4agze Cams?

[briigo82]

Lads

Ive been contemplating lately a few cool mods I can do to my daily driven smallport gze. Atm its running a factory cooler, pulley and factory ecu. Only mods are a 20v headers and the abv mod.

Ive got a set of 270* 8.1mm lift cams lying around not doing anything and was thinking how cool ot would be to have big cams again but is there any advantage in running cams of this size or not? Would bigport cams be better suited to it?

And I am planning on changing to a fmic and a nevo pully as well. (have both ready to go)

Discuss

[Jimmee1990]

I would say the cams would definitely help, more so with the better cooler and more boost. 270 degree with 8.1mm lift is perfectly fine on my n/a daily (even gets better fuel economy than before) so I can't see them having any negative effects combined with the supercharger.

Definitely not an expert with supercharged engines however.

[jaz_ae86]

If you have a way of monitoring inlet temp then it may be worth while but I doubt it.

The supercharger is positive displacement pump, giving fixed volume of air per revolution. It produces more air than the motor can consume thus creating postive pressure in the inlet manifold. That is, boost pressure is generally measured in the inlet manifold, so you are measing the backpressure of the supplied air to that which can pass through.

Going larger cams will allow more air to pass through the motor, unless you adjust the cam timing to minimise overlap but you will lose what your trying to gain.

For a turbo motor it is automatically compensated via the wastegate, but for a supercharged motor it simply means less manifold pressure. Cleaner combustion due to additional scavange doubtful to make up for the short fall.

This is a theoretical reason and I am happy to be proven wrong. If you had 256's I'd say go for gold, 264 worth a try, 272 please prove me wrong but I would be monitoring inlet air temp as a measure of how hard the supercharger is working.

[Jacobxxx]

I'd change pulley before doing cams

14psi is your friend