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jluetjen jluetjen is offline
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Join Date: Oct 2001
Location: Westford, MA USA
Posts: 8,596
Higher RPM = Higher HP is the "easy" way to do it. Getting more HP without increasing the RPM is the better way to do it. The F1 guys have gone in the same direction as Porsche has too, For the last few years their engines have stayed at about 19,000 peak RPM while their HP has increased (in general terms ) from just short of 900 HP up towards 950 HP. This is inspite of having longer engine lives.

In the case of Porsche, when comparing the air-cooled to the water cooled engines, they are almost "chaulk and cheese". The big improvement over the air-cooled engines are the 4-valve, penta-roofed heads. Copied from the Cosworth DFV, these heads have or allow the following benefits:
- Increased CR: More HP across the rev range, better combustion.
- As Steve said, better flow, especially at low lifts. So this also increases the flexibility and HP across the rev range.
- Increased turbulance by using the port design to cause "tumble" as the air flows into the chamber. This causes the mixture to be more consistant across the combustion chamber.
- The compact combustion chamber increases the thermal efficiency and reduces the requirement for spark advance.
'69 911E

"It's a poor craftsman who blames their tools" -- Unknown
"Any suspension -- no matter how poorly designed -- can be made to work reasonably well if you just stop it from moving." -- Colin Chapman

Last edited by jluetjen; 03-04-2006 at 03:13 PM..
Old 03-04-2006, 03:38 AM
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