Quiet or otherwise aftermarket exhausts

[paul mac]

Interesting as the general idea behind turbos is zero back pressure allows the turbo to spool quicker, and generally speaking bigger is better.

 

Wez thats exactly what i have read and thought so am a bit nonplused to explain whats going on, i gave the car a bit of a blat today up to 0.8 bar and it feels quicker even on boost but thats subjective and could be in my mind, the facts however are it makes boost 400rpm earlier

[Homer]

Thats interesting Paul

 

I'm going to be playing around with the exhaust next week so might pop the 2nd cat back in and see what happens to the spool.

 

I haven't re-read the thread but recall Chris mentioning something about the exhaust being tuned to the correct resonance to produce peak power. I wonder if it might be a bit of a fluke that 2nd cat is helping on your setup?

[paul mac]

I wonder if it might be a bit of a fluke that 2nd cat is helping on your setup?

 

i wondered that to but there is nothing special about my set up

T61 3" down and mid pipe into a superdragger, be interested to see your results

[ROCKETMAN]

Firstly, my knowledge of mechanical wisdom is ZILCH!

 

I have a Jspec TT with a double de-cat(whifbitz), restrictor ring and RSR (4") backbox. The system was just too loud. I fitted the baffle in to the back box. Apart from a very acceptable exhaust note and more pleasing sound in the cabin the throttle response was noticeably sharper. The car seems to drive more smoothly, this may be down to the lack of noise!!??

 

Am I causing damage to my engine just by fitting a baffle? Surely not when the standard exhaust is just as/or more restrictive in the first place?

 

Yours pretty ignorantly:innocent:

 

ROCKETMAN

 

Ask me about bikes, I know about them:cool:

[imi]

I went for an Apexi N1 Evo exhaust on the recommendation of Whifbitz. Compared to other aftermarket exhaust it doesnt hang too low and it isnt loud at all when cruising, only on full chat does it come into its own which is exactly how the car should sound.

 

not sure how it compares to the stock one when it comes to efficiency....

[JohnA]

Be careful not to misinterpret the 'zero backpressure' principle.

 

It is correct as a general rule.

But if something has been designed with a specific amount of backpressure 'priced in' you may create problems if you just reduce it willy-nilly.

Smoking turbo exh seals are one example, stock turbos expect a specific air pressure balance each side of the seal. Fiddle with it at your smoking peril.

 

Some people fit a 'free flow' wickid leviathan on a stock (otherwise) system and reduce the exh backpressure* on the outer part of the seal. High pressure inside, Low pressure outside, guess where the oil will now try to go;)

 

 

* Technically incorrect term, but what the heck

[tDR]

If you want something real quiet have a look into Mines exhausts - real quiet when driving normally and at idle and opens into a throaty muted growl at WOT. Had one on the Supra I imported for 2JayZ on here and was very impressed with it

 

Cheers,

 

Brian.

[Nic]

Firstly, my knowledge of mechanical wisdom is ZILCH!

 

I have a Jspec TT with a double de-cat(whifbitz), restrictor ring and RSR (4") backbox. The system was just too loud. I fitted the baffle in to the back box. Apart from a very acceptable exhaust note and more pleasing sound in the cabin the throttle response was noticeably sharper. The car seems to drive more smoothly, this may be down to the lack of noise!!??

 

Am I causing damage to my engine just by fitting a baffle? Surely not when the standard exhaust is just as/or more restrictive in the first place?

 

Yours pretty ignorantly:innocent:

 

ROCKETMAN

 

Ask me about bikes, I know about them:cool:

 

I assume the RSR is a cat back exhaust, ie. everything from the second cat backwards? You should be fine with the baffle fitted, although normally they will reduce power a little.

[ROCKETMAN]

I assume the RSR is a cat back exhaust, ie. everything from the second cat backwards? You should be fine with the baffle fitted, although normally they will reduce power a little.

 

Correct with details of the exhaust. Thanks for a straightforward and informative reply Nic!

[carl0s]

The RSR baffle caused my UK car's boost to drop from 18.2psi to 13psi..

It also makes the tailpipe look stupid.

 

Did I mention the Greddy PE-II that I got from Chris Wilson is lovely with no cats? It has about the same restrictive properties as the baffled RSR though, and looks huge. I like it though.

[ROCKETMAN]

The RSR baffle caused my UK car's boost to drop from 18.2psi to 13psi..

It also makes the tailpipe look stupid.

 

Thanks for the tech info Carlos, and letting me know my tail pipe looks stupid! I must agree it looks way better without the baffle but is far offset by the reduction in noise intrusion inside the car. can't stand boy racer noise from an exhaust-especially on a Soop.

 

Think I now have to have the boost checked!! Money money money (and an extra 'money') before people start quoting ABBA!