Can anyone explain why porting an engine results in less low end torque, and what the effect of porting the intake has vs. porting the exhaust?

 

Hate to sound like a broken record, however if you do a "search" under porting or ports most of your questions will be answered.

 

It moves the operating range of the engine to a higher RPM. It actually has more torque at a higher RPM after porting, assuming intake and exhaust are set up correctly. Of course for a daily driver, porting isn't always the best choice. That low end torque sure is useful. If you're racing and don't spend very much time in stop 'n go and low RPM in general, porting is great.

I don't really know what effects porting intake vs prting exhaust has. That's why I recently started a thread where the main theme is stock vs T2 spec exhaust ports, and what their intended uses will be. I think I've narrowed it down though. Small ports good for low RPM and driveability down low. Larger ports have more overlap and only really start to work well at higher RPM.

I guess it depends on your driving style and what you want in the end. My projects have some differing driving characteristics and will be used for completely different tasks. I probably would have prefered stock exhaust ports for both, but one set of rotor housings already had some bad ports which needed correcting. So then I set out to make the best of a bad situation and have arrived at a conclusion, I think. Well, I will soon.

 

Read this thread. It has some very interesting info on porting and torque.

http://www.nopistons.com/forums/inde...howtopic=67369