07-03-2014, 06:28 PM
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CC Member
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Join Date: May 2006
Location: St. Louisville,
Oh
Cobra Make, Engine: A&C 67 427 cobra SB
Posts: 2,444
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Not Ranked
First decide if you want a centrifugal or positive displacement blower. The positive displacement will give you much more low end torque. Torque can be pretty much a straight level line over a wide rpm range. The centrifugal will give almost no boost at low RPM and it will steadily climb as RPMs increase, which gives a torque curve that looks like a mountain.
In my opinion, trying to run a centrifugal blower in an auto-cross, would suck. At every turn you would have a different amount of torque available. I depends a lot on what you intend to use if for.
Then choose a cam based on the blower and how you intend to use it. When you can get the power with more boost, you do not need to go so radical on the cam. Since you are going to stay with EFI, keep in mind that a lot of overlap on the cam will let un-burned fuel/air into the exhaust and cause the O2 sensor to falsely see a lean condition.
You may need to keep the compression lower to allow the boost you need to make the power you want. I know higher boosted engines typically keep the compression down around 8:1, with an after cooler.
I did see quite a few blower and turbo cars at the London car show this year. More than I have seen in the past. Maybe some can chime in.
Hope that helps and good luck.
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