thebull

ive seen that people have tihs down as a mod. what exactly does this do,and what type of hp gains does it give. also how difficult is this to do by yourself?

brubenstein

This is a non-trivial thing to do. It requires pulling the heads and removing the valves just to start doing something. A very basic porting involves matching the port in the intake manifold to the intake port of the head, removing any casting flaws in the intake port and getting the valve seats recut (usually a multi angle cut for the intake). Reshaping the intake port (for a significant power increase) takes the right tools, experience and a flow bench. A simple clean-up port job is probably good for a 10% increase in power and won't make the engine any peakier. A more extensive port job will tend to trade off some lowend for high end power. Polishing is just smoothing things out with 240 grit paper. You really don't want a high polish in the port, because it will create a thicker boundary layer between the fuel air mixture and the wall. A good race port/polish would probably be good for 50 HP.
It's the kind of mod that is most appropriate for real racing, where you have to do mods within rules. For instance, if you're running in a street stock class, you may not be able to change the intake or exhaust, but you can do a "clean up" port and good valve job. Since it's probably cheaper to put on a supercharger, than have an experienced race shop prepare your heads, it's not very cost effective for street racing. Another difference between streep prep and real race prep.

flyry110

Dude, to do it right it costs a few grand. especially to CNC port and polish em

Jeff92se

iTrader: (82)

Hey good topic.

Porting and polishing head comments from brubenstien is pretty much right on the money. But I would like to add to the porting of the intake ports. There would be gains if the basic design can be improved on. If it's already good, then it's pretty hard to get it to flow more efficently. Of course making it larger will make it flow MORE but it would result in a loss of lowend like you mentioned. I would say a good valve job and a good port matching of the in/exhaust ports + the intake manifolds would be nice. It all depends on what you have to work with. Again if the basic combustion chamber design is good, no gains will be had. Maybe some unshrouding of the intake or exhaust valve area might work. From what I've seen on the VG and VE heads/manifolds, there is not alot of casting flash or rough surfaces that can be removed. It's pretty damn good from the factory.

I think people have sucessfully ported some VG heads. As these give good low end anyway, I would sacrifice some to get better breathing in the mid and top ends. But I want to know if porting the VE heads are a good idea??? Again, they look pretty damn good to me. I've seen them close up.

FAST4EN

Porting the VE's? Are you serious? Has anyone actually ever done that to a VE?

Lordrandall

iTrader: (4)

Page 15 of the Summit Racing catalog has a do it yourself porting, polishing, and deburring kit. Anyone for a go?