port and polish intake manifolds

[davjos81]

how much hp could one expect to get from port and polishing thier upper and lower intake manifolds??

[KBeezy]

<blockquote>quote:</font><hr>Originally posted by davjos81:
how much hp could one expect to get from port and polishing thier upper and lower intake manifolds??<hr></blockquote>

I have pondered the same things about getting my upper and lower ported ...

[Arctc Wolf]

assuming that ur car is a 2002, and based on ur mods, not very much. Have you removed ur maf screen yet? if ur car is a 2002 u will be able to pick up at least 5 rwhp and 5 rwtq from it. after doing that, I'd say a modest 3-5 rwhp gain at higher rpm's will be seen, based on ur mods. this will help even more if you ever port/polish ur heads, do a cam, and open up ur exhaust more, as well as up ur rpm limiter. I don't know how much they port the runners and plenum, so u may see a gain in the mid-range rpm's as well. I know that polishing it alone will improve air velocity to the heads. I'd say that u'd benefit from doing this mod since u have the other bolt-on's done.

[ January 20, 2004: Message edited by: Arctc Wolf ]</p>

[Guardsman]

Actually, there's not a whole lot to port, there a couple of spots in where the intake runners open up to the main plenum on the upper intake manifold that could use some work.

However, they (GM) didn't leave much meat on the intake runners, so you have to be really careful if you work on that part.

As to the lower manifold, other than port matching, there's not much to be doen there either. I was looking at the way that the injector boss sticks into the runner, and some work could be done with it (mainly, adding material ahead of it, and making it blend better), but I don't know if they designed it the way they did to induce turbulence into the air, so that it gets mixed properly.

[12secondv6]

Well, I had my upper and lower intake manifold ported to hell!

I could not put a # on the gains.

I did notice everything flows better, especially when you add a power adder

[Guardsman]

Did you have them work the injector boss?

[KBeezy]

Mines on a 3.4 -- I forgot to mention that, if it has any bearing on how much it can be ported as compared to the 3.8

[navyblue2000]

i've done mine, and have pics (as well as them for sale)...

i can say there's a bit of material to be worked, especially if you want to gasket match the ports.

and it's worth a few more than 3hp, Patrick.

[Arctc Wolf]

I was being conservative, as usual. U know I don't like to get ppl's hopes up, and have them come back to haunt me cuz of something not going as well as expected. also, I believe I said 3 rwhp, which can vary of course depending on other mods to the drivetrain and engine.

James, who ported ur manifolds?

How much work was dome to yours navy? Most ppl who port things tend to do the major stuff, meaning increasing plenum and runner volumes and port-matching to gaskets, but did you also try to smooth out anyquick transitions, add any material to improve velocity around the injector bosses like was mentioned above, port & polish after material was added? are ur heads completely polished ont he inside? I'm not able to see ur pics, so that's why i'm asking all of this.

[ January 22, 2004: Message edited by: Arctc Wolf ]</p>

[BirdmanV6]

Unless you have aftermarket heads or a power adder, you do not need to port and polish the intake.

[navyblue2000]

while i didn't add any material, i went and port matched, and put a mirror finish on the upper manifold, the lower manifold where it meets the upper manifold, and a satin finish where the lower manifold meets the head.

I don't think there's really any need to add material.

and YES, you can still see some gains birdman. Go look at the inside of the intake manifold sometime, you'll understand.

[KBeezy]

<blockquote>quote:</font><hr>Originally posted by BirdmanV6:
Unless you have aftermarket heads or a power adder, you do not need to port and polish the intake.<hr></blockquote>

...Who said I dont? ;)

[oil pan 4]

If you ever look at a (1994) 3.4L manifold you can clearly see what needs to be cut.
I wouldn't know about the upper on a 3.4 because my upper and lower plenum is from a 2.8L (also P&P).
I did the P&P my self.