ANOTHER help my 60’ post…. *updated with more info*
#437843
08/14/09 04:09 PM
08/14/09 04:09 PM
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Joined: Jan 2003
Posts: 3,616 Riverside, Ca
G_bob
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OP
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Ok, here’s my story as to not hi-jack the other thread…. Very similar to his story. 67 coronet, 3580 race weight (all-in). Backhalved, pro-street 4 link (urethane-bushed rod ends), single adjustable Vari-shocks. Dana, spool, 4.56, 32.2” tall Phoenix slick (radial) – 32-13.6-15 Launching off a brake with two-step at 4800 Shift light set at 6400 (probably shifting at 6500 or so) Last time out went 60 ft ---- ET ---- MPH 1.440 - 10.139 - 133.37 1.458 - 10.139 - 133.54 1.477 - 10.141 - 133.54 8” converter, flashes 5800 7000 rpm through the traps (hit the rev limiter with a 7000 pill right at the traps all three runs) Slip calcs out a little over 10% On the engine dyno, motor made peak TQ at 5000, peak HP at 6500 1/8th mile times on the above runs were: 6.462 @ 106.47 6.470 @ 106.70 6.484 @ 106.87 So, based on where the peak HP and TQ numbers are, what kind of flash range should I be looking for to get the best 60’ times?
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Re: ANOTHER help my 60’ post….
[Re: Cab_Burge]
#437845
08/14/09 05:02 PM
08/14/09 05:02 PM
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Joined: Jan 2003
Posts: 11,786 Portage,michigan
B3422W5
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I Live Here
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If peak torque is at 5000, the convertor should be 200-300 above that, IMO.
I like to think about 1500 below shift point(flash on convertor)and 200-300 above torque peak. So in your application i would think something around 5200 flash would be optimal taking shift point and torque peak together.
5800 is too high, IMO. I bet you would see a nice gain tightening it up 600rpms or so in the 60 foot.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight 418 BPE factory replacement headed stroker, 565 lift solid cam, footbrake street/strip car Best so far, 10.32 1/4 1.41 best 60 foot 6.56 at 104.17
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Re: ANOTHER help my 60’ post….
[Re: Cab_Burge]
#437846
08/14/09 05:07 PM
08/14/09 05:07 PM
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Joined: Jan 2003
Posts: 3,616 Riverside, Ca
G_bob
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Quote:
Was the track temps going way up from first to last run? The 60 ft. times varing that much and the 1/4 mile ET and MPH not changing the same or more amount has me wondering How about trying a low low gear set
I think the track temps were fairly consistent. Time of runs were 3:06pm 3:35pm 3:57pm
One note is that this was a street legal day, so starting line conditions weren't great.
First two runs were in the left lane (which they were prepping a bit for me before my runs by putting down that powder, I'm assuming rubber, and spraying) and the last was in the right lane which they didn't prep. Also, I upped the two-step to 5000 on the last hit as well.
Don't know why the ET's could be so consistent when the 60's were so far apart.
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Re: ANOTHER help my 60’ post….
[Re: G_bob]
#437847
08/14/09 05:11 PM
08/14/09 05:11 PM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
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master
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Canton, Ohio
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One rule of thumb for the vert stall is 500 RPM over peak torque. With your 5800 rpm stall your close enough. Some cars will even et better with the stall closer to peak HP. I feel your 60 ft. numbers are almost perfect for your ET and MPH. Perfect IMO would be 60fts. around the 1.39 1.40 range. With your 1.44 you have darn near, perfect numbers for the run IMO. Your tune is for your ET is at 95% I say have a couple cool ones and dont worry about that last 5% mike
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Re: ANOTHER help my 60’ post….
[Re: Sport440]
#437848
08/14/09 06:31 PM
08/14/09 06:31 PM
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Joined: Jan 2003
Posts: 10,082 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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Each combo is different, but I am a fan of loose. I picked up about .05 going to a much looser converter, 6400+rpm compared to 5500rpm before in front of a 528 BB with peak torque at 5100 rpm. Each combo will differ, and those chasing the best ET will have more than one converter to test. For what it is worth, a loose converter will have less hit in the first few feet, but average better to the 60 ft clocks. If you have a situation like mine, too much launch torque, then loose makes more sense. Especially if there is spin off the line, which starts the lockup process early and decreases torque output to the input shaft. If you are allready way above max torque, it only gets better with a little slippage. Check out how the ET falls off on a car with a tight converter (roughly at or below peak torque for flash) when they experience slippage at the line.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: ANOTHER help my 60’ post….
[Re: gregsdart]
#437849
08/14/09 07:13 PM
08/14/09 07:13 PM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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1/4 mile mph seems high for ET 1/8 mile mph seems low compared to 1/4 mph, 27mph increase
Gen 3 power 6.22@110, 9.85@135 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: ANOTHER help my 60’ post….
[Re: Sport440]
#437852
08/14/09 09:36 PM
08/14/09 09:36 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
I feel your 60 ft. numbers are almost perfect for your ET and MPH. Perfect IMO would be 60fts. around the 1.39 1.40 range. With your 1.44 you have darn near, perfect numbers for the run IMO.
I'd actually expect it to be quite a bit quicker, based on my own car pulling 1.459+ 60-fts. w/a much milder combination on only 275/60R15 DOT drag radials. "G" has 7 MPH more than me, but his 60-ft. times are pretty soft for the power level he's making.
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Re: ANOTHER help my 60’ post….
[Re: G_bob]
#437853
08/14/09 10:18 PM
08/14/09 10:18 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
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Quote:
Ok, here’s my story as to not hi-jack the other thread….
Very similar to his story.
67 coronet, 3580 race weight (all-in). Backhalved, pro-street 4 link (urethane-bushed rod ends), single adjustable Vari-shocks. Dana, spool, 4.56, 32.2” tall Phoenix slick (radial) – 32-13.6-15 Launching off a brake with two-step at 4800 Shift light set at 6400 (probably shifting at 6500 or so)
Last time out went 60 ft ---- ET ---- MPH 1.440 - 10.139 - 133.37 1.458 - 10.139 - 133.54 1.477 - 10.141 - 133.54
8” converter, flashes 5800 7000 rpm through the traps (hit the rev limiter with a 7000 pill right at the traps all three runs) Slip calcs out a little over 10%
On the engine dyno, motor made peak TQ at 5000, peak HP at 6500
1/8th mile times on the above runs were: 6.462 @ 106.47 6.470 @ 106.70 6.484 @ 106.87
So, based on where the peak HP and TQ numbers are, what kind of flash range should I be looking for to get the best 60’ times?
For your MPH it should be running 10.0, I think your stall is too high and your spending too much time below the stall at the shift points, I believe that is also giving you the 10% slippage(which if you could go higher in the revs it wouldnt be that much slippage)... your going through the traps right at the right RPM(10% above peak HP RPM). I try to shift AT LEAST 1500 rpm above the stall point your shifting 700 rpm above stall.... what is you drop in rpm's between gears
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Re: ANOTHER help my 60’ post….
[Re: gregsdart]
#437854
08/14/09 10:35 PM
08/14/09 10:35 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
Each combo is different, but I am a fan of loose. I picked up about .05 going to a much looser converter, 6400+rpm compared to 5500rpm before in front of a 528 BB with peak torque at 5100 rpm. Each combo will differ, and those chasing the best ET will have more than one converter to test. For what it is worth, a loose converter will have less hit in the first few feet, but average better to the 60 ft clocks. If you have a situation like mine, too much launch torque, then loose makes more sense. Especially if there is spin off the line, which starts the lockup process early and decreases torque output to the input shaft. If you are allready way above max torque, it only gets better with a little slippage. Check out how the ET falls off on a car with a tight converter (roughly at or below peak torque for flash) when they experience slippage at the line.
I don't think 5800 is going to hurt the 60'. it being on the rev limiter at the the end may be though.
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Re: ANOTHER help my 60’ post….
[Re: MR_P_BODY]
#437855
08/15/09 10:25 AM
08/15/09 10:25 AM
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Joined: Jan 2003
Posts: 11,786 Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,786
Portage,michigan
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Quote:
Quote:
Ok, here’s my story as to not hi-jack the other thread….
Very similar to his story.
67 coronet, 3580 race weight (all-in). Backhalved, pro-street 4 link (urethane-bushed rod ends), single adjustable Vari-shocks. Dana, spool, 4.56, 32.2” tall Phoenix slick (radial) – 32-13.6-15 Launching off a brake with two-step at 4800 Shift light set at 6400 (probably shifting at 6500 or so)
Last time out went 60 ft ---- ET ---- MPH 1.440 - 10.139 - 133.37 1.458 - 10.139 - 133.54 1.477 - 10.141 - 133.54
8” converter, flashes 5800 7000 rpm through the traps (hit the rev limiter with a 7000 pill right at the traps all three runs) Slip calcs out a little over 10%
On the engine dyno, motor made peak TQ at 5000, peak HP at 6500
1/8th mile times on the above runs were: 6.462 @ 106.47 6.470 @ 106.70 6.484 @ 106.87
So, based on where the peak HP and TQ numbers are, what kind of flash range should I be looking for to get the best 60’ times?
For your MPH it should be running 10.0, I think your stall is too high and your spending too much time below the stall at the shift points, I believe that is also giving you the 10% slippage(which if you could go higher in the revs it wouldnt be that much slippage)... your going through the traps right at the right RPM(10% above peak HP RPM). I try to shift AT LEAST 1500 rpm above the stall point your shifting 700 rpm above stall.... what is you drop in rpm's between gears
thats kinda exactly what i thought... i have a hard time believing a car that is shifted 700 rpm above the convertors flash is ever going to run as good as it can. That 1500 rpm spread seems like a very good general rule to me, and i know its way closer to optimal than 700 is.
My thought is that torque is what gets a car moving(especially, like in the OP's case its an almost 3600 pound car). my guess is that the closer the convertor flashes to the cars torque peak,(optimally just a hair over) the better the car is going to launch and the better its going to accelerate at gear changes, assuming he can get the power hooked up.
I suspect this is why in this cars case the 60 foot is soft and the 1/8 mile times are as well.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight 418 BPE factory replacement headed stroker, 565 lift solid cam, footbrake street/strip car Best so far, 10.32 1/4 1.41 best 60 foot 6.56 at 104.17
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Re: ANOTHER help my 60’ post….
[Re: B3422W5]
#437856
08/15/09 05:58 PM
08/15/09 05:58 PM
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Joined: Jan 2003
Posts: 10,082 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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Does your car have tire slippage at launch? Also, when you said 7000 rpm pill, a light went on. Sometimes those will start before 7000, costing you mph. This car sounds like it has more in it by a fair aqmount. Try at least a 7200 pill, and lower your launch rpm to 3200 for starters to see just what happens.
Last edited by gregsdart; 08/15/09 06:36 PM.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: ANOTHER help my 60’ post….
[Re: gregsdart]
#437858
08/15/09 06:47 PM
08/15/09 06:47 PM
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Joined: Jan 2003
Posts: 3,616 Riverside, Ca
G_bob
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Quote:
Does your car have tire slippage at launch?
I need to get video, but so far have been alone at the track with no one to watch.
From feel, I'd day no on the first two runs and yes on the third.
Ealier in the day I had been running with the exhaust closed and launching at 4200 with 60's in the 1.50-1.53. I definitely felt spin on those as the rear moved a little to the right on launch. The first good run with the exhaust open (the 1.440 60), I felt the difference in the hook. Felt the front tires pick up and set down. That was the first run with the two-step set at 4800. I made the assumption that that somehow hit the tires harder and they planted better.
My first run with the exhaust open, I screwed up and didn't set the trans brake and actually launched off idle foot braking and it spun them big time. 1.641 60'.
That's kind of what lead me to think the 4800 hit them harder and planted them better.
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Re: ANOTHER help my 60’ post….
[Re: gregsdart]
#437860
08/15/09 07:39 PM
08/15/09 07:39 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
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Romeo MI
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Quote:
If you have worse spin off idle than using the brake, sounds like your suspension needs some serious loosening up. Anyone else care to comment?
I cant leave from idle either... I believe it slaps the converter too hard and blows the tires off... if I leave at high rpm's it hooks
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Re: ANOTHER help my 60’ post….
[Re: MR_P_BODY]
#437861
08/15/09 10:18 PM
08/15/09 10:18 PM
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Joined: Jan 2003
Posts: 10,082 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
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My experience has been that with my car, off idle gave better traction due to time for the suspension to react. A transbrake is like dropping a clutch, shocks the suspension and might overcome too stiff of a setup. Just my opinion, because our cars are so different. More input should shed some light on this situation. How stiff are your springs? Shocks?
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: ANOTHER help my 60’ post….
[Re: gregsdart]
#437862
08/15/09 10:31 PM
08/15/09 10:31 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
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Quote:
My experience has been that with my car, off idle gave better traction due to time for the suspension to react. A transbrake is like dropping a clutch, shocks the suspension and might overcome too stiff of a setup. Just my opinion, because our cars are so different. More input should shed some light on this situation. How stiff are your springs? Shocks?
My springs are 90# and my QA-1s are set at 9(12 total) with a 4-link
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