Exhaust Note

[WYTSKY]

Hey guys, I own an R33 GTS4, got it professionally converted from an N/a to Turbo last week.

It runs really well now, just a few questions about it.

I have a FMIC etc now, but before the coversion I had a 3-3.5 inch momo exhuast system with a 5 inch tip(pretty big for an n/a) along with stock dump pipe and extractors and the engine gave a real growl, sounded awsum (most ppl throught I had extractors).

Currently i still have the exhaust system, but with a stock turbo dump pipe and stock turbo extractors and it is sooo much quieter then before, only at about 5k does it start to sound remotely grunty, someone please tell me why and how I get it sounding as it was before! Thanks

would a new set of extractors do it ?

Also, it is now idling at about the same, but the engine is reving very lightly constantly, from about 760rpm ~ 810rpm roughly, is this due to the turbo?

Thanks for the help!

Adam :laughing-smiley-014:

[blind_elk]

It is unlikely that you will ever get the same exhaust note. One of the beauties of a turbo is that it utilises some of the energy in the exhaust gasses to spin the turbine. If there isn't as much energy present by the time it comes out the muffler, then it can't emit as much sound.

As for yopur idle, is it on an aftermarket ECU or factory? As it's a RB25DE -> RB25DET conversion, I doubt a factory ECU could work quite right because it was designed to operate that exact configuration of engine. But, have a look at the AAC valve - it might be slightly gummed up and sticking, so give it a clean.

PS - it's THAN, not THEN - quieter THAN before

[WYTSKY]

It is unlikely that you will ever get the same exhaust note. One of the beauties of a turbo is that it utilises some of the energy in the exhaust gasses to spin the turbine. If there isn't as much energy present by the time it comes out the muffler, then it can't emit as much sound.

As for yopur idle, is it on an aftermarket ECU or factory? As it's a RB25DE -> RB25DET conversion, I doubt a factory ECU could work quite right because it was designed to operate that exact configuration of engine. But, have a look at the AAC valve - it might be slightly gummed up and sticking, so give it a clean.

PS - it's THAN, not THEN - quieter THAN before

LOL thanks for the help and the english lesson! English me speak good you better watch your spelling though --> "As for yopur idle" btw it has a new s1 r33 rb25det ecu, exactly the same as mine, except for being turbo, so I did not think that was the prob for idle.

I also just wanted to know how to make it louder again, would extractors make a decent diff?

Cheers Adam.

[foznice]

if you want it loud, get a stainless dump/front, and ditch the cat.

Until you get hassled, then you'll wished you would've left it quiet.

[mad082]

turbo cars will never be as loud as a N/A car. 3" on a N/A would be massivly louder than on a turbo.

you have 2 options firstly (and this should be done anyway) get a highflow cat and new dump pipe. this will make it a touch louder.

secondly you could cut out the centre muffler. this will add a bit more bark to it.

[WYTSKY]

Thanks for advice, so extractors/headers will not make that much difference? only high flow cat and dump? Because I was planning to do them soon enough anyway.

Thanks again, Adam.

P.S wot about the idle issue?

[mad082]

it may be that your idle control valve is slowing getting blocked. what ecu are you running? is it the turbo ecu or the NA?

[vinnie32GTS4]

titanium exhaust with no cat will sound a treat

[MANWHORE]

If you have mufflers, remove both mufflers. If you hvae them replaced with straight pipe, it should be louder and sound meaner.

Cat - same deal

Bigger dump/front pipe makes a bit of difference but nothing like changing mufflers.

Bigger turbo makes a huge difference to the exhaust note and volume. - after all, this is essentially the only difference between what you used to have and what you have now - think of it as a big butt plug in the exhaust (literally)

[WYTSKY]

Thanks for the advice guys, I am running a stock ecu, from a s1 r33 turbo, so the same as mine + turbo, which I thought was good, and the engine never did this before... I thought it was the turbo setup that did it? please advise.

In terms of taking out mufflers etc.. I may consider removing the system (middle) one, as it is a b*stard over speed humps, but I don't want to make the car more illegal then what it is.. considering I am a P plater... Plus I am really happy with my current exhaust sys.. just hoping the cat etc.. could be fixed up..

No one has mentioned the extractors... are they not as good on turbos as they are on N/A's ?

And thanks for the butt plug explanation.. it all makes sense now

I did give the car a bit of a go and at 5k it is pretty mean.. nuthing what it used to be...but anything below sounds as quiet as a little civic.. no offence, small price to pay I guess.

Cheers, Adam

[mad082]

if you want more noise you could go a screamer pipe, but on the stock turbo it can leak a bit, and will only make it louder when it comes on boost. and is rather illegal.

but do you really want extra attention from police, with the increasingly strict laws that keep bringing in?

[WYTSKY]

Nah ur right, I know I don't, I guess I just wanted the deeper note I used to have... But a highflow cat and dump is good for perfomance as well? Still, wot about the extractors?

Thanks, Adam

[r33cruiser]

this may be a stupid answer, but if u remove the mid muffler from the exhaust(if u have one) it will sound nice.

did this recently and makes a big difference

cya

[cheez]

there are no extractors on a turbo sky. it runs an exhaust manifold which the turbo bolts to and then the exhaust itself runs out of the turbo.so its like a small combinatioon of pipes (6 of them) that run to the turbo, then a dump pipe from the tubo throught 2 the front pipe and then the exhaust begins.

when you talk extractors on a turbo skyline, your talking front piep and dump pipe. they can be an all in 1 system like FLYN sell or a split dump front like just jap sell.

FLYN - http://www.skylinesaustralia.com/forums/in...howtopic=166815

JustJap - http://www.skylinesaustralia.com/forums/in...howtopic=155238

as for note, wanna make it louder, remove the rear muffler, im guessing its and oval type muffler and replace it with a cannon muffler.

[mad082]

no, extractors are just oversised headers. turbo skylines can still have them. it is just an aftermarket manifold. it won't really change your sound much as thet are before the turbo and the turbo is what makes it quieter in the first place.

[cheez]

i stand corrected. well then just change the front pipe and dump as well as ur rear muffler to a cannon and away u go. i had a kakimoto 3" system with cannon muffler first and at idle i was 97dB and at full noise i was 108dB, that was loud and after a while the drone got to me.

so yeh put a cannon on.

[WYTSKY]

Thanks guys,

Very helpful, I decided I will change the dump pipe and cat, as well as remove the middle muffler. Think that should give me a decent increase in growl, I'm definitely not after drone, even if it means sacrificing volume. Thanks a lot for the help!

Power wise though, a 3.5 inch sys and 5 inch tip is definitely big enough for a turbo to blast out exhaust fumes? I thought it would be.

Thanks, Adam

[mad082]

even a 3" is big enough for mild rb25s.

[WYTSKY]

well yeh.. its a 3 or 3.5... not 100% sure.. as long as it is sufficient

Thanks, Adam

[cheez]

a 3" system will be sufficient for a rb25 running 270-300rwkw. only bigger when u chasing more than 300rwkw.