Stage 2 blower cams on an N/A car
11-27-2007, 11:41 PM
#1
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Stage 2 blower cams on an N/A car
Ok since I am getting cams and I can't decide what I wanna get, will I make good power if I put in a set of stage 2 blower cams and run it on an N/A car and get a supercharger maybe 2 years down the road when I am done school? My motor is being built and the final compression is going to be up somewhere around 10.1:1 with forged pistons and forged rods.
11-28-2007, 06:28 AM
#3
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RE: Stage 2 blower cams on an N/A car
10:1 is not too high for boost, just too high for 10lbs and a bad tune. If it's tuned right you'll be fine. And make sure you buy a good MAF, like the SCT or be in fear of peging it on a cold night. Doughboy46 did it last summer right after we built his forged motor.
11-28-2007, 01:21 PM
#6
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RE: Stage 2 blower cams on an N/A car
Ill tell you what.. Since Im such a good person, Ill make a deal with you. Buy the cams and have them shipped to my house.. Ill put them in my motor, dyno it, and then get you the results.. That way you will know what kind of power gains you'll get. Then you can just order you a set. How about it?
11-28-2007, 03:40 PM
#7
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RE: Stage 2 blower cams on an N/A car
No they will not make good power. NA cams and blower cams are very different. The biggest difference is the LSA (overlap). Overlap is used on a NA motor for scavanging, the rush of fresh air into the cylinder forces the spent gasses out of the exhaust valve. On a blower motor the overlap is much smaller because you will lose boost if the exhaust valve stays open as long as on a NA engine. Another draw back is that on a blower cam the intake valve doesnt stay open as long as it does on a NA cam. With a blower the air is forced in which is why it doesnt have to stay open as long, NA it is drawn in buy the piston traveling to the bottom of the cylinder.
So bottom line you won't have as much fresh air/fuel mix in the combustion chamber with a blower cam as you would with a NA cam which is why you wont make good power. Don't get me wrong you will get a power increase because of the lift of the cam is higher it just wont be as good as it could be.
So bottom line you won't have as much fresh air/fuel mix in the combustion chamber with a blower cam as you would with a NA cam which is why you wont make good power. Don't get me wrong you will get a power increase because of the lift of the cam is higher it just wont be as good as it could be.
11-28-2007, 03:44 PM
#8
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RE: Stage 2 blower cams on an N/A car
ORIGINAL: oxfordgt
No they will not make good power. NA cams and blower cams are very different. The biggest difference is the LSA (overlap). Overlap is used on a NA motor for scavanging, the rush of fresh air into the cylinder forces the spent gasses out of the exhaust valve. On a blower motor the overlap is much smaller because you will lose boost if the exhaust valve stays open as long as on a NA engine. Another draw back is that on a blower cam the intake valve doesnt stay open as long as it does on a NA cam. With a blower the air is forced in which is why it doesnt have to stay open as long, NA it is drawn in buy the piston traveling to the bottom of the cylinder.
So bottom line you won't have as much fresh air/fuel mix in the combustion chamber with a blower cam as you would with a NA cam which is why you wont make good power. Don't get me wrong you will get a power increase because of the lift of the cam is higher it just wont be as good as it could be.
No they will not make good power. NA cams and blower cams are very different. The biggest difference is the LSA (overlap). Overlap is used on a NA motor for scavanging, the rush of fresh air into the cylinder forces the spent gasses out of the exhaust valve. On a blower motor the overlap is much smaller because you will lose boost if the exhaust valve stays open as long as on a NA engine. Another draw back is that on a blower cam the intake valve doesnt stay open as long as it does on a NA cam. With a blower the air is forced in which is why it doesnt have to stay open as long, NA it is drawn in buy the piston traveling to the bottom of the cylinder.
So bottom line you won't have as much fresh air/fuel mix in the combustion chamber with a blower cam as you would with a NA cam which is why you wont make good power. Don't get me wrong you will get a power increase because of the lift of the cam is higher it just wont be as good as it could be.
BUT... If he is for sure getting a supercharger down the road then there is no reason in buying and installing 2 different sets of cams.
11-28-2007, 03:45 PM
#9
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RE: Stage 2 blower cams on an N/A car
Ok screw it, I'll just get n/a cams. Thanks guys. If I do decide to go FI when I am done school I will just swap them out 2 years from now.
11-28-2007, 03:51 PM
#10
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RE: Stage 2 blower cams on an N/A car
Oh and on the 10.1:1 compression is great for boost just not for a street car running pump gas. But if you can run race fuel all the time (at like $9 a gallon) then right on.
You need to talk to your engine builder if you really plan on going FI down the road so he sets your engine up right. He will more than likely set your ring gaps up to stock specs which isnt great for FI. Stock is .004 X bore size for the top ring and .005 x bore size for the bottom ring. For FI you want the top ring to be .006-.007 x bore size and the bottom ring to be .0063-.0073 x the bore size. The oil ring should always be at .015 regardless of what the motor is used for. This is to make up for the heat created by the FI which will expand the rings.
You need to talk to your engine builder if you really plan on going FI down the road so he sets your engine up right. He will more than likely set your ring gaps up to stock specs which isnt great for FI. Stock is .004 X bore size for the top ring and .005 x bore size for the bottom ring. For FI you want the top ring to be .006-.007 x bore size and the bottom ring to be .0063-.0073 x the bore size. The oil ring should always be at .015 regardless of what the motor is used for. This is to make up for the heat created by the FI which will expand the rings.