Question about boost?
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 9,220
Likes: 17
From: San Diego California
Question about boost?
I keep reading posts that say any boost below 7 psi is simply not worth it?
I have a high compression engine (11:1). To add a supercharger with this compressionwould limit the amount of boost I can run (6 psi max.?). But most people from the FI world say this is a waste. While I realize that more boost makes more power, I actually have an upper limit of 550 rwhp I would run, but I would be happy with anything over 500. Currently the engine does 438 rwhp. Lets say it will do 400 rwhp once cam and exhaust changes are made before the blower is installed. Could the supercharger install make 500+ rwhp?
So would the S/C experts consider an 11:1 compression engine running at 6 psi a diminishing return?
I have a high compression engine (11:1). To add a supercharger with this compressionwould limit the amount of boost I can run (6 psi max.?). But most people from the FI world say this is a waste. While I realize that more boost makes more power, I actually have an upper limit of 550 rwhp I would run, but I would be happy with anything over 500. Currently the engine does 438 rwhp. Lets say it will do 400 rwhp once cam and exhaust changes are made before the blower is installed. Could the supercharger install make 500+ rwhp?
So would the S/C experts consider an 11:1 compression engine running at 6 psi a diminishing return?
Safety Car
Joined: Jan 2008
Posts: 4,797
Likes: 52
From: Boise
It has nothing to do with psi. Psi is a term people use when they don't know what they are talking about.
7 psi on a Vortech S-trim is going to be completely different than 7 psi on a F1 Procharger
Is your 11:1 compression built? If you have forged internals you can honestly make a lot more than 500 whp even if you have high CR, I think you will unfortunately be limited to the crap 91 octane you get in CA unless you can find some E85 or race gas.
7 psi on a Vortech S-trim is going to be completely different than 7 psi on a F1 Procharger
Is your 11:1 compression built? If you have forged internals you can honestly make a lot more than 500 whp even if you have high CR, I think you will unfortunately be limited to the crap 91 octane you get in CA unless you can find some E85 or race gas.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 9,220
Likes: 17
From: San Diego California
It has nothing to do with psi. Psi is a term people use when they don't know what they are talking about.
7 psi on a Vortech S-trim is going to be completely different than 7 psi on a F1 Procharger
Is your 11:1 compression built? If you have forged internals you can honestly make a lot more than 500 whp even if you have high CR, I think you will unfortunately be limited to the crap 91 octane you get in CA unless you can find some E85 or race gas.
7 psi on a Vortech S-trim is going to be completely different than 7 psi on a F1 Procharger
Is your 11:1 compression built? If you have forged internals you can honestly make a lot more than 500 whp even if you have high CR, I think you will unfortunately be limited to the crap 91 octane you get in CA unless you can find some E85 or race gas.
Last edited by SDLS1Rider; May 18, 2011 at 12:32 PM.
Burning Brakes
Joined: Nov 2002
Posts: 1,092
Likes: 356
From: Houston Texas
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Hello, I was in the same situation as you almost a year ago. To save on time I have attached my old thread with the results. IMO it will be a matter of time of when the stock bottom will let go.
http://forums.corvetteforum.com/c5-f...-na-to-fi.html
http://forums.corvetteforum.com/c5-f...-na-to-fi.html
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Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 9,220
Likes: 17
From: San Diego California
Hello, I was in the same situation as you almost a year ago. To save on time I have attached my old thread with the results. IMO it will be a matter of time of when the stock bottom will let go.
http://forums.corvetteforum.com/c5-f...-na-to-fi.html
http://forums.corvetteforum.com/c5-f...-na-to-fi.html
I have been thinking of installing forged (dish) pistons. But I can just image what that would do to my labor costs? Anybody know what that would cost?
Burning Brakes
Joined: Nov 2002
Posts: 1,092
Likes: 356
From: Houston Texas
2025 C8 of the Year Finalist - Modified
2024 Corvette of the Year Finalist - Modified
2023 C5 of the Year Winner - Modified
2023 Corvette of the Year Finalist (C8) - Modified
2023 Corvette of the Year Finalist (C6) - Modified
2022 C8 of the Year Winner - Modified
2022 C6 of the Year Winner - Modified
My engine on had 18.5K on her when she let go
Thanks for the link. I did notice that you had much more radical mods than I did. Your power levels were coming in almost 100HP more than what I am looking for. Can I ask how many miles the engine had on it?
I have been thinking of installing forged (dish) pistons. But I can just image what that would do to my labor costs? Anybody know what that would cost?
I have been thinking of installing forged (dish) pistons. But I can just image what that would do to my labor costs? Anybody know what that would cost?
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
Im around 10.9cr and running 10 1/2lbs of boost for around 700rwhp. The high compression makes it extremly "peppy" when you're not in boost (which is most of the tiime unless you race 
)
It will eventually let go, but I'm running it really rich with lots of Meth and and its making some good power now
)It will eventually let go, but I'm running it really rich with lots of Meth and and its making some good power now
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 9,220
Likes: 17
From: San Diego California
Im around 10.9cr and running 10 1/2lbs of boost for around 700rwhp. The high compression makes it extremly "peppy" when you're not in boost (which is most of the tiime unless you race )
It will eventually let go, but I'm running it really rich with lots of Meth and and its making some good power now
)It will eventually let go, but I'm running it really rich with lots of Meth and and its making some good power now
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
I have a stall, so if I floor it, I am in boost instantly, since the stall lets it flash to 3000+, and vacuum drops to zero. If I ease slowly into it, it comes on more gradually, just like any other system. I have a 3.7" pulley, so it gets there quick. I'm not set up any differently than a lower compression system, except I have to run less timing (17*) lots of meth, limit my max rpm to 6200 (rod bolts) and I will obviously not go any higher with my boost.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 9,220
Likes: 17
From: San Diego California
Depends on how I accelerate. I have a stall, so if I floor it, I am in boost instantly, since the stall lets it flash to 3000+, and vacuum drops to zero. If I ease slowly into it, it comes on more gradually, just like any other system.
I have a 3.7" pulley, so it gets there quick. I'm not set up any differently than a lower compression system, except I have to run less timing (17*) lots of meth, limit my max rpm to 6200 (rod bolts) and I will obviously not go any higher with my boost.
I have a stall, so if I floor it, I am in boost instantly, since the stall lets it flash to 3000+, and vacuum drops to zero. If I ease slowly into it, it comes on more gradually, just like any other system. I have a 3.7" pulley, so it gets there quick. I'm not set up any differently than a lower compression system, except I have to run less timing (17*) lots of meth, limit my max rpm to 6200 (rod bolts) and I will obviously not go any higher with my boost.
Last edited by SDLS1Rider; May 19, 2011 at 02:30 PM.