3 replies to this topic

[postve]

Hello,

Supercharged 1293 and looking at upgrading to a different CAM to get the max torque out of the rev range - currently have a Piper 255 and looking at the following two alternatives- can someone with more knowledge shed some light on whether I would see a major difference or basically don’t waste my time? Thx for all who provide thoughts!

Kent - 286 spec

intake 34/66
exhaust 71/39
duration
inlet 280 exhaust 290
lift intake 0.315" exhaust 0.324"
lca inlet 106 exhaust 106

Swift tune - SW10 spec

intake 34/66
exhaust 70/30
duration inlet 280 exhaust 280
lift intake 0.291" exhaust 0.291" (7.39)
lca inlet 106 exhaust 110

Piper BP255K spec (I have this one)

Intake 27/63
Exhaust 64/28
Duration Inlet - 270°
Duration exhaust - 272
Valve Lift Inlet - 10.29mm (.405)
Valve Lift Exhaust - 9.88mm (.388)
LCA intake/exhaust inlet ATDC - 108°
Power Band - 1000-6000 RPM

[DeadSquare]

You can run just as hot a cam in a sooped, as an atmospherically aspirated engine, but the greater the overlap, the higher the fuel consumption.

 

Apparently, in the days of the blown Bentleys winning Le Mans, they would belt along The Hogs Back in Surrey, in the dusk, and the riding mechanic would note how far along the exhausts, they were glowing red, because too much overlap allowed unburnt fuel, to burn in the exhaust pipes..

 

It was a balance of power against fuel stops, and the cams were swapped until they found ones with the ideal opening times.

 

As with any sporting cam, other that an out and out racing cam, go for the best / broadest torque band.  Ignore peak BHP.

[postve]

Thx Dead and agree with Torque focus!

[postve]

Thx Dead and agree with Torque focus!