Where should my stall be?

[Jake Conant]

anyone have any insight on where the stall should be on a car if I show you the power curve? I always thought you wanted the stall around your peak tq or just below it to utilize that tq to get the car moving. so if my tq curve is flat from 3800-5200rpms, wouldnt I want a converter flashing around 3600-3800?

http://img.photobucket.com/albums/v482/BBBjake/Oct08vsJan09.jpg

[Bob Ackerman]

Jake,
I can only tell you what has been told to me by Reher Morrison and a previous engine builder. Converters should be flashing/stalling at peak tq. which is in your case would be approx. 4200 rpm. Your launch rpm should be around 600-1,000 rpm's lower than stall so that you flash up to that the peak tq rpm of 4200. Variables will be the condition of your tires and the track which play a major role in adjusting up or down that rpm value.

Peak hp also tells you where you should be shifting the car and since you are somewhat flat from 5500 to 6200 rpm you should be within those rpm points to find the right shift rpm. Trial and error on this one based on e.t.

Peak hp also tells you the best rpm to be going through the traps at as well. Reher Morrison states that you should be trapping the car at 300-400 above peak hp so in your case you would want to see a trap rpm at around 6000 to 6500 rpm's. Tires and/or rear end gear ratio will be the items you will need to play with in order to find the trap rpm to be within that range. Trapping rpm any higher than than 6500-6600 rpm is putting undo strain on the motor that really isn't necessary. Then you would play with a gear change or a smaller or taller tire based on where that trap rpm is. There are math formulas to help in making those changes to suit the rpm range you need to get.

Good luck - Swede

[Jake Conant]

thanks Bob.

well with the new trans/converter, Dynamic has the stall at 5k. now to be honest, its working pretty damn good. I was at MIR this past weekend for Pinks All Out and I got 3 passes. heat played a huge role on the top end for my blower car but the 1/8s dont seem too bad.

1.46
4.28
6.63 @ 104.19
8.68
10.41 @ 129.48

dropped tires 1/2lb to 12psi and a few degree's cooler

1.44 - personal best
4.24
6.59 @ 104.44
8.63
10.36 @ 130.35

next day, warmer, 11.75 in the tires

1.42 - personal best AGAIN
4.22
6.57 @ 105.17
8.61
10.36 @ 129.08 - was hurting up top

Thats my best slip off the juice ever. Im am completely satisfied w/ the 60s and 1/8 but just feel the converter is too high. yet it seems to be working. I was leaving off the 2 step/brake at 3500 also. so 1500 below the stall.

[Greg Barsamian]

Your stats look good, Why look to change?
Anyone can offer you the next best thing in converters, but you'll have to buy it & test it to really find out if it works!

If your using Lupo's converter, you've got one of the best on the east coast!

[Jake Conant]

Your stats look good, Why look to change?
Anyone can offer you the next best thing in converters, but you'll have to buy it & test it to really find out if it works!

If your using Lupo's converter, you've got one of the best on the east coast!


yea its a Lupo converter. just because I feel Im overshooting all that tq!

[Bob Ackerman]

Jake,
I see that your slips and comments that you say it is "the best slip leaving off the juice - ever". The tq and hp numbers you gave Frank Lupo when he spec'd out the 5k stall converter, were they dyno pulls "on juice" numbers or straight off the motor no juice ? Frank is the East Coast guru when it comes to converters (mine are from Frank) so I would have complete trust in his intuition. We just race the damn cars, he has to build stuff for us that makes us happy when we race but I do agree that from a numbers perspective the converter is about 800-1,000 rpm's higher than what I know commonly works the best. My torque numbers are 6200 peak and Reher Morrison wanted 6000 stall and that is what Frank spec'd as well. It has been in my car now 6 years and refreshed by Frank 3 times and works as well as it did from day one.

Why don't you try leaving at 4000-4200 off the 2 step and see if there is a difference in 60's and 1/8 mile numbers. Talk with Frank and see what he would recommend and your comment of "overshooting all that torque".

Good luck

Swede

[Jake Conant]

Jake,
I see that your slips and comments that you say it is "the best slip leaving off the juice - ever". The tq and hp numbers you gave Frank Lupo when he spec'd out the 5k stall converter, were they dyno pulls "on juice" numbers or straight off the motor no juice ? Frank is the East Coast guru when it comes to converters (mine are from Frank) so I would have complete trust in his intuition. We just race the damn cars, he has to build stuff for us that makes us happy when we race but I do agree that from a numbers perspective the converter is about 800-1,000 rpm's higher than what I know commonly works the best. My torque numbers are 6200 peak and Reher Morrison wanted 6000 stall and that is what Frank spec'd as well. It has been in my car now 6 years and refreshed by Frank 3 times and works as well as it did from day one.

Why don't you try leaving at 4000-4200 off the 2 step and see if there is a difference in 60's and 1/8 mile numbers. Talk with Frank and see what he would recommend and your comment of "overshooting all that torque".

Good luck

Swede

yea..it was spec'd off the bottle. switching to the nonlocking c4 I figured I wouldnt have much room for juice (which I dont). i said i wanted it for the motor/blower only.

I want to get back asap and try a few different things including changing the 2step launch rpm.

[Jim Dayotas]

Your stats look good, Why look to change?
Anyone can offer you the next best thing in converters, but you'll have to buy it & test it to really find out if it works!

If your using Lupo's converter, you've got one of the best on the east coast!

Converter advice from a stick guy.. :eek: Just kidden. Anyways everyone has a different opinion on converters. I had one of Franks from Dynamic and it sucked. I have always had great luck with ATI. Gary Kaye also has a guy that does converters and you could talk to him or leave in what you have. My advice/experience with driving a 3600lb car with over 900 horses is to have a tranny temp gauge mounted on the hot side. When the covertor slips the temp climbs way quick. You could spend a little cash on a gauge and a mounting block rather than a grand on a convertor you might not need. I also speak from experience on this. Numbers look good though.

[Jake Conant]

Converter advice from a stick guy.. :eek: Just kidden. Anyways everyone has a different opinion on converters. I had one of Franks from Dynamic and it sucked. I have always had great luck with ATI. Gary Kaye also has a guy that does converters and you could talk to him or leave in what you have. My advice/experience with driving a 3600lb car with over 900 horses is to have a tranny temp gauge mounted on the hot side. When the covertor slips the temp climbs way quick. You could spend a little cash on a gauge and a mounting block rather than a grand on a convertor you might not need. I also speak from experience on this. Numbers look good though.

well using a "converter slip calculator" here online, using my rpm/speed/gears/tire specs it said it was only 2% slip. not sure how accurate that is or not.

my sensor is in the pan. it does get warm quick.