As expected it didn't take long to do the necessary modifications to develop some
big power results, a engine management system, bigger injectors, intercooler, fuel pump and a few bits and pieces. Using our 3" development system the car was again sent to the dyno , ran well to around 270kw @ wheels Dean returned his car, so we could make a new larger exhaust system suited for this type of engine power

This high performance exhaust system is made in 304 stainless steel and tig welded throughout

The original factory turbo assembly
with cover removed

Move over image to see
inside the turbo housing

After careful consideration and what was available we decided [i was told] to make my own dump pipe as long as it had a separate wastegate pipe. The 3" dump pipe we made has a small separator between the wastegate and the engine pipe to ensure perfect gas flow and minimal leakage between the 2" waste gate pipe and the 3" dump pipe

Almost at the end of the dump just before it steps up to 3 1/2" the wastegate pipe has been spliced at a very fine angle to ensure the maximum scavenging affect. This pipe is been replaced with a 4" single pipe, with
very good results, dyno results soon

A popular brand Metal Substrate catalytic converter has been used, firstly to make
sure this car still passes current emissions standards and also ensure maximum exhaust gas flow, the cat will be the only restriction
if at all in the exhaust system.

When i purchased this hi flow catalytic i questioned the supplier on how the substrate was held into position , i couldn't see anything that would stop the substrate from moving back in the casing, [very common problem] only twelve months later and
with very few km's done, the substrate was pushed right back blocking exhaust flow

The cat back exhaust system is 3 1/2" the muffler is straight through for maximum flow
The new exhaust system almost sits as high as the original system, flanged in a similar position to the factory exhaust for very
easy removal if required

As the 3 1/2" pipe goes over the rear sub frame we split the pipe into twin 3" so we can have left and right tailpipes, The hard part is making the y section so it can be removed. The collectors are welded on the inside, this way we are sure to get even
gas flow into both tailpipes

As the the pipes come around to the bumper bar we again split the pipes,this time to twin 2 1/2", again collectors are welded on the inside to ensure even gas flow, The twin 3" Stainless Steel tips each side finish this exhaust off perfectly. The rear bumper is cut to suit [exact opposite to the rhs]. After the new 3 1/2" exhaust system was finished the car was again returned to the dyno with great results, a gain of 20kw , after a re tune the car runs at 303kw @ wheels before
our 4" dump pipe was fabricated and fitted

click here
for close up of staggered tips

Finally time to see the difference in power between a single 4" dump and the 3" pipe with the separate wastegate pipe. Because the first catalytic failed [substrate came loose a very common problem] a new Xforce metal substrate hiflow catalytic converter [rated at 750crm] was also fitted .The inlet was modified to suit the 4" dump, the outlet was left at 3 1/2" to suit the exhaust system

Dyno results

Twin dump 303kw @ wheels

Dyno results

4" dump 321.7kw @ wheels

I would like to thank Dean in allowing us to try different exhaust systems on his car. I have been doing Dean's exhaust work for a few years now, and by allowing us to use his latest car from start to finish we all can get the facts and figures from a customers point of view ,we now know what size exhaust is suited to ? kw