ppritchard

I have a downpipe and matching midpipe that the previous owner had never installed. I am planning on installing the DP, but a number of posts on the forum suggest that these paired pipes might not fit to the regular cat midpipe very well, if at all. So my question is
If I get the downpipe on, find it doesnt hook up correctly with the cat midpipe, then if I use the new open midpipe am I risking boost creep or any other problem? No performance mods currently, only reliability ones. Also without the stock midpipe, will the car be a lot louder?

thanks for any help

fendamonky

iTrader: (6)

Going from a stock/hi-flow MP to a free flow MP will certainly increase the noise level of your exhaust (I just went free flow a couple weeks ago).

Unless you have an aftermarket ECU, quality boost controller and correct fuel upgrades I would steer clear of a free flow mid-pipe, it's a pretty significant modification (and not road legal in many places).

I can't say whether or not your DP will match up to the stock cat without knowing more about the DP. Though I would say that it shouldn't be a problem, I've fit two different DP's to my car (previous owner told me the stock DP was still in, so I bought an M2 DP before returning from Iraq and seeing my car for the first time) and neither one had fitment issues.

If you MUST fit the free flow than I would look into finding some restrictor plates (somebody here has the template for making them, I can't remember who off the top of my head though) to provide back pressure, making boost levels more reasonable for your current mods. An otherwise stock car without any restriction in the exhaust can certainly expect boost creep, and just higher boost levels in general.

dgeesaman

iTrader: (7)

What flow mods do you currently have in place?

If you have a cat-back and intake installed, you're very likely to see boost creep. No controller or fuel/ecu mods will address that problem.

The problem with the downpipes is they wouldn't bolt up right. Just see if it fits first. If you have enlarge the holes to fit, so be it.

4CN A1R

iTrader: (6)

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

spandy

iTrader: (1)

I was going to replace my midpipe for a resonated cat, but decided to port the wastegate instead since it was all out of the car anyway.


When compared to reliability mods, the midpipe will only give you a negative on your reliability, and then throw the fact in that you have really no performance parts in place, there is no reason no put a midpipe on. Sure, you will gain a few ponies, but really it's a small pay off for potential big problems.

If I creep at all when I finish my project, I'll be ditching the midpipe.