Exhaust pipe size w/LS1 in a street rod??
Exhaust pipe size w/LS1 in a street rod?? I'm getting ready to build the exhaust for the '32 Coupe. What are the optimal size pipes to run on a stock LS1, 2¼" or 2½"? Due to frame rails, engine placement, etc, I'll be using block hugger headers if that helps with the sizing.
Thanks,
Mike
Thanks,
Mike
How big is the collector on your headers?
For the love of God, do not listen to the size recommendations that an exhaust shop makes either, unless it's a sponsor here. Most shops think that an LS1 is an ol' 350, and that the same rules apply. Most of the aftermarket exhaust systems for LS1s are 3", but 2.5 would honestly be plenty, especially if its just going to be a cruiser.
You will know that your shop hasnt got a clue about LS engines if they mention their little catch phraze: "Back Pressure"
For the love of God, do not listen to the size recommendations that an exhaust shop makes either, unless it's a sponsor here. Most shops think that an LS1 is an ol' 350, and that the same rules apply. Most of the aftermarket exhaust systems for LS1s are 3", but 2.5 would honestly be plenty, especially if its just going to be a cruiser.
You will know that your shop hasnt got a clue about LS engines if they mention their little catch phraze: "Back Pressure"
Last edited by KurtRardin; Jun 24, 2009 at 03:24 AM.
Thanks Thanks to everyone.
Kurt, I won't be listening to an exhaust shop, I'll be the one fabbing this system. I've got a great, cheap (free) source for the stainless steel tubing including the bends, elbows, etc. I just needed to know the recommended size, looks like it will be 2½".
Thanks again,
Mike
Kurt, I won't be listening to an exhaust shop, I'll be the one fabbing this system. I've got a great, cheap (free) source for the stainless steel tubing including the bends, elbows, etc. I just needed to know the recommended size, looks like it will be 2½".
Thanks again,
Mike
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No, not quite that low, but they'll start rambling about how dual 3" pipe will make it loose power, burn more fuel, burn valves... and that an x pipe's job is to add back pressure and does not change exhaust tone... and that mandrel bent pipes don't flow any better than crush bent pipes.
I bought a welder and swear never to go to another shop that thinks my 5.7 liter is a 350.
I bought a welder and swear never to go to another shop that thinks my 5.7 liter is a 350.
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From: Turnin' Wrenches Infractions: 005
I have 2.25" on mine and as of now with this tune I don't make any more power with cutouts open than closed. Cutouts are a foot or less behind the headers, exhaust goes all the way to the back.
But if I were running a new system I would go 2.5" just to be safe and maybe be a little louder.
But if I were running a new system I would go 2.5" just to be safe and maybe be a little louder.
No, not quite that low, but they'll start rambling about how dual 3" pipe will make it loose power, burn more fuel, burn valves... and that an x pipe's job is to add back pressure and does not change exhaust tone... and that mandrel bent pipes don't flow any better than crush bent pipes.
I bought a welder and swear never to go to another shop that thinks my 5.7 liter is a 350.
I bought a welder and swear never to go to another shop that thinks my 5.7 liter is a 350.
I run true dual 3" all the way back and I had some of the best numbers for a bolt on ls1 at my local tuner, and then turned some of the fastest times ever run by a bolt on ls1 rx7
To the original poster, keep it simple and run exhaust the size of the collectors on your headers, which are probably 2.5". I think X pipe really makes the car sound better, but thats more opinion than anything else
That's the point that I was trying to make too, but most exhaust shops will try to tell you otherwise. You should have seen the looks when I proposed the idea of a 4" merge collector on my Y pipe... they thought I was crazy. Well, a cam, 4.10s, and a 4" y pipe later and I still get 28mpg on the highway.
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From: Michigan
I can only nod my head yep to what’s being said here lol I had 3 of my buddys PREACH for WEEKS saying the headers I put on my car were “too big” and would kill back pressure and burry my torque because I went with 1 7/8 primary’s to 3in collector with 3” dumped x-pipe just blew them off well long story short after the awesome results I had my buddy ditched his 1 5/8 / 2.5in collector headers and got nice gains on the dyno......
these were also the same people who nagged me to death when I ordered my 4,000 stall converter saying it would make my car slower than stock lmao
these were also the same people who nagged me to death when I ordered my 4,000 stall converter saying it would make my car slower than stock lmao