Rear muffler kws?

[benl1981]

Hi there.

I was wondering if anyone knew how many kw a good cat back exhaust will gain in rear wheel kw. Will the dump alone with standard cat back give more gain than say a 3 1/2 free flow cat back with standard dump and front pipe?

Thanks

[|PRESA|]

I'm fairly confident that depending on the amount of boost it can vary on the amount of extra power gained, a full 3" turbo back exhaust can gain up to an additional 15kw. With more boost this setup would allow the exhaust to flow a lot more than standard setup, I can strongly recomment getting a 3" dump/front and a highflow cat, the standard dump/front pipe are pretty dam restrictive.

I have had a mate back to back a highflow cat to a straight through cat (illegal) and picked up 5kw.

[benl1981]

Thanks for the feedback.

I have a kakimoto cat back on a the moment (3/12 inch) with standard dump/front.

I have a 3" dump/front ready to go on but I'm thinking of picking up a stock cat back. The kakimoto is fairly quiet but I have recently driven a few stock skylines and like the quieter exhaust.

So how much would I lose running fairly stock boost on RB25DET (7psi) by putting the stock cat back on rather than the kakimoto?

Would it be a fairly even power trade if I put the 3" front pipr/dump on rather than having a good cat back section?

Thanks

Also how restrictive ar the standard nissan rear mufflers? Are tey universal between all the turbo nissans? if you chopped out the first rear muffler/resonator would the system still be quiet yet flow better?

[benl1981]

anyone?

Anybody just upgraded cat back and felt much difference? kws? 1/4 mile times?

Anybody just upgraded the dump/front and felt much difference?kws? 1./4 mile?

Thanks

[siksII]

the stock cat/muffler back is quite restrictive and you will lose lots of power. dotn bother putting a large dump/front pipe if you are going to remove the cat back.

just change the muffler on your cat back to one that is quieter, i have a turbo back 3' exhaust and you can barely hear it from inside, it has a normal straight through muffler(not a canon) and a resonator

[benl1981]

thanks Siks. Do you know which part is restrctive? the fact that it is 2.5" or the resonator/middle muffler or the rear muffler.

I tought the dump was the most important though? Not true?

Mines prety quiet in the cabin, just people notice it when your in the carpark or something. Not real loud but people do turn around sometimes...

[benl1981]

anyone?

[benl1981]

what sort of a rear muffler does a standard gtr have - would this be a good compromise?

thanks

[benl1981]

anybody got a pic of a standard Gtr muffler?

thanks

[siksII]

hey,

the whole std cat back is restrictive ie bends, size, and muffler.

standard gtr muffler is similar, and is also quite restrictive, it is a twin exit muffler like on the gtst...dont bother.

the dump is not the most important part, thats probably the least important... biggest difference will be made with a good catback and muffler, (which you have already) so keep that and fit a good dump/front pipe and u will gain power.

[benl1981]

I was under the impression that in a turbo car where it comes out of the turbo all hot and expanded is the most important part to have less restrictive, allowing turbo to spool up more easily.

[siksII]

with a good dump spooling will be quicker yes but for outright power increase a cat back will do a lot more than a dump if you have a standard catback/muffler

[Abo Bob]

I have a fujitsubo cat back back which made about 10-15 rwkw extra when stock and is pretty quiet. I asked for a quiet one and got it. Has two mufflers that flow well but keep the noise down.

Later I put a split dump on for more power but I didn't try dump with original zorst sorry. Seems a bit silly to me.

[benl1981]

Far out - so a cat back will give you 10-15 rwkw

- maybe ill keep mine then. where is most of the gain coming from? The rear muffler? or the pipe?

Maybe I get the stock rear pipe and then fit a higher flowing rear muffler.

[benl1981]

siks..was this on the dyno - o just seat of the pants?

Thanks'

[siksII]

ben, the main gain is from the pipe, although mufflers definetly make a difference ie stock muffler compared to a straight through muffler.

noise is mainly to do with the muffler, not the pipe, so if you fit the stock pipe and a straight through muffler it will be defeating the purpose of making it quiet.

unless you want to lose lots of power, leave it how it is (catback) and if you are really set on making it quiet, if it has a canon definetly change it to a normal straight through muffler.

[benl1981]

Everybody agree with this? I thought the 2.5" pipe should flow enough from the cat back. It hasn't got a canon at the moment it has a kakimoto muffler though..fairly quiet