Dynamic compression
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Joined: Nov 2001
Posts: 2,985
From: In a house by the bay
Brian,
Yes, Chuck runs NPG and also recommends a BASF coolant I'm not real familiar with.... believe Mercedes uses the same coolant. Then again, Chuck does alot of things that he doesn't recommend people doing at home.
If you're in that line of work you can afford to push the limits through research and just plain knowing your shiznit. I do believe his coolant temps were higher than 120. When I talked with him about evans, he mentioned that his coolant temps were ~220* but the point he made was that coolant temperature was not a clear indication of critical area temperatures along the water jacket and combustion chamber. Of course he's in R&D, does alot of testing, rigging engines with sensors and stuff like that so he can make more "educated" choices than you or I can.
We would do well tol err on the safe side.
On static compression my thought is this.... if the compression is too high to run pump gas, then why not just go with a compression ratio that makes the most power for the application. There's a bit of power there.... not much but here we're usually talking about engines in class racing where you're seperated by a few tenths. Every bit helps in that case but it's probably not worth much one way or the other for a race car that's gonna see street time (non competitive).
-Mindgame
Yes, Chuck runs NPG and also recommends a BASF coolant I'm not real familiar with.... believe Mercedes uses the same coolant. Then again, Chuck does alot of things that he doesn't recommend people doing at home.
If you're in that line of work you can afford to push the limits through research and just plain knowing your shiznit. I do believe his coolant temps were higher than 120. When I talked with him about evans, he mentioned that his coolant temps were ~220* but the point he made was that coolant temperature was not a clear indication of critical area temperatures along the water jacket and combustion chamber. Of course he's in R&D, does alot of testing, rigging engines with sensors and stuff like that so he can make more "educated" choices than you or I can.
We would do well tol err on the safe side.
On static compression my thought is this.... if the compression is too high to run pump gas, then why not just go with a compression ratio that makes the most power for the application. There's a bit of power there.... not much but here we're usually talking about engines in class racing where you're seperated by a few tenths. Every bit helps in that case but it's probably not worth much one way or the other for a race car that's gonna see street time (non competitive).
-Mindgame
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Joined: Jan 2002
Posts: 442
From: Houston, TX
Originally posted by Mindgame
I respectfully think the guy is full of poodoo.
I respectfully think the guy is full of poodoo.
Yeah, i shouldn't be rude... but he started at school the same time I did, and he just does a ton of reading. So it's not like he know's this stuff from experience. He's a real nice guy and I appreciate him trying to help me out... but it's almost like he always has to disagree with whatever I say just to be mister mocha. lol, oh well, who cares life goes on
Thanks for all the help... you are saying the same thing pat did. If it's a race gas motor then I'm fine with the compression. I'm sure dcr has it's place in the street motor world running with octane limitations like you mentioned (and I tried telling him this earlier)... but for me, if I can run 9.7 without detonating on race gas, there's no reason for me to want to lower my compression.
Thanks for the thoughts...
Later
Chuck
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Joined: Jan 2002
Posts: 442
From: Houston, TX
He just wrote me this, so I thought I'd post it if any of you were interested in seeing a little bit of his opinion... This is his general thought on the matter.
"My point is that people who build real pro stock engines are of the opinion that you can have too much compression for certain cam specs."
It's not like he's an idiot. He definitely know's his stuff... I'm just not sure where he's getting all this from as far as the whole dcr thing goes. Or what his reason for believing what he has read is...
Later
Chuck
"My point is that people who build real pro stock engines are of the opinion that you can have too much compression for certain cam specs."
It's not like he's an idiot. He definitely know's his stuff... I'm just not sure where he's getting all this from as far as the whole dcr thing goes. Or what his reason for believing what he has read is...
Later
Chuck
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From: Buffalo, New York
This has become a really muddy discussion, and I am not up to writing an essay (for a change). As was suggested, a search may be in order as this has been extensively discussed here in the past.
The one point I want to make strongly is to dispute the idea that CR doesn't matter. Note I didn't say "DCR", though that's the crucial thing. Static CR is one of the two major factors that determine DCR, as well as intake closing point. So they are both important. If DCR doesn't matter, than static CR doesn't either, 'cause they are directly related (all else being equal).
As to how much is enough, but not too much, other than the generalizations that Mindgame posted fore street motors, you won't find answers without be much more specific. Fuel used, engine operating temp, air density, rpm, VE, quench, etc., all will play into the equation. And I don't think most of the people here (at least not me) can give you a definite answer. I'd say stick with what's known to work, unless you have a large R&D budget!
Rich Krause
The one point I want to make strongly is to dispute the idea that CR doesn't matter. Note I didn't say "DCR", though that's the crucial thing. Static CR is one of the two major factors that determine DCR, as well as intake closing point. So they are both important. If DCR doesn't matter, than static CR doesn't either, 'cause they are directly related (all else being equal).
As to how much is enough, but not too much, other than the generalizations that Mindgame posted fore street motors, you won't find answers without be much more specific. Fuel used, engine operating temp, air density, rpm, VE, quench, etc., all will play into the equation. And I don't think most of the people here (at least not me) can give you a definite answer. I'd say stick with what's known to work, unless you have a large R&D budget!
Rich Krause
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Registered User
Joined: Jan 2002
Posts: 442
From: Houston, TX
Originally posted by rskrause
This has become a really muddy discussion, and I am not up to writing an essay (for a change). As was suggested, a search may be in order as this has been extensively discussed here in the past.
The one point I want to make strongly is to dispute the idea that CR doesn't matter. Note I didn't say "DCR", though that's the crucial thing. Static CR is one of the two major factors that determine DCR, as well as intake closing point. So they are both important. If DCR doesn't matter, than static CR doesn't either, 'cause they are directly related (all else being equal).
As to how much is enough, but not too much, other than the generalizations that Mindgame posted fore street motors, you won't find answers without be much more specific. Fuel used, engine operating temp, air density, rpm, VE, quench, etc., all will play into the equation. And I don't think most of the people here (at least not me) can give you a definite answer. I'd say stick with what's known to work, unless you have a large R&D budget!
Rich Krause
This has become a really muddy discussion, and I am not up to writing an essay (for a change). As was suggested, a search may be in order as this has been extensively discussed here in the past.
The one point I want to make strongly is to dispute the idea that CR doesn't matter. Note I didn't say "DCR", though that's the crucial thing. Static CR is one of the two major factors that determine DCR, as well as intake closing point. So they are both important. If DCR doesn't matter, than static CR doesn't either, 'cause they are directly related (all else being equal).
As to how much is enough, but not too much, other than the generalizations that Mindgame posted fore street motors, you won't find answers without be much more specific. Fuel used, engine operating temp, air density, rpm, VE, quench, etc., all will play into the equation. And I don't think most of the people here (at least not me) can give you a definite answer. I'd say stick with what's known to work, unless you have a large R&D budget!
Rich Krause
So hopefully I clarified myself good enough.We're just going to try it and see how it goes. It's a pretty well balanced setup, so if all goes well it should be a runner. I'll keep you all posted. But for now I've got the basic question/thoughts answered/confirmed that I was after...
Thanks
Chuck
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