Sleeper Exhaust Systems

[r34unit]

Looking to build or buy an exhaust that is super stealth and quiet but is non restrictive up to around 350kw. (no i do not want to go a varex muffler)
Currently running 3inch turbo down to cat then a 4inch kakimoto.
I was thinking from cat back run a 3inch exhaust with 2 mufflers ? any other ideas or sneaky stuff people have done ?

[kingtube69]

Get HKS Silent hi power

http://www.hks-power.co.jp/en/product/exhaust/muffler/silent/

My mate has one on his 32GTST and it sounds good, not loud unless at WOT and seems to flow well.

[Ben C34]

What do you mean sneaky?

I ran a hooker aero chamber and a Berkeley straight through at the rear. Was under the legal vole by a fair bit, no drone and flowed over 300 rwkw.

Research exhaust design. Two mufflers the same don't do much more than one. Fit the biggest mufflers you can fit. Look at branch resonators if you have a particular frequency drone you want to cancel.

I tried a few combos until I was happy with the result.

[Therealsandybang]

Nismo 3inch turbo back

No not the gay 2.5 inch flange one

I have one and Charles 89 has one on our gtts. You can't beat it for quietness plus performance.

[Ben C34]

Power figures?

And mine had a pipe through the cat. So would have been a touch quieter with a real cat there.

Edited February 5, 2015 by Ben C34

[Therealsandybang]

I'll let you know if the Nismo cat can withstand the flow.

I'll have an atr43ss2 fitted in on sat at dvs jez so ill pick it up in a week and see

Edited February 5, 2015 by Therealsandybang

[mattie4270]

AES can do this

[r34unit]

By sneaky I mean running a stock cat back exhaust then running a waste gate with a small pound spring to vent out exhaust gases.

Like so ^

[Dose Pipe Sutututu]

By sneaky I mean running a stock cat back exhaust then running a waste gate with a small pound spring to vent out exhaust gases. ImageUploadedBySAU Community1423175348.468724.jpg

Like so ^

very cheeky indeed, similar to how OEM cars get away with noise. If you crack open a stock EVO muffler it uses a little flapper to control noise when doodling around town.

[RBrennan25]

I have the HKS silent hi power on my GT-t. Has a Hypergear SS2 turbo, custom 3' dump and front pipe and hi flow cat and its really quiet at idle. I can confirm that the nismo is quieter having been on a few cruises with Raj.

And I'm currently making 320.6 rwkw at 22psi on E85 so it doesn't appear to be too much of a restriction

[MrFijiGold]

And must I say, the Nismo oval muffler looks very smart on the car.

[RBrennan25]

And must I say, the Nismo oval muffler looks very smart on the car.

It absolutely does haha

[BLITZ-26]

plus one for the Nismo.... i put one the 3" version on a N/A skyline and it was still very quiet and sounded batter than any custom system i had heard before.... i was very suprised when we started and drove the car.

another option is like the exhaust i have i think its a fubijsbu its a twin 2.25 inch system with a single straight through muffler at the rear and 2 resonators, passed EPA and flowed 350kw

[r34unit]

Is this the nismo exhaust every one is referring to ? http://www.sau.com.au/forums/topic/292940-nismo-exhaust/
it seems two mufflers is the key

[Ben C34]

I'm going to say the waste gate in exhaust idea is crap.

A decent exhaust will work well and be quiet (enough) all the time.

[Therealsandybang]

Check the beginning of my build thread. That's the one in referring to. I think it has a dump/front pipe. Rather than separate.

[SiR_RB]

I got a full 3.5" turbo back exhaust with a custom oval 3.5" muffler and a custom AES 3.5" rear round muffler

Nice and quiet and doesn't drone, been pulled over for rbts and by random cops in the city and even asked to rev the car and they were happy with the volume

So far flows 450kw ample for your power

[choyda]

AM performance does at titanium 3.5" to 4" system and stays below 90db. I agree that a well designed system can flow and be quiet - isn't cheap though

[r34unit]

Thoughts on adding a muffler to existing cat back ?

[GTSBoy]

If that thing had any mufflers in it in the first place!! They are both far too small to do anything. Replace the centre one with the biggest oval centre-centre muffler you can. Replace the rear one with the biggest muffler (probably oval again) you can. Instant fixup.