SameerP

I noticed they make a hi flow cat and 3" DP for the A4 1.8T, and that is what ive been looking to add to my car. Among my current options are:

1) wait for Pictureboy's unit to come out
2) buy a magnaflow cat and have an exhaust shop do up a custom exhaust
3) Buy ATP's DP and/or cat, have a shop do up a custom off it.

The above cats are in the 300 range, which is alot cheaper than the 600+ the metallic race cats go for...but i have to wonder what sort of flow they have.

Cheers,
Sameer

[ej257]

what exhaust will you be using?

I would thing 2.5 to 2.75 would be optimal...unless the T28 makes enough back pressure.

SameerP

the idea is that a big DP with a turbo car will reduce spool-up as it maximizes the pressure differential between the two sides of the turbo.

That said, the idea i was kicking around was a 3" DP (there does appear to be enough room) with a reducer to mate to a 2.5" exhaust, or a 2.75". Some people ive queried have claimed the turbo would spool up 300 rpm earlier with this configuration.

Power is a product of air, fuel, and spark. A big turbo car pumps alot of air into the engine, thus making more power...so logically a big turbo A4 is producing more exhaust gas than a KO3, right? So, considering the extra exhaust volume, it seems odd that a 2.5" exhaust suitable for a KO3 flows sufficiently for a larger turbo with its commensurate larger airflow. Looed at from another angle, many other cars making 250+hp have exhausts of 2.75-3.0...what is different about a 1.8T making those levels of power?

I wish i owned a shop with a lift where i could test different exhaust diameters, guess im just speculating at this point.

This all stems from the fact i have a 2.25 Borla, so i know its a restrictor, and i plan in the spring to make a change and open up that exhaust side, unless i get the urge to do it sooner.

Cheers,
Sameer