now why would HKS only make there downpipe 2.5"? is the 3" better or does it lose lower end power?

just curious cuz i thought hks is known for having the "best" stuff.

any thoughts

thanks

 

Because with a stock turbo, its really all you need - most of the JDm spec downpies are only 2.5-2.7 inches. its basically the best overall blend of downlow mid and top end power, and keeps noise in check

 

Depends on your cat back and cat. If you got 3 in go for the buschar if not go with hks.

 

Ok, bigger exhaust increase low end torque God damn it...

 

Thanks you saved me a post.

 

WRONG, look at MP5, he has a 2.5 and others have 3 it cost him about 10hp on the dyno.

 

you need a little back pressure for low end power. You can't go wrong with the HKS dp.

 

it costed me some high end power but the HKS is quality. I get low end power as well. If u r planning to KEEP the stock turbo, go with HKS. Plan to get a bigger turbo, go with Buscher.

 

MP5- how am I wrong then? Its the best OVERALL blend of downlow and top end power...that is all I said,a nd its why many companies offer it that way.

The 3 inch dp on a stock turbo will cost you a bit of power downlow, and a bit of torque compared to the 2.5. On the flip side, the 3.0 inch will flow a bit better at the top end compared to the 2.5 inch

 

thanks for teh info

 

If the HKS 2.6 is hurtful, then why does HKS offer it with thier 3037 turbo upgrade.. I think they have a lot of knowledge to know what kind of downpipe to offer with thier products..!! Especially since they've been working with the EVO since it's creation.. I'd go with the HKS.. Unless you put something rediculously big on your car like a 25G, or Greddy t-78/88... Then the 3" would be the way to go..

 

It's my understanding that the "ultimate" turbo back exhaust (for best flow & performance) would "taper" from the back of the car (it's largest diameter) to the front of the car/turbo outlet (it's smallest diameter). So 2.5"DP mated with a slightly larger mid pipe and 3" axel back section would produce the "best" results...

http://www.vishnutuning.com/news_pvnrt.htm

" the ideal turbo exhaust system would smoothly taper in the other direction- from smaller diameter (the same size of the turbine discharge outlet) to larger diameter over a short pipe length. "...

The diameter of (our) turbine discharge outlet is 2.5"; so a 2.5" DP is "optimal.". Building the "back end" involves some imagination. This is why I have not gone with a 3" turbo back exhaust. Hope this helps...

4-BNGR

 

Backpressure is always a bad thing even for low end. I think you;re confusing flow velocity with backpressure. VERY different things. Go 3 inch is possible. It is always best to go as big as possible with turbo cars. Better power across the board.

 

I'm blue in the face over this myth... exhaust gas scavenging people... if pulse "slows" too much in the exhaust system, you will loose some power. Never is back pressure "good" for your turbo/exhaust valves... If a 2.5" produces more power than a 3" it is because the 3" allows the exhuast pulse to expland and "slow" more than the 2.5". Leave the old school hot rod myths with the V8 guys.

 

PS There is a lengthy spill on this, by Turbonetics, dispelling this myth... but what would they know?