Which Cams

[JeffersonC]

Getting the engine together and trying to decide on which cams. Bottom end is all built and the head has some mild port work. Using Apexi twin turbos.

Tomei 260/9.15

HKS 264/8.70

Kelford 282/8.95

[Skym]

Ask engine builder to send turbo, engine specs, head flow data, etc to these people and they can suggest (for a small fee) the cam specs to suit turbo, engine, etc -

https://www.capella.co.nz/sites/kelford.co.nz/design-shop/

Tomei Poncams are for stock head, stock ports, stock valves, stock to N1 size turbo's (also HKS 25/30 turbo's and Garrett equivalent) on stock exhaust manifold while using stock intake manifold, stock cam gears.

Tend to get more hp throughout powerband with the Tomei Procams, but needs more Tomei products to go with the Tomei Procams (lifters, valve springs, etc).

More aggressive the cam specs with duration, lift, the more hp, torque you get at mid to high rpm vs loss in bottomend, so think about application of the car (street, racetrack, dragracing, etc). Also valve train components can wear out quicker (usually race engine only).

[Dragon Humper]

My cams are dinky. Usually, the bigger the turbos the smaller the cams can be. When smaller turbos are working harder you want to free up some pressure to control heat. Big turbos don't heat up the air much so smaller cams can make big power without a big heaping of extra turbo lag the big cams would produce.

I like the Kelfords (the 182B with 234 deg of duration at 1mm), decent duration without huge lift to make the valve springs last longer. Should keep the motor very responsive too.



Jon.

[caliber676]

Dragon humper, would you suggest a poncam vs procam for a twinscroll BW s300sx fmw setup? I have a 270 duration, 10.25mm procam but was thinking of going smaller procam for cost and ease of install

[JeffersonC]

Did you open up the spring pockets for the Kelford cams?