Its pretty straight forward what size piping you running and how much Hp & Tq you making? When is 3" to small and 3.5" or 4" needed?

 

Well the prevailing thought on evom is bigger is better....That said, I have not seen a test with 2.5" vs. 3" vs. 3.5" piping. I am guessing most of the benefits with aftermarket setups is from the muffler design (very loud) and /or test pipe. Buschur runs his 3" exhaust on cars with crazy power, so I doubt you need to worry about going larger than 3".

 

There is a very mathematical way of determining what size exhaust would be best for a certain power range. There are reason why there are 3" setups all the way to 5". The different exhaust sizes will cause different amounts of back pressure on the turbine wheel of the turbo. In most cases you want to eliminate as much back pressure as possible to have the turbo spool up quicker. But, some level of back pressure is needed to have optimum turbo spool. In big time race cars you will see many pressure sensors located throughout the motor; manifold, pre-intercooler, post-intercooler, exhaust, etc.

 

3" will serve your need just fine. You won't need anything bigger than that.

 

8in will be necessary for a 8 turbo

 

Oh forgot to put that im going for 600whp in the first post. I just got to thinking as ETS has 3",3.5", and 4" turbo backs. Must be a need for bigger than 3" or atleast an atvantage of going bigger.

cssaddictm4, are you gonna post the mathematical why to know what size exhuast to go with or just talk about it, lol.

 

if you have a 3" downpipe whats the point?

 

^^^^^^^^if going with a 3.5" or 4" TBE that would make the downpipe 3.5" or 4"

 

If you go 3.5 make sure you have a good pair of ear plugs.

I have the ETS 3.5 and it's loud. But then again my entire car is loud. GT4088 twin scroll with open dumps. So it's not like it's the quietest Evo on the block but I enjoy it.

 

I was thinking ets 4" lol. with open dump. Should set a couple car alarms off.

 

WRONG.

You want to maximize the pressure differential across the turbine wheel. That means the biggest post turbine exhaust possible.

 

^^^^+1,000,000 AND u want the SHORTEST exhaust possible on a turbo car for maximum power.

OP, there are hundreds of evos making more power than ur goal running a 3" exhaust, but its ur car. do what makes YOU happy, not anyone else

 

Everyone says 3" is fine even on 600whp setups, but i have seen a ton of dyno sheets showing a big difference between a restrictive 3" and a good 3". I see no reason why a 3.5" wouldnt make more power even if its only 10whp its still better.

 

http://www.tercelreference.com/terce...st_theory.html

This article has some good information.

 

Obivously, routing the WG dump to atmosphere reduces potential backpressure in the downpipe. Depending upon the size of the DP, the turbo, and the expected power levels, this may or may not be a significant factor.

FYI