Shift light, tach, by ear, rev limiter; what's your choice

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I always set all of my gauges to read at 12 o’clock. My tach was set for shift point at 12 also. You could read all of them with peripheral vision or just a quick glance.
 
Along the same line of questions but a bit different. In the above comments, all responses are for which method do you use to indicate shift points.

My question is at what RPM do you select your shift points. My car is a RB 512 with about 550 hp for example. I have a 727 with Transgo2 shift kit, quicksilver shifter, 3.91 ratio 8 3/4 rear end and a gear vendors overdrive. The torque converter stalls at 3500 rpm according to the dyno guy. (I know a bit low but it is what I have for now.) I have not raced it since I put in the overdrive and only had 425 hp at the time. I am an inexperienced racer and my sons will probably do most of the runs. They are also not experienced racers at the drag strip but race a challenger on road course. If I have a dyno for HP and Torque curves, at what rpms do you try to shift. At max torque? 300 before that? at max HP? etc.. ... We only have the Holley Super Sniper EFI programmed to 6500 rpms but that could change if needed. I don't think we would even need to use the gearvendors OD but I am no expert.

I have a tach with a light and I want to set the light to shift correctly. I may have to have the light come on a couple hundred RPM before the shift point and I can run a datalog on the sniper to see exactly what rpm we reached before shifting. Knowing the data for the shifts helps but knowing what shift point is correct for my car is more important. How do you determine what is best????

Thanks for any help.

If I should start a new thread let me know. I do not intend to hijack this one.
 
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I use a buzzer; doesn't matter where your eyes are looking, you will hear a buzzer....
 
Kent mosby said:
Along the same line of questions but a bit different. In the above comments, all responses are for which method do you use to indicate shift points.

My question is at what RPM do you select your shift points. My car is a RB 512 with about 550 hp for example. I have a 727 with Transgo2 shift kit, quicksilver shifter, 3.91 ratio 8 3/4 rear end and a gear vendors overdrive. The torque converter stalls at 3500 rpm according to the dyno guy. (I know a bit low but it is what I have for now.) I have not raced it since I put in the overdrive and only had 425 hp at the time. I am an inexperienced racer and my sons will probably do most of the runs. They are also not experienced racers at the drag strip but race a challenger on road course. If I have a dyno for HP and Torque curves, at what rpms do you try to shift. At max torque? 300 before that? at max HP? etc.. ... We only have the Holley Super Sniper EFI programmed to 6500 rpms but that could change if needed. I don't think we would even need to use the gearvendors OD but I am no expert.

I have a tach with a light and I want to set the light to shift correctly. I may have to have the light come on a couple hundred RPM before the shift point and I can run a datalog on the sniper to see exactly what rpm we reached before shifting. Knowing the data for the shifts helps but knowing what shift point is correct for my car is more important. How do you determine what is best????

Thanks for any help.

If I should start a new thread let me know. I do not intend to hijack this one.
Click to expand...
I found that shifting at peak power worked best for me, however, I was not running a 550 hp big block, my engine peaked at around 5500 rpm, so in the beginning I shifted when I felt it start to fall off. I would expect that you will need to make some passes at varying shift rpm and analyzing the timeslips or data logger if you have one to determine what will give you the best results.
As others have mentioned, it is helpful to take your reaction time into account when determining the setting for a shift light, a few hundred rpm before you reach your intended shift point. Traction is an important factor as well, if you're overpowering the suspension and tires, making a smokeshow, you're not going as fast as you could be. I have probably not helped you with this answer, but for me getting seat time is the best way to find the sweet spot.
 
Kent mosby said:
Along the same line of questions but a bit different. In the above comments, all responses are for which method do you use to indicate shift points.

My question is at what RPM do you select your shift points. My car is a RB 512 with about 550 hp for example. I have a 727 with Transgo2 shift kit, quicksilver shifter, 3.91 ratio 8 3/4 rear end and a gear vendors overdrive. The torque converter stalls at 3500 rpm according to the dyno guy. (I know a bit low but it is what I have for now.) I have not raced it since I put in the overdrive and only had 425 hp at the time. I am an inexperienced racer and my sons will probably do most of the runs. They are also not experienced racers at the drag strip but race a challenger on road course. If I have a dyno for HP and Torque curves, at what rpms do you try to shift. At max torque? 300 before that? at max HP? etc.. ... We only have the Holley Super Sniper EFI programmed to 6500 rpms but that could change if needed. I don't think we would even need to use the gearvendors OD but I am no expert.

I have a tach with a light and I want to set the light to shift correctly. I may have to have the light come on a couple hundred RPM before the shift point and I can run a datalog on the sniper to see exactly what rpm we reached before shifting. Knowing the data for the shifts helps but knowing what shift point is correct for my car is more important. How do you determine what is best????

Thanks for any help.

If I should start a new thread let me know. I do not intend to hijack this one.
Click to expand...

I'll go back and edit my post for more info. You should run power loops. Get a base line, then try shifting at different rpm till you get the lowest ET. Make 2 or 3 runs at each rpm to get a good read.
 
66fs said:
I'll go back and edit my post for more info. You should run power loops. Get a base line, then try shifting at different rpm till you get the lowest ET. Make 2 or 3 runs at each rpm to get a good read.
Click to expand...
Yep, that's it^^^^^^. Pick a very safe rpm to shift at, get a consistent number, then increase rpm, and test. (Trying not to exceed BOOM rpm)
Best et shift point is often a couple hundred rpm above hp peak, but not always. Shifting at peak torque is a guaranteed way to slow way down.
I have found with my 440 that it et's as well at 5900 as it does at 6300, probably due to the 906 heads, even though it will easily turn 6500. So, I shift it at 5900. No reason to high rpm shift if not necessary.
 
318, 904 auto, 7 1/4 w/ 2.76's
PXL_20220421_034043913.PORTRAIT (1).jpg

I set my tach under the line of the door so it looks like I have nothing special when someone next to me looks in. When I am just cruising alone and playing; I use the tach to shift because I can look over at it. (exactly at 5500) But I have found when I am really pushing it, I have to go by ear since I can't look down, get off the gas, shift, get back on the gas then look up. (funky transmission does not shift at full tilt.) Then I shift at around 6300-ish. (reckless I know with a mystery built 318, but it pulls until around 6500 so it must be fine)
 
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