Ka-T exhaust blockage???

[Florida240sx]

Just wasted my whole day tuning my car and $150....another story thoughAfter horrible dyno numbers I came home ant cutoff my 1yr old exhaust system, at the cat trying to elimate possibilities.... It fixed my problem..might still have another slight one but there is 20x more feel to the car now....I have IAP kit with t3/t4 turbo mr DP to cusotm 2.5" piping to 2.5"muffler NO CATOn the dyno my car choked itself bad. 166hp 191ftlb at 8lbs....with crower cams and arias 8.8 pistons.... My car lossed power after 4000rpms.......Was too pissed to get a printout trying to think of what it is...Car would choke on itself and couldn't even go to redline......Would keep constant 8PSI and would keep perfect air/fuel ratio...

Car now hauls complete a$$ and has waken everyone up in the county...Still seems to struggle a bit up top but my a/f ratio was in the 10's... So now just need to adjust the fuel to carry me home...

So what exhaust do you have for 15psi+ cars??? I need something that will let my car breathe...I'll do a video tomorrow so everyone can hear it

[DammitBobby]

What exhaust system were you running? What was wrong with your exhaust system? Glad to hear you finally fixed your problem.

[Florida240sx]

Had 2.5" custom exhaust from downpipe back. went in a 2.5"muffler out a 2.5" opening wher eit split to a Y pipe that had 2 2.5" tips on it... looked bone stock....

[C-Kwik]

What muffler? 2.5 inch should still work. MY XS kit did not feel that weak with the Greddy MX (60 mm) I initially ran with it. The 80mm SP2 I ran later definitely made more power, but I'd guess it was 10-20 HP at most with an increase in response.

Also, which Crower cam are you running?

[DammitBobby]

I am running 3 inch downpipe to a custom crush 3 inch pipe, minus cat to BRM 2.5 exhaust out the back. I haven`t notice any when I was pushing 10psi at the track but I haven`t gone to the track since the engine rebuild and JWT ECU. The only problem I see so far that I don`t reach full boost around 14 psi until around 4.2k. with T3/T4 and AR .48 stage III wheel. I think I should be there somewhere around 3k. I wonder if the 2.5 exhaust is slowing me down?

[Structure240sx]

i dont think 2.5 should be restricting you either especially with that turbo at that much boost

i was running full 3" from the turbo back, GP sports spec D exhuast.

[Florida240sx]

Car certainly breathes a lot better. When I was at 17psi I could only get 42% airflow, at 11psi I had same flow %... I don't think it is my piping I think it is the muffler.... I paid $255 for my system. Installed with custom bending....It is a no name muffler think the baffles are blocking it. My car is quieter than my friend who has 2 1/4 piping piping at 5psi while I was at 17psi..... kinda making sense now

[Chezedik]

3" DP back with no cat. Coming from 2.5" at the turbo. But then again, I am in KS.

[lrb_2000]

2.75" downpipe, 3" test pipe, 3" catback. ... I don't see why'd you go lower than 3" on a turbo setup. 3" has the most gains even while N/A.

[Florida240sx]

All I could get at the time... Enjoy my videoshttp://forums.nicoclub.com/zerothread/208978

[WDRacing]

RS*R titanium FTW...ran it on my Skyline and now my 240. I'm keeping it even when I switch to the LS1, except I'll have a 4" dump installed.

Glad the exhaust fixed your problem man, get back to the dyno tune it and get that thing to the track.

[C-Kwik]

Car certainly breathes a lot better. When I was at 17psi I could only get 42% airflow, at 11psi I had same flow %... I don't think it is my piping I think it is the muffler.... I paid $255 for my system. Installed with custom bending....It is a no name muffler think the baffles are blocking it. My car is quieter than my friend who has 2 1/4 piping piping at 5psi while I was at 17psi..... kinda making sense now

Hmm...baffled muffler. Probably the cause. Use a straight through designed muffler. Walker UltraFlo and Magnaflow makes good ones.

[Florida240sx]

Seems I still have a slight restriction feel... Would my 2" IC piping be doing this?? Before I hit the dyno again I want it to be ready......

[Edub1]

I'm still confused as to the sequence of events. You tried to run a stock exhaust then went to a 2.5" w/ baffled muffler and still got bad results?

For an exhaust, consider that X HP worth of exhaust gas must pass through 1 pipe instead of 2 which is more typical in the 200 plus power range. Also, consider that a 2.5" pipe has has a surprizing 31% less area than a 3". Plus, a baffled muffler = bad.

Magnaflow makes a great straight through, perforated core design wound with SS mesh for ~ $80. I went with that, a few 3" mandrel bends and a local shop.

[Florida240sx]

At the time, The guy could only do 2.5". He was suppose to get me a good muffler but I guess not. It was soem cheap **** and it never gave me problems. I was fine when I was stock motor at 10psi...but then the car sat for 6months before having any flow... Guess it happened then......Could my 2" IC piping be holding me back as well??t3/t4 with .48ar suppose to have upgraded wheels