Solving the HKS 272 Cam Timing Mystery
I am using the -4,-1 setting on my Stage 1 plus car. All I can say is my car moves, even with my high flow cat.
It feels as strong as Smogrunner's old 91 tune w/running catless.
Thanks Smoggy...
It feels as strong as Smogrunner's old 91 tune w/running catless.
Thanks Smoggy...
I'm running my 264/272 setup at -3/ -1.5 and vacuum went up from 15-16 in/hg to 19-20 in/hg, idle is smooth.
My only problem is that it sometimes stalls with A/C on. The stall only happens from a full stop when I get on and off in stop and go traffic. Any solution to this?
My only problem is that it sometimes stalls with A/C on. The stall only happens from a full stop when I get on and off in stop and go traffic. Any solution to this?
Originally Posted by Ted B
I didn't run the -2/-2, but it would tend to build torque just a shade earlier and sign off a shade earlier as well.
Also, Currently my car is custom tuned by Shiv for the -2,-2 set up. If i venture to change it to -3,-3 will my car have to be retuned or should i be fine(just wondering because since adjusting the cam just seems to shift the torque band)? Theoretically, should the -3,-3 set up pull harder down low through the 1/4 than my current set up? At what rpm does your -3,-3 set up come hit?
Do you have the hotside or the TME turbo?
Let me know.
Thanks
Originally Posted by evowilling
Did you mean that the -2,-2 set up should come on earlier and sign off earlier?
Also, Currently my car is custom tuned by Shiv for the -2,-2 set up. If i venture to change it to -3,-3 will my car have to be retuned or should i be fine(just wondering because since adjusting the cam just seems to shift the torque band)? Theoretically, should the -3,-3 set up pull harder down low through the 1/4 than my current set up? At what rpm does your -3,-3 set up come hit?
Do you have the hotside or the TME turbo?
Let me know.
Thanks
Also, Currently my car is custom tuned by Shiv for the -2,-2 set up. If i venture to change it to -3,-3 will my car have to be retuned or should i be fine(just wondering because since adjusting the cam just seems to shift the torque band)? Theoretically, should the -3,-3 set up pull harder down low through the 1/4 than my current set up? At what rpm does your -3,-3 set up come hit?
Do you have the hotside or the TME turbo?
Let me know.
Thanks
Andre is correct. The difference between -3/-3 and -2/-2 will be only slight on the dyno and indistinguishable behind the wheel.
Just to let you know however, advancing the cams brings the power in lower in the rpm range, and obviously, retarding them has the opposite effect.
Just to let you know however, advancing the cams brings the power in lower in the rpm range, and obviously, retarding them has the opposite effect.
Even if you change your cam settings to -4/-1, it won't affect your WOT tuning much. We've proven this on the dyno.
Andrew, my statement is correct Retarding the cams moves the power later in the power band. Advancing them brings it on earlier. Advancing them considerably will bring it on early enough to bring about a tendency for preignition at low rpm.
Andrew, my statement is correct Retarding the cams moves the power later in the power band. Advancing them brings it on earlier. Advancing them considerably will bring it on early enough to bring about a tendency for preignition at low rpm.
I might add that the single most important cam timing event is the point at which the intake valve closes. With the 272 set, this seems to be not much of an issue, possibly because there is enough duration under the lobe to advance the cams considerably and not see a significant loss of top end hp. If you'll recall, Joe (wherever he is) advanced his 272 cams to the +2/+2 setting, and has a powerband that begins spooling at 2500rpm and is at full boost by only 3500rpm with no apparent loss in top end power. However, he must use MeOH/H2O injection to attenuate the tendency for preignition at lower engine speeds.
