I have an older Greddy TT kit with the pre cast down pipes, these pipes are pretty small and look like ****, I am thinking about fabricating a custom down pipes that would go from the turbo all the way to the catback exahaust, so it would be a downpipe and testpipe all in one. now my question...

What size should it be?

I have an HKS Ti True Dual exhaust which is 60mm piping, should i make the custom down pipes 2.5in or 3in. If i go 3in what is the advantage since the rest of the exhaust is smaller? thanks again everyone for the input!


-George

 

Hey george dont know your answer but trade me your exhaust!!!!

 

George, hang tight. We'll be carrying 3 inch downpipes with dump tubes for the Greddy kit. It will be 3 inch from the turbo, all the way back to your exhuast system. They are in the final production stages...just a week or so more.

 

sounds good sharif, could you me more details? please? do you need a test mule??

 

hey sharif do you think it will be done by atleast next week or so and let us see some pics.

 

perfect timing shariff, this my big project is to begin this month, but my name on a set. Tony and I were talking about making a set but he was telling me how much of a PITA it would be to make and also how much difficult it would make it to install these things! anyways Ill give you a call tommarow. Thanks!

 

i have been working on this for a few weeks with some of the best in the exhaust industry. the exit from the greddy style mistu turbo is only 2". to go from 2" to 3" in a 6" section with a bend will cause turbulence at a very high flow/velocity area. the current downpipes can actually help the draw of gasses out with the velocity at high rpm. once making it past the first portion of the exhaust and letting it expand at a smooth rate will keep the velocity up with no turbulence. the key is keeping the air flowing with no turbulence. you will want the highest velocity right after the turbo to make it efficient, then a drawing force in the exhaust afterwards to drop the back pressure.
the tial wastegate dumps are sad. they almost go backwards into the exhaust stream. not to mention the the poor accessibility. all of this will be remedied very shortly.

 

^^^Exhuast gas scavenging is more benificial to NA cars, and not as applicable to turbocharged cars...within reason of course.^^^

Stepping from 2.5 inch to 3 inch is no disruption at all on a turbo car...its done all the time. The 38mm Tial wastegates are good for 400whp or so...each, so 700-800whp through the Tials is feasible.

 

Why must i keep planning on spending more money I've been waiting for this for a while now.