Who Has ported Stock 00-02' Exhaust Manifolds?
01-22-2010, 06:44 PM
#1
Who Has ported Stock 00-02' Exhaust Manifolds? I'm not looking for exhaust suggestions..I'd like to hear from anyone with experience porting the stock manifolds. I know Hinson supercars(?) ports them and individuals on here have also, and I'd like to hear the details of what they did. I know it's only worth a few hp, but I'm going from longtubes to stock manifolds and I want to salvage all the hp I can. Anyone?
01-22-2010, 06:49 PM
#2
I haven't done it, but I think it's a great idea.
As good as headers are for performance, they have too many drawbacks. By my eye, the stock manifolds look like they flow pretty good. Probably even better if you smooth out the roughness on the inside.
As good as headers are for performance, they have too many drawbacks. By my eye, the stock manifolds look like they flow pretty good. Probably even better if you smooth out the roughness on the inside.
01-23-2010, 02:01 PM
#6
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https://ls1tech.com/forums/parts-cla...manifolds.html
01-25-2010, 10:33 AM
#7
I just found a pair of 00' manifolds for my swap. After looking at them, they do seem to be a much better design than the 98-99' ones. I know I've heard of people porting them, but it's kinda hard to tell what exactly to port because they look pretty good stock. I'm going to look into extrude honing, but I'm guessing it may be more expensive than it's worth for a few hp.
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01-25-2010, 08:51 PM
#9
I looked into this a few years ago. your going to wnat to use the newer ones. The 98-99 had one side that was a really shitty long. Not sure of anything would fit, but you could try and see how much work. But the LS7 ones are the best, and there a lot of newer gen4 stuff now.
But on the 00+ Fcars one side has a better outlet. I think one was 2.45 the other was only 2.20. you can see it in the gaskets, If you dont have a set off right now. I bought the bassia Y that was really nice over the stock. But for max power Id build one with a better Y and have the I pipe bigger, 3.5 after the Y. The inlets didn't seam that bad, and didnt notice any restricions were the turn and run downward like most cars. I think the gains would be on the outlets, opening them up as big as you can after 3 cly. meet to were the 4th one. And to the outlet flange, opening it up to 2.5+ as big as you can and still have the meat for the studs, and the gasket to seal to. Then you would open the flanges up, and use tubing that side. Smooth bends, no cats, and a good Y. There might be pics up stil, I made some cat delete pipes an sold them on here. Went 114mph with them, NA, stock heads,cam,manifolds,Ypipe,catback.
But on the 00+ Fcars one side has a better outlet. I think one was 2.45 the other was only 2.20. you can see it in the gaskets, If you dont have a set off right now. I bought the bassia Y that was really nice over the stock. But for max power Id build one with a better Y and have the I pipe bigger, 3.5 after the Y. The inlets didn't seam that bad, and didnt notice any restricions were the turn and run downward like most cars. I think the gains would be on the outlets, opening them up as big as you can after 3 cly. meet to were the 4th one. And to the outlet flange, opening it up to 2.5+ as big as you can and still have the meat for the studs, and the gasket to seal to. Then you would open the flanges up, and use tubing that side. Smooth bends, no cats, and a good Y. There might be pics up stil, I made some cat delete pipes an sold them on here. Went 114mph with them, NA, stock heads,cam,manifolds,Ypipe,catback.
01-26-2010, 10:21 AM
#10
I looked into this a few years ago. your going to wnat to use the newer ones. The 98-99 had one side that was a really shitty long. Not sure of anything would fit, but you could try and see how much work. But the LS7 ones are the best, and there a lot of newer gen4 stuff now.
But on the 00+ Fcars one side has a better outlet. I think one was 2.45 the other was only 2.20. you can see it in the gaskets, If you dont have a set off right now. I bought the bassia Y that was really nice over the stock. But for max power Id build one with a better Y and have the I pipe bigger, 3.5 after the Y. The inlets didn't seam that bad, and didnt notice any restricions were the turn and run downward like most cars. I think the gains would be on the outlets, opening them up as big as you can after 3 cly. meet to were the 4th one. And to the outlet flange, opening it up to 2.5+ as big as you can and still have the meat for the studs, and the gasket to seal to. Then you would open the flanges up, and use tubing that side. Smooth bends, no cats, and a good Y. There might be pics up stil, I made some cat delete pipes an sold them on here. Went 114mph with them, NA, stock heads,cam,manifolds,Ypipe,catback.
But on the 00+ Fcars one side has a better outlet. I think one was 2.45 the other was only 2.20. you can see it in the gaskets, If you dont have a set off right now. I bought the bassia Y that was really nice over the stock. But for max power Id build one with a better Y and have the I pipe bigger, 3.5 after the Y. The inlets didn't seam that bad, and didnt notice any restricions were the turn and run downward like most cars. I think the gains would be on the outlets, opening them up as big as you can after 3 cly. meet to were the 4th one. And to the outlet flange, opening it up to 2.5+ as big as you can and still have the meat for the studs, and the gasket to seal to. Then you would open the flanges up, and use tubing that side. Smooth bends, no cats, and a good Y. There might be pics up stil, I made some cat delete pipes an sold them on here. Went 114mph with them, NA, stock heads,cam,manifolds,Ypipe,catback.
01-26-2010, 12:18 PM
#12
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Per sig:
98Trans Am M6() patriot stage II heads, 93pony custom cam, ls6 intake, pacesetter longtubes w/cats, gmmg w/ magnaflow bullet, powerbond pulley, ported tb, pro 5.0, 3.73's, racetronix 255, eibach pro-kit, bmr lca's w/relocation brackets, umi panhard bar, bmr st brace, kb double diamonds, poly bushings, !a/c and more.
Hinson is right down the street from me. I've bought a bumper from them, but never any performance mods. They seemed like pretty good people from what I gathered with the 20 minutes I was there.
01-26-2010, 12:24 PM
#13
I know that for most it would be a waste. To me it's worth it though, cause I will appear stock and have a stock manifold that flows similar to an aftermarket shorty. Besides..if I bought a shorty header I'd want the best quality, and JBA stainless/coated shorties go for a rediculous price of nearly $900, and thats without a y-pipe!!
01-26-2010, 12:27 PM
#14
That's good to hear, since I'll probably be using them. They do seem real nice, only thing is that I've called twice and both times they say I need to speak to Brian and they will have him call me....AND he has yet to call lol. I assume that means they are pretty busy :-).
01-26-2010, 02:24 PM
#15
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That's good to hear, since I'll probably be using them. They do seem real nice, only thing is that I've called twice and both times they say I need to speak to Brian and they will have him call me....AND he has yet to call lol. I assume that means they are pretty busy :-).
01-26-2010, 03:51 PM
#16
I will most likely send them my 00' manifolds, or buy one of their ported 01-02' manifolds. I'd rather send mine out though, because I don't want to drill and tap the 01+ manifolds for my egr.
01-28-2010, 12:01 PM
#17
So I measured the outlets on the stock manifolds and they are roughly 2.5" on the drivers side and 2 1/4" on the passengers side. Anyone know why GM would design their manifolds to have different outlet diameters? I can't think of any reason physically why they would have to be different, so what is their thinking behind doing something like this? Anyone have any insight? I mean, no aftermarket manufacturer designs headers with different collector diameters, so why would GM do this with their manifolds?
01-31-2010, 08:51 AM
#19
There was a back to back dyno comparison done on this a few years ago and the ported manifolds didn't make any more power. If you live in Cali, use smog-legal shorties or just don't waste your time/money.
There's a lot more involved in making power with headers than just bigger tubes.
There's a lot more involved in making power with headers than just bigger tubes.