CSX3170 in Scottsdale

[olddog]

Alph-N is a poor strategy to run an engine off of. However Speed Density and Mass Flow both have some sort of Alph-N built into them. When an engine is running steady state, SD and MF control much more precisely than Alph-N. Alph-N could never come close to doing as good of a job at steady state. That said, when there is a major upset in running conditions SD and MF cannot react as fast as needed. Both SD and MF look at what ever type of Alph-N strategy they have built in during these upsets to help them out until things settle out. So the better you can get the Alph-N strategy tuned the better the SD or MF system will run.

I have no idea what EFI you are running, and I'm no expert. I am assuming your EFI does use the Alph-N tune to assist it during upsets when it is running Speed Density. Therefore I would recommend getting the Alph-N tuned as good as you can before switching it to Speed Density. Good as you can, means reasonably well everywhere. There is no point in trying to get everything perfect, as then there is no point to go to speed density. It should be in the ball park everywhere you operate at. I would try to dial in the areas that you run the most fairly good, and let the areas you run the least be the trade off to getting the important areas right.

[Cobra #3170]

I changed to load indexed speed density and it runs great now. The engine builder had the alpha N tune all screwed up it only worked well at wot and high rpm. Fastman EFI did the new tune and it is really good fuel air ratios are right on for 114 fuel and it starts right up with out touching the throttle. I could not be happier with it, FAST man is about my age and really knows his stuff he has been tuning for years and knows both software and hardware. He also is an engine builder and Top Alcohol drag racer. My system is a FAST XFI 2.0 with traction control. If I had it to do over again I would buy the Holley port injection system because their self learning is so good.

[Racer_X]

Nice run! I used to autocross a '93 Mustang I had built up and had a blast with it. I was taught wiggling the cones is where you want to be, on the edge.
Oh well, they all have their rules, for whatever reasons.
Glad you got the tune figured out.