to back in the day was a FD pump, FCD, Turboback. The fd pump bumped the base FP up for safety. Some just upgraded the secondarys to 720cc and left it at that with the FCD. Rich? yes. Safe? absolutely.
I didnt know the USDM and JDM main cat was the same though. Interesting.

 

in 2024 if you need to run more boost than fuel cut, you'd be way ahead by getting an ecu that is tunable.

however if you had a setup that maybe hit fuel cut on a cold day or something, then its ok, i don't know that i would buy one though.

 

Its been so long since i did a full standalone. I think the last one I had was a power fc with the bonzai Fc harness. What is the go to today? Haltec Plat?

 

I was going to say more fuel and at least a safc would help.

When I had a safc, I used the boost pressure sensor as the throttle input to the safc so fuel adjustments would be based on rpm and boost level. I got the idea from the DSM guys doing it with success.

I’d sit on that for a bit as a potential solution in your case.

At that point a stand-alone would get the job done the right way.

I haven’t messed with any of the new standalones since haltech e6x. Im currently running a power-fc and have yet to try the fc-tweak self tuning software for power fc (I just need to stop being lazy). But I hear great things about the software and turns the power fc into an inexpensive option.

 

I had a haltec e6k lol Really want a simple solution cause i dont want to hack the car up. The idea of using the boost pressure sensor is actually quite a gd idea.

 

the Power FC has a new thing for it called FC Tweak, and its new interface box, and it is really good.
the important thing is the auto-tuning which works amazingly well

that being said, with just a JDM down pipe it might not even hit fuel cut at all

 

Im looking at buying the PFC from bonzai. I havent heard about the new auto-tune feature Ill have to look into that. However, If I can get away with the DP and a FCD i may just do that. Worst case maybe pick up a AFC and a WB. Side question, The turbo to DP gasket is hard to find, I now its metal should i bite the bullet and pick one up for 75$?

 

But what allows it to overboost? The FCD. In my opinion the only right way to "defend fuel cut" is giving it more fuel so there is no risk of a lean mixture at all.

 

i think you could probably put the DP on and it wouldn't hit fuel cut at all.

 

Agree

 

Car is getting delivered today. Typical Rx7 fashion the alternator isnt charging LOL

 

I’ve gotten away reusing the turbo to downpipe gasket many times without issue. I honestly don’t even know if I’ve ever bought a new one.

 

The main cat looks pretty clogged ( 120k )so it looks like Im going to replace it with a vibrant resonator. That being said I guess a FCD and 720cc or 680cc high impedence for some safety until I can get a standalone?