04-22-2024, 01:33 PM | #1 |
Drives: 2023 ZL1 - Modified All Bolt On's Join Date: Dec 2022
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hitting max torque vs max HP and shifting...
My brother in law are in a friendly discussion that goes something like this:
He says: For a 1/4 mile track, you will go slower (time not speed) if you red line/shift your car for each gear vs shitting when you hit the max torque for each gear. I say, both need to hit their max during each gear, no matter which one, torque or HP hits first vs second. So is there any logic in either opinion? This conversation started after we saw a dyno graph for a 2021 ZL1 that showed the below and he said "that guy needs to find the max torque for each gear and shift at that rpm! max Max Power = 715.62 @ 6659rpm and Max Torque = 696.51 @ 4443rpm
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04-22-2024, 01:54 PM | #2 |
Drives: Chevrolet Camaro Join Date: Apr 2022
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I also am shitting when I hit the max torque for each gear... lol
You will absolutely go far slower shifting at 4500 rpm, do it on the street and see how it feels for yourself. The next gear will be trying to come back up from probably 3,000 rpm, that's far from performing to its potential.
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04-22-2024, 02:15 PM | #3 |
Drives: 6th gen Join Date: Aug 2013
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I believe that argument is about hit max torque in the gear you are shifting to. So you start that pull in that gear at max torque.
This may apply in the 1-2 shift. You shift at the right rpm in 1st so you’re at peak torque in 2nd.idk I alway just wring it out. This might work on the 1-2 or 2-3. Prob would have to test it out.
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04-22-2024, 02:18 PM | #4 |
Drives: 2023 ZL1 - Modified All Bolt On's Join Date: Dec 2022
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18.2SS.1LE & 6spd... interesting info. I'll get the dragy app and give it a try !
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2023 ZL1 Auto - CSP 2" Long Tubes by Stainless Works | Gesi G-Sport High Flow CATs | Stainless Works Legend NPP Axle Back | Roto-Fab Big Gulp | Kong NM103mm | Kong X-Port | Griptech 2.3" Upper | ATI Super Damper w/9.45" (18%) Lower | TooHigh PSI Port Injection w/Siemens 875cc Injectors | Brisk RR14S Plugs | Granatelli Malevolent Coil Packs | Katech Low Profile Billet Valve Covers | Katech Duel Fuel Pump System | MightyMouse Wild 1000HP CC | DSX Flex Fuel Kit | DSX Billet Lid | DMS 2gal Fender Tank | Unlocked T93 TCM | NT555R2's 285/305 | Katech Tuned | Straight E85 = 784rwhp / 678rwtq @ 19psi
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04-22-2024, 03:19 PM | #5 |
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Torque is to get you moving...once moving you want to stay up in peak power to accelerate the fastest.
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04-22-2024, 06:22 PM | #6 |
Drives: 2018 Camaro ZL1 Join Date: Aug 2018
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Here's a good way to test it out. Do 1 run shifting at your max torque, let's say 4500 and then do another run shifting at max HP, let's say 6600 rpms.
I bet you'll have a faster time AND speed during the 2nd run. |
04-22-2024, 07:06 PM | #7 |
Drives: 2021 Camaro ZL1 A10 Join Date: Nov 2018
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You’ll be slower shifting at max torque because the torque sent to the rear wheels is lower than the torque sent to the rear wheels at a higher rpm and lower gear—the lower gear multiplies the torque. Horsepower, or power, is the amount of work done over time. Torque is just a force. So hp wins races because it’s work over time—more power equals more work over the same amount of time. Torque feels fast in a short time frame but may not actually be that fast.
But it’s also true that for a given gear your car will accelerate fastest at the torque peak. Eg. 3rd gear will accelerate faster at 4500 rpm than 6000 rpm when the engine torque has begun dropping off. Most cars accelerate the quickest shifting after the hp peak.
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04-22-2024, 07:12 PM | #8 |
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The torque multiplier effect for each gear drops when you upshift. So the power put to the ground through the rpm range up to redline in that gear exceeds the power put down in the next gear. If you want to go fast and quick you shift as close to redline as you can.
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04-23-2024, 05:46 AM | #9 |
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Good info above! So with out me knowing the physics involved, I feel I was on the right track. Hit max HP and shift. I guess it would take a dyno graph for each gear to know your cars max HP for a 1/4 track run (1st - 3rd or 1st - 4th). But good info, good discussion!
I've not considered a trans tune yet. But is this why they are actually really important or not? Thanks
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2023 ZL1 Auto - CSP 2" Long Tubes by Stainless Works | Gesi G-Sport High Flow CATs | Stainless Works Legend NPP Axle Back | Roto-Fab Big Gulp | Kong NM103mm | Kong X-Port | Griptech 2.3" Upper | ATI Super Damper w/9.45" (18%) Lower | TooHigh PSI Port Injection w/Siemens 875cc Injectors | Brisk RR14S Plugs | Granatelli Malevolent Coil Packs | Katech Low Profile Billet Valve Covers | Katech Duel Fuel Pump System | MightyMouse Wild 1000HP CC | DSX Flex Fuel Kit | DSX Billet Lid | DMS 2gal Fender Tank | Unlocked T93 TCM | NT555R2's 285/305 | Katech Tuned | Straight E85 = 784rwhp / 678rwtq @ 19psi
Last edited by 2023_ZL1-AUTO; 04-24-2024 at 08:55 AM. |
04-23-2024, 07:58 AM | #10 |
Snackbar Tuning
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Just follow GM's OEM logic. 1st gear shifts 300 RPM early. 2nd gear shifts 100-200 rpm early. 3-4-5-6-7 shift close to redline.
This is how you go the fastest. Don't overthink it.
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04-23-2024, 05:46 PM | #11 | |
376 cubic inches of fun
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Quote:
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04-23-2024, 06:49 PM | #12 | |
Drives: 2021 Camaro ZL1 A10 Join Date: Nov 2018
Location: Idaho
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Quote:
And I also already said FOR A GIVEN GEAR you will accelerate fastest at torque peak. However, when there’s a lower gear available that multiplies the torque more than the torque has dropped at peak power it will accelerate faster, so for a car with gears, it will be fastest shifting at or beyond peak hp. How do you think low torque/high revving cars accelerate quickly? Low gears that allows them to get into the power band.
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04-23-2024, 06:55 PM | #13 |
Drives: 2021 Camaro ZL1 A10 Join Date: Nov 2018
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Look at it this way: if torque won races then the ZL1 would pull away from a GT500. But it doesn’t. Above 60 mph or so the GT500 accelerates quicker.
ZL1 is 240 lbs lighter and has 650 ft lbs of torque vs 625 ft lbs in the GT500. Difference is 650 hp vs 760 hp. Similarly, a GT3 RS has about half the torque as a ZL1 but 83% of the weight, yet it is about as quick as a ZL1 in a straight line due to gearing taking advantage of the high revving low torque engine.
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04-24-2024, 07:38 AM | #14 |
Drives: 2015 Camaro ZL1 Join Date: Oct 2020
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Average horsepower is what makes them fast.
Shifting ~500rpm after peak power will typically result in the highest trap speed. Every combo is different. You can get close with a dyno but testing at the track or with a dragy are what actually matter. |
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