RPM shift points ?

[Mike Gaines]

Leaving this coming Friday for 10 days at the track.
No real experience with 1000HP HEMI motors (like mine).
Made 3 passes about a month ago but I had restrictor plates closing down the twin Dominators by 50% so no real performance data there. (Car went 140+ easily)
I have the restrictor plates out and will be running it wide full open.
I plan on Launching off the transbrake about 4000RPM.
I know I need anywhere from a 1.28 to 1.32 60' to get the results I am hoping for.
I know the motor has to hit well over 7000RPM thru the lites (probably 7700/7800 or so) to get the MPH I am looking for (high 140's to mid 150's)… 32" tall tires with 105" rollout and 4.56 gears.
I was thinking of shifting 1-2 at about 6500 and 2-3 about 6500 and then letting the motor wind up in high gear the rest of the way. If I shift at 6500 (both shifts) I will be into high gear at about the 300-400 foot mark.
Do this sound like a reasonable plan ?
Input from Big Motor Racers is certainly appreciated.
Thanks, Mike

 

[dvw]

If it makes power to 7200-7300 the true shift point for best ET could be as high as 8000. I'd set the shift light at 6500 1/2 and 6800 2/3. Then work your way up. Guaranteed it needs more than true 6500. But there is lag time between the shift light and the actual shift point. You won't know how much without a replay tach or data logger. Billet valve body's have less lag time than a modified stock core VB
Doug

 

[biomedtechguy]

Good luck Mike Gaines and I'll be....

 

[Mike Gaines]

If it makes power to 7200-7300 the true shift point for best ET could be as high as 8000. I'd set the shift light at 6500 1/2 and 6800 2/3. Then work your way up. Guaranteed it needs more than true 6500. But there is lag time between the shift light and the actual shift point. You won't know how much without a replay tach or data logger. Billet valve body's have less lag time than a modified stock core VB
Doug

Thanks for input.
Motor (off the Dyno Sheet Printout) makes the most HP @7100 (1011HP).
I have a Go Pro Camera snapped to my helmet so I will be able to see exactly when I made the shift and how far tach falls back on the shift.
I will set the shift lite at 6500rpm and motor will probably be around 6800 when shift goes thru, plus I will let it wind up just a little bit more for the 2-3 shift.
Will go from there. Thanks again.

 

[LemonWedge]

I have nothing of any worth to offer on how to run a 1000 hp Hemi..... but I can’t wait to read your reports! Go get em, Mike Gaines!

 

[66Satellite47]

Mike, you know I have no experience with that HP level, but you have RPM potential, I'd be shifting at 7000 both 1-2 & 2-3 and let it run from there. IMHO

 

[stage3]

i have heard that the shift lite should be set 500 rpm's before the actual point, because of the mechanical action of pulling the lever and the lag time it creates,,,,so having said that, if 1 was to put the tach into the dash, and mount the shift lite only on top of the dash, in front of your face, would acomplish the same thing because thats all u r really looking for/at while racing,,who actually relies on there tach's for shifting? use the lite, and check memory playback for fine tuning. right?

 

[66Satellite47]

My shift light is about 100 RPM lead.

 

[biomedtechguy]

Mine is set 400 RPM below the rev limiter, and I haven't hit the limiter yet, so I'm probably hitting the gear w/in 200-300 RPMs of the light coming on.

 

[dvw]

My shift light is about 100 RPM lead.

Do you data log or have a play back tach? A stock based cast valve body will not complete the shift in 100 rpm.
Doug

 

[66Satellite47]

Do you data log or have a play back tach? A stock based cast valve body will not complete the shift in 100 rpm.
Doug

Doug, you may be correct, might be 150 RPM. Yes play back tach. The bigger question is how fast do I react to the shift light? I'm sure the billet valve body can be quicker.

 

[biomedtechguy]

The bigger question is how fast do I react to the shift light?

Exactly! Even if someone is only focused on reacting to a light being turned on, and only having to push a button, RT still takes time. So add that built in delay to whatever has to happen to physically engage the next gear, and add to that whatever else is taking up attention and activity bandwidth, and it takes a bit of time between the light coming on and the next gear going to work.
My Roadrunner at WOT with the 5 speed is a full time job, but that's about to get easier, with a complete new front suspension system and a lot of rear suspension traction aids.

 

[NSS Guy]

Leaving this coming Friday for 10 days at the track.
No real experience with 1000HP HEMI motors (like mine).
Made 3 passes about a month ago but I had restrictor plates closing down the twin Dominators by 50% so no real performance data there. (Car went 140+ easily)
I have the restrictor plates out and will be running it wide full open.
I plan on Launching off the transbrake about 4000RPM.
I know I need anywhere from a 1.28 to 1.32 60' to get the results I am hoping for.
I know the motor has to hit well over 7000RPM thru the lites (probably 7700/7800 or so) to get the MPH I am looking for (high 140's to mid 150's)… 32" tall tires with 105" rollout and 4.56 gears.
I was thinking of shifting 1-2 at about 6500 and 2-3 about 6500 and then letting the motor wind up in high gear the rest of the way. If I shift at 6500 (both shifts) I will be into high gear at about the 300-400 foot mark.
Do this sound like a reasonable plan ?
Input from Big Motor Racers is certainly appreciated.
Thanks, Mike

View attachment 914213

Any updates? time slips?
Us midwesterner's are cold and bored let's here some racing updates

 

[dvw]

Doug, you may be correct, might be 150 RPM. Yes play back tach. The bigger question is how fast do I react to the shift light? I'm sure the billet valve body can be quicker.

The other thing is the shift time is a constant. So the quicker the car accelerates the more the rpm will climb in a given time. Agreed driver reaction time plays a part as well. Not to mention how quickly the band can stop the intermediate drum. I have a sneaking suspicion that even though a iron drum is heavier it stops rotating quicker than an aluminum drum. I think it it due to coefficient of friction between the two types. Before my Turbo Action VB was modified it took every bit of 600-700 rpm to complete the 1/2 shift. 2 different cars, same result
Doug

 

[66Satellite47]

Doug, neither of my Cheetah valve bodies took more than 200-250+/- with 5 or 6 different 727's & a few different band, clutch material, lever, & front clutch spring combination. Griner brake VB same. My Cope valve bodies sure seem in that 100-200 at most. I don't think I have the power you do. But in my 9.3/147 Arrow, the 1-2 shift came pretty quick & it sure wasn't lagging 600 RPM. Just say'n.

 

[biomedtechguy]

in my 9.3/147 Arrow

Pix?
Oh, and....

I saw a Sox and Martin Plymouth Arrow in 1978? It had some kind of experimental Hemi headed Mopar engine that usually would not have Hemi heads.
They made one very fast run in practice (that may have been a record if it was during competition) but on the first comp run the engine blew.

 

[66Satellite47]

Pix?
Oh, and....

I saw a Sox and Martin Plymouth Arrow in 1978? It had some kind of experimental Hemi headed Mopar engine that usually would not have Hemi heads.
They made one very fast run in practice (that may have been a record if it was during competition) but on the first comp run the engine blew.

Here's a few. Sorry they are sideways.