View Full Version : Camshafts for turbo SR's

Leroy Peterson
05-07-2017, 02:00 PM
So there are quite a few camshaft options for FWD/AWD SR20, some being GTiR specific (requiring lash/mech heads) and some less aggressive ones being suitable for DE engines (hydraulic lifters).

Tomei, JUN, Jim Wolf Technology (JWT), Kelford, Camtech, Piper. (Clive Cams in Vic do custom grinds up to 10mm or 11mm lift too)
Most companies have street and race grinds available, and the way the specs are measured sometimes vary too.
Stock cams are supposedly - 248 duration 10mm lift

My current cams are JUN 272 duration, 11mm lift intake, 12mm lift exhaust. For GTiR, purchased through RHD Japan. Head has titanium retainers and BC springs. Engine builders were open to the idea of the staggered lift on the exhaust side due to the value size (from memory...)
Here's the dial-in sheet that came with the cams, though I was told it doesnt provide the sort of information thats usually supplied with other aftermarket camshafts. From memory, not a lot of it is useful info.


Prior to that, the motor was running Tomei 260 duration, 11mm lift cams. As far as sub-4000rpm I cant say there is much of a difference that I noticed. Both need a fairly high-idle which is annoying for road cars, but my setup has had a lot of work done so might not be as bad for others.
Lately I'm seeing more and more people opt for small(er) cams in turbo (and particularly E85) applications. The people who know what they're doing with street-driven high-hp turbo cars know the powerband for the turbo is usually over once the big cams kick in, so they pick smaller cams for better down-low and aid the turbo getting up to speed at lower rpm. Then for peak power just let the turbo do its thing (E85 obviously allows more timing and boost to get the most out of it).

My current cams aren't great to drive with, its not a pig to drive, but the high idle (noise/warm-up/touchiness with the clutch) and the lack of low-down power is getting annoying. So originally I was thinking of trying a very mild aftermarket cam from Piper (250-ish duration, 9.5mm lift) but for the money, thought might as well test out the OEM cams and see how that goes. I'm not sure how its going to behave with all the porting and valve-train work (its cant be a bad thing?) or even if it will have an affect on the turbo response. I'm curious to see what would happen, however, fitting new cams, dialling them in plus a re-tune is $$$.
Anyone have any thoughts? worth a few hundred bucks to test it out and maybe get a much nicer to drive car? (I know its a track car, but with the turbo (and torque) running out by 6500rpm, theres not need to rev further anyway).