Sefveron

Hello all, im in australia and i have a near stock 2000 Model Type RS JDM Spec Rx7 and recently the catalytic converter for the stock midpipe colapsed so i ordered a 3 inch Midpipe with 3 inch catalytic converter from SMB Exhausts and i was wondering would it be safe to install in my car with the stock computer?

My car only has a 3 inch aftermarket catback exhaust and apart from the radiator and AST is pretty much dead stock, Grant at SMB said it should be alright but i thought id post it on a forum to see what people say about it.

ksu-chewie

iTrader: (14)

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/what-i-need-w-full-exhaust-543979/#post5699718

Sefveron

I had a good read of that doofy and it doesnt answer my question... its a bunch of guys talking about various setups they have with higher than stock boost levels.

Im planning on having the car running with a Stock ECU,Stock Boost Levels, 3inch Midpipe fitted with a 3 inch catalytic converter, with a 3 inch jasma catback, and the dump pipe is remaining stock.

Mahjik

iTrader: (1)

If you can control the boost to keep it at stock levels, it's fine.

Sefveron

Hmmm, so if i use a electronic boost controller to keep it set at the stock 11psi , it should be fine then? ok cool thanks for that

adam c

iTrader: (2)

Yep

JM1FD

iTrader: (1)

If a boost controller can keep the boost in check then the ECU should be able to as well. If the ECU can't keep it under control, then neither will a boost controller, due to limitations in the wastegate hardware. As I recall, the wastegate is too small, at least on our 93-95 North America cars to keep boost 100% under control...the solution was to port the wastegate opening. On later cars, this may be a non issue.

If you're really worried, swap back to the factory muffler and that should keep everything in check.

adam c

iTrader: (2)

I completely disagree with this. The stock ecu does not do a very good job of controlling boost. With the mods on this car, wastegate size is not a factor.

Sgtblue

iTrader: (16)

Boost controllers a good for holding boost down from spike (intake). But creep issues from open exhaust are another issue. Or more specifically (as adam c suggested), a wastegate issue if you have too many exhaust mods...which I don't think is the case. You probably safe from creep fine as long as you have a cat in there. The down-pipes on the RHD models also seem like they might be a bit more restrictive...which would be in your favor if your worried about creep.

Sefveron

There seems to be alot of mixed opinions on the subject, but i do know replacing the dump pipe requires a complete retune due to the increase in volumetric efficiency completely screwing up the MAP sensors readings and because boost instantly jumps to about 14psi but as for the midpipe... i dont know, here in australia its not really that talked about of a problem, more FD's die due to AST's disintegrating.

I suppose i could believe the word of a professional exhaust manufacturers whose been making exhausts for FD's more than 15 years.

no_more_rice

Don't mess around with boost creep, that killed my engine