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Supra OG
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1,002 Posts
RSA Supra said:


It is retard exhaust 3 degrees and advance intake 1 degree not marks. Some cam gears like the HKS mark every 2 degrees, so you would end up out of whack if you move 3 marks.

These setting are what have been found to be most effective on BPU cars, obviously every car with different mod combinations will vary, so dyno tuning would help.
Ryan,

What you said is a common misconception but it is absolutely incorrect. What most people back in the day found to be a good conservative baseline (+1 i / -3 e) is actually indeed measured in MARKS. All the cam gears are marked in single cam degree increments. The confusion exists because the crank is rotating twice as fast as the cam, meaning that 1 cam degree = 2 crank degrees.

I know common cam nomenclature is in crank degrees (i.e. a 272 duration HKS cam means it is "on" for 272 crank degrees, not 272 cam degrees), but when any Supra owner mentions their cam gear settings, out of convenience we always speak in CAM degrees. Cam degrees are exactly what the marks on the cam gear tell you.

When I originally installed my cam gears, I tried +1 marks intake and -3 marks exhaust. (Same as 1 cam degree of intake cam timing advance and 3 cam degrees of exhaust cam timing retard). I then dyno tuned and gained the most power at +1 marks intake and -4.5 marks exhaust, which is how my cam gears are set now.

Regards,
Andi
 

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Supra OG
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1,002 Posts
I gained 13rwhp at +1/-4.5 marks = cam degrees compared to 0/0 (stock).

Does your HKS cam gear say "each mark = 2 degrees crank" like all the other cam gears (UR/AEM/etc) or does it just say "each mark = 2 degrees"?

Either way, I'd still bet that each mark is 2 degrees CRANK. Since cam timing nomenclature is usually in crank degrees..... It's just us dumb Supra folk ;) that made up the +1/-3 stuff in cam degrees instead...... but we did that because the dumb folk that make cam gears ;) put a mark every cam degree. They should have put a mark every crank degree and it would've been a lot simpler.

Let me reiterate... I have my cam gears set to +1 CAM degree intake and -4.5 CAM degrees exhaust. This is equivalent to +1 marks intake and -4.5 marks exhaust (unorthodox racing cam gears). This is equivalent to +2 crank degrees intake and -9 crank degrees exhaust.

This is how I gained the most power (+13rwhp compared to 0/0).

Regards,
Andi
 

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Supra OG
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1,002 Posts
Supra93TT said:
Thanks for the replies everyone. Judging by Andi's dynotuning,
-4.5 marks exhaust, and +1 intake may be the best. If i remember correctly, Andi is full BPU which I am close to so I think I will try these settings.


I'm confused what Ryan said here?

----- what ryan said:
So what you're saying is that it is indeed supposed to be minus
3 marks, or 6 cam degrees, and by your settings it would be
minus 4.5 marks.

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Is minus 3 marks really 6 cam degrees? or is it just 3 degrees. which is still 6 crank degrees? Ryan, did you mean to type 6 crank degrees in this statement? I just want to be sure of everything 100% before i install my cam gears.

Thanks,
Zach
Ryan did screw up there. What he meant was 3 marks, or 6 crank degrees.. or by my settings, 4.5 marks, or 4.5 cam degrees, or 9 crank degrees.

Andi
 
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