converter flash RPM vs Shift RPM

Posted By: 340RICK

converter flash RPM vs Shift RPM - 04/02/13 10:58 PM

What typically are you looking for 1500-2000 rpm above converter flash?

I don't have any dyno #'s

Thinking about loosing my converter up for some better 60fts, but don't want to get to close to my shift point.

Posted By: Triple Threat

Re: converter flash RPM vs Shift RPM - 04/02/13 11:24 PM

1500 is a good number. That's about what my new converter was spec'd for, maybe a little less. My last converter was closer to 1000rpm and worked great still.

Posted By: gregsdart

Re: converter flash RPM vs Shift RPM - 04/02/13 11:28 PM

We need a lot more info to come up with a reasonable answer.
A somewhat rule of thumb is 1300 rpm shift points over stall speed, given the converter is set up to stall just above the torque peak. Your shift rpm will depend on your combo. If you post your entire engine combo, someone with a similar combo can give you a decent estimate of shift rpm.

Posted By: 340RICK

Re: converter flash RPM vs Shift RPM - 04/03/13 12:18 AM

Quote:

We need a lot more info to come up with a reasonable answer.
A somewhat rule of thumb is 1300 rpm shift points over stall speed, given the converter is set up to stall just above the torque peak. Your shift rpm will depend on your combo. If you post your entire engine combo, someone with a similar combo can give you a decent estimate of shift rpm.

Well Greg no one has a combo like mine

I am just looking for the rule of thumb answer. I wish I could have put my 3G on a engine dyno to find peak TQ....But chassis dyno is useless for finding that and that is all I have done.

Steffs motor would be somewhat close to mine cant wait to see his #'s

Thanks for the replys

Posted By: rickseeman

Re: converter flash RPM vs Shift RPM - 04/03/13 02:48 PM

I think 1500-2000 is way too much if you want your best leave. I don't think your combo matters at all. Everybody has their own ideas on this. But if you have a slant 6, a mountain motor or something in between, pick your shift point, lets say that is 6500. Get a converter that "stalls" (when I say stalls I mean the first number you see on the tach when you leave the starting line) 1000 rpm's below that. This should put you near your torque peak like some people want. Some people put their launch rpm 1000 below stall speed, but lower may work better. I like to leave at the lowest rpm I can. Sorry for the long answer I guess I just should have said 1,000 rpms.

Posted By: B3422W5

Re: converter flash RPM vs Shift RPM - 04/03/13 03:40 PM

Rick...

Any car i have had i tried to set the flash up to be 1500-1700 rpm below the shift point, and around about the torque peak as well.
My Duster i shifted at 7000, and i suspect the peak torque was about 5200 or so. The convertor flashed about 5400 or so.
Remember as well that the compression you have( or lack thereof) will also effect your 60 foot.Relatively big head, and relatively low compression.
Its entirely possible you actually have the convertor pretty darn close.

Posted By: mopar dave

Re: converter flash RPM vs Shift RPM - 04/03/13 03:46 PM

the peak torque on my 408 is 5100,so dynamic built my vert to stall at 5400. they told me that stall should be 300-400rpm above peak torque. my peak hp is 6800,so I shift at peak hp. I will be trying some different shift points below 6800 to see if that helps et or not this season.

Posted By: MR_P_BODY

Re: converter flash RPM vs Shift RPM - 04/03/13 03:56 PM

Rick.. without having the engine on the dyno it would
be a guess... you would know the peak torque.. you
want the shift to fall back to it.. the peak HP would
be the shift point and go across the line at 10%
above peak hp... the chassis dyno wont work to find
those points due to conv loses... in older style engines
it was pretty close to 1500 rpm on a dyno from the
peak tq to peak hp

Posted By: JD Dart

Re: converter flash RPM vs Shift RPM - 04/03/13 04:08 PM

My peak torque is 6800 that makes 7100-7200 with that I have nothing left mine works best below peak torque by 400. Not every combo will fit the formula. Nothing wrong with trying to get it close make a pass then send it back and have them adjust.

Posted By: rickseeman

Re: converter flash RPM vs Shift RPM - 04/03/13 04:46 PM

Quote:

What typically are you looking for 1500-2000 rpm above converter flash?

I don't have any dyno #'s

Thinking about loosing my converter up for some better 60fts, but don't want to get to close to my shift point.

You say you want to improve your 60' but you didn't say what they are now. The book "Hook and Launch" is good reading and has some charts that give you an idea what your car should do.

Posted By: KOS

Re: converter flash RPM vs Shift RPM - 04/03/13 05:24 PM

Quote:

Quote:

What typically are you looking for 1500-2000 rpm above converter flash?

I don't have any dyno #'s

Thinking about loosing my converter up for some better 60fts, but don't want to get to close to my shift point.

You say you want to improve your 60' but you didn't say what they are now. The book "Hook and Launch" is good reading and has some charts that give you an idea what your car should do.

who is the author of that book?

i am going through the same situation myself just sent my best converter out to get loosened up(ported stator)and make it slightly more effient.will see the results in a shortly but i went approx 1100rpm below shift point.was 1300rpm before.

Posted By: rickseeman

Re: converter flash RPM vs Shift RPM - 04/03/13 05:48 PM

Dick Miller wrote "Hook and Launch". It's got a lot of good info in there for door cars. Rick Jones' and Jerry Bickel's books are good for chassis cars.

Posted By: dartman366

Re: converter flash RPM vs Shift RPM - 04/03/13 06:27 PM

Mine stalls about 900-1000rpm below my shift point,,5800 stall and a 6800 shift point.

Posted By: KOS

Re: converter flash RPM vs Shift RPM - 04/03/13 06:46 PM

Quote:

Mine stalls about 900-1000rpm below my shift point,,5800 stall and a 6800 shift point.

thats exactly what i was shooting for.i also shift at 6800 converter was 5500 now 5700rpm or so i hope.
what does your car run? 60ft? t-brake?

rickseeman thx for the author.....might just check out the book

Posted By: 340RICK

Re: converter flash RPM vs Shift RPM - 04/03/13 09:18 PM

A good guess my peak TQ would be around 5500 range

I have Fast EFI on my car and it has a data logger with it. So I can see exactly where my converter is flashing too. which is 5200-5300. At 5200 or so the rpms will go flat it lugs the engine down and will not pick up any RPM. So that's why I think it may need loosend a lil bit.

On the chassis dyno it was still picking up HP at 7400 RPM when I got sceered and stop the pull.

So far the tune on the car is somewhat close and I have been shifting at about 7200 so the RPMS really fall off between gear changes.

So I guess for it to be optimal it should stall purty close to 6000RPM.

I do street drive the car so I really don't want to get to crazy with the converter but I hate the 1.38 60ft times.

oh well thanks guys for your input

Posted By: dartman366

Re: converter flash RPM vs Shift RPM - 04/04/13 08:11 AM

Quote:

Quote:

Mine stalls about 900-1000rpm below my shift point,,5800 stall and a 6800 shift point.

thats exactly what i was shooting for.i also shift at 6800 converter was 5500 now 5700rpm or so i hope.
what does your car run? 60ft? t-brake?

rickseeman thx for the author.....might just check out the book

Last year it was 60 footing 1.32-1.33,,yes it has a transbrake and it weight's in at 3170 with me in it and race ready, car runs 9.90's to 10.00's in the heat,, this year the weight may change a little, lighter I hope.