New to the Ls1
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5th Gear
Joined: Jan 2019
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New to the Ls1
Hi Guys! Just joined the forum. Purchased a99 c5 Convertible with a stock ls1, and A4 automatic. My upgrades are going to include 17/8 long tube headers. CAI, Btr stage 2 cam kit, Dormer ls6 intake, and 90mm. Throttle body. Holly LS fuel rails.Also a power tune. I'm still gonna run the stock cathedral heads. My goal is 450hp at the flywheel. Will this combination get me there? Thanks for the help! Not looking for a beast, just a quick street car.
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Joined: Aug 2018
Posts: 10,079
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From: South Hill Wa
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
I would say yes.
I couple things to note, I know a lot of folks have had good luck with the Dorman intake but I myself have just seen too much junk from them in the last 10 years. I've seen a lot of there parts fail on diesel engine. Just cant trust them. I think you can make 450 to the flywheel with an LS6 manifold and a stock throttle body honestly.
You may want to consider some light transmission work and a quality torque converter.
Good luck on your quest and enjoy the car.
I am going to be doing a build similar with the same cam only with some CNC 243 heads and manual trans.
I couple things to note, I know a lot of folks have had good luck with the Dorman intake but I myself have just seen too much junk from them in the last 10 years. I've seen a lot of there parts fail on diesel engine. Just cant trust them. I think you can make 450 to the flywheel with an LS6 manifold and a stock throttle body honestly.
You may want to consider some light transmission work and a quality torque converter.
Good luck on your quest and enjoy the car.
I am going to be doing a build similar with the same cam only with some CNC 243 heads and manual trans.
No Hostility Be Happy
Joined: Aug 2018
Posts: 10,079
Likes: 7,398
From: South Hill Wa
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
You're welcome. Nice choice on the Cam as well. It's amazing how many guys over cam these motors just for the hell of it.
Also not trying to sway you from the Dorman, it's your engine and not mine. I just think you can make the same power in different ways.
Also not trying to sway you from the Dorman, it's your engine and not mine. I just think you can make the same power in different ways.
Last edited by Mr. Black; Jan 19, 2019 at 12:06 PM.
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Joined: Apr 2017
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From: Hickory NC
2025 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
2020 C5 of the Year Finalist - Modified
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I agree with Mr. Black; your proposed mods should easily take you to 450hp at the flywheel (about 370hp at the wheels).
Are you considering the Dorman simply for the cost? Although they may be a little easier to find and possibly a little lower cost, my impression of dyno tests of the Dorman is that it produces a little less horsepower than the LS6 intake and definitely less than the FAST90/92 intakes.
Are you running a 3.15 rear? That makes a nice performance gain over the base 2.73 diff. If you’re going to move up from a 2.73, I would suggest going to a 3.42 or more. If you already have the G92 3.15 diff, I don’t think the mild jump to a 3.42 is much benefit. I did this so I can speak from experience but my big motivation was to go to a well prepared 3 rib differential in place of my single rib.
An upgraded converter, as suggested by Mr. Black, will really wake up your car, too.
Enjoy your mods!
Are you considering the Dorman simply for the cost? Although they may be a little easier to find and possibly a little lower cost, my impression of dyno tests of the Dorman is that it produces a little less horsepower than the LS6 intake and definitely less than the FAST90/92 intakes.
Are you running a 3.15 rear? That makes a nice performance gain over the base 2.73 diff. If you’re going to move up from a 2.73, I would suggest going to a 3.42 or more. If you already have the G92 3.15 diff, I don’t think the mild jump to a 3.42 is much benefit. I did this so I can speak from experience but my big motivation was to go to a well prepared 3 rib differential in place of my single rib.
An upgraded converter, as suggested by Mr. Black, will really wake up your car, too.
Enjoy your mods!
