Exhaust System ?'s

[bbade]

I am currently running a 3" downpipe and Racing Beat single tip catback exhaust. I am thinking about replacing the stock main cat with either a resonated midpipe or high-flow cat.

Has anyone had experience using either, I'd like to know about differences in sound and performance. I'd rather not have a super loud car, but I would like the improved performance. Thanks!

[7_rocket]

If you don't a loud car just get a hi flow cat.

[dregg100]

with the racing beat cat-back it wont be unbearable. if you are after performance go with the resonated midpipe, if you need to pass emissions (we dont have emissions testing) then go with the cat.

[Brent]

On my VR FD, I have a high flow cat and a racing beat dual tip. It has a very very nice tone to it. At idle you don't even know it has an exhaust, it really comes alive when you open up the throttle though. I drive on the interstate alot and I prefer this set up. Many years ago I ran a straight through exhaust, and while perfomance is better, I'm not trying to make my VR FD the fastest car in the world... it's a nice comprimise. My T78 FD is loud enough for the both of them. I have a resonated midpipe on the T78 and it does make it a little more quite.

[SPICcnmFD]

I have a single tip with open exhaust and it's not to loud, I was actually surprised how quiet it really was. It does start to make some noise once you open up the secondary turbo though, but for driving around it's not bad.

As for performance their is a big difference in the stock cat and a midpipe. You do need to make sure your wastegate is ported if you change it though.

[bbade]

Ah i completely forgot about having to port the wastegate. Would this be necessary with a hi-flow cat?

[David Jerome]

If you are still running sequential switching to a midpipe will not make the car extremely loud. The sequential cars are much quieter than non-seq and you really wont notice a lot of exhaust note change at idle or partial throttle with the RB exhaust.

[bbade]

Yeah I am running sequential and don't intend to change it anytime soon. Does anyone have any info on porting the wastegate (cost, difficulty, etc...)?

[Phoenix7]

Ah i completely forgot about having to port the wastegate. Would this be necessary with a hi-flow cat?Necessary? Not if you get this:
http://www.rotarycarclub.com/showthread.php?p=19652

Little-to-No downtime is always a plus.

[SPICcnmFD]

But then you don't get the hp advantage of an open exhaust.

To port the wastegate you are going to have to take the turbos off then take it to a good machine shop.

In single mode the exhaust is really quite its only after the transition is it loud and it's not super loud. It's actually pretty neat to be cruising down the interstate and know what mode you are in by the sound.

[bbade]

What kind of job is pulling the turbos, am I looking at pulling the entire engine?

[Phoenix7]

^^hopefully not but I don't know what the removal calls for.

[bbade]

Yeah i'm pretty sure I can take the turbos to KDR for the porting so that is covered (I like to give Dave my business anyway, great guy). I'm just wondering what kind of a job I am looking at here. I have the tools and mechanical knowledge to take apart the car, I'm just concerned from a time standpoint. I also don't want to shell out the cash for someone else to do the grunt work.

[SPICcnmFD]

You don't have to pull the engine. It's pretty much just take-off/unhook everything over there off, Intake, IC piping, DP, vac lines, oil lines, coolant lines, etc. If you've never done it, it will probably take 2-4hrs to get them off and a little longer to get them back on. It's not very hard, just a PIA to reach the front oil return line and the 7 or so bolts that hold them to the engine is probably going to be a pain to get off. You may want to spray them wiht some penetrating fluid and let it set over night once you get to that point.

[cewrx7r1]

A restrictor plate still makes good power with minimal loss as it is a small restriction less that 1/8" in length as compared to a cat. When I went non-seq and before porting my WG, I reached 170 mph at 12psi boost while testing it out with stock ports. I tested both a 2.75" and 2.5" which were made by me out of SS sheet. Had to use the 2.5" one.

You can port your own WG with a Dremel tool and save money.

[tom93r1]

With stock exhaust ports, down pipe, RB cat-back, and a high flow cat you likely wont have any trouble with boost creep. If you go with a resonated mid-pipe then you might have something to worry about.

[bbade]

Thanks for your help guys, I think for now I am first going to purchase some FEED sideskirts and either the 99 spec or FEED spoiler.

[Oliv]

I run a rx7store hiflow cat and I spike like hell. will fix it hopefully with BC.
No creep.

Mods= intake, DP, HFcat, cat back all 3", PFS SMIC, HKS elbow, Knightsport ecu