quote:

Originally posted by Allen Chamberlin:
I run the Holley dominator setup on my car. I run it in alpha n mode. It just uses throttle position and rpm. I ran speed density at first but found it hard to tune with the big cam and inconsistent vacuum. Learn allows the computer to make changes to your base map but you have to transfer them to make them permanent. You want to turn that off as soon as you can. I have the closed loop % turned down. With what we do I think it is best to limit what it can do.

You could leave it in Speed Density if you wanted to, rather, run it in Mixed Mode, which lets you specify the rpm and load range it will run in Alpha-N (for idle area) then switch to Speed Density once out of that area.

But why bother, these are naturally aspirated engines, Alpha-N works just fine. Been running that way for 20 years......

I only mention it because some of the forced induction stuff I have done have HUGE cams, especially blower cars, and trying to run them primarily on Speed Density sucks! I run them on the Mixed Mode, that solves the problem!

I agree with you Mike. I ran the combo setup for a little bit and didn't think it was worth it

I did have some good EFI help for one full pass. It rained and I've been on my own since.

I hear you. It was a big learning curve. I did look at the sniper kit and for the people looking at this thread. You don't want something that is self learning only for a racecar. Can you adjust the fuel map and timing map on the sniper? If you cannot adjust learning and closed loop I don't know how good it would be on a bracket car. The HP and the dominator would be your best bet. If you add a 5 to the end of an Edelbrock intake a lot of times it is setup for injection. I use the 29275 on a big block Chevy

I am going to give the Sniper a try. I don't think it is going to be all that hard. I plan on putting the car on the dyno to get a good closed loop tune and a base AFR. Then use that as a target AFR in closed loop but only running close loop right after I come off the converter. So the only RPM range closed loop will see is 5000 to 7400. I have spoken with a guy who is doing this and he is having great success with this approach. In a pure drag racing application you only need it to run at three speeds, idle, on the converter and WOT. I am going to try to simplify the approach with the objective being consistent.

quote:

unlike a carb, you do not need air speed to draw fuel out of the bowls.

That is a very interesting point, I had never considered that.

Any updates?

Actually yes – The update is - for me anyway - after talking with many people, including people currently running the Sniper, I came to the conclusion that I was going to spend a lot of money for something that wasn’t going to give me significantly better consistency or performance. The common opinion from people running them was that they were just as good as a good carb, not necessarily better. I have been led to believe that full port injection will produce more consistency over a throttle body, but with a much greater learning curve. I have a great carb, so I decided to save myself money and time working out a new tune and stick with what I have.

I ran a fast system for 7 years or so bracket racing and it was great, not quicker or faster, but I did feel like it was more consistent then my carb....ran it on gas and ally, no issues. Just bought me new setup to play with on the pro charger motor