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intake manifold question

2 July 2000
Raleigh, NC
Hello all, I just recently purchased an intake manifold off of ebay with the idea of sending it to extrude hone. Any ideas if there would be any hp to be gained on a NA motor? I'm sure there would be a considerable increase on a forced induction setup, but otherwise I am unsure. I mean it couldn't really hurt could it? I don't think one could go wrong with more air flow. Can anyone think of how it would have a neg. effect on performance or reliability? Just ran across this on ebay and it was cheap enough so I figured why not. Anyone dealt w/extrude hone at all and or would have an idea of what this would cost? Sorry about the 20 questions, thanks for any advice or opinions.

When I talked to ExtrudeHone last year they wanted around $600-$700 to do the intake. On a NA car I think one can expect a hp gain of somewhere between 0 and 5 hp.

I had Larry polish my intake manifold when I had it out when removing my NOS. That wouldn't be as extensive as what you are talking about. Since it was already out though, he only charged me for the hour or so of work it took. It's been running smoother and feels a bit more peppy, I like the difference, but nothing huge. If it's already out, and you are at the shop where it can be done there and not cost much, it's worth it like I had it done. $600-700... no way.
I've also HEARD that extrude honing the intake manifold makes it so smooth on the inside that sometimes the fuel has problems atomizing (sp?) and you end up losing power due to poor fuel delivery...
I dont know if this is true or not..
The fuel pooling effect is true, but it depends on where the fuel is introduced. If the fuel is introduced where it is not ported, and the port work is BEFORE the spray then it would not be a problem.

Kenji Ligon
I'm not sure that the benefits (as a %) on a forced induction system would be much greater than an NA as you suggest. In many ways, boost is the great equalizer that overcomes the little things which can limit flow in an NA motor. If you can reach the desired boost then the minor things such as this are relatively less important. Don't you think?
Well as for port design and the benefits, well it all depends on how efficient the port design is versus the amount of improvement or potential of that port if augmented. The more efficient the intake port, the easier the air will flow along with quantity (volume). Another words, you can have 5psi of boost but with more airflow(volume) versus 5 psi with a more restricted airflow (less volume).

Kenji Ligon