Size counts!

[mmt 15]

Hi guys,

how many hp is the gti6 std exhaust manifold good for? 

 

I am aiming for about 220 hp in my gti6 engine.. Will the std exhaust manifold be up for the job? 

 

OD of of the four tubes is approx 38 mm. I have similar design mi16 exhaust manifold with 45 mm od tubes. It made 215 hp with my old mi16 engine. My mate says the std gti6 will never be able to flow enough to be able to make 215-220 hp.  

 

Any views or hands on experience? 

 

 

[welshpug 1,657]

seems to be fine on my 2.2, roughly 240 bhp.

[welshpug 1,657]

oh yeah, they will flow enough for 400+ with a supercharger.

 

flow is not the issue, as you push the envelope with n-a tuning the more important primary and secondary lengths make more difference than the bore size.

[Miles 331 1 Cars]

Can go on for ever this one, with the 4-2-1 which I supply on mildly tuned engines I have seen a good 10bhp gain, this has been on 5 car's all at different places to the same spec of engine, Never tested one on a engine with 220bhp against a std manifold as it takes too long to swap over and RR costs, I use the long 4-2-1 on mine but it's a 306 so allot more room and is well on the right side of 250bhp

[petert 586]

If you use this online calculator, which uses the formulas by Graham Bell, you should be at 1.75" for 7500rpm and 500cc per cylinder. My engine makes approx. 240hp with GTi6 pipes. I'm sure you'll be fine.

 

http://precisionmoto.com/1803-2/

 

 

[mmt 15]

Thanks guys. Solid answers as always. Thanks!

 

I´ll let you know the result when I get there. 

Edited January 25, 2018 by mmt

[petert 586]

Pub talk finishes here!

 

http://youtu.be/O1bXPNy1Yn4