Just received my midpipe and it looks amazing. The box was about halfway open (damn UPS) but everything appeared to be in working condition. There were two bolts floating around inside the box. Just to clarify, are three bolts needed or just two? I didn't really have time to check everything out since I had to go to work but I'm just making sure that UPS didn't lose a bolt.

Ok thanks Charles. I needed to run by home depot anyway for that plug. Damn UPS bastards

I mean USPS. sorry I'm at work on my iPhone

I stand corrected; for the tiny percentage of midpipes sold for racing vehicles, a cat is likely useless (too much flow for the amount of time available in the cat for reactions I would guess). For the 98% (or so) of no-cat pipes used on the street, the power gains are minimal if any (over a hi-flow cat) and the noxious fume emission is maximal. If the goal is the latter, a no-cat pipe accomplishes that quite well.

I've heard several times that our engine can be made to pass emissions sniffer tests without a cat, but doing so results in exhaust conditions that would quickly kill a cat.


Agree? Disagree? Opinion?

My mind is more tracking along the line of 'if I can get my engine to pass a sniffer test without a cat, why would I have a cat? Just one more part to fail. One that has caused me problems in the past'

I'm not everyone of course.

Just threw in the last phrase you quoted as the reasoning I have heard for Mazda not doing this, since regulations specify a cat must be in place, so they can't take advantage of simply tuning it properly.

Damn exhaust shop. I took it to get it put on today and I told them I didn't know which bung the plug goes in but to make sure it's in good and of course I hear a slight rattle once I get home and show my buddy. Pretty sure it's the plug and is also causing a slight leak. Other than that I love the added aggressiveness of my exhaust. Need to break it in a little but as usual a great product from BHR.

They do nice work.....

Opinion? Maybe, depending on what the sniffer sniffs and under what conditions. The "native" problem with rotaries is unburned hydrocarbons and it's native advantage is low NOx. Leaning the mixture reduces the former and increases the latter. If one went to an a/f of say 15.5 across the board, it might pass but be virtually undriveable and risk detonation and possibly high EGT's.

Yeah we got it all sorted out. On my way back from the Tennesee/Kentucky game today my car started losing power and acting up. My afr was all over the place and higher than usual and my car would barely go up a hill. Pulled over, it died, and was flooded. I could smell gas like crazy. No leaks in exhaust causing this either, only thing I can figure is my MAF is dirty as hell. I had to have it towed to my house. I swear to god it's always something with me and this car.

Ok this question is mostly geared to anyone that has or is currently using the Rotary Performance Supercat. I currently have the supercat paired with my Racing Beat REV8 exhaust. I love the sound but im afraid the cat is soon toast due to my track driving over the last two summers. My question is, will the BHR pipe sound better and give me more gains than the supercat, or would I be better off just ordering another supercat. I'm looking to get the maximum power out of my car at the track. I've also been considering the BHR pipe with a cat just to avoid the smell and CEL. Any input is welcome. I will be making the purchase decision sometime next week.

I had the RP Supercat with the borla before I bought the BHR midpipe. The sound will be deeper and quieter but loud over 5K when you're stomping on it. The midpipe has no drone whatsoever which is something that almost made me put my stock cats back on with the Supercat. I believe it will give you gains simply because it does not have a cat. I can't say if it'll have gains with a cat over the RP. Not really my realm of knowledge.

Out of curiosity, how do you know your cat is going to die soon? Any CELs?

It has about 20,000 miles on it and 6 track days. I can't imagine it is in flawless shape. I'm also looking for something new to put on the car.

Do you have nice sticky track tires? Thats the first thing you should get ;)

Yea i have Star specs and I'll be going to R888's soon.

You said you were looking for a power increase why not try the Cobb AP if your cat is still fine... then you wont get a CEL either if u then decide on the BHR midpipe when the cat does die....

I already own the Cobb AP and I attended the dyno day in Jersey with Jeff. We got the car tuned and managed to put down 192 hp. That was with BHR coils, RP supercat, RB exhaust, and K&N filter. Jeff mentioned that their pipe should net me a noticeable increase. So I'm just deciding right now between the straight pipe or the catted version. Thanks again

Stupid / Silly question but I figured i'd get it out of the way real quick .... flames with davesport?

Noted thanks.

Well they better find a way to clear our the CEL for no cat on the s2 by the time i order this midpipe (spring) or I will have to get the davesport on it :( lol

Sorry if this question has already asked, but would there be much power different between a race pipe and a midpipe with the BHR res on it?

Depends on how well the race pipe was manufactured. The BHR pipe will keep the noise tolerable while still increasing the power. I'm pretty sure there's basically no flow restrictions with the BHR pipe.

That's what I'm hoping for. I have a RB dual res midpipe and just picked up a used RB race pipe. Was looking at welding in a BHR res on the race pipe for the track and then welding in a high-flow cat on the RB dual res midpipe so that I can run in STX next year.

A non-resonated race pipe will have less restriction than the bhr midpipe. By how much? I dont have numbers but my guess is not much more restrictive.

Huh, interesting. I just figured with the shape of the internal resonator it was bound to have some restriction but I guess not! Cool :)

just got to drive with the mp on again. sounds goooood.

thanks bhr!