Exhaust bore size...

[Rexy]

Right is there a golden rule to an exhaust bore size?

I've had a 2.0 nova and used a full ashley system with a 2 1/2" bore i've always thought this would be pretty well suited for the xe. Now i'm looking at an exhaust for the xsara VTS.

It looks like im going to have to get one made up so was wondering if i could squeeze some extra power by having a larger bore or would it start to lose power due to the size etc.. I need some tech boff help here boyo's...

[Philsutton]

i run 2 1/2 inch on my corsa, i would say 2 inch would do a 2lt fine

[Ben]

Best bet for tuning advice for the VTS is too look on the GTi-6 forums as everything from there will be applicable to the Xsara as they both use the 167BHP engine.

Im not overly familiar with the Xsars but i know the 1600 16v Saxo VTS responds very well to a 4 branch and a decat.

[maccas]

just read somewhere that if the engine is developing between 140bhp and 185bhp then a pipe of 2 1/4 inch outside diameter is about right

maccas

[ben lee]

below is the recomended size exhaust bore to bhp

80 -120bhp 1 7/8in
110-140bhp 2in
130-150bhp 2 1/8 in
140-185bhp 2 1/4in
180-220bhp 2 1/2
210-265bhp 2 3/4in
250-320bhp 3in

[burgo]

2 and half is plenty and probably the cheapes option as its widely used

[Ben]

2.25 is nigh on 1/3rd of the price of 2.5.Is a massive jump when you upto 2.5".

[maccas]

ben lee do you have the book four stroke performance tuning aswell? lol

[ben lee]

yeap lol thats where i got the info from lol.

[maccas]

good book lol

maccas

[Aamir]

below is the recomended size exhaust bore to bhp

80 -120bhp 1 7/8in
110-140bhp 2in
130-150bhp 2 1/8 in
140-185bhp 2 1/4in
180-220bhp 2 1/2
210-265bhp 2 3/4in
250-320bhp 3in

I wonder what the 1000bhp supras use ??? :)

[craig green]

Is'nt there a Skyline running 5" pipework? Keith Cowies IIRC.