2G OEM intake manifold modification evaluation

[scottyaurorav8]

Alright so I purchased an excellent used 2003 Seville STS intake manifold from eBay for $50. Its the same manifold for the aurora, Bonneville , Lucerne etc for 2001 and up. I figured since I ported all the imperfections on my throttle body with success maybe the same could be done with the intake manifold like the corvette LS2 guys do on their stock unit. I first inspected the main inlet. Surprised enough, it was a smooth straight shot all the way down to a half moon shaped plate thats angled so once the air hits it, it disperses all the air to the runners. Basically there would be nothing I could do to clean up the inside inlet. The walls were thin enough and porting it further would probably make it rougher than the smooth plastic inside. Next I I flipped it over and figured I could port each of the 8 outlets. Figured there would be casting imperfections, thick walls etc...but the fact if the matter was each outlet wall was smooth on the inside as well and again the walls were thin enough that if I were to port it, it wouldn't make any difference. I'd say for a stock unit, its actually
a real decent design however a metal replica would greatly benefit the car because then it could be smoothed iht and ported enough to allow more volume and still be stronger than the plastic. I know CHRFAB makes a intake but it isn't designed for our car nor would it fit under the hood. It be nice to see someone develop one for our cars. There would be some changes in design to make the air funnel more direct. Either way it was worth the $50 for me to find out. I can't believe how much gunk was in it that u cleaned out with degreaser. I'd say our biggest culprit and turbulence issue is that stuff inside our stock unit.

[XJSman89]

Yeah with a plastic intake manifold there wouldn't be any casting imperfections. They'll have the molds perfect before they make a manifold out of it.

[scottyaurorav8]

It be interesting if someone wished to tackle making a custom one. A full piece of aluminum with The center body with separated runners design I bet would be a hell of a lot better for flow. The injector location and vacuum attachments would remain unchanged. There definitely is power to be Made. If I had the money for the R&D I'd jump on it in a second but until then....oh well

[plato442]

i'd stick with the molded plastic like OEM, not aluminum. saves on weight, its still durable, etc. Alot of the LS1 guys buy the FAST upper/lower intake either 92mm or 102mm for serious mods, and they are all made of polymer as well. i think if someone could expand our stock intakes and widen the inlet and add a little volume, i think that would be a winner!

[plato442]

IE: LSX™ 92mm Black Intake Manifold from FAST

[scottyaurorav8]

yep..when I had my 05' vette I thought about buying that FAST manifold bt it was expensive. Instead I had a guy tune my car and on the same day , ported my stock mani, then sealed it b.c apparently it leaked in certain areas from the factory (which is a common problem with the LS2 intake). It be amazing to have a FAST version of our Aurora mani's....but if we were to expand the inlet...the issue would be that we'd need to somehow match it to everything else....apparently caroll shelby did something to our stock manifolds...I dont see what else he could have done....so maybe he went ahead and made the inlet wider.