What Will It Run?

[NSS Guy]

Rpm at finish is right at 7,000. Trying to shift at 6,250. Rear tires are 30" tall, I have only launched twice so far with the new converter. I was trying to leave between 2,500 and 3,000. the 1.499 is my best 60' time to date.

Next time out leave at 2000 and shift at 6000 or 5800, bet you can get that 10.999

 

[BSB67]

1) If you are trying to learn something specific enough to make good decisions as to why, and what to do next, you need good run-specific atmospheric data and standardize the results. I have seen seemingly similar days have a net impact of 0.20 sec. and 2 mph.

2) Sometimes a converter might help in one place, but lose ground in another.

 

[NSS Guy]

Our motors are similar, mine is 493ci, .620 lift cam 108, factory crossram, 1407 eddy's, 8" ati , 4.30, 29.5 tire, I run thru mufflers. Car ran 10.20 this spring @130 can go even quicker. Nothing fancy, weighs 3340 without driver. You can get there, just keep at it.

 

[padam]

Next time out leave at 2000 and shift at 6000 or 5800, bet you can get that 10.999

Next time out leave at 2000 and shift at 6000 or 5800, bet you can get that 10.999

I'm curious. I've heard people say low shift points will improve et. Seems to be the opposite on my car, but I'm no where near dialed in.
Can you explain why this works?

 

[NSS Guy]

Depends on motor power band, I run a "small" cam compared to most and the crossram seems to have a sweet spot of 6000 or so shift point. Been racing this combo for about 20yrs now. I couldn't tell you anything about what's good for a single plane or dual plane single 4bbl.

 

[ohiokm]

Update and new personal best. Engine set up remains unchanged. I did make some minor jetting changes. The big change is a new PTC 8" converter. I am still trying to get dialed in to launching with this converter. Below are times from two runs (about 2 months between the runs), If anyone can shed any light on what is going on, I would appreciate it. By comparing the first half of the runs, my 11.031 run seems like it should have been faster, the only change in set up between the two runs was the converter. Weather was very similar...temp and humidity. The only difference there is was the 11.040 run was during a sunny day and the 11.031 run was at night. I have mph'd as fast as 121 with slower et's. Where did I lose a couple MPH and pick up the ET? How do I put them together to get that elusive 10.xx timeslip??? One more big change coming. I have a set of 4.30 gears sitting in my living room (finally going to get the 4.88's out). Appointment is set at the shop for December 17 for install.

Run 1:
60': 1.545
330: 4.492
1/8: 6.992
mph: 97.37
1000: 9.168
1/4: 11.040
mph: 119.45

Run 2:
60': 1.499
330': 4.453
1/8: 6.953
mph: 97.62
1000: 9.144
1/4: 11.031
mph: 118.79

Soo a custom PTC race converter compared to a mild street converter...has no current benefits in ET reduction? Thats very odd, unless you have traction issues with the new converter?

 

[383man]

You are not doing bad at all as the 11.03 run with a 1.49 sixty is not a bad pass for 118 to 119 mph. You may want to see if you can find a little more hp in her as if you get to pulling 120 mph and more you should be in the 10's. My 493 in my 63 Sport Fury usually runs 124 to 125 mph. And my ets are in the 10.70's to 10.90's as most of the time I run in the 10.80's at 124 but I tried a different carb last time out and it did not like it as it only ran a 10.91 at 123.33. Mine is a street car I drive to the track and run through the full exh on pump. But I think you have more hp in it as just a little more hp and mph should get you in the 10's. My 60's are not great as my best 60 is a 1.50 on a 10.76 pass at almost 125. But I average from 1.51 to 1.53 sixty fts and I just use SS springs and a Dynamic 9.5 street/strip converter. I dont know what your car weighs but mine is not lightened any as it goes just over 3700 before I get in it and I am 190. Your car looks great and I wish you good luck getting her to run just where you want. But if you can tune a few more hp and mph you should hit the 10's with no problem as your right there now pulling 118 to 119 mph by your last posted passes. Even if you can take a little weight off will help. Good luck in that cool looking Mopar. Oh and I run 18 psi in my radial slicks as they hook good at that psi. Ron

 

[ksurfer2]

Made it out to the track yesterday. Turned out to be a very frustrating day. Since I have been chasing the 10.XX timeslip, I have made a couple of significant changes to the car that I thought would move me in the right direction. First was in the install of a PTC 8" converter. This was installed prior to my last trip. I did pick up with the converter change, but only .03. Definitely not what I expected. Last month, I pulled the 4.88 gears out and had a set of 4.30's installed. Yesterday was my first trip to the track with the gears. I made 4 runs with a best of 11.082 @ 119.28 and a slow of 11.160 @ 119.30. It was a pretty warm day with temps in the low 80's and DA of about 1700ft. Here are the details of the best run:

60' 1.550
330 4.496
1/8 7.009
mph 97.44
1000 9.203
1/4 11.082
mph 119.28

This is .05 off my best run with the PTC converter and the 4.88 gears. I did like that at the stripe, the rpms were only about 6200 as opposed to 7000 with the 4.88 gears. So definitely easier on the motor.

 

[440rb]

So in a guessing 3550lb@line car?, 121mph is 523fwhp and a slip would look like this on a good day.
60 Foot E.T. : 1.53 Seconds
1/8 Mile E.T. : 6.96 Seconds
1/8 Mile Trap Speed : 97.68 MPH
1/4 Mile E.T. : 11.03 Seconds
1/4 Mile Trap Speed : 121 MPH
However with your motor spec you would think it would be making quite a bit more than that, a 1.50 60 would normally be in the 10.7's@124, there has got to be something in the tune or parts but if its running real good/hard then perhaps thats all the motor has in it as if it runs the same with 4.88's and 4.30's and 6200 and 7000 stripe rpm makes no difference then either theirs an issue or you need to short shift more to see, thats quite a small cam for the motor size without knowing [email protected] duration. Try different shift points to judge where its the fastest. Mph can drop off if you 60 better as you cover the distance faster with less time to build mph generally.
Just a few thoughts.
Our 589ci wedge motor with 4.500" stroke and a .625 260/[email protected] roller cam and -13 heads made max dyno power from 5500- 5900@10:1CR and 33 total timing just for added info.

 

[NSS Guy]

Made it out to the track yesterday. Turned out to be a very frustrating day. Since I have been chasing the 10.XX timeslip, I have made a couple of significant changes to the car that I thought would move me in the right direction. First was in the install of a PTC 8" converter. This was installed prior to my last trip. I did pick up with the converter change, but only .03. Definitely not what I expected. Last month, I pulled the 4.88 gears out and had a set of 4.30's installed. Yesterday was my first trip to the track with the gears. I made 4 runs with a best of 11.082 @ 119.28 and a slow of 11.160 @ 119.30. It was a pretty warm day with temps in the low 80's and DA of about 1700ft. Here are the details of the best run:

60' 1.550
330 4.496
1/8 7.009
mph 97.44
1000 9.203
1/4 11.082
mph 119.28

This is .05 off my best run with the PTC converter and the 4.88 gears. I did like that at the stripe, the rpms were only about 6200 as opposed to 7000 with the 4.88 gears. So definitely easier on the motor.

Add a 1/2" 4 hole spacer under the carbs and double check wide open throttle. That should pick it up a tenth, it does on my car.

 

[RemCharger]

I am pretty sure the car would run better with a different carb/intake set up, but what is cooler than a crossram with dual quads on it???? Since this isn't a max effort all out race car, I will keep the crossram. I do see a different converter on it in the near future though.

 

[ksurfer2]

Add a 1/2" 4 hole spacer under the carbs and double check wide open throttle. That should pick it up a tenth, it does on my car.

Prior to Saturday, I had 1/4" open spacers under the carbs. I recently purchased 1/2" 4 hole spacers. I did one run with a 1/2" 4 hole spacers under the carbs. My first run of the day was with the spacers. I believe that run as an 11.16. I was concerned with the height the air horns ended up in the scoop and potentially restricting air flow, so I removed them after the first run. The 11.082 run was with the spacers removed. I ordered 1/4" 4 hole spacers today. Now I have some options to figure out which will perform the best....no spacers, 1/4" open, 1/4" 4 hole, or 1/2" 4 hole.

 

[ksurfer2]

Made it back out to the track on Saturday night. Good weather with temps in the mid-60's. A few changes to the car including adding 1/4" four hole spacers under the carbs, adding high flow needle and seats, and drilling some holes in the weights on the secondaries to lighten them up some. Made three runs.

Run 1 (within 4 thou of my personal best):
60' 1.549
330 4.479
1/8 6.972
Mph 98.23
1000 9.157
1/4 11.035
mph 119.52

Run 2 (new personal best):
60' 1.558
330 4.488
1/8 6.981
mph 98.00
1000 9.155
1/4 11.021
mph 120.44

run 3:
60' 1.521
330 4.441
1/8 6.936
mph 98.01
1000 9.113
1/4 10.980
mph 120.60
FIRST RUN IN THE 10'S!!!!!!!!!!! Man, it feels good to get that monkey off my back! Now....what is my next goal?!?!?!

 

[cdr]

Very cool, congrats, did you ever get a race weight on it ?

 

[33 IMP]

Basically, a 1.55, a 1.56, and a 1.52 60 foot. So three hundredths got you four hundredths on the big end. A little better starting line later in the day?
Next goal.....
1.499.
Edit: second run, 98.00, third run 98.01 . Then improved the 1000ft time by .04
Mid range of third gear is where it picked up.
2nd edit: almost forgot... CONGRATULATIONS! I remember my first 12 second pass like it was yesterday, though it was more than forty years ago.

 

[ksurfer2]

This past weekend was the NMCA event in Bradenton FL. Great event with a lot of awesome people. Got a bunch of runs in. I did get a new personal best:

60' 1.548
330 4.469
1/8 6.957
mph 98.41
1000 9.123
ET 10.977
mph 121.22

Times over the weekend ranged from this time of 10.977 to a slow run of 11.184, but this run was in the heat of the day with a headwind of about 15mph. Below is a log I have been keeping of my times. What I am not understanding is the inconsistencies in how a good 60', 330', and/or 1/8 mile time will not consistently reflect in the 1/4 mile time/speed. Is this related to shift points, something in the tune, or something else. Green highlights reflect best time/speed, red is worst. You can see on the log where I changed from 4.88 gears to 4.30 gears. Advise and criticism are welcome! I did get the car weighed. It came in at 3418 with me in it (about 190).

 

[NSS Guy]

This past weekend was the NMCA event in Bradenton FL. Great event with a lot of awesome people. Got a bunch of runs in. I did get a new personal best:

60' 1.548
330 4.469
1/8 6.957
mph 98.41
1000 9.123
ET 10.977
mph 121.22

Times over the weekend ranged from this time of 10.977 to a slow run of 11.184, but this run was in the heat of the day with a headwind of about 15mph. Below is a log I have been keeping of my times. What I am not understanding is the inconsistencies in how a good 60', 330', and/or 1/8 mile time will not consistently reflect in the 1/4 mile time/speed. Is this related to shift points, something in the tune, or something else. Green highlights reflect best time/speed, red is worst. You can see on the log where I changed from 4.88 gears to 4.30 gears. Advise and criticism are welcome! I did get the car weighed. It came in at 3418 with me in it (about 190).

View attachment 1258555

View attachment 1258582

What are you running on top of the carbs? Air cleaners w/ filters? Velocity stacks w/ screens?

 

[ksurfer2]

What are you running on top of the carbs? Air cleaners w/ filters? Velocity stacks w/ screens?

Velocity stacks with screens.

 

[dvw]

Throw out the quickest and the slowest. Now what do we see? Mph looks pretty steady. So from a power stand point, things look pretty consistent. The 60ft is all over the map. So are the R/Ts. But the two don’t line up. Slow R/T’s with a quick 60ft’s or vice versa. So I don’t think this issue is being caused by inaccurate staging. At this ET level unless something is really wrong, traction shouldn’t be an issue. So that to me leaves two items I’d look at. Carburetion and converter. One or both isn’t right
Doug

 

[PRHeads]

The way I see it....... it doesn’t have enough power(speed) to run a significantly better ET.

The 60’ times still seem a tad weak for a 500” motor in a 3400lb bracket car.

What does the current converter flash to on the hit?

Without reading back through everything..... are the cam specs and compression ratio known?
Cam part number perhaps, or all the specs besides just .600 lift?

Going by the Moroso chart, to go from 121mph to 125mph will require about another 50hp.

Edit- I see some engine data is in the opening post.