Does rev matching actually have any effect in LFS?

And what is the purpose of heel and toeing, in real life that is? Is it to rev match the dog teeth, or to rev match the clutch? Because I don't see how it'd help to rev match the dog teeth unless you actually double clutched whilst heel/toeing.

Quote from sinkoman :

Does rev matching actually have any effect in LFS?

And what is the purpose of heel and toeing, in real life that is? Is it to rev match the dog teeth, or to rev match the clutch? Because I don't see how it'd help to rev match the dog teeth unless you actually double clutched whilst heel/toeing.

Heel-toeing is to match the output of the powerband of the gear. If the rev is dropped too low, the power will not be sufficient enough to exit the corner.

You can't shift very well in LFS unless you revmatch. It just won't switch gears.

You don't quite understand how transmissions work do you? When you're heel and toeing, your right foot is on the brake, slowing for a turn, and on the gas raising revs, while your left foot is on the clutch. Heel and toeing just gets the transmission in the correct gear to exit the upcoming turn. And with synchros, it's not too necessary to double clutch. Just bring the revs up to prevent driveline shock and stick the shifter into gear.

Also, the input shaft is connected to the clutch by a splined end. Can't move one without moving the other.

Quote from Secondaries :

You can't shift very well in LFS unless you revmatch. It just won't switch gears.

You don't quite understand how transmissions work do you? When you're heel and toeing, your right foot is on the brake, slowing for a turn, and on the gas raising revs, while your left foot is on the clutch. Heel and toeing just gets the transmission in the correct gear to exit the upcoming turn. And with synchros, it's not too necessary to double clutch. Just bring the revs up to prevent driveline shock and stick the shifter into gear.

Also, the input shaft is connected to the clutch by a splined end. Can't move one without moving the other.

Well, I probably just didn't write what I meant very well.

I understand how transmissions work perfectly well. Maybe not exceptionally well, but I know how, lets say double clutching, works.

I just don't understand the ultimate purpose, and intricate details, behind blipping the throttle whilst downshifting. I just know that if you don't do it, you risk transmission shock, and locking your rear tires, and THOUGHT it was because the lower gear ration means higher input shaft speed, meaning a shit tonne of engine braking when your engine makes contact with the input shaft/clutch, and that heel/toeing keeps the engine rev up so that when it makes contact with the input shaft, there's less mess.

And what I meant by "rev matching clutch" is rev matching your engine to your transmission input shaft.

Maybe I don't understand the inner workings of a tranny as well as I think I do...

Quote from sinkoman :

Well, I probably just didn't write what I meant very well.

I understand how transmissions work perfectly well. Maybe not exceptionally well, but I know how, lets say double clutching, works.

I just don't understand the ultimate purpose, and intricate details, behind blipping the throttle whilst downshifting. I just know that if you don't do it, you risk transmission shock, and locking your rear tires, and THOUGHT it was because the lower gear ration means higher input shaft speed, meaning a shit tonne of engine braking when your engine makes contact with the input shaft/clutch, and that heel/toeing keeps the engine rev up so that when it makes contact with the input shaft, there's less mess.

And what I meant by "rev matching clutch" is rev matching your engine to your transmission input shaft.

Maybe I don't understand the inner workings of a tranny as well as I think I do...

Heel toe in most normal driving with modern syncros is not really required, you can downshift and unless there is a huge difference between the current revs and the required revs you will hear the syncro do its job. You might feel the car slow but you are not on the tyres limits so there is no risk.

When you heel-toe/blip all you are really doing is rev matching as you downshift to help with car balance. Say you are trail braking down to an apex and you want to downshift to setup for the exit.

If you are already on the limit of grip on the tyres and then downshift and let out the clutch the extra load on the tyres from engine braking will cause the powered wheels lose traction.

When you blip to the correct revs there is no impact from the shift on the balance of the car. Another added benefit is you should now be in the correct part of the powerband to get the best exit from the corner.

If you are not braking on the limit of the tyres you can downshift and use the engine braking to help with the slowdown. This technique makes it harder to trail brake as the cars balance is far less predictable.

I vote for "rev match the clutch/flywheel". The synchros do their work when you push the gear lever into the required gear, before you start lifting the clutch, at which point the dog teeth are engaged.

The main reason for matching being that otherwise the tyres have to do the work of spinning the engine up to speed, in addition to gripping the road, which could push them over their limit of grip.

I may well be wrong though!

Definitely rev-matching the clutch. You'll need to do this with or without synchro.

Does anyone else have trouble heel-toeing with a G25? The dang gas and brake pedals are too far apart...

Anyways.. how would one left-foot brake in a standard tranny car? Is it as simple as putting your left foot half on the brake and half on the clutch pedal?

Quote from MAGGOT :

Anyways. how would one left-foot brake in a standard tranny car? Is it as simple as putting your left foot half on the brake and half on the clutch pedal?

I don't think anyone would every consider using one foot for operating both the clutch and the brake at the same time (I think that's what you're suggesting but I'm not sure...). If you want to left foot brake in a car with a manual transmission (where the clutch pedal is required to shift) then you'd do all shifts normally (i.e. left foot on the clutch, right foot braking and blipping the throttle) then jump both your feet over to he right at the same time (i.e. right foot solely onto the accelerator and left foot solely onto the brake). Coincidentally, I watched a video on the Autocar website where Chris Harris explains how he exploits the peculiarities of the diff on the Focus RS using left foot braking. It contains decent footage of left foot braking in a car with a manual box.

Quote from MAGGOT :

Does anyone else have trouble heel-toeing with a G25?

I still do it though. The most annoying thing I find is I'm tending to lift off the brake more than i want to just to get my foot up to the accellerator.

I also have trouble in 6 gear cars with knocking it out of 6th gear, but that's just because my desk is restrictive.

I wonder if the bolt spacing on the pedals is the same as in a real car? Might be able to replace the pedals with wider ones. Having said that there is a little lip on the accelerator, and it's probably OK in shoes.

I don't really want to wear shoes though, because there's less resistance than in a real car you don't get enough feel in shoes.

Quote from MAGGOT :

Does anyone else have trouble heel-toeing with a G25? The dang gas and brake pedals are too far apart..

You can try this

Not only too far apart, but the throttle is the same height as the brake, and being displacement sensitive it's far too hard to modulate brakes and blip the throttle. So I don't bother much.

Thanks for the link amp88, good info in there. I must admit, I do need to practice my heel-toe a lot more than I do, I'm still quite bad at it, and, *gasp*, I find myself racing with auto clutch because of it

Has anyone tried mounting a set of aftermarket pedals on their G25? Is it more or less a direct bolt-on, or does it require some modification? Moreover, has anyone tried anything to move the brake pedal closer to the gas to make heel-toeing easier?

[EDIT] I'm slow. :P

Quote from NitroNitrous :

You can try this

I'd love to do that... I just don't want to open up my pedals =/ Maybe once I finally get around to building that cockpit I've been planning on...

Quote from tristancliffe :

Not only too far apart, but the throttle is the same height as the brake, and being displacement sensitive it's far too hard to modulate brakes and blip the throttle. So I don't bother much.

Do you mean you don't bother blipping? I've found the cars (RWD especially) become extremely unstable if I don't blip, especially into slower corners coming from high-speed straights (Aston hairpin, for example), where the braking zone is harder than in medium speed corners.

this might give u some ideas...

my friend putted wood block under gas pedal so he raised it a bit and before mounting pedal on that wooden block he moved it little closer to the clutch...

http://i58.photobucket.com/alb ... ecortin/Rest/0ff1b5e7.jpg
http://i58.photobucket.com/alb ... ecortin/Rest/52bc6f06.jpg

You only have to double clutch on a transmission without sychros. I've tried it before, and it's hard for me to do, but I can feel the difference on downshifts, I don't feel my synchros spinning up to speed obviously, since everything is at the same speed already.

I don't double clutch much, but I do heel and toe throttle blip my downshifts. The synchros on the transmission have already spun the transmission input shaft up to speed, all your throttle blip does is make sure the flywheel is at more or less the same speed as the clutch/input shaft so you don't send a shock through your driveline and lock your wheels.

Now, I drive a FWD car, so I'm not gonna lock the rear wheels and spin if I mess up a downshift, but it's not a very pleasant feeling not rev matching.

You might try this brake pedal spacer for the G25. You put behind the brake petal so that you can move it over to the right.

I assume that is a blueprint? How thick should the material be, and what should it be made of?

If I get some time soon this is definately something I'll need to do.

As others pointed out, the main reason for heel-toeing is that when you push in the clutch the engine rpm drops (or remains pretty much unchanged for an instant). When you downshift and release the clutch again, the clutch plates speed up the engine a bunch in a very short period of time until the clutch plates are locked together again. Action/reaction: If the engine speeds up very quickly over a fraction of a second as a result of the clutch plates, the driven wheels will also slow down very quickly, acting just like you stabbed the brakes momentarily, but only at the rear wheels. If you're already at the limit of braking then you'll go over it on the rears, and if you're turning at the same time you'll upset whatever balance you had going into the corner. It's a lot like you flipped the brake bias momentarily toward the rear for a fraction of a second until the engine rpm rose to where it should be in the new, lower gear.

This may or may not upset the car/tire combination. Some won't care much while others might. If the engine has extremely low inertia it can change speeds quickly while hardly hitting the rear wheels. In such a car you might not need to bother with it, especially if the gear ratios are close together.

In Atari's Hard Drivin' way back in the day, which was really the first real sim, I didn't know about heel toeing and it hadn't occurred to me. In that sim I found that letting the clutch out slowly during the downshifts was enough to keep things stable. I do this in LFS too rather than trying to operate both the brake and gas with one foot. In the arcade F355 challenge I did the heel toe thing because the pedals were set up a bit better for my feet than the G25 ones are. In LFS now I generally shift directly to the gear I want and then very slowly let out the clutch so the engine rpm rises gingerly to the new, higher rpm. In reality this is probably a bad idea as it causes a lot of unnecessary clutch wear. However, I don't have to replace the clutch in LFS so I'll keep right on doing this for a bit