Exhaust set-up

[RayW]

Hi All
 
I have a Kakkimoto Full Mega N1 exhaust without a bung it registers 107dB at 4500RPM. With a bung on it reads 99.7dB:eek: I lose 0.2 bar of boost and it\'s no fun and it doesn\'t feel right. I run a T04e single turbo @ 0.9 bar.
 
My question is: from your experience, in order to go onto most track days under 105dB what exhaust do you recommend/run that works? I need one that also does not restrict too much power.
 
I\'m thinking of the REA dolphin exhaust or HKS hi-power silent.
I also need to get a de-cat pipe, any help or pointers?:cool
 
 
Any help appreciated
 
Cheers
Ray

[jm-garage.co.uk]

Its the age old power/noise. Unfortunatly its always a comprimise to a certain extent. The RE Amemiya Dolphin is very good system and one i could supply but i couldn\'t 100% guarantee that you\'d get under the 105DB mark.
 
Knightsports do their FD800SS which is 80mm cat back with good muffling.
 
Another that flows well is the Greddy/Trust MX cat back. 80mm piping with 115mm tip. This is rated at between 88-94DB in the book if you like i will happily get you a price tomorrow.
 
All the best
James

[lockwood77]

I\'ve got a 5Zigen box, not sure which one, but it registered 91db static at Cadwell and has no problems with Donington\'s 98db drive-by limit. No doubt I am a bit down on power compared to the massive thing that was on before though!

[Speedworks]

custom made double 60mm tubing with mid and rear box (double 60m in and out).

More flow than a 3 inch (even 3.5) and less sound.

sound is definited by a resonance wave. This wave resonates between the walls of your tubing. the bigger the tubing (fe; 80mm) the bigger the wave, the louder the exhaust.

smaller tubing gives a shorter wave, less sound but you need to double it to get thesame (or more) flow.


I never understood why brands like HKS or Greddy (or any other) offer cat backs wicht 100mm or bigger end tips.  If you look at high performance cars (BTCS etc) they run exhaust withe thesame size end tips as their tubing.

This is the way to create a good venturi effect, to ensure constant flow. Not oversized tubing where exhaust gasses start dwelming around halfway, creating back pressure on the turbo\'s.

The theory that turbo engines need exhaust tubing as big as you can get is complete bullocks. What you need is constant  and optimal speed for the exhaust gasses to get them out as quickly as possible.

Looking at \'brand\' prices, you can easily have a custom exhaust made for thesame price.

[RayW]

Thanks for the reply
 
I would love t have the REA dolphin exhaust, but if it\'s the same result noise wise then that\'s not much help to me.
 
The custom set-up is an interesting option, I might explore further.
 
Does anyone that does regular trackdays around the country in an FD, let me know their set-up or opinion?  Thanks:Thumbs-up

[RayW]

Forgot to mention, want to run a de-cat as well, so hunting for one, I suppose I have to take this into account when considering noise levels?
 
Are these typically in the £200 region? Any particularly good ones?
 
Oh.  Anyone shed some light  on the FD exhaust layout?
 
I Used to own a DC2 type R
 
The layout was \'Exh. Manifold - Cat - Exhaust backbox/catback\'
 
Can someone explain this in similar way, as I haven\'t looked under the car yet.