i have 264i/272e hks cams with vishnu cam gears set at -2/-2, and i have some questions...

can someone explain the reasoning behind this cam choice and cam gear setting?

what happens if you advance the cams? 0/0, +2/+2, etc.

if you advance the cams does that mean that you have to pull out more timing?



i bought this car the way it is setup right now and vishnu did all the work and tuning...the car runs great the way it sits, but i am just trying to get a handle on why it is setup the way it is, along with how the car was tuned...

thanks for any input...

 

Bump for some help

 

so from what i have been reading, the only thing that advancing or retarding the cams will do is move the powerband around, is this right?

 

For the most part yes. The reason the settings are -2-2 is because that is the best all around tried n tested setting for that particular setup as the end result is a broad powerband. The reason for the cam choice is that the 264/272 setup has generally yielded the most streetable setup in terms of 'driving comfort.' It provides awesome power, without the crazy lumpy idle like some cams.

 

This is just a snapshot of the way the cams gears work.
For example using the the formula Hp= tq x rpm/5252 if we shift the power band
(TQ=300) 200 rpm we get:

300tq x 5000rpm/5252 = 285.6
300tq x 5200rpm/5252 = 297

Even though there is a small increase, the formula does not portray the whole story. If cams are advanced or retarded too much there may be a power loss in the upper, lower or even the whole rpm range.

 

cam timing will also play an important role in cylinder pressures, and knock deterrance.