how important is valve size in a supercharged motor?
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Joined: Aug 2002
Posts: 527
From: Orlando, FL
Re: how important is valve size in a supercharged motor?
Originally Posted by marshall93z
nah, i'm pretty sure it was the valve size. 2.08 is huge for a 3.903 bore!
nothing was changed in the tune.
nothing was changed in the tune.
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Posts: 6,518
Re: how important is valve size in a supercharged motor?
How does velocity NOT matter?
IF the air density goes up (which is how forced induction works) velocity becomes more important.
If you think having LOTS of velocity is important on a NA motor you might want to read around on the boards a little more.
Marshal.... what else changed on the motor A gain from 632-750rwhp is not caused by a decrease in actual cfm the head flows. Sounds like more than just a change in the cylinder heads and the heads PROBABLY didn't flow that 330cfm number to start.
Bret
IF the air density goes up (which is how forced induction works) velocity becomes more important.
If you think having LOTS of velocity is important on a NA motor you might want to read around on the boards a little more.
Marshal.... what else changed on the motor A gain from 632-750rwhp is not caused by a decrease in actual cfm the head flows. Sounds like more than just a change in the cylinder heads and the heads PROBABLY didn't flow that 330cfm number to start.
Bret
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Joined: Feb 2003
Posts: 2,639
From: Mooresville, NC
Re: how important is valve size in a supercharged motor?
jdizzell, we thought the same thing about velocity with a blown motor, thats why we decided to go with large valved heads. and boy were we wrong!
bret, i did forget one SMALL thing! the D-1 locked up on the dyno, so an F-1 was put in place of it. he is only running one more pound of boost now(worth 20-25 hp i guess). and you're right about the heads, they probably didnt flow 330 to start with. a guy that does nascar heads did them, and his stuff is usually on par with what he says. looks like this time they might not have been, or the large valve was killing it.
bret, i did forget one SMALL thing! the D-1 locked up on the dyno, so an F-1 was put in place of it. he is only running one more pound of boost now(worth 20-25 hp i guess). and you're right about the heads, they probably didnt flow 330 to start with. a guy that does nascar heads did them, and his stuff is usually on par with what he says. looks like this time they might not have been, or the large valve was killing it.
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Re: how important is valve size in a supercharged motor?
Posted by: marshall93z
jdizzell, we thought the same thing about velocity with a blown motor, thats why we decided to go with large valved heads. and boy were we wrong!
bret, i did forget one SMALL thing! the D-1 locked up on the dyno, so an F-1 was put in place of it. he is only running one more pound of boost now(worth 20-25 hp i guess). and you're right about the heads, they probably didnt flow 330 to start with. a guy that does nascar heads did them, and his stuff is usually on par with what he says. looks like this time they might not have been, or the large valve was killing it.
jdizzell, we thought the same thing about velocity with a blown motor, thats why we decided to go with large valved heads. and boy were we wrong!
bret, i did forget one SMALL thing! the D-1 locked up on the dyno, so an F-1 was put in place of it. he is only running one more pound of boost now(worth 20-25 hp i guess). and you're right about the heads, they probably didnt flow 330 to start with. a guy that does nascar heads did them, and his stuff is usually on par with what he says. looks like this time they might not have been, or the large valve was killing it.
Registered User
Joined: Aug 2002
Posts: 527
From: Orlando, FL
Re: how important is valve size in a supercharged motor?
Originally Posted by SStrokerAce
How does velocity NOT matter?
IF the air density goes up (which is how forced induction works) velocity becomes more important.
If you think having LOTS of velocity is important on a NA motor you might want to read around on the boards a little more.
Marshal.... what else changed on the motor A gain from 632-750rwhp is not caused by a decrease in actual cfm the head flows. Sounds like more than just a change in the cylinder heads and the heads PROBABLY didn't flow that 330cfm number to start.
Bret
IF the air density goes up (which is how forced induction works) velocity becomes more important.
If you think having LOTS of velocity is important on a NA motor you might want to read around on the boards a little more.
Marshal.... what else changed on the motor A gain from 632-750rwhp is not caused by a decrease in actual cfm the head flows. Sounds like more than just a change in the cylinder heads and the heads PROBABLY didn't flow that 330cfm number to start.
Bret
Thread Starter
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Joined: Feb 2003
Posts: 2,639
From: Mooresville, NC
Re: how important is valve size in a supercharged motor?
Originally Posted by n2oblkz
Well, I wonder now. Was there a problem with the D1 which was causing the low HP numbers? Do you know if it was running good boost with the D1 or not? It would be interesting to see the numbers with the F1 and the older heads that supposedly flowed 330 CFM! The F1 is a good supercharger and should make more HP than the D1, but not to the extent of this difference so there may be another underlying factor, which makes me wonder if there was a big problem withe the D1.
just a little problem! it had just been sent back from procharger, and on the first pull the thing locked up. as in "quit spinning"!
metal went every damn where!
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