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?
John's carbs are good. I have only a little practical experience with his carburetors so you might call & get his thoughts on richening the carb near peak tq. The low resolution of "spikiness" indicates that the emulsion/hsab system is working well. Your car will definitely pickup if slightly richer at the rpm range closer to peak tq. (As long as it leans back out closer to and beyond peak hp.)
Yes, I will give him a call next year when I also have a little more data.
My plan for next year is to figure out what curve and O2 numbers produce best MPH (i have one in each collector now) and then work on cylinder to cylinder balance using individual O2's.
One thing I will add, and this may have just been a fluke, but I had two identical runs....same 60ft, same 1/8 et and 1/4 et. to the .001. the mph was within 1/2 mph. never had that and I've been at this a while off and on. I thought I'd try his carbs looking to reduce the lean spike on the shift....the lean spike is still there, but to a lesser degree and it does feel different on the shift. Maybe there's a consistency benefit to higher signaling carbs.
I have to add that it was a good idea for you to explain how your twin blades functioned as far as signal strength goes. I had always assumed they were more geared towards just higher airflow in 4150 bolt pattern limited classes. I will keep them in mind for any future projects.
Thanks for your input on this forum.
