I apologize if this has been covered a bunch already, but I had a question regarding the shift light.. Does it actually have any technical specifics to when it lights up, for upshifts? Right now I've got it set to light only on upshifts, but I'm wondering which is actually "better", the shift light or my "trained ear". So yeah, I was wondering if it just has a general point for lightup on upshifts, or if that's actually the overall best upshift point for each specific car/gearing setup etc?

Thanks, (and Happy Holidays to any who celebrate this time of year..)

The upshift point is the point in time where when you shift up the revs will drop down such that the power that is produced when you shift remains the same. As such, the optimum shift point is both power curve and gearing related and it is therefore difficult to determine the right one just by listening. One initially keeps an eye on it with his periferal vision and shifts as it comes on. Once you get a good feel for it, you don't really pay much attention to it, but shift by instinct. Still, it is best left on.

I often shift just before the light or a soon as I see it, so long as you're shifting straight into the power band of the next gear then it shouldn't really matter that much. I think using the light is quickest because everyone who sets WR seems to shift at it.

Got it, thanks.

The LFS Shiftlight appears as soon as the Torque in the next Gear is higher than in the current One.

At least thats what i heard.

Quote from Highsider9 :

The LFS Shiftlight appears as soon as the Torque in the next Gear is higher than in the current One.

At least thats what i heard.

Acceleration = Force / Mass
Force = Torque at the Wheels / Tyre Radius

Acceleration = Torque at the Wheels / (Tyre Radius * Mass)

Tyre Radius and Mass are constant.

Acceleration = Torque at the Wheels * k
Torque at the Wheels = Engine Torque * Gear Ratio

Acceleration = Engine Torque * Gear Ratio * k

Acceleration before the gear change should be equal to acceleration after the gear change.

Acceleration1 = Acceleration2

Engine Torque1 * Gear Ratio1 * k = Engine Torque2 * Gear Ratio2 * k
Engine Toruqe1 * Gear Ratio1 = Engine Torque2 * Gear Ratio2

Power = Torque * RPM
Torque = Power / RPM

(Power1 / RPM1) * Gear Ratio1 = (Power2 / RPM2) * Gear Ratio2

Gear Ratio / RPM is a constant because velocity doesnt change during the shift.

Power1 = Power2

OR

Acceleration = Force / Mass

Power = Force * Velocity
Force = Power / Velocity

Acceleration = (Power / Velocity) / Mass

Mass is constant. Velocity doesn't change during the shift so that is constant too.

Acceleration = Power * k

Acceleration before the shift is the same as after the shift.

Acceleration1 = Acceleration2

Power1 * k = Power2 * k
Power1 = Power2

I hope that makes sense.

too much thinking there for this time of the year. but thanks!

Quote from Tinytacohead :

too much thinking there for this time of the year. but thanks!

Yes, I'm quite surprised I'm still capable of that after all the intoxication last week... still have to survive new year's tho.

ditto, hahaha.

Not that simple though. When to shift up if the car's specs are like this?

That car has peak power quite late = Acceleration not so good, high speed very good.

(RPM = rounds per minute. Better use rounds per second if trying to calculate power/torque)

OT: found also this interesting site: http://www.northamptonmotorsport.com/

Quote from Tinytacohead :

I apologize if this has been covered a bunch already, but I had a question regarding the shift light.. Does it actually have any technical specifics to when it lights up, for upshifts? Right now I've got it set to light only on upshifts, but I'm wondering which is actually "better", the shift light or my "trained ear". So yeah, I was wondering if it just has a general point for lightup on upshifts, or if that's actually the overall best upshift point for each specific car/gearing setup etc?

Thanks, (and Happy Holidays to any who celebrate this time of year..)

My advice is to leave the dummy light alone. AFIK it's pretty accurate

That's my intent. I was just wondering because if it wasn't a good meter to go by, I was going to turn it off. What about the downshift light, worth having on? (given I'm not a total idiot about shifting, lol) Currently I just drive with the upshift on..

You can easily feel and hear if a car is not in the powerband and is therefore a gear lower than it should be. When I had the downshift light on I knew I should downshift but by instinct upshifted so it actually just started pissing me off. Also it is good to downshift before the corner and use engine braking (balancing it correctly with the throtle blip) so you should know how many gears to pull in each braking zone. Shift light won't help you there because it only works when you put your foot down out of the corner.

That's what I was thinking, but figured I'd doublecheck, since I'm new to the game. Thanks again..