Don Terrill’s Speed-Talk

I would like to get some input on the fast fuel injection set up im looking at putting one on my new W9 motor should be around 700 hp is it easy to tune and get set up and what size injectors are you running thank you for your help

I believe you will be surprised at how easy the fast efi unit is to get up and running. We performed a lot of the beta testing on new Fast XFI boxes. The new features on the xfi are very nice and user friendly. If you purchase it from a good dealer he should supply you with a file that should have you up and running in no time. The injector sizing will varies some with who's tune up you start with. A 42lb-55lb injector would be pretty close on one of our maps, but again there are many setups which depends on fuel psi, duty cycles, etc. Hopes this helps, Tracy

Good starting point

I never used the new FAST but the old one works real nice. Only problem I ever had was with the datalogger. I think the new box has it included.

A 42lb injector will be maxed out on gas at 672HP with a .5 BSFC with a 100 duty cycle. The 55lbs are good for 880 flywheel HP and 748HP at 85% duty cycle. Bigger is better in this case.

Unfortunately I have had a lot of problems with the FAST EFI system (the old system). I use the EFI computer along with the FAST e-Dist (distributorless ignition), and the FAST Data Logger.

I experienced "no start" conditions at least a dozen times in the last year (twice at the starting line during eliminations). I have also experienced high rpm ignition cut out, sudden lean conditions for .2-.3 seconds (up to 15.5:1 A/F ratio), sudden rich conditions for .2-.3 seconds (down to 10:1 A/F ratio), and the data logger did not work on about 5% of my runs. Without touching a thing, it might work great the next run. FAST has offered to "lend" me a replacement EFI, e-Dist, and Data Logger at the races, but they won't swap mine out and when I send it to them for testing they always show "no problem found".

The staff their try to help, but usually don't identify the problem. The tech guys at the races (they usually have someone at the NHRA national events) are parts changers.

I hope the new system is better, but I have too much invested in this system (~$3500) to just scrap it and try their new system. I have spend ~$350 in Fed-Ex overnight charges sending it back and forth to them (I've sent it back ~6 or 7 times in the past 1 1/2 years) trying to get the problem solved before the next race. I am running the system at a much higher rpm than most of their customers (~12k rpm).

I don't have anyone else to recommend and I hope I'm the only Lemon that they have out there.

Greenlight, I'm sorry to hear of your problems with your car. I've never experienced that kind of problems. I install quite a few a year on drag cars and run them on all my cars. But I must admit I've never revved one to 12000rpm with a edist. I race most NHRA national and div4,5,3 events and sure don't mind taking a look at it anytime. Also I have some old style boxes that are proven to run, I would send you one to run anytime in hope of helping find the problem. Also if you ever wanted to try a new unit I would send one out for you to try. Let me know if there is anything I could do to help. Tracy

I've tried several, and at 11,000 plus have experienced similar problems. Not with the fast system but with others. More than likely you are having some type of magnetic interference. Honestly, I'd try the new box first but more than likely it won't help ya. Are you running MAP or MAF based system?

I ran the older FAST system and never had any issues within the system. Seemed rock solid, easy to tune once you knew what you were doing.

I've heard good things about the BigStuff3...

What are you guys using for a throttle body and how big are you using

let r eat wrote:I've tried several, and at 11,000 plus have experienced similar problems. Not with the fast system but with others. More than likely you are having some type of magnetic interference. Honestly, I'd try the new box first but more than likely it won't help ya. Are you running MAP or MAF based system?

The engineers at FAST have suggested that I might have some interference issues, so I ran shielding wiring around the crank and cam wires and grounded the shielding wires as suggested. Still no improvement. I've rerouted injector harnesses and magnetic pickup harnesses, with no change in the situation.

I havent used one yet, but plan to one the new motor for my truck. I'm undecided between the XFI and the BS3's. I did find this cool little write up on Mopar Engines West's website though: Step by step EFI tuning, it helped me understand what I'm getting into. Also you can go to FAST's (and I'm sure most EFI companies) websites and download the software and play around with it to see how you like the control panels and stuff. One question I do have.......when building a fresh motor and running an untuned EFI system, how does one go about doing cam breakin??? I'd hate to have bad AF ratios on initial startup and wash the cylinders while trying to break the cam in. I've heard of people running a carb on the motors for cam breakin, then swapping to the EFI setup afterwards. Opinions?