Supercharged cam application, with all hp being equal...
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
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From: Houston Texas
Supercharged cam application, with all hp being equal...
I have discussed this with several people and of course I have gotten many different answers. If I have 2 engines, one with a stock cam and 8psi making 600hp, and a engine with a mild blower cam at 6psi making 600hp. Is there any advantage with the cam motor, and is there less stress if you will on the cam motor. Because the car is requiring less boost to make the same power, is it easier on that engine, or is it 6 one way 1/2 dozen the other?
Melting Slicks
Joined: Mar 2002
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From: Tx
Originally Posted by mdhmi
I think I remember my tuner answering that question with a question: What weighs more - a pound of steel or a pound of feathers?
Mark
Mark
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
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From: Houston Texas
Yeah, I here ya, I guess the only way that I see it can possibly help is more on the exhaust side because theoritically, it will get the exhaust gases out quicker and flow better, but on the intake side your overall compression with boost (can't remember the proper term) should still be the same.
Le Mans Master
Joined: Oct 2005
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From: Metro Detroit Michigan
Assuming peak RPM is the same, I think the blower cam motor is less stressed, except for the valve train.
The stock cam motor requires more boost, meaning that intake air temps would be higher, and more total horsepower would need to be generated for the same output, because more is lost to drive the blower at the higher pressure.
Same thing on the exhaust side. With the stock cam, higher cylinder pressure on the exhaust stroke results in increased drag, which must be overcome by burning more air/fuel.
Our power output is usually detonation limited, so an example would be that a larger cam typically allows greater RWHP on the same gas.
The stock cam motor requires more boost, meaning that intake air temps would be higher, and more total horsepower would need to be generated for the same output, because more is lost to drive the blower at the higher pressure.
Same thing on the exhaust side. With the stock cam, higher cylinder pressure on the exhaust stroke results in increased drag, which must be overcome by burning more air/fuel.
Our power output is usually detonation limited, so an example would be that a larger cam typically allows greater RWHP on the same gas.
Thread Starter
Safety Car
Joined: Aug 2004
Posts: 4,067
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From: Houston Texas
That makes perfect sense, an 8 psi engine is going to make more heat than a 6 psi engine which will reduce the risk of detonation, and I definitely agree with you on the exhaust side, the more you can get out the better, thanks for info. 
Race Director
Joined: Mar 2000
Posts: 17,602
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From: Palm City Florida
Originally Posted by mdhmi
I think I remember my tuner answering that question with a question: What weighs more - a pound of steel or a pound of feathers?
Mark
Mark
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Safety Car
Joined: Jul 2005
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From: Vancouver WA
600 HP is 600 HP. It takes a X amount of cylinder pressure to make X amount of HP. The less boost you can do it in is on your favor for sure because the motor is running more efficient.
Also a bigger cam will lower the dynamic compression ratio, which has the same effect as running lower compression pistons. .
Also a bigger cam will lower the dynamic compression ratio, which has the same effect as running lower compression pistons. .
Melting Slicks
Joined: Mar 2002
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From: Tx
Originally Posted by RED99
600 HP is 600 HP. It takes a X amount of cylinder pressure to make X amount of HP. The less boost you can do it in is on your favor for sure because the motor is running more efficient.
Also a bigger cam will lower the dynamic compression ratio, which has the same effect as running lower compression pistons. .
Also a bigger cam will lower the dynamic compression ratio, which has the same effect as running lower compression pistons. .
I think the point of the post was to ask about equal cylinder pressure. One being created with x psi and the other being created with x-2 psi, but with a more agressive cam.
Thread Starter
Safety Car
Joined: Aug 2004
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From: Houston Texas
All very good points, I think we can all agree that 600hp is 600hp, but as I felt all along is that the more boost put into a engine to make the same amount of hp has more potential danger than less psi and a nice cam to allow the engine to breathe. But as Quick duely noted in another post about stress and hp, "nothing is free" 600hp is going to strain the stock bottom end.
I think I have decided on the cam I will use, I want it to be a sleeper and keep it close to stock idle. I am not as concerned with the intake duration, more on the exhaust durations, let me know what you guys think;
LS2 engine; D-1, 7psi 218/224 .581 115 or 116 LSA
Should make about 575 - 600rwhp on a stock block, and keep good power, and torque throughout the rpm's
I think I have decided on the cam I will use, I want it to be a sleeper and keep it close to stock idle. I am not as concerned with the intake duration, more on the exhaust durations, let me know what you guys think;
LS2 engine; D-1, 7psi 218/224 .581 115 or 116 LSA
Should make about 575 - 600rwhp on a stock block, and keep good power, and torque throughout the rpm's
Advanced
Joined: Jun 2004
Posts: 92
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From: Portland OR
Also keep in mind that Timing needs to be taken out with increased boost and at lower RPMs the Camed motor should make more HP, they both peak at 600.......but the cam motor should have more under the curve.