kickinassrt-10 said:
I read on another site that if you port your air intake manifold it can produce big HP gains...about 2HP per a CFM gained? Is that a true statement? If it was how would you get your air intake manifold ported?:dontknow:
Porting
heads can provide gains of 1.9 - 2.0 H.P. per c.f.m. or more, but that is
WITH the right support equipment- Compression & Camshaft being 2 of them. AND that also assumes the gains in c.f.m. aren't at the expense of efficient combustion i.e. A/F separation. In that case, you may gain c.f.m. and LOSE power.
Porting a decent stock manifold may increase flow and give
you a higher peak HP/TQ number , but will likely lower TQ AND HP a bit in the lower r.p.m. ranges because of the drop in velocity caused by the larger passages.
If the manifold is a poor design to start with (say some 90 degree turns in it) you may seem some improvement with porting (say extrude honing) in the LOWER r.p.m. ranges as well, simply because the extrude honing process would have turned a poor design into something better than before. Air typically doesn't like to go around square corners without a fight and that is where extrude honing can really help...
It depends on what you are trying to do AND it depends what you are calling BIG HP gains (as per your post).
Not quite as simple as it all may seem...
You can port a manifold with a Dremel and bits/stones and or you could have it extrude honed which removes material with an abrasive paste forced through the passages.
If you have yours ported properly, you will have more power than you had before...
Ronnie
