A little better this time
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Legend
Joined: Feb 2005
Posts: 8,058
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From: Fort Worth, TX
A little better this time
This is with hemifever's 94 tune, methanol turned off, 93 pump gas. No pinging.
After 23 runs (2 groups of 8 and a group of 7 back to back, with 10 minutes between groups), the trans cooler (under bed w/ 10" fan) was still lukewarm.
3.9 V6
1.7 HS RR's
clutch fan delete/180 stat/190 fan
4.10's
2000 stall convertor
V8 TB
265/70-16 AT's
Shifted at 5000 RPM even, trapped at 4500 RPM in second. I didn't catch the RPM fallback. The 60 and 330's really tell the tale of the tirespin. It was also bogging mid-track on some runs, wouldn't make power/RPM after the shift, if I pedaled it, then it would clear up and make power. so that's why some of the 330's are down even though the 60's are good. The intake's bellypan is dry, no vacuum leaks, so I'm not sure what was going on, or if it was just loading up with fuel post-shift.
The best pass was a 60- 2.435 ; 330- 7.074 @ 48.44 ; 660- 10.986 @ 60.43 and the average of the "good" runs was 60- 2.517 ; 330- 7.168 ; 660- 11.120 .
To compare to my last outing, the best pass then was a 2.610, 7.282 @ 48.95, 11.132 @ 62.91 . The only change is 93 to 94 tune and convertor.
I knew the convertor would be way too loose on the top end, but it gave me a bunch of numbers down low ( roughly 2 tenths at 60 and 330 versus .146 at the 660), and I know if I hook up good, I can get that top end back a little and get back in the 10's solidly and get the MPH back where it belongs. Even the 10.98 pass was spinning, I think there's a low 90 or high 80 in it with methanol turned off, maybe .05 with the methanol on and another .10-.15 with a good all-out tune in it. Maybe more/maybe less, hard to say. But a locker is definitely next on my big mod to-do list.
20130310_192513-1.jpg
20130310_192157-1.jpg
20130310_192404-1.jpg
After 23 runs (2 groups of 8 and a group of 7 back to back, with 10 minutes between groups), the trans cooler (under bed w/ 10" fan) was still lukewarm.
3.9 V6
1.7 HS RR's
clutch fan delete/180 stat/190 fan
4.10's
2000 stall convertor
V8 TB
265/70-16 AT's
Shifted at 5000 RPM even, trapped at 4500 RPM in second. I didn't catch the RPM fallback. The 60 and 330's really tell the tale of the tirespin. It was also bogging mid-track on some runs, wouldn't make power/RPM after the shift, if I pedaled it, then it would clear up and make power. so that's why some of the 330's are down even though the 60's are good. The intake's bellypan is dry, no vacuum leaks, so I'm not sure what was going on, or if it was just loading up with fuel post-shift.
The best pass was a 60- 2.435 ; 330- 7.074 @ 48.44 ; 660- 10.986 @ 60.43 and the average of the "good" runs was 60- 2.517 ; 330- 7.168 ; 660- 11.120 .
To compare to my last outing, the best pass then was a 2.610, 7.282 @ 48.95, 11.132 @ 62.91 . The only change is 93 to 94 tune and convertor.
I knew the convertor would be way too loose on the top end, but it gave me a bunch of numbers down low ( roughly 2 tenths at 60 and 330 versus .146 at the 660), and I know if I hook up good, I can get that top end back a little and get back in the 10's solidly and get the MPH back where it belongs. Even the 10.98 pass was spinning, I think there's a low 90 or high 80 in it with methanol turned off, maybe .05 with the methanol on and another .10-.15 with a good all-out tune in it. Maybe more/maybe less, hard to say. But a locker is definitely next on my big mod to-do list.
20130310_192513-1.jpg
20130310_192157-1.jpg
20130310_192404-1.jpg
Code:
Assuming the driveline is 83.3% efficient [15% loss is considered the average, I compared chassis dyno and oem ratings to get the 83.3 number] and neglecting rolling resistance due to traction compound and resistance of inertia, My best sixty foot is a 2.435 with the 29" tires and 4.10's [7.074/330 @ 48.44, 10.986/660 @ 60.43]. Let's assume my truck weighs 4200 pounds. Force = Mass * Acceleration Mass = 4200 pounds / 32.168 = 130.56 slugs Acceleration = 60 feet in 2.435 seconds = 10.11 feet per second squared (was 8.835) Force = 4200 pound-mass * (10.11 / 32.168) G = 1,321.23 pound-force (was 1,153) Torque at hub = Force x Distance [radius] Torque at hub = 1321.23 pound-force * 1.208 feet = 1,596.05 pound-force-feet (was 1,393) Torque at driveshaft = Torque at Hub / rear gear Torque at driveshaft = 1,596.05 pound-force-feet / 4.10 = 389.280 pound-force-feet (was 339.956) Torque after driveline losses = Torque at driveshaft / 0.85 [efficiency conversion] Torque after driveline losses = 389.280 pound-force-feet / 0.85 = 457.977 pound-force-feet (was 399.948) Torque at input shaft = Torque after driveline losses / 2.74 [first gear ratio] Torque at input shaft = 457.977 pound-force-feet / 2.74 = 167.144 pound-force-feet (was 145.966) OK, so mathematically, not accounting for external losses, my truck produces 167 pound-feet of torque with 29" tires and 4.10 gears. Now let's reverse all of that and calculate with a 23.5" racing slick and if I remove the 66 pound spare tire and 12 pounds of weight per corner from the smaller tires: 167.144 pound force feet * 2.74 = 457.977 * .85 * 4.10 = 1,596.05 [this shouldn't change since the tire radius doesn't effect it] = Torque at hub (was 1,393.818) 1,596.05 pound-force-feet / 0.98 feet = 1,628.622 pound-force (was 1,423) Force = 1,628.622 pound-force = 4086 pound-mass * (X / 32.168) G 1,628.622 pound-force / 4086 pound-mass = 0.3985 G (was 0.3438) 0.3985 G = (X / 32.168) f/s^2 0.3985 * 32.168 = 12.822 feet per second squared [remember, this was 10.11 originally] (was 11.206) Acceleration = 12.822 feet per second squared = 60 feet in X seconds sixty foot time = sqrt(60/12.822) = 2.163 seconds per this calculator -> http://www.wallaceracing.com/etcalc.php actual: 2.435, 7.074, 10.986 @ 60.43 calc'd: 2.435, 7.03, 11.05 @ 61.49 calc'd: 2.163, 6.25, 9.82 @ 69.23 If I can beat the calculated by 0.248 at the 330 [3.4% error] and 0.698/5.45 at the 660 [6.27% and 8.66% error respectfully] and those offsets hold true, 6.25 - .248 = 6.002 sec 9.82 - .698 = 9.122 sec 69.23 + 5.45 = 74.68 mph 6.25 * 0.966 = 6.038 sec 9.82 * 0.9373 = 9.20 sec 69.23 * 1.0866 = 75.225 mph So basically, I SHOULD pick up 1.7-1.8 seconds and 15 mph in the 1/8 mile from the smaller tire. Thus, to hit 8.99, I need to run a 10.70 or so with the current tires.