plentum porting

[clarkey3]

has any body with a ecotec ever taken off the cover of their plentum(intake manifold)and seen the dirty little bits of carbon/fuel build up? its worth cleaning it out.i was wondering has anybody ever tried porting their intake manifold? or dose this upset the computer?due to a factory set measurment of air flow.:wax:

 

[yZoH]

If you clean it or port it, remove the plenum & the manifold from the car so u dont get metal shavings an **** down in ur motor!

Cheers
MaT

 

[Immortality]

cleaning it iseasy, just a rag and some solvents will do the trick. there isn't probably a lot of porting to do in the plenum end of the manifold as it already has large radiused edges going into the runners. maybe port matching the runners to the head would be of more benefit but would require removing the intake manifold from the engine. some have suggested that the plenum could use a little more volume and that the runner need to be longer but unless your going to design an entirely new manifold and produce it there isn't a lot that ca nbe done. maybe have look at the walker V6 manifold. top righthand picture. link below

http://www.walkerperformance.com/index.html

 

[sircruisealotVS]

that walker manifold is so crazy, i should have saved my money and bought that, it would be wicked.
as for the topic at hand, like immortality said, port matching the manifold and runners is said to give some gains so it would be a case of both or dont bother.
as for the crap inside the manifold, if you feel like pulling it off (its not hard) go nuts with some throttle+carby cleaner, it gets most of it off....remembering it'll probably be back to how it was in a couple of months though.

 

[Immortality]

weird looking thing ain't it. love to see somoene put it on there engine with some before and after results etc. i probably wouldn't bother port matching the intake untill you have ported the heads as well

 

[sircruisealotVS]

weird looking thing ain't it. love to see somoene put it on there engine with some before and after results etc. i probably wouldn't bother port matching the intake untill you have ported the heads as well

damn straight its weird looking, but it would be so awesome.
i actually emailed walker today, lol...i couldnt help myself. unfortunately anthony tells me they are no longer available:cry: ...."due to the extensive fabrication required, only a few V6 crossrams manifold were made"
so even if i did come up with the dosh they dont have any left to sell!
oh well.

 

[Immortality]

damn straight its weird looking, but it would be so awesome.
i actually emailed walker today, lol...i couldnt help myself. unfortunately anthony tells me they are no longer available:cry: ...."due to the extensive fabrication required, only a few V6 crossrams manifold were made"
so even if i did come up with the dosh they dont have any left to sell!
oh well.

would still be interesting to see how they perform vs the stock manifold

 

[sircruisealotVS]

yeah, definately..the torque would be great with those long runners!
while the dont manufacture those particular ones anymore, anthony did say he could design a similar type of twin plenum manifold if i was interested.
might be something i look into next year.

 

[chook231]

If/When you remove your lower intake you can see the parts of the lower intake that is actually overhanging the ports entering the heads , as there wil be a carbony deposit left from the blow back (but the gasket surface should be clean, it will be obvious once you take it off) as un-burnt air/fuel mix escapes back into the plenum.

If your interested there is a small (upto 20 hp -according to COME RACING on the 4.3 ltr) to be gained from porting the lower ends of the ecotec intake/runner area on the ecotec motor.

also try port matching the plenum to the lower intake (runners).
You could also try extending the runners inside the plenum by tack welding a few bellmouth extensions to the base of the plenum.

hope that helps cheers
Chook

 

[Immortality]

If/When you remove your lower intake you can see the parts of the lower intake that is actually overhanging the ports entering the heads , as there wil be a carbony deposit left from the blow back (but the gasket surface should be clean, it will be obvious once you take it off) as un-burnt air/fuel mix escapes back into the plenum.

If your interested there is a small (upto 20 hp -according to COME RACING on the 4.3 ltr) to be gained from porting the lower ends of the ecotec intake/runner area on the ecotec motor.

also try port matching the plenum to the lower intake (runners).
You could also try extending the runners inside the plenum by tack welding a few bellmouth extensions to the base of the plenum.

hope that helps cheers
Chook

basically you mean port matching the intake runners to the head? this is common. that is probably 20hp on there 4.2 stroker which i bet had a bigger cam in it also and probably a really good tune. i recon you wouldn't see even half of that on a near stock engine. tack welding extensions into the runners would be very dificult and time consuming as you would need to make sure there sealed properly to the original base. i'd maybe suggest using a product like "knead-it" it sets as hard as metal alsmost and you could form it into the shape you like and then leave it to set. and if it doesn't work out as you though it would require a lot less effort to remove it. using this technique i guess you could get maybe another 1" to 1 1/2" off runner legth. another thing to maybe consider is trying to increase the volume of the intake manifold?