Ideal shift RPM for 10r80?

[armykyle1 [HACKED ACCOUNT]

I think 1-5 are 7800 on my car (ported mani) and 6th 8000. I assume that's to help keep it out of 7th.

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[brucelinc]

According to the gear ratio calculator I used here: https://spicerparts.com/calculators/transmission-ratio-rpm-calculator and the stated trans gear ratios posted above in the OP ;

When shifting at 7500 from 1st to 2nd the RPMS should theoretically drop to below 5000.. But in my logs this never happens possibly due to wheel spin?

Shifting at 7500 from 2nd to 3rd the RPMS should drop to 5400.

But 3rd to 4th and onward at 7500 and they should drop to 6200+.

This is why I think the ideal shift point may be really high for 1-2 and 2-3 and 7500 or even lower for the rest. In my logs the 1-2 never drops below like 6000 though, but I almost always get wheel spin on that shift so its hard to know whats accurate or best.

I also dont know if I am excluding some characteristic of torque converters during shifts. I also dont know if dropping into more hp but less torque could help prevent wheel spin?

Does anyone know if its possible to change individual gears shift points?

I suspect what is missing in this calculation is the torque converter multiplication factor. I am quite certain that my A10 doesn't drop below 6000 on the 1-2 shift. Yes, there is a bit of wheelspin on that shift even with drag radials but I think the gearing is actually lower (higher numerically) than 2.99 due to the torque converter being unlocked and adding some multiplication.

 

[Idaho2018GTPremium]

Here we go...

So the ideal shift point is at 7500ish RPM (maybe higher; can't tell from the blue RunFile) for 1st, 2nd and 3rd. 7250ish RPM after that because the torque drops off a tad too fast to make it worthwhile to wait till 7500. Then of course there's the 9th-10th shift but not really relevant...

You're the man. Nice.

 

[AZ18yote]

I wonder why shaun is not tuning Boosted 18s

He does my 18 NA flex tune. When asking him about this while planning for future, he mentioned he would not do boosted 18+ unless straight e85 or race gas. Probably the higher compression engine.

 

[Jetnoise]

Based on that graph, I would shift at whatever RPM puts me to at least 5700 in the next gear, but no more than 7500.

Why 5700?

 

[Andy13186]

I tried changing my 1-2 and 2-3 shift to 7800 and didnt get a better 0-60. The 1-2 and 2-3 at 7500 drop into more torque, and I do spin/chirp the tires on those shifts even with drag radials.


Heres my best run this was with the 7500 shift points for all gears you can hear how short it stays in 2nd gear..




This next run was with the 1-2 and 2-3 shifts at 7800, identical 1/8th mile times, identical 60 foot times, different conditions , this one had better DA but the top one had a tail wind (results posted at end of video). First run reported a better 0-60, this run reported a .01 better 330 foot, identical 1/8th mile. No spinning on the 1-2 or 2-3 with the shift point at 7800 , maybe because of the lower torque? I really dont know which is better but this was my results from trying both 7500 for all shift points and 7800 for the 1-2 and 2-3. My best 0-60s so far were with the 7500 shift points and that was with spinning vs not spinning on the 7800's, so 7500 for all shifts is probably better but I am not 100% sure, and I dont know why.





With these 10r80s the dragmode shifts are so fast the car actually seems to accelerate faster during the shift , its so violent so, more shifts may actually benefit your times it seems..


Both runs had identical 0-50 mph too.. so I am thinking the early shift on the first run put it through 60 mph a bit faster..

 

[Zinc03svt]

I shift 7500-7600 in my S drag mode. Tuned base 300a.

 

[Zinc03svt]

They do accelerate on the shifts. Record your speedo sometime. The rear wheels are going faster as the torque is thrown into each shift.

 

[NC85]

8k and beyond. CJ.

 

[jmeiers]

For what it's worth, my 11.06 @ 125 run in my sig was done with 7800 rpm shift points.

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