D1SC boost question
Thread Starter
Melting Slicks
Joined: Nov 2005
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From: Odenton MD
D1SC boost question
How effecient is the D1SC head unit in a low boost application. For example, 5.0 PSI on a 427??
In this case, the head unit might be spinning only 43,000 to 45,000 RPMs.
In this case, the head unit might be spinning only 43,000 to 45,000 RPMs.
Last edited by WeaponsGradeTorque; Jul 28, 2007 at 05:05 PM.
Safety Car
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From: waterloo ontario
St. Jude Donor '08
The D1 is a very effecient unit right up to redline-it will be hard to put a number on boost until you have it on your car-so many factors like cam, heads come into play.
Thread Starter
Melting Slicks
Joined: Nov 2005
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From: Odenton MD
Good. Right now I have a P1SC. I want to switch over to the D1SC (because i can get a good deal on one). I plan on running 5.0 - 6.0 PSI and want to make sure I won't lose any power.
Thread Starter
Melting Slicks
Joined: Nov 2005
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From: Odenton MD
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Joined: Jul 2003
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From: http://www.mphparts.com 800-364-1975
Interested in what kind of efficiency you see in practice at that level vs. a P1SC.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
Melting Slicks
Joined: Apr 2005
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From: Chicagoland Area IL
Interested in what kind of efficiency you see in practice at that level vs. a P1SC.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
Mike
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,165
Likes: 26
From: Odenton MD
Interested in what kind of efficiency you see in practice at that level vs. a P1SC.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
I noticed the Procharger C6 Z06 kits use a P1SC-1, most of them only going to 6psi. So I am wondering if it is expense or other reasons driving them to put a P1SC instead of a D1SC on a 427.
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Thread Starter
Melting Slicks
Joined: Nov 2005
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From: Odenton MD
Are you agreeing that the D1SC might not be efficient at lower boost pressure ratios? (i.e. boost 5-6 on an LS7?) Love to hear your opinion on this.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
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From: Chicagoland Area IL
Most look at max RPM of blower but when you look at say vortech's maps you can see that max RPM efficiency is not that great.
The D1SC will be operating closer to efficiency sweet spot but definitely not in it. Poor efficiency adds up in both heat and parasitic loading, or you have to shed more heat and your pulling more power from crank.
As far as LS7 kit from Procharger with P1SC, I'd suspect they want upgrade $$$ to D1SC or they get you later with upgrade (win, win). Or it can be self governing in terms of it can't put out much past that.
I think D1SC will get you better results then P1SC even at your boost numbers. There is a considerable difference between stock cube LS1/6 and LS7 in terms of mass flow demand (at least 25%). Just look at when people run out of blower on LS1/6 with P1SC... Also P1SC is probably done at about 900 CFM speaking from a efficiency standpoint.
Without compressor maps it's just speculation on both our parts...
Mike
EDIT --- Got same color C6 but not Z06. Can you get a good deal on F1A?
Last edited by Skunkworks; Jul 29, 2007 at 09:38 PM.
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From: http://www.mphparts.com 800-364-1975
WRT running a D1SC on lower boost apps, if you are out of an ideal location on the island with that head unit and low boost -- a restrictor might be appropriate. The smaller pulley size/restrictor combo would push you closor to where you want to be at lower RPMs while keeping you from going off the deep end at upper RPMs.
Amazing how something so simple as a restrictor plate -- which was largely unbeknownst to the C5 FI community only 1.5 to 2 years ago -- bears so much utility when it comes to C5 FI today.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
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From: Chicagoland Area IL
I think you are right on this one Mike.
WRT running a D1SC on lower boost apps, if you are out of an ideal location on the island with that head unit and low boost -- a restrictor might be appropriate. The smaller pulley size/restrictor combo would push you closor to where you want to be at lower RPMs while keeping you from going off the deep end at upper RPMs.
Amazing how something so simple as a restrictor plate -- which was largely unbeknownst to the C5 FI community only 1.5 to 2 years ago -- bears so much utility when it comes to C5 FI today.
WRT running a D1SC on lower boost apps, if you are out of an ideal location on the island with that head unit and low boost -- a restrictor might be appropriate. The smaller pulley size/restrictor combo would push you closor to where you want to be at lower RPMs while keeping you from going off the deep end at upper RPMs.
Amazing how something so simple as a restrictor plate -- which was largely unbeknownst to the C5 FI community only 1.5 to 2 years ago -- bears so much utility when it comes to C5 FI today.
Not trying to hijack a thread, so I'm out.
Mike
Thread Starter
Melting Slicks
Joined: Nov 2005
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From: Odenton MD
I would think your better off with D1SC... you'll be operating at better efficiency then P1SC.
Most look at max RPM of blower but when you look at say vortech's maps you can see that max RPM efficiency is not that great.
The D1SC will be operating closer to efficiency sweet spot but definitely not in it. Poor efficiency adds up in both heat and parasitic loading, or you have to shed more heat and your pulling more power from crank.
As far as LS7 kit from Procharger with P1SC, I'd suspect they want upgrade $$$ to D1SC or they get you later with upgrade (win, win). Or it can be self governing in terms of it can't put out much past that.
I think D1SC will get you better results then P1SC even at your boost numbers. There is a considerable difference between stock cube LS1/6 and LS7 in terms of mass flow demand (at least 25%). Just look at when people run out of blower on LS1/6 with P1SC... Also P1SC is probably done at about 900 CFM speaking from a efficiency standpoint.
Without compressor maps it's just speculation on both our parts...
Mike
EDIT --- Got same color C6 but not Z06. Can you get a good deal on F1A?
Most look at max RPM of blower but when you look at say vortech's maps you can see that max RPM efficiency is not that great.
The D1SC will be operating closer to efficiency sweet spot but definitely not in it. Poor efficiency adds up in both heat and parasitic loading, or you have to shed more heat and your pulling more power from crank.
As far as LS7 kit from Procharger with P1SC, I'd suspect they want upgrade $$$ to D1SC or they get you later with upgrade (win, win). Or it can be self governing in terms of it can't put out much past that.
I think D1SC will get you better results then P1SC even at your boost numbers. There is a considerable difference between stock cube LS1/6 and LS7 in terms of mass flow demand (at least 25%). Just look at when people run out of blower on LS1/6 with P1SC... Also P1SC is probably done at about 900 CFM speaking from a efficiency standpoint.
Without compressor maps it's just speculation on both our parts...
Mike
EDIT --- Got same color C6 but not Z06. Can you get a good deal on F1A?
Mike,
Thanks for the input. All of your points certainly make sense. At the time of purchase, upgrading was only like $200
I am going to move forward with this experiment. I'll keep you guys posted. Maybe I should think about the F1 instead of the D1 while I am at it!!
p.s. And Lemans Blue is a great color!
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From: http://www.mphparts.com 800-364-1975
Would be interested in seeing the parametric study -- if restrictors kill efficiency more at low end instead of high end that would go against everything we know about restrictors in practice and why they are used. Not saying it doesn't happen on paper, but it just seems there are so many examples of dropping pulley size, adding restrictor, gaining low end, and softening top end. If the OP feels this is a hijack I apologize, I thought it was relevant to the question at hand.
WeaponsGradeTorque, regarding the nose dive at 6400RPM -- that may be belt slip, or like you said, it could just be the limits of the blower. I don't recall seeing any 700rwhp dyno graphs from a P series so I am leaning towards efficiency.
WeaponsGradeTorque, regarding the nose dive at 6400RPM -- that may be belt slip, or like you said, it could just be the limits of the blower. I don't recall seeing any 700rwhp dyno graphs from a P series so I am leaning towards efficiency.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
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From: Chicagoland Area IL
Would be interested in seeing the parametric study -- if restrictors kill efficiency more at low end instead of high end that would go against everything we know about restrictors in practice and why they are used. Not saying it doesn't happen on paper, but it just seems there are so many examples of dropping pulley size, adding restrictor, gaining low end, and softening top end. If the OP feels this is a hijack I apologize, I thought it was relevant to the question at hand.
Remember you have two exponential curves (restrictor and supercharger). The part that is hard to factor in on paper is how the compressor reacts at low RPM when it just starts to flow well. The restrictor allows you to push more RPM (blower) thus getting it to flow better faster.
If you want I can dig up my old calculations.
Mike
Last edited by Skunkworks; Jul 30, 2007 at 04:12 PM.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Mike,
Thanks for the input. All of your points certainly make sense. At the time of purchase, upgrading was only like $200
I am going to move forward with this experiment. I'll keep you guys posted. Maybe I should think about the F1 instead of the D1 while I am at it!!
p.s. And Lemans Blue is a great color!
Thanks for the input. All of your points certainly make sense. At the time of purchase, upgrading was only like $200
I am going to move forward with this experiment. I'll keep you guys posted. Maybe I should think about the F1 instead of the D1 while I am at it!!
p.s. And Lemans Blue is a great color!
Mike
