Digital ignition curve input

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mbaird

mbaird
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I am at taking the plunge into the world of digital ignition and would like some input on what my curve should look like.

The ignition is a Daytona Sensors CD-2 .

The engine is a 408
Cam = 246/250 -108 - .648 lift solid roller
Heads are W2 Race closed chamber ( Polished and ported) and .036 Quench
Intake is a Victor W2
Carb is a Pro Systems custom 850+ Cfm DP
TTI. ...1 7/8 to full 3 " exhaust

Dart Swinger 4 sp. 3.55s for street...3.91 + for the track.
 
Sorry... got waylayed for a bit.

My distributor is locked using a 4secflat plate . I figure I will set my initial low for ease of starting and use the digital curve to advance just off idle.

My son will have to interface the laptop to it because I am totally inept at anything computor related...lol
 
IDK,
but I can tell you this;
at 850 rpm with a 2.66 low gear and 3.55s and 29" tires; your slowest speed without riding the clutch is ~7.8mph. With 22* idle-timing and say 185psi cylinder pressure(aluminum heads) or 165psi (iron), she will be real jumpy down there, if you try to drive slower. So with a digital, I would start pulling timing fast, about 50 rpm below idle before it twists the driveshaft off,lol.
I ran a DC 292/292/108 in my 367 at 185psi, which IIRC I measured at [email protected];I too ran 3.55s, the 2.66low, but with 28s; Hyup real jumpy. At 5* it was tame enough, and came down to 600rpm, but the 750DP had to be set right on. Any lower than 600, needed some toe on the clutch.
Yeah I ran that combo with a 10.5 PV too. Like YR (I think it was) said; the PV discharges thru the boosters. With the throttle closed, the mains are dead so you can run any PV you dern well want to. I just happen to like the 10.5 in my combo, with one jet size smaller than "normal"; ON THE STREET.

Also, on the street and with a 4 speed, I found it very easy to run too much advance; or rather to run advance than might be considered normal for an automatic. The engine just got too doggone eager, always pulling on the reins. By delaying the timing just a few degrees the pressure spikes occur with the piston a lil further down the bores, and the pressure is easier on the tires,lol. So......., that won't impress your back-seat-buddies none, but it sure became easier to drive at Part Throttle below 3000 rpm/26mph in first gear. To get the timing back for cruising, I just modded my Vcan to get up to 22/24*. For you, with a map sensor, you can do anything.
 
My tires are 28" 255/60-15 SS Drag Radials... You may be right about 3.55s being jumpy in which case I will go with 3.91s
With a digital curve I can drop the advance just off idle and bring it back in around 1600 rpms.
3.55s will net me 7.94 mph @ 900 rpms

I was told MAP sensors arent real accurate at measuring Vacuum and that I should just tune my pod on the distributor.
 
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If Map sensors dont read vacuum well how do the aftermarket FI system work? Is it the TPS ?
 
Probably Speed Density or preprogrammed below a set point.... IDK.
But if you're keeping the V-can,you may have your hands full, cuz it doesn't work well either at low vacuum.......
 
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