coop

I am getting ready to put a 3" bonez downpipe into my FD. If the exhaust system is stock am I going to have any problems?
From what I have learned, the downpipe replaces the Pre-Cat (?)... so it bolts between the turbo and the CAT? Will I have any fitting problems at the turbo or Cat end of the DP?
Any help would be wonderful,
-Dave

Jetlag

No problem, it'll be alittle louder than stock.

13BAce

That downpipe should fit very well. The hardest part will be taking the stock parts off. You may need some WD40 or liquid wrench to get the nuts off. Try putting anti-seize on all of the bolts before you assemble everything.

coop

sounds good. I will give it a try once finals are over with.
Thanks
-Dave

SAGE

With the down pipe on there it will sound and drive a lot better and yes will get rid of the pre cat which over time breaks up and screws up the main cat. By replaceing it this will make the turbos spool up much faster and also will make it sound pretty beefy. I would throw on a nice 3inch midpipe and a cat back while i am down there and it will really run nice.

SAGE

13BAce

Good luck.

RX7_RCR

Might want to add some more fuel while you're at it too.

Brad

Add fuel??? What in the hell for?? Look at the history of RX-7's people free up exhaust and intake ALL THE TIME and do nothing for fuel...

Not like the RX-7 has a reputation for being unreliable or anything...

13BAce

This may be a good sire for him to check out: http://www.rx7turboturbo.com/robrobi...od_pro_con.htm

RXlexi

Hey, on a related note, I want to install a downpipe on my '89 TII. I rode in a friends TII with downpipe/midpipe and the difference is incredible...immediate power! I am going to leave the rest of the exhuast stock, at least for now. Will I have any problems with the stock mufflers with the downpipe on? How difficult will it be to install, and should I do a midpipe at the same time?

Thanks a lot for any help !

13BAce

It will work fine with the stock cat back. I've done it before with the RB downpipe/presilencer. The power increase was VERY noticeable, but you'll probably hit fuel cut.

RXlexi

what can I do to avoid hitting fuel cut? I've already hit it a few times and it's not enjoyable. Also, will I experience any boost creep? If so can I just turn down my boost to compensate? I apologize for my lack of knowledge, thanks for the info.

13BAce

You'll need a fuel cut defencer. The easiest one to use is the RB FCD. You may get some boost creep, but with the stock catback you should be ok.

crai6m4ck

Just bought a M2 3" SS Downpipe and I am concerned that it will not bolt up correctly to the main cat. Isn't the stock exhaust diameter 2.5"? So I would be going from a 3" downpipe and trying to bolt it up to a 2.5" main cat? Like dave said "Any help would be wonderful"!

es

All of the popular downpipes bolt right up to the turbo manifold, & stock cat. Pettit, HKS, M2, PFS, any sold at rx7store.net.

Yes the exhaust path will neck down from 3" to 2-1/4"ish, but it will still greatly outflow the stock pre-cat & make your car cooler & more reliable at the same time.

chaste94

I just ordered an M2 SS Downpipe yesterday. I picked it because it is supposed to be the best fitting and easiest to install. They said I should receive it (along with my dual tip exhaust!! yay) at the middle of next week. I've heard M2 is sometimes slow to ship. Did you get your downpipe pretty quickly?
Thanks,
Tracy

crai6m4ck

I actually just bought mine off a guy who bought one brand new and before installing it decided to go single. Should be here next thursday! I'm contemplating on whether or not to install it until I get a ECU.

crai6m4ck

Damn!!! I thought it was a full 3" from turbo manifold to main cat! Its the same thing that happened when I bought my Apex'i N1 catback, I was told that it was 3" but wasn't told that it started from the cat at 2.25 - 2.5".

THE ROCK

I'm surprised no one has mentioned anything about the studs! Be careful, due to years of extreme heat, the studs may break.