850-900. I haven't found I've needed to back the idle screws out.
Timing curve mystery
- Thread starter mbaird
- Start date
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Lol, yes the similarities stack! I too have a 4 speed, a W2 dual plane, and a Pro Dominator tunnel ram. I think I am going to try the Pro Dominator with 2 650 AVS 2 carbs.
How did that dual plane work out ?
Never got to it, like many things in life, plans bigger than time to do them. It will happen at some point.
Totally awesome! Can you show the linkage on the tunnel ram please?
Awesome, thanks!
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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- Jan 19, 2014
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I know this may not help you at all. but here goes anyway.
My first combo was an 11/1 367 with alloy heads, and the 292/292/108 cam.
I run a manual trans and 3.55s in a 3650 car with me in it.
With a modest T-port exposure, and a small amount of Idle-Bypass Air that engine liked mid to high 20s for idle timing. But was undriveable at low roadspeeds with that stinking 2.66 low gear. Eventually, I got her down to under 600rpm in low gear pulling herself on hard flat level pavement, at the same modest T-slot, but with the Idle-timing at just 5*. But it was a lil lazy coming up off that 5*.
>The lowest Idle-timing it liked was 18*. But she would put up with as little as 12* ..I choose 14* as the base line.
>For power-timing, my data logger showed no better performance at 36* than at 32* so my Power-Timing was chosen to be 32 to 34.
>I was running 87E10, so I arbitrarily targeted All-in no sooner than 3400rpm.
Then I just had to connect the dots, and make sure to not run into detonation.
After weeks and months of dinking around; I pulled the springs out of an old 318 and slammed them in there. One of the springs in this set had one long loop that stopped the soft one at ~2800, and then together, those two slowly crept up to the all-in at 3200 to 3400; close enough for me..
>So that left the idle to 2800. After firing 3 or 4 different springs at it, I found a really soft one that started advancing at about 900/1000rpm and I was finally done.
so to recap then, this is what that combo liked;
A two-stage curve, beginning at 1000 and rapidly advancing to 28* by 2800; then slowly proceeding to 32/34 by 3200/3400. This, to burn 87E10 at WOT with full Power-Timing and no detonation, at a DCR of 8.9@sealevel. She pumped over 190psi on my gauge.
>To get down to 5*@idle, I installed a dash-mounted, dial-back, spark box; and just cranked it back until she wants to stall.
>I got rid of that 2.66low-gear box in favor of an A833od box with it's 3.09low. My slowest driveable speed was then 4.0mph/ a fast walk. And no jumpiness from that cam/combo. I found that I could toe the clutch, down to 3.5mph, on occasion.
> But that box was horrible for use with 3.55s, But I used it to prove what I needed to do which was to get rid of the 3.55s............ which then led to 4.30s
yadayadayada....... By fall, less than a year of debue, that cam was outta there.
Just hoping to help.
My first combo was an 11/1 367 with alloy heads, and the 292/292/108 cam.
I run a manual trans and 3.55s in a 3650 car with me in it.
With a modest T-port exposure, and a small amount of Idle-Bypass Air that engine liked mid to high 20s for idle timing. But was undriveable at low roadspeeds with that stinking 2.66 low gear. Eventually, I got her down to under 600rpm in low gear pulling herself on hard flat level pavement, at the same modest T-slot, but with the Idle-timing at just 5*. But it was a lil lazy coming up off that 5*.
>The lowest Idle-timing it liked was 18*. But she would put up with as little as 12* ..I choose 14* as the base line.
>For power-timing, my data logger showed no better performance at 36* than at 32* so my Power-Timing was chosen to be 32 to 34.
>I was running 87E10, so I arbitrarily targeted All-in no sooner than 3400rpm.
Then I just had to connect the dots, and make sure to not run into detonation.
After weeks and months of dinking around; I pulled the springs out of an old 318 and slammed them in there. One of the springs in this set had one long loop that stopped the soft one at ~2800, and then together, those two slowly crept up to the all-in at 3200 to 3400; close enough for me..
>So that left the idle to 2800. After firing 3 or 4 different springs at it, I found a really soft one that started advancing at about 900/1000rpm and I was finally done.
so to recap then, this is what that combo liked;
A two-stage curve, beginning at 1000 and rapidly advancing to 28* by 2800; then slowly proceeding to 32/34 by 3200/3400. This, to burn 87E10 at WOT with full Power-Timing and no detonation, at a DCR of 8.9@sealevel. She pumped over 190psi on my gauge.
>To get down to 5*@idle, I installed a dash-mounted, dial-back, spark box; and just cranked it back until she wants to stall.
>I got rid of that 2.66low-gear box in favor of an A833od box with it's 3.09low. My slowest driveable speed was then 4.0mph/ a fast walk. And no jumpiness from that cam/combo. I found that I could toe the clutch, down to 3.5mph, on occasion.
> But that box was horrible for use with 3.55s, But I used it to prove what I needed to do which was to get rid of the 3.55s............ which then led to 4.30s
yadayadayada....... By fall, less than a year of debue, that cam was outta there.
Just hoping to help.
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