Figure out the converter slip. Looks like you are driving right through whatever converter you are using. Need tire height.
OK, RPM (with no converter slip) = 336/tire height X rear axle ratio X MPH. 336/28 X 4.10 X 93 = 4576. You are going through the traps at say 5800. That is like 27% slip. The converter is too loose?
Im running a little bit more power / tq with a 4500 converter that flashes right around the advertised rating. 4:56 gear TH 400. with 29.5" tires. and shift @ 5800. go through the traps under 6000 on the 1/8 mile 1.42 60' and 6.60's at 102 mph.
Went to the track again yesterday..Last day for the next few months...slower time but much of the same. Ran 7.33,36,37 and a .67 in the bad lane. Best 60 ft was a 1.61 when loading up on the converter top the max..around 2600-2700. My goal is a 10 sec street car so my mind will be churning this Christmas.
Based on your mph ie Horsepower, you're going to need to see around 4200 flash stall. Try it two ways once off the footbrake while up on it , then off idle, granted you would need to be at the track and hooking to get accurate numbers. Or just get one built for your setup over the winter, don't let 4200stall scare you, I drove mine everywhere with 4200flash stall if uts a good converter it's not that bad. 3500 3800 etc just isn't going to get you where you want to be
It would go to around 2800 brake stall before it started to spin. If I brake stalled it I would see about 4k flash stall, if I stabbed if from 1500 it would hit 4200. It 60'd better if I got up on the converter tho
The MPH shows that you're missing about 100 HP from your dyno numbers. Did you dyno with the FiTech? I think 33 degrees should be in the ballpark. 608 HP at 3700lbs should run high 10s easily but it's going to need to be around 100mph at the 1/8th
Yes we did dyno with the fitech. Looking at data logs...it may be running a little rich...the a/f ratio is 12.6 which is our target at WOT but the O2 sensor is reporting a lambda below 100 which indicates a rich mixture so we'll take a look at that and timing adjustments the next time out.
OK guys been a while but I finally got some good data and actually learned how to read it. If you look at the RPMs on the attached logs I'm going straight from stall speed to 5ooo rpm which is near the top of my power band. The RPMs were also climbing a bit faster than I could shift (hence the high rpm shifts). I spoke with the engine builder and he recommends a 4000-4500 stall, considering where I make max torque. I recently purchased a converter from Coan the should do the trick. Will follow-up with and update once installed and raced. Mike
What size M/T ET Street tires? Height? What is your brake stall rpm and flash stall rpm with the converter?
