Could be the tune or something else in your setup. Its not the turbos. We have made 457whp @ 20lbs and 413 @16 on those turbos. The Racing Beat catback alone is probably costing you 10-15 hp. Are you injecting straight water or meth?

 

And the motor are st ported .Wish IRP was close to where i'm at i would ship[ my car to you guy to get it tune.

 

Ship it over. Just had a car shipped from Florida. Was around $700.

 

I'm thinking about doing it but i'll wait til late spring or summer shipping will be faster .Winter take longer to ship.

 

Just let us know.

 

I have the same exact exhaust at the moment with similar other mods, no WI but a much larger intercooler, and just had a stock ported motor with new BNRs dynoed, and got only a little more rwhp.

I strongly suspect, but don't know, that the Pettit high flow cat is not actually very high flow. I'm replacing mine with an SMB.

 

What dyno type? Lots of inflated numbers flying around the internet. Running a quiet and catalyzed exhaust will hold your peak numbers down.
BNRs don't make significantly more power than regular twins from anything I've seen. They're capable of pushing more boost more reliably.
You run the stockers out to 20psi and they'll put up 400+ too, just not for long. The more boost you run, the better the BNRs look compared to stock.

 

If you are not making more power with BNRs than stock twins with all other factors consistent, you have a problem with your setup or you need to find a new tuner. Id love to see stock twins break 400 whp at 16lbs. And yes the cat is hurting your power numbers. The only ones we run are Bonez.

 

I'd love to see that time slip.

 

This particular car is set up for the road course so a time slip would mean nothing. I'll offer this: buy a set of BNR Stage 3s from me, I'll install them and retune the car, leaving all other things the same. If the car doesn't make more power at the same boost over the twins, the turbos are on me.

 

Another vendor / tuner on here has very specific complaints about the RB exhaust as well. It happens to be my favorite, but supposedly it's much more restrictive than most think.

 

I should be so lucky, to send my car to your shop. We're on opposite coasts, but when the time comes you're one of a handful of shops I would consider/recommend.

Wonder if the single tip is any better...

 

Yeah, I read that too. Can't be more restrictive than the cat though, so that's going first.

 

We've seen gains as much as 20whp at the 500whp level when replacing a Racing Beat catback with a higher flowing catback. The single tip flows marginally better than the dual, but its not a huge difference.

 

I'm going to change back to Bonez cat my old one broke that is why i got Pittit cat and may be change the RB catback also.If i do that do i need to get a retune?Right now it tune @ 15 psi injector duty is about 76% on power fc at when i hit full boost .

 

Yes, that would be best.

 

Appreciate that

 

You will be changing the flow so yes a retune is best to be safe and to maximize the gains.

 

Does anyone have a flow comparison or a dyno comparison between the Pettit and Bonez cats? I've always been curious if there was any difference. From the outside they both look like pretty standard issue ceramic cats.

 

Id love to see a trip to the strip. We can ignore ET but Trap speed should tell us a lot.

 

Couple things id note on this thread

The smb cat, while is pretty, is still a cat and going to rob significant power on our boosted cars. I took my smb cat off and made 30 more rwhp instantly.

the rb CB is fine. i made 366 on the rb with stock twins at 15psi and ran 118 traps consistently and if i recall some 119 and 120s.

While IRP has made a ton of power my best guess is that the BNRS on average are only a slight improvement over stock. Although i will add a disclaimer that people (other than IRP) have spent a ton of time on the dyno and as a result have made more than slight improvements. But that is hard to replicate i have found. I am looking at hundreds of dyno sheets over the years versus like 5 that have done some amazing stuff. To me that's an anamoly and not the norm. If you want big power the best path is single and this is well documented

To narfle point, I 1000% agree. We need trap speeds. Thats not a knock on anyone. I been syaing that for all eternity. Id love to know what a 425-455 bnr powered fd runs for one. There have been a few over the past decade and i never seen a slip. Having said that, i think i made 413rwhp on my current setup which is bnr powered. I will be heading to strip as soon as i can. But i must say i havent been thrilled with this car (this is a different fd than i mentioned above). It also made 370 on lower boost but i think my traps were 114-116mph. I am not sure if thats due to my 18inch rims or if the power output is fraudulent. I dont know the answer. But i will report back what i run at the strip soon. Call it april. Once it warms up around here. Its almost a right of passage to me. I couldnt mod the hell out of these cars and take a dyno sheet as proof of anything. Thats just me. I want to know what it does on the road. So i will go.. I will get a few runs in and probably never return.

 

The thing about exhaust restriction is, it gets worse at the top of the rev range. For most of the curve area it's probably not a huge damper. But, at the top it'll cost you peak power.

If you want to run big boost on the stock frames, BNRs are proven. The original sets just won't hold together. And, I'm sure the other improvements differentiate the BNRs more and more, the more boost you run.

 

I have tuned multiple cars with the RB exhaust, it's nice till around 400whp and then becomes massive restriction. Get rid of the RB exhaust at the least.

 

I will say the biggest factor after the setup is the tune, and many so called "tuners" have no clue what the are doing. I am fortunate to have one of the best rotary tuners on my team.

 

Do the Stage 3 BNR turbos bolt right up to a stock '94 FD? Any grinding of metal required, or other issues? And will use of stock waste gate be a problem? Not looking for more HP, just a fresh turbo system that doesn't blow oil smoke out the exhaust (like our OEM turbos with 113K miles on them).