While sitting here idle due to the virus watching the racing season go down the toilet, I’ve been looking a lot through dyno records, et slips, and 60’ times from the past couple seasons. I’m going to try to think through some issues on my e.t.
Currently run a full spool, bigger shafts, baseline suspension outlaw kit, etc, but still stock 3.27 gear. Also running a stock gear 4R trans with 28 10.5 m/t slick out back. My best 60’ to date (before aluminum block rebuild this year and some other weight reduction) has been 1.40, which I believe is pretty sad. I run mostly 1/8th mile which I shift into 3rd right at the traps at 6.668 at right around 100mph. I have the notion to swap in a 3.73 and see if it would be better. By raising the rear gear, I would not have the tendency to over power the tire at the shift point which, by looking at the datalog info, I see a spike before the shift which would indicate such. As I shift, it’s two-fold, rpm drops several hundred rpm and wheel speed decreases which would indicate it gaining traction again during the shift.
By looking at dyno curves, I’m hitting 615ftlbs at 4k and flatlines to redline, and 650hp at 5500rpm, also launching around 35-3800rpm, shifting around 6500, by the datalogging I can see the 1-2 shift drops quite a bit of rpm and I believe that’s where I’m losing the most power and time. I am able to build 10psi on the turbos off the transbrake at launch and it seems to hook, but as my suspension guru says, it doesn’t seem to launch very hard.
I have a lot of people telling me I should be going faster than I am and I’m trying to encompass the big picture. By raising the rear gear, I could possibly change my 60’ but would it change the overall picture? My thinking is the wheel speed would be slower throughout the 1/8th without the loss of traction, but because of such the rpm drop between shifts would not change.
I guess what I’m trying to see here is if a gear change is the right route, or if the rpm drop on shifts that is essentially dropping me out of the power and is the underlying issue. Obviously the only fix seems to me to be raise the shift point higher, therefore the 1-2 shift would still be in the peak power rpm band, but like I said, I’m suspecting loss of traction as a factor at the shift as a factor to the bogging of second gear.
Let me know all your opinions, I’m welcome to suggestions!
Currently run a full spool, bigger shafts, baseline suspension outlaw kit, etc, but still stock 3.27 gear. Also running a stock gear 4R trans with 28 10.5 m/t slick out back. My best 60’ to date (before aluminum block rebuild this year and some other weight reduction) has been 1.40, which I believe is pretty sad. I run mostly 1/8th mile which I shift into 3rd right at the traps at 6.668 at right around 100mph. I have the notion to swap in a 3.73 and see if it would be better. By raising the rear gear, I would not have the tendency to over power the tire at the shift point which, by looking at the datalog info, I see a spike before the shift which would indicate such. As I shift, it’s two-fold, rpm drops several hundred rpm and wheel speed decreases which would indicate it gaining traction again during the shift.
By looking at dyno curves, I’m hitting 615ftlbs at 4k and flatlines to redline, and 650hp at 5500rpm, also launching around 35-3800rpm, shifting around 6500, by the datalogging I can see the 1-2 shift drops quite a bit of rpm and I believe that’s where I’m losing the most power and time. I am able to build 10psi on the turbos off the transbrake at launch and it seems to hook, but as my suspension guru says, it doesn’t seem to launch very hard.
I have a lot of people telling me I should be going faster than I am and I’m trying to encompass the big picture. By raising the rear gear, I could possibly change my 60’ but would it change the overall picture? My thinking is the wheel speed would be slower throughout the 1/8th without the loss of traction, but because of such the rpm drop between shifts would not change.
I guess what I’m trying to see here is if a gear change is the right route, or if the rpm drop on shifts that is essentially dropping me out of the power and is the underlying issue. Obviously the only fix seems to me to be raise the shift point higher, therefore the 1-2 shift would still be in the peak power rpm band, but like I said, I’m suspecting loss of traction as a factor at the shift as a factor to the bogging of second gear.
Let me know all your opinions, I’m welcome to suggestions!