Intake runner porting-TIII mainly!

[turbovanman²]

Maybe I am overthinking but I have a large plenum, ported head but the runners, aprox 4 inchs long, are untouched. Should I open them up or leave them stock?

2 reasons, in my mind, to leave them stock-keep up some port velocity to make it more driveable and help reduce lag so to speak.

Or will porting it make the whole package better and stop overthinking, this isn't an N/A engine.

[Dave]

It depends on your power band. What RPM are you revving to now and what will you plan to rev later?

[turbovanman²]

99% street with some drag duty. I rev at the track from 7-7500 if needed.

[bakes]

Do you have a spare intake ? If so get creative with the spare one over the winter that way you can do a comparison. then run the on that work for you.

[turbovanman²]

Trouble is, the one in my van is heavilly modified.

[bakes]

if it was me and its not . i would hog it out

[GLHNSLHT2]

open it up. bigger at the opening and gasket matched or matched to your head at the bottom That seems to work well on my modified 2 piece.

[turbovanman²]

Ironically, I had to grind off the lower port on the head as there was a big mismatch, aprox 1/8 of an inch.

Guess I will finish porting it this winter.

[Dave]

7,500... I'd hog the crap out of the them. Especially on the size of your turbo, the amount of pressure you're running, and how efficient that engine is, it handle a bunch of porting... in fact I'd go as far to shorten the runner length if you could. 4" may be a tad long for 7,500.

[turbovanman²]

Its pretty short, check the photo's in my lounge thread.