FAST --- Crank ref. angles

[Chuck Leeper]

Craig-Lance, Anyone, I'm Looking at a program on a V-6 BUICK turbo for someone and see that 2 of the previously installed programs show the crank reference angle being set to 7*. The "bible", and the "demo" program say DIS on a BUICK is to be at 10*. [None of the 6 listed applications show 7 as a value to be used]
The questions are:
1. Will this affect the tuning and how?
2. Is this setting something that should/could be changed to enhance the performance?
3. If it's acceptable to do this, what are the limits?

back to lookin'

 

[Glen]

Crank Reference Angle is similar to initial timing. The Buick V6 uses 10*. This is a setting for the ECM to use to figure total timing. In the FAST ECU, it works much the same way. At any given load/rpm point, you have a timing figure, inputed by the user. So, if you want 20* at 2000 RPM, with the CRA @10* the ECU will give 10* for a total of 20*. Any time the CRA is changed, the ECU will either + or - from your desired total timing . With the Buick, or any crank triggered ignition, it is best to leave the CRA @ the factory setting.

 

[Chuck Leeper]

CRA

Thanx for the input, Glen. That is the way I understand it too. I'm wondering why there are folks using other values. It would not make sense to me unless they wanted to change the entire timing map w/out making a forced change or changing each cell.

I'm going to put it back to the recommended value of 10* and go from there, unless I get some other input and logic as why not to.

ANYONE????

 

[HighPSI]

NEVER just set it at 10 without checking the timing. If you are using a BHJ balancer it will be closer to a CRA of 6. You really need to bring the rpms up and compare the timing map with the actual timing, then adjust the CRA appropriately.
A good analogy would be degreeing a cam vs just aligning the timing gear dots.

 

[Chuck Leeper]

CRA

THANX, Cal!! That's what I did on mine and when I saw 2 other setups, both at 7*, that got me to wondering.... Neither of the setups had been done "on the car". They were "written" elsewhere and then loaded into the ECM's after the fact.
The help section says "small" changes may need to be made to the CRA. I guess I didn't think that 30% could be called small. Now that you have mentioned the "variations" w/ the BHJ, maybe it's not so much afterall!


THANX!