ss2.4lvvt

well as the title says, since the gmpp header is just a stock ported header just wondering why people arent taking the stock one to a machine shop and porting it instead of buying 300.00 headers and then having a stock header laying around in storage and wondering if its gonna fit to aftermarket exhausts and stuff..
when i owned my 00 toyota celica lots of people dynoed with aftermarket headers and they made no more hp or tq but the stock ported header was the only thing that helped exhuast flow..
well thats my plans anyway and i cant see a port job on a header being more than
$100CAD...

Brandon97Z

iTrader: (1)

because the gmpp is horned not ported. Here's an article to explain it http://www.superstreetonline.com/tec..._extrude_hone/

8cd03gro

yep.

LaserblueSS

iTrader: (1)

wow, i read the article and have no idea what that meant. i wish they had pictures to go along with that explanation.

Brandon97Z

iTrader: (1)

In short it removes all the little bumps and imperfections caused by mass production. This helps provide a smoother surface inside the runners, causing less turbulance and better airflow.

Doc

It'll cost more than $100 to port the stock manifold....that thing is cast and hard as hell. If you can get it to flow better than the extruded manifold I'd almost be willing to give you $100.....I just don't see it happening.

g5mike

I think what he was referring to was "honing" and to answer his question he is correct,I have been quoted a 120.00 to have mine honed.This being said the gm honed manifold is a stocker,so go ahead and find a machine shop to do it

Doc

good luck with that....try it and see how close it is to the extruded/honed manifold.

g5mike

one member had his honed manifold "extra honed" and he loves it,It think its Nucleur.Important to keep the collector the same specs as the honed manifold or the car will lose some low end grunt

ss2.4lvvt

well im giving it a shot anyway.. if i can save 200.00 and not having spare parts laying around in the basement to get in the way im gonna do it.. and yeah i meant honed i just couldnt remember the word on the gm site that they used.. but i guess used "porting" because every port and polish job ive seen on heads made the openings bigger and smoother..
im gonna call the local machine shop on monday and see what price they gave me.. with my old celica i was gonna rebuild the motor but i ended up trading for the cobalt, they only wanted around 150CAD for a full port and polish on the head.. so i cant see a header being that high..

hubes

Actually Im planning on doing something similar this summer. Im planning on getting a header next summer so itll just be to hold me over. But basically Im just gonna take off the exhaust manifold and take a dremel, scothbrites and emery cloth to it. It probably wont be as good as the gm extrude honed one, but it should be better than stock and a lot cheaper. and like I said, itll only be to hold me over.

IonNinja

so whats the difference between honing and porting because with that explination it sounds the same to me.

hubes

its similar, but honing is taking out just enought material to make it smooth, wheras porting is taking out material to make it bigger. honing also gives a very smooth finish.

ss2.4lvvt

well this plan is down the drain for now... no one in nova scotia does honing at all just port and polishing, but i found a engine shop that can get better deals on gmpp stuff so might get the gmpp honed one if its not too rediculusly expensive....

sugardaddy2885

I have opened up a stock ss exhaust manifold that I bought used off ebay to put on my 2.2 LS. I spent a weekend using a dremel grinding out the insides and making the inside of the collector larger. It was a real pain to get the dremel pen inside around the bends but Isn't impossible. I pained it with high temp silver paint. It made my GMPP Catback sound louder at higher RPMs and looks cool too