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      10-02-2020, 08:33 PM   #45
KoenG
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Originally Posted by CanAutM3 View Post
That's not quite how it works...

While your statement is true for a given gear ratio, it isn't when that gear ratio is changed. Acceleration can be defined with the following formula: a=P/(mv). So for a given road speed, the gear ratio for which the engine makes the most power for that road speed, will provide the most acceleration.
While that's 200% correct: 650Nm in 2nd gear brings much more force to the road than 650Nm in 5th, the suggestion in your previous post seduces me a bit less. There you suggest that when you shift up, that you have to land on the power peak. Actually, I've never seen an ICE being able to do this. And I repeat my previous post... you should land in the higher gear near the max torque. Certainly, when you would still have access to higher HP in previous gear, you didn't have to shift up in the first place of course. HP to the wheel is independant of gear (near constant), but torque to the wheel is certainly dependant (reducing with higher gears)! When you're near Belgium some day, we have to meet and discuss between nerds.
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      10-02-2020, 08:46 PM   #46
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Quote:
Originally Posted by KoenG View Post
While that's 200% correct: 650Nm in 2nd gear brings much more force to the road than 650Nm in 5th, the suggestion in your previous post seduces me a bit less. There you suggest that when you shift up, that you have to land on the power peak. Actually, I've never seen an ICE being able to do this. And I repeat my previous post... you should land in the higher gear near the max torque. Certainly, when you would still have access to higher HP in previous gear, you didn't have to shift up in the first place of course. HP to the wheel is independant of gear (near constant), but torque to the wheel is certainly dependant (reducing with higher gears)! When you're near Belgium some day, we have to meet and discuss between nerds.
Sorry to say, but you're wrong. What you are saying is one of the most common misconception about ideal shift points. We don't need to wait for me to be in Belgium to discuss that, although I'd gladly do so with a good beer in hand .

I never said you need to land on the power peak. However, what I do imply is that you need to hold onto a gear until the power available in the higher gear exceeds the power in the current gear, or hit redline. In other words, you need to constantly maximize power to maximize acceleration.

I agree, power to the wheels is independent of gear ratio, and that is exactly the point. Remember: a=P/(mv). Think about it a little, and it will come to you .
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Last edited by CanAutM3; 10-02-2020 at 09:00 PM..
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      10-02-2020, 08:56 PM   #47
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Quote:
Originally Posted by CanAutM3 View Post
Sorry to say, but you're wrong. What you are saying is one of the most common misconception about ideal shift points. We don't need to wait for me to be in Belgium to discuss that, although I'd gladly do so with a good beer in hand .

I never said you need to land on the power peek. However, what I do imply is that you need to hold onto a gear until the power available in the higher gear exceed the power in the current gear or hit redline. In other words, you need to constantly maximize power to maximize acceleration.

I agree, power to wheel is independent of gear ratio, and that is exactly the point. Remember: a=P/(mv). Think about it a little, and it will come to you .
Yes, that's correct. LOL
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      10-02-2020, 09:04 PM   #48
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Originally Posted by CanAutM3 View Post
Time to geek out a bit. I believe there would indeed a bit more performance to be had through a higher redline with the 6MT given its gear ratios. From the S58 technical doc, we know the S58 can still theoretically make ~460hp (~345kW) up to 7,500rpm.

Using the gear ratios published in the press release, we can find the RPM in the next gear when shifting at redline. Knowing that torque plateaus at 406lb-ft from 2,650 to 6,130rpm, we can calculate the power in the next gear. As you can see, the starting power falls quite significantly below 460hp in the lower gears:
Re-assessing your post, you're stating that the 6MT is too wide spaced and could do with a few gears more to keep it on power after shifting up. So actually, you need to get the ZF8HP instead of the MT.
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      10-03-2020, 06:31 AM   #49
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Originally Posted by KoenG View Post
Re-assessing your post, you're stating that the 6MT is too wide spaced and could do with a few gears more to keep it on power after shifting up. So actually, you need to get the ZF8HP instead of the MT.
Indeed yes. However the two transmissions are paired with very different engine tunes. It is kind of odd that they made a tune with a narrower power band for the wider spaced 6MT ratios. Maybe they wanted it to feel more linear, more like a NA engine.
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      10-04-2020, 01:43 PM   #50
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Quote:
Originally Posted by CanAutM3 View Post
Indeed yes. However the two transmissions are paired with very different engine tunes. It is kind of odd that they made a tune with a narrower power band for the wider spaced 6MT ratios. Maybe they wanted it to feel more linear, more like a NA engine.
I liked your little chart, I do the same sort of thing but I do it for torque applied to the diff through the rev range - same ultimate goal of course as discussed in the last few posts.

I mentioned this earlier but it is a shame they didn't keep 550nm all the way through - to copy paste what I said earlier:

They could have kept 550nm all the way to 6500rpm to have the manual make 375kw from 6500rpm to 7200rpm like the 8AT


That would make it feel much more N/A like and revvy
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      10-04-2020, 01:48 PM   #51
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Originally Posted by brad850csi View Post
I liked your little chart, I do the same sort of thing but I do it for torque applied to the diff through the rev range - same ultimate goal of course as discussed in the last few posts.

I mentioned this earlier but it is a shame they didn't keep 550nm all the way through - to copy paste what I said earlier:

They could have kept 550nm all the way to 6500rpm to have the manual make 375kw from 6500rpm to 7200rpm like the 8AT


That would make it feel much more N/A like and revvy
Agreed, that would have made it even better while still keeping it limited to 550N-m (406lb-ft).
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      10-05-2020, 11:38 AM   #52
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Originally Posted by upsidedownfunnel View Post
I've been theorizing that they would release a higher revving version with the manual version. I guess I was wrong. I don't think it'd require a new version of the engine. It would likely just be an engine tune since I know this engine has a horsepower rating of 473hp @ 5600-7300rpm.
Possibly just a map for the car.

Turbo charged car does not need to rev so high.
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