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ANOTHER help my 60’ post…. *updated with more info*

Posted By: G_bob

ANOTHER help my 60’ post…. *updated with more info* - 08/14/09 08:09 PM

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?
Posted By: Cab_Burge

Re: ANOTHER help my 60’ post…. - 08/14/09 08:48 PM

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
Posted By: B3422W5

Re: ANOTHER help my 60’ post…. - 08/14/09 09:02 PM

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.
Posted By: G_bob

Re: ANOTHER help my 60’ post…. - 08/14/09 09:07 PM

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.
Posted By: Sport440

Re: ANOTHER help my 60’ post…. - 08/14/09 09:11 PM

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
Posted By: gregsdart

Re: ANOTHER help my 60’ post…. - 08/14/09 10:31 PM

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.
Posted By: sixpackgut

Re: ANOTHER help my 60’ post…. - 08/14/09 11:13 PM

1/4 mile mph seems high for ET
1/8 mile mph seems low compared to 1/4 mph, 27mph increase
Posted By: Brian Hafliger

Re: ANOTHER help my 60’ post…. - 08/14/09 11:24 PM

Quote:

1/4 mile mph seems high for ET
1/8 mile mph seems low compared to 1/4 mph, 27mph increase



I agree! It looks like something is wrong. I would expect you engine to push your car to at least 110mph. in the 1/8...
Posted By: sixpackgut

Re: ANOTHER help my 60’ post…. - 08/15/09 01:16 AM

Quote:

Quote:

1/4 mile mph seems high for ET
1/8 mile mph seems low compared to 1/4 mph, 27mph increase



I agree! It looks like something is wrong. I would expect you engine to push your car to at least 110mph. in the 1/8...



thats how my car acted with the sheetmetal ram on it
Posted By: BradH

Re: ANOTHER help my 60’ post…. - 08/15/09 01:36 AM

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.
Posted By: MR_P_BODY

Re: ANOTHER help my 60’ post…. - 08/15/09 02:18 AM

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
Posted By: Quicktree

Re: ANOTHER help my 60’ post…. - 08/15/09 02:35 AM

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.
Posted By: B3422W5

Re: ANOTHER help my 60’ post…. - 08/15/09 02:25 PM

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.
Posted By: gregsdart

Re: ANOTHER help my 60’ post…. - 08/15/09 09:58 PM

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.
Posted By: G_bob

Re: ANOTHER help my 60’ post…. - 08/15/09 10:35 PM

Here are all the numbers from those three runs.

--60-----330-----1/8-----MPH------1000-----1/4-----MPH
1.440 - 4.149 - 6.462 - 106.47 - 8.452 - 10.139 - 133.37
1.458 - 4.161 - 6.470 - 106.70 - 8.457 - 10.139 - 133.54
1.477 - 4.182 - 6.484 - 106.87 - 8.463 - 10.141 - 133.54

As a point of comparison, here are the numbers from the previous best run which was at Vegas. It was first time out and just the 5th run on the new motor. Launch and shift RPMs same as the above runs.
But, this run was prior to having the converter worked on and flash RPM was lower, "I think" more in the 5300 range.
Tires were 31-16.5 hoosier QTP's with 4.30 gears. Trap rpm was close to 7000, but it didn't hit the limiter. Slip here came out around 13-14%

--60-----330-----1/8-----MPH------1000-----1/4-----MPH
1.467 - 4.190 - 6.514 - 105.61 - 8.518 - 10.218 - 132.32
Posted By: G_bob

Re: ANOTHER help my 60’ post…. - 08/15/09 10:47 PM

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.
Posted By: gregsdart

Re: ANOTHER help my 60’ post…. - 08/15/09 11:03 PM

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?
Posted By: MR_P_BODY

Re: ANOTHER help my 60’ post…. - 08/15/09 11:39 PM

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
Posted By: gregsdart

Re: ANOTHER help my 60’ post…. - 08/16/09 02:18 AM

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?
Posted By: MR_P_BODY

Re: ANOTHER help my 60’ post…. - 08/16/09 02:31 AM

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
Posted By: Brian Hafliger

Re: ANOTHER help my 60’ post…. - 08/16/09 05:25 AM

I don't see how you can go through the lites at 7000rpm with 4.56 gear and 32" tire????
My duster has 4.56 gear, 28.5" tire and it goes through at 7100rpm!

Glenn, I know you opened up the exhaust, but removing the exhaust completely and bolting on a nice collector extension about 10-12" would probably net you 1-2 more mph. Between the weight and the fact that your engine/cam/heads are not designed for an exhaust system should net you more HP, which likely is the reason the engine wants to be shifted lower in rpm.

I also think your suspension needs alot of tuning to really make good USE of your HP. You have to overcome a heavy car, so good working suspension is even more important than on a lighter car IMO.

Sounds like I need to be there next time you go out....would be good to go back to the races!!
Posted By: G_bob

Re: ANOTHER help my 60’ post…. - 08/21/09 12:59 AM

Quote:

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





I've got single adjustable Vari-Shocks with 150 lb springs. Shocks are set at 9 of 16 total.
Spring platforms are about an inch up the threads (per chassisworks instructions), which yielded the eye-to-eye measurement they recommended.

Going out again saturday and plan to drop the exhaust and put the extensions back on it was dynoed with.

We'll start there and then try some shock adjustments.
Posted By: Dodgem

Re: ANOTHER help my 60’ post…. - 08/21/09 02:33 AM

I would say you are also shifting 500 rpm too soon.
peak hp at 6500 shift at 7000 to get all the benifits.
Posted By: Bob_Coomer

Re: ANOTHER help my 60’ post…. - 08/21/09 03:30 AM

Didnt bother reading the other reply's so here is mine.
1000-1200 rpm flash below shift point. This would be near peak torque out put.
Posted By: G_bob

Re: ANOTHER help my 60’ post…. - 08/23/09 03:18 AM

Got back out today, two time trials and 3 rounds of eliminations. New best, but 60's are basically the same.
Dropping the exhaust and adding the extensions saved 50 lbs, so new race weight is 3,530. On run two I dropped the cold air pressure to 12 lbs (was 13 after the run) and set the shocks at 6 clicks, which is basically the middle of the adjustments.

- 60 --- 330 --- 1/8 --- MPH --- 1000 --- 1/4 ---- MPH
1.486 - 4.160 - 6.453 - 107.50 - 8.429 - 10.111 - 133.49
1.452 - 4.099 - 6.372 - 108.10 - 8.336 - 10.006 - 134.30
1.444 - 4.113 - 6.394 - 108.06 - 8.358 - 10.115 - 124.94
1.458 - 4.118 - 6.396 - 107.81 - 8.361 - 10.030 - 134.10
1.469 - 4.131 - 6.414 - 107.48 - 8.384 - 10.056 - 133.96

Did finally notice that on the best run, when I "accidently" forgot to make the 1/2 when the light came on at 6500, and shifted at 7000, it semmed to like it, so maybe the extensions helped there. But, I made the 2/3 shift at 6700 and the needle on the tach didn't drop at all.

I'm pretty sure I need to have some converter work done and then I'll have to hold this thing back.
Posted By: Diego_Ted

Re: ANOTHER help my 60’ post…. - 08/23/09 03:27 AM

way to go G looks like the plant is starting to get broke in!!
Posted By: Jeepmon

Re: ANOTHER help my 60’ post…. - 08/23/09 03:43 AM

Knockin on the door of the 9's...
Posted By: RobX4406

Re: ANOTHER help my 60’ post…. *updated with more info* - 08/23/09 03:44 AM

Quote:

urethane-bushed rod ends



I'd get rid of those.
Posted By: 68Fastback

Re: ANOTHER help my 60’ post…. - 08/23/09 04:04 AM

Just curious what chip are you using now. Did you ever take Bryan Sloan up on using his converter. Lots of MPH so you got a easy 9.80
Posted By: G_bob

Re: ANOTHER help my 60’ post…. *updated with more info* - 08/23/09 04:46 AM

Quote:

Quote:

urethane-bushed rod ends



I'd get rid of those.



Rob
Yeah, I'm thinking new four-link rods and ends are in my future. I actually talked to my local chassis fab guy about that back when he did the new down bars and motorplate tabs.


Quote:


Just curious what chip are you using now. Did you ever take Bryan Sloan up on using his converter. Lots of MPH so you got a easy 9.80



Chris,
I've got a 7000 chip in it now. It just shouldn't be rev'ing that high for the mph I'm running. The TCI converter slip calculator has that at between 9 and 10 percent slippage.

Never did try out Bryan's converter. I had munsinger tweak mine. It's better than it was, but still not right. It's tighter on the big end, which is good, but flashes higher, which isn't. I think that's a piece of the 60 ft problem, along with chassis and shock issues.

After Pinks, I'm going to pull it out and have Mike work it some more. With the additional data we've got since he tweaked it, we know we need to take about 400 out of the flash and also tighten it up more.
Posted By: PUNK

Re: ANOTHER help my 60’ post…. *updated with more info* - 08/23/09 06:08 AM

10.00 @ 134+ mph. I LIKE IT! I cant wait till you actually air it out at a track closer to sea level and not in humid and hot air. You definitely have a 9 second ride on your hands.
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