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Thread: Peak timing for "BIG" Cams

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Posts: 1-10 of 20
2012-07-16 18:32:17
#1
Peak timing for "BIG" Cams
When i went from a 91 intake cam to BC2 cams i didnt change the timing much. Never been on the dyno either.. I was running a peak timing of about 40 or 41 deg... Its felt good on the butt dyno lol..

Well now i have BC3 cams and springs

Just wondering what some of you guys are running for peak timing with big cams like BC3/JWT C2 or bigger etc...?

I have my current peak/Max timing at about 34 deg right now.

Im up to posting/sharing some timing maps here.
Last edited by Haulin200sx on 2012-07-22 at 21-10-43.
2012-07-16 21:16:41
#2
I'd like to see your timing maps for the BC2 cams!
2012-07-16 22:27:30
#3
What CR its your Motor??
40-41 its wayyy too much
Maybe 30-32 if you are 10:1 on 93 US octane
On what fuel octane??
2012-07-16 22:28:42
#4
By peak timing, you mean torque peak right?

30 degrees is max I'd go on stock cams at torque peak and that is pushing it on 93 octane. Keep in mind with higher flowing cams, you need/want less timing at torque peak. And your torque peak will move to higher RPM. I'd start around 26 degrees BTDC at torque peak and work from there.
Last edited by BenFenner on 2012-07-16 at 22-33-04.
2012-07-16 23:48:50
#5
hopefully his mechanical timing was retarded and in reality he was running like 32* max lol.
2012-07-16 23:54:36
#6
I ment, like whats the max timing that you guys are running ie 6,400rpm and above.

Ben, and this talk of peak torque timing. Do you mean what is my timing at peak torque? I've never been on the dyno but i assume your asking my timing around 4,000 to 5,000rpm (where peak torque should occur if im not mistaken).

My fuel is just supreme which is 91 octane here on the east coast
2012-07-18 22:38:48
#7
Here are the 2 timing tables:

The first table i used to use when i had just a 91' intake cam and then BC2 cams.

The second table (lower timing) is the table i am currently using with my BC3 cams.

feedback more than welcome!
Last edited by Haulin200sx on 2012-07-22 at 22-11-03.
2012-07-22 21:08:50
#8
.....
Last edited by Haulin200sx on 2013-06-29 at 23-13-31.
2012-07-22 21:27:54
#9
Is this general rule of big cams or big displacement motors true:

That they like less timing? If so just a bit less or a lot less?

In the WOT range of the table (last 2 columns),
should the timing rise slowly and then jump to meet the max/peak timing? (lower timing in the low to mid range)

OR

should it rise rapidly and smoothly to the max/peak timing (more timing in the low to mid range)
Last edited by Haulin200sx on 2012-07-23 at 00-48-06.
2012-08-06 21:43:49
#10
anyone else want to help out or share their timing map for a all motor de?

I have come up with a 3rd revision of the timing map that seems to work well. I will post it later tonight...

I think im close to what i need with a max timing of about 32deg.........

Just wondering how long i should hold it at around 32deg? only from around 5,000rpm and up or should i hold 32 deg from a lower rpm like 3-4,000rpm?

From posts ive found here on the forum it seems like a all motor de, likes just a bit over stock timing below 5K and about 32deg from 5K to the limiter.
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