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Gearing question
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(42 posts, started )
Quote from AndroidXP :Yes, that would be the optimal case, though it might not be always possible for every car and every gearbox. However, that's not a disadvantage, since everybody suffers the same bad car design then

Great. Since I've got it close now I need to work on the thing between the wheel and the pedals. Is there a setup guide for that?
Quote from AndroidXP :Only indirectly, the real "driver setup" comes from practice

Yeah I've been sleeping with that under my pillow. Doesn't seem to help LOL


Thanks again for the help. I'll get this thing figured out eventually,
Quote from jarmenia :Thanks for the info. So to go a step further. Once I know the powerband, when I shift, I'm going to want the next gear to drop me at the low end of the power band again correct?

Quote from AndroidXP :Yes, that would be the optimal case, though it might not be always possible for every car and every gearbox. However, that's not a disadvantage, since everybody suffers the same bad car design then

@AXP
That's misleading, if it was true you would use linear gearing as mentioned above. There has to be a comprimise between using the torque multiplication of the transmission/differential vs increased resistances like you mentioned above, which as you already said is why we need non linear gearing in every case. Or did I misinterpret that?
Yes of course, what I meant was that it's not necessarily possible to tune the gearing to be in the powerband at all times, for example if you have a very narrow powerband but too few gears available or of course due to the compromises you have to make in general. Just so Mr. jarmenia doesn't waste too much time trying to obtain the unobtainable

Maybe I should've worded that differently...
I see what you're saying though. In the context of the previous definition of the word "powerband" though I had nightmares of Jarmenia tuning each shift to land near the torque peak :scared:

edit: I still think that's what he was indirectly asking or pondering - if that's the case - don't do that!

Jarmenia, remember wheel torque is what matters. Consider the result of whatever torque the engine is generating being multiplied by the reduction gearing of the transmission / differential.
Draw a graph of wheel torque (engine torque multiplied by gear ratio) against wheel speed (road speed, ignoring slip) for each gear. Then you can see how much wheel torque you'll have for a given set of ratios, visualise the layout of the curves etc etc.

But to do that you need an accurate torque curve, and the only ones we have at the moment are Bob's old guesstimates.
Quote from Ball Bearing Turbo :I see what you're saying though. In the context of the previous definition of the word "powerband" though I had nightmares of Jarmenia tuning each shift to land near the torque peak :scared:

edit: I still think that's what he was indirectly asking or pondering - if that's the case - don't do that!

Jarmenia, remember wheel torque is what matters. Consider the result of whatever torque the engine is generating being multiplied by the reduction gearing of the transmission / differential.

Well you were right, that's what I would have done. Hmm, just when I thought I was beginning to understand.
Just don't confuse wheel torque with engine torque. Wheel torque is the key of course since that's the end result.

For ONE GIVEN gear ratio, yes, the engine's torque peak will match peak torque at the wheels. But if you were to change to a shorter ratio whilst acheiving the same speed, the engine would be turning faster and past it's torque peak, but in any normal situation (read: realistic engine curves) your wheel torque will be higher due to greater torque multiplication from gearing. Hence you want to be near peak power at vMax since you're taking advantage of using the shortest gear possible before the engine's torque begins to REALLY take a dive to the point where more multiplication through gearing would be irrelevant.
Quote from Ball Bearing Turbo :Just don't confuse wheel torque with engine torque. Wheel torque is the key of course since that's the end result...

Just a question: does wheel torque plays a role in LFS or this conversation is about real life?

By the way, really informative thread here guys. I learned a lot of new things .
Both.

Math wise this is very simple, and it works in real life and also in LFS for the same reasons.

Think about it:
For your vehicle to get a move on, there has to be a torque generated at the axles of the driven wheels. Though really, most people forget about the fact that the torque at the axles is not just a product of the engine's output, but rather it's a product (even in the mathematical sense) of the entire drivetrain. If I wasn't a lazy SOB I would post some numbers about wheel torque in different gears vs engine output etc, but the concept is straight foward enough.

Wheel torque is directly related to engine torque BY the gear ratios in between the said engine and wheels. The implications of that are what don't occur to everyone right off the bat.
Quote from [GR]Evolution :Just a question: does wheel torque plays a role in LFS or this conversation is about real life?

By the way, really informative thread here guys. I learned a lot of new things .

I agree. They've been very helpful and despite my dumb questions not flamed me once
Quote from Ball Bearing Turbo :Both.

Math wise this is very simple, and it works in real life and also in LFS for the same reasons.

Think about it:
For your vehicle to get a move on, there has to be a torque generated at the axles of the driven wheels. Though really, most people forget about the fact that the torque at the axles is not just a product of the engine's output, but rather it's a product (even in the mathematical sense) of the entire drivetrain. If I wasn't a lazy SOB I would post some numbers about wheel torque in different gears vs engine output etc, but the concept is straight foward enough.

Wheel torque is directly related to engine torque BY the gear ratios in between the said engine and wheels. The implications of that are what don't occur to everyone right off the bat.

Ok, thanks for the explanation . I just didn't knew that wheel torque is indeed an LFS feature. After reading all this, gearing seemed a much more complicated thing than it used to be, to me. Maybe, as jarmenia said, I should just pay a little more attention to it as I like making my own setups (at least in LFS for now ).
The ultimate setup is to have the gears (and driver) setup so that you change up when the acceleration in your current gear dips just below the acceleration in the next gear up. But this of course just assumes that you get your transmission curve right in the first place. I am working on some power/torque curves based on a cars performance as this is something I've always wanted...

@jarmenia - what sort of racing are you looking to do? I'm a fairly accomplished drag/caterham racer IRL and I have been able to help people iron out issues in their driving styles after watching a few laps.

Would you be able to send me a replay of you doing say 10 laps around the track you're having issues with?


EDIT:
Also, someone mentioned the red light being the ultimate time to change up? Personal experience has lead me to beleive this is not so, I find it far too high in most cars, including the XFG the FXO and the RB4 as three examples...
Quote from Kamrock :The ultimate setup is to have the gears (and driver) setup so that you change up when the acceleration in your current gear dips just below the acceleration in the next gear up.

That's question of shift points though, not gear ratios (assuming the rev limiter doesn't get in the way).

Quote from Kamrock :Also, someone mentioned the red light being the ultimate time to change up? Personal experience has lead me to beleive this is not so, I find it far too high in most cars, including the XFG the FXO and the RB4 as three examples...

I believe it comes on where the curves cross, so is quite accurate in that regard. Seeing that tho rev limiters were reduced in a recent patch, and it most of the cars slower, I'd say those high revs were indeed useful.
Quote from Kamrock :The ultimate setup is to have the gears (and driver) setup so that you change up when the acceleration in your current gear dips just below the acceleration in the next gear up. But this of course just assumes that you get your transmission curve right in the first place. I am working on some power/torque curves based on a cars performance as this is something I've always wanted...

@jarmenia - what sort of racing are you looking to do? I'm a fairly accomplished drag/caterham racer IRL and I have been able to help people iron out issues in their driving styles after watching a few laps.

Would you be able to send me a replay of you doing say 10 laps around the track you're having issues with?


EDIT:
Also, someone mentioned the red light being the ultimate time to change up? Personal experience has lead me to beleive this is not so, I find it far too high in most cars, including the XFG the FXO and the RB4 as three examples...

Right now I'm taking part in the OWRL and, being very new to racing am kind of just trying to find out enough to start. Its kind of you need to do it to know what questions to ask if you know what I mean.
Quote from Bob Smith :
I believe it comes on where the curves cross, so is quite accurate in that regard. Seeing that tho rev limiters were reduced in a recent patch, and it most of the cars slower, I'd say those high revs were indeed useful.

I dunno, I thought the drop in speed on the cars was a more accurate model of engine inertia and transmission drag?

Nah, I always find I get better pull from these car just changing up anything from 500 to a full 1000rpm earlier than the shift light:eclipsee_
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Gearing question
(42 posts, started )
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