custom exhaust

[truss]

afternoon peeps
ive got a mate who works for a custom exhaust place, and i need help with getting the specs to get the best system made up as posible.
i want it from people who use the same car as me for the best results rather than a salesman.
Its an ibiza 20vt and want to know; do i change the down pipe to a bigger size, sports cat or de-cat, and the best pipe size for the rest of the system.
or do i say balls to this and buy a blueflame or miltek?!!

 

[Ric 2001]

Most restrictive is the down pipe and cat, I went for a miltek which is 2.75" system throughout then 100 cell cat and has a larger down pipe to... so basically you'd be copying an already made system. Just see what the price would be from your mate and compare it to blueflames/milteks prices. Will it be made from the same grade of steel?

I wouldn't do a de-cat as that would through up a CEL light and you would require a remap to map out the 02 sensors. And thats extra cost.

 

[truss]

would a stage one map get rid of the codes?
am i right in saying as little back pressure on a turbo'd car is best?
i cant comment on the grade of steel if im honest. ill compare prices then!

 

[Damoegan]

would a stage one map get rid of the codes?

No mate, it wonte. You will have to ask the mapper to specificly map it out.

 

[truss]

okie doke, thanks

 

[kriso]

am i right in saying as little back pressure on a turbo'd car is best?

There is already a load of back pressure on a turbo'd car - the turbo itself There's no performance advantage with going larger than 2.75" on the 1.8T plus there's the added weight and mounting problems. The turbo size and exhuast manifold are the most restrictive parts of the exhaust on a turbocharged car.

 

[truss]

im talking turbo back back pressure.

 

[kriso]

im talking turbo back back pressure.

Yea you don't want any restriction after the turbo really on these engines. The turbos are quite small so spool up easy. With a larger turbo the restriction after the turbo stops can stop them from spinning up too early.