Exhaust manifold - XPowerForums

maddog · 08-02-2010, 12:32

Hi, can anyone tell me if it is possible to remove the contents of the cat on the manifold? I want to imrove performance.

Maxxed_Ross · 08-02-2010, 12:50

What car is it on?

I dunno if there's much point for the amount of work that was needed

I fitted janspeed manifolds and a sports cat (apparently as good as no cat at all) to my ZS 180 - and on a rolling road it only saw a 4bhp increase over standard!

it did sound alot nicer right enough

However I did a full de-cat on my ZR 105 and it totally transformed it! More responsive, better MPG and it pulled up hills like a 160 would

CHARGER · 24-02-2010, 01:09

I wouldnt, as nasp engines do rely on back pressure !

G

Roverdose Motorsport · 24-02-2010, 06:31

no engine wants back pressure. back pressure stops exhaust gas leaving the cylinders so you'll get less air/fuel in them = less power.

on a 1.8? i dont think you'll get any gains from taking the insides out of the cat, the manifold isnt designed for it.

Drew

shortie2 · 24-02-2010, 12:43

http://en.wikipedia.org/wiki/Manifold_(automotive)
read this, exhausts are near the end

08-02-2010, 12:32	#1
maddog Registered User Join Date: Jan 2010 Location: Wirral Posts: 19	Exhaust manifold Hi, can anyone tell me if it is possible to remove the contents of the cat on the manifold? I want to imrove performance.

08-02-2010, 12:50	#2
Maxxed_Ross If in doubt, flat out! Join Date: Sep 2005 Location: Falkirk / Livingstone / North Sea! Posts: 1,426	Re: Exhaust manifold What car is it on? I dunno if there's much point for the amount of work that was needed I fitted janspeed manifolds and a sports cat (apparently as good as no cat at all) to my ZS 180 - and on a rolling road it only saw a 4bhp increase over standard! it did sound alot nicer right enough However I did a full de-cat on my ZR 105 and it totally transformed it! More responsive, better MPG and it pulled up hills like a 160 would __________________ "Project Moneypit" - 2001 BTCC ZS Max Power Top 75 Car - Scottish Modified Car Show 2010

24-02-2010, 01:09	#3
CHARGER Registered User Join Date: Mar 2008 Location: in a house Posts: 2,861	Re: Exhaust manifold I wouldnt, as nasp engines do rely on back pressure ! G

24-02-2010, 06:31	#4
Roverdose Motorsport Registered User Join Date: Jun 2002 Location: Baldock, UK Posts: 617	Re: Exhaust manifold no engine wants back pressure. back pressure stops exhaust gas leaving the cylinders so you'll get less air/fuel in them = less power. on a 1.8? i dont think you'll get any gains from taking the insides out of the cat, the manifold isnt designed for it. Drew

24-02-2010, 12:43	#5
shortie2 Registered User Join Date: Dec 2008 Location: scotland Posts: 59	Re: Exhaust manifold http://en.wikipedia.org/wiki/Manifold_(automotive) read this, exhausts are near the end

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