Agreed Mike.
My theory is : the faster i can get the engine up on clean AFR between pump shot and the boosters, the quicker the 60's and 330ft.
When i see a really rich first gear, not cleaning up before 5500- 6500 , i feel im leaving money on the table with too "long" a shot, thus, my efforts to really tune the pump shot "to" the booster flow .
I may find this to be an effort in futility but, im working to either be wrong or, correct. Data and time sheets will prove me foolish or not
If you guys see an error in my thinking, please advise.
A few quick thoughts Rusty. A flat afr through the rpm range is not ideal. You want a richer condition at peak tq than peak hp. There's also a lot going on in low gear. G-forces cause inertia-effects in the entire fuel system that will cause a momentary fuel psi spike that will definitely contribute to a richer condition. It's good to have the regulator and fuel inlet mounted behind the carb to help this. Also, keep in mind that the engine will be closest to peak torque at the leave (especially foot-braking). Since peak tq has the highest fuel demand; a little rich here is helping more than you might think. Lastly; if you can program the timing curve, add a couple of degrees at the hit and ramp it out so that it's back to normal when the afr normally 'cleans up'. You'll be surprised at how much this helps.
How would you go about tweaking a flat fuel curve to a slightly rich early to leaner later.......Main air bleed or changes in the e-bleed area?
There are several ways to do this. Tell us about your combination... (Car/engine/power/e.t./mph/trans/carb/rpm range/fuel/dyno results if you have them/etc...)
I was mostly asking as a general question as I help with a couple of different cars/combos....but on my car/test mule, it's a 493 cu.in. indy std. port, flat tappet 13.3-1 tunnel ram currently w/1.585-1.750 skirted booster Dambest carbs C12 fuel....although most of my experience with this car has been with 750 cfm annular and downlegs.....car weight 2600 w/driver, 3-speed 9-inch converter(tried various converter/gear combos) shift @7000, falls back to approx.6100 and if I'm looking at the graph correctly the "flash" of the converter is about 5800-5900, 4.56 gear and 32 inch tire. No dyno results.
best et and mph so far 9.08@146 1600ft.DA That was with the 750's w/annulars. I only have one test session with the Dambest's so far, but they look to be the most promising(only 2 runs and air was 2600 ft. that day, so they didn't give me a new best yet).......the fuel curve with them was as flat as I've had and the least "spikey" if that's a way to describe the graph.
I know Dambest's are a bit of a different animal with extremely high signal so they
may require something out of the norm?
