I want to get a high-flow cat now!
 

I am just amazed at the difference, the 'felt difference' there is in my car now that it has the RB catback on it.
The ass dyno doesn't lie....I can tell you that. The car revs so fast and hard now that the rev limiter buzzer is my constant companion now....and this from an AUTOMATIC car! :eek:
I swear....when I bury my foot in it now it is just like a whole different car.....so NOW I want to complete this exhaust by getting a high-flow cat.

Is N-tech still around? Is that the unit to get? Other options?

high flow cat on MY car added 5hp

midpipe added 25hp...dyno proven

Gotham Racing Hi-Flow cat!!! $320 on sale now....

GoodfellaFD3S (Rich) has helped me a lot in the last couple months, talk to him!!

I'm totally satisfied with my N-Tech hi-flow. However, you will have to weld on the tube for the airpump, but that was no big deal.

Edit: Bolting on the hi-flow to my FD with no other changes resulted in substantial power gains in the midrange, with not quite as much of a gain on top. But I can say it was definitely more than 5 hp, at least on my FD.

I agree. When I put on my Random HF Cat it was like 15-20 HP. No dyno proof but it was definitely a real eye opener (ear opener too :)

Frank

just get a MP the hi flo cat will eventually clog up due to the rotaries extremely hot exhaust temps.

Not if you get the Bonez high flow cat from Rotary Performance.
It was design for rotaries and it has some kind of metal mesh???

I have the Shane Racing cat, it is at least 4 years old and for 2 of those years didnt have air pump going to it. Still not clogged and feels like it adds 20HP on the butt dyno, I just had the stock cat on for a couple days thinking that was part of my emissions problem which it turned out to not be.

Some people have to do the smog thing. Not to mention, if you have a DP, MP, and CB you'll likely have to port your wastegate.

Frank

I got 10hp with my HF cat, dyno proven. You might gain 25HP with a midpipe but you will lose power on the bottom end.

what else did you have for intake/exhaust?

It's all on my site but I have a custom intake, DP, and GReddy cat back. The HF cat is by ATR, which is the company that directly produces many of the other rebadged cats.

just a mid pipe? wouldn't it cause worse stench from the exhaust plus loudness? And would you agree that the Bonez high flow cat doesn't clog?:confused:

I think your ass dyno is mostly in your head....you got a new part and the car got a little louder so now it seems so much faster. Cat backs don't add all that much. sorry

mine (n-tech) is now a bottleneck for my exhaust, and will shortly be up for sale, only used 1k miles, tube already done. pm me.

also the stock cat is a very large cell OEM cat...almost equivalent to a high flow

I beg to differ. My car was completely stock except for a downpipe when I added the M2 dual catback. The car immediately gained a few pounds of boost at low RPM and was spiking to 15 psi during transition! This with the stock intake and cat! I had to add a much larger pill to the wastegate to control the boost.

The peak horsepower number on the dyno may not change, but I guarantee there is much added horsepower before peak since the turbos are able to build max boost more quickly. Peak horsepower and power band are two different things. You can make no more peak horsepower but by increasing the width of the power band the car WILL accelerate faster.

haha right on bro tellem
I agree you guys are on crack the catback is high flow already and having the stock cat in there is the real restriction

dont get a high flow cat unless you have to do emissions and you think that youll pass with that. A midpipe adds the craziest amount of power. I felt more power with the midpipe at 10psi then when I went from 10 to 12 psi with the stock cat. And then 12psi along with the midpipe on the stock intercooler with pettit ecu had me trapping 112s. With 10psi stock cat I was doing 106max

well I'll give you, with the boost spike to 15lbs it'll be a significant difference.

Well, different people have different experiences, obviously, but I can tell you for sure that there is a significant difference with the RB catback on my car as opposed to the stock unit. Don't know why or the physics of it unless somehow the stock muffler was overly restrictive for some reason.
I agree that some of the "felt difference" is due to the fact that now you can HEAR the exhaust, so you are naturally putting your foot into it a little more.
But at the same time I can say that it is not like I adopted a different driving style for making "hell runs", in other words both before and after having the catback installed I always did things the same way, namely just planting my foot to the floor and taking off. And with the RB catback on I have (well had.... :( ) a LOT more wheelspin, and reached my acceleration checkpoints MUCH quicker than with stock. For instance, one place that I practice hard, fast launches from has a bridge just over a 1/4 mile from the stop sign I start from. Stock, I would be just right at or under 120 when I crossed the bridge. With the RB on it was EASY to be well over 125 approaching 130.
When my engine blew last month I didn't happen to glance at the boost gauge to see any huge boost spikes, I know I didn't hit fuel cut which I had seen fairly often in the past, somewhere around 12 psi on my boost gauge.

Just my real-world observations, take them or leave them, for what it's worth. :cool:

so anyone have experience with the pettit cat? it seems like there are many more options out there for HF's than i thought.... i just wish we had the info to say brand X is the "best" ... also, the HF cat that im planning on buying is going on my 20b conversion.... i live in cali. and while ill probably have to get the car illegally smogged anyway, i still dont want to be spewing all kinds of un-nessisary crap out of my tail pipe for an extra few HP..... yup 20b w/ a HF cat... ok let the flaiming begin :wink:

flame! flame! flame! :p: