setting digital ignition curve

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mbaird

mbaird

mbaird
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I just ordered a Daytona CD=1 ignition and plan on locking out the distributor and setting the curve via laptop.
I get how it will mimmick the mechanical advance but how do I compensate for vacuum advance ?
Are there sensors available for a carb'd car that will read vacuum ?
 
I have used MSD's and they did not have a vacuum circuit. Used a total advance 32-36 degrees all in by 3000 rpm. With this Dart I am using a Fast, with a Fast distributor. It used a 20 degree BTD initial and a total of 34 degrees at 3000 rpm.
 
The reason I ask is because I see reference to a 3D map and MAS . I wasnt sure if there was some way of sensing vacuum or load that I was unaware of.
I guess I will just have to tune the vacuum circuit the old fashion way.
 
Sorry I am not familiar with what you are using, I have no experience Daytona. With the MAS is for EFI system, Good Luck
 
I see they have a 1 bar MAP sensor and harness for NA engines. I am not familiar with their systems at all, but it “seems” you could use it and set up the timing map to add timing at certain vacuum/rpm points. This would be dependent on the system capabilities. I would contact them and discuss if it’s possible to do.
 
I looked at their website. They have a plot of a timing map. If you look at the green part the front is at high MAP, that happens at wide open throttle. The rear is under light load or coast. It shows vacuum advance does about 10 degrees of advance. The advance decreases with MAP voltage. Typical normally aspirated engines use 1 bar sensors. Boosted engines use 2 to 3 bar. 1 bar is about 14.7 psi at sea level. MAP sensors read absolute pressure. If you are familiar with vacuum readings of inches of mercury (hg), it is necessary to re calibrate your thinking.
On the left looks like timing is mainly locked down at lower RPMs. Starting at 2000, timing increases, then holds after 4000. A real timing map has much more detail, if time is spent making the engine run best for all RPM, and MAP/load conditions.
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You need to connect an intake vacuum tube to the ECU.
If the ECU doesn't have a port for this you probably need to buy a separate MAP-sensor.

Is this a race only unit/setup?
How will you be using this setup? For street-use you really need a MAP (vacuum-input) into the ECU otherwise it serves no purpose going digital.
 
Thanks... thats the kind of info I was looking for.
Where do I install the MAP sensor on a carburated engine ?
Obviously I need to do some more research.
 
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