Thread: F-Body/L26 fusion?

Originally Posted by GTPpower

I doubt you'd see any difference. Power is majorly dependent on the turbo. The intake has very little effect on it.

...except for varying where the lean/rich cylinders are.....5,6 run leaner than 1,2 on the TR

Originally Posted by Turbocharged400sbc

...except for varying where the lean/rich cylinders are.....5,6 run leaner than 1,2 on the TR

Is that due to air or fuel distribution?

Originally Posted by GTPpower

Is that due to air or fuel distribution?

Originally Posted by wstefan20

I'm guessing that's due to the fact our throttle body tilts forward towards the rear and a straight plenum tends to throw the air towards the rear and miss the closer runners? I've seen a few intake models and that seemed to be the case.

inertia is a *****. GN guys have played with this issue since the early days of the UIM power plates, meant to provide flow restriction for more even air distribution to all cylinders. early SI 3800's have a "ski jump" at the end of the TB adaptor where the air enters the plenum. this was changed in later SI production to the more modern low plenum wrapover runner (early are alum, later plastic) manifold design that was eventually applied across the whole range of GM V type engines due to cheapness of molding/die casting. everything is a result of compromises.....no compromise gives you the larger/harder to package Lehmann style intakes and the nearly perfectly even air/fuel distribution.....most modern high performance boosted engines use a variation of it...modified usually for easier injection molding of a plastic unit.

Originally Posted by wstefan20

Interesting! So you're saying that our overall stroke is too short to support airflow at high rpms?

the whole engine is too short, to save $ and weight, GM circumcised an extra inch off the deck height it means a horrible rod stroke ratio, which means ****ty high rpm cylinder filling and drop in pumping efficiency. readup on rod/stroke ratio and youll see why indycar/high reving engines run a near 2:1 rod/ stroke ratio while our L67 has a horrible 1.5:1
a hybrid SI/SII would allow for a 1.96:1 ratio....and even then the offset journal crank would make me leery of going over 7k