Latest build of iRacing has kick out LFS from the place where it was the leader of all sims - transmission simulation. This was another time when competition has proven that LFS had something revolutionary but wasn't polished up to the maximum. LFS still has advantage having engine stalling and clutch overheating, but pure transmission simulation is designed better in iR now.

First lack of the LFS transmission model is that we have only syncromesh H pattern gearbox. It is mounted in GTR cars (UFR, FZR) instead of H pattern dog box, where you can do clutch-less up/down shifts without need to exactly match engine rpm to gearbox rpm. LFS have dog boxes but only sequential one (you can up-shift just by lifting off, no need to wait till revs will drop to the level of next gear).

Second LFS' transmission problem is that you can get out of gear in H pattern box when transmission is loaded (full throttle or engine braking). Only in sequential gearbox it is implemented correctly, but I don't know why it isn't in H pattern one.

Of course gearbox grind noise should be implemented when driver wants to change gear and revs are not matched, but this was suggested many times before.

I have also suggestion for ignition switch button in LFS.
Short pressing of this button should just turn on/off the ignition. To initiate the starter driver should press and hold it for one second.

It should behave like below:
-> Short press
---> Long press

Ign ON -> Ign OFF
Ign OFF -> Ign ON
Ign ON ---> Ign ON + Engine starting (with starter gear grind against fly wheel)
Ign OFF ---> Ign ON + Engine starting

Very good post

Quote from yaper :

First lack of the LFS transmission model is that we have only syncromesh H pattern gearbox. It is mounted in GTR cars (UFR, FZR) instead of H pattern dog box, where you can do clutch-less up/down shifts without need to exactly match engine rpm to gearbox rpm. LFS have dog boxes but only sequential one (you can up-shift just by lifting off, no need to wait till revs will drop to the level of next gear).

They used to all have sequentials. They were changed to H-Pattern to introduce a bit of a disadvantage to help balance the classes, particularly the FZR. An H-Pattern dog box wouldn't give the disadvantage, so they may as well have kept the sequential in that case.

Quote from yaper :

Second LFS' transmission problem is that you can get out of gear in H pattern box when transmission is loaded (full throttle or engine braking). Only in sequential gearbox it is implemented correctly, but I don't know why it isn't in H pattern one.

Originally, LFS stopped you getting out of gear unless the clutch was depressed, but it was changed to allow the box to go into neutral without pressing the clutch pedal.

This was largely done to stop people cheating by putting the physical shifter into the next position early, then briefly mashing the clutch at the right time to change gear much faster and more reliably.

Short of FFB shifters, I'm not sure how this issue could be solved.

Quote from yaper :

I have also suggestion for ignition switch button in LFS.
Short pressing of this button should just turn on/off the ignition. To initiate the starter driver should press and hold it for one second.
...

I know that would add a little realism, but would there really be any situation in LFS where you would want to turn on the ignition and *not* the engine?

Currently LFS simulates all the ignition stages that matter (stalling keeps ignition on and you have to reset to start the engine; pushing while on turns it off; pushing while off turns it on.

In the past (right before engine stalling was implemented IIRC) the starter actually engaged with the engine for a little while, and it was possible to move the car with the starter. I'm not entirely sure why that was removed. Ed: I suppose it's possible that the starter hasn't got enough torque to move the car

Imo, the only things to fix in LFS transmission modeling are:

1. Proper ignition cut. The way Scawen has currently coded it is wrong and slow, the ignition cut doesn't mean killing the ignition of the whole engine (and I'm pretty sure it does just that, although then turbo boost would be dependant only on throttle pedal position). In real life it's enough to cut the ignition on only 2-3 cylinders of the 6 or 8 cylinders in the engine, just enough to unload the transmission and enable the dogs to catch next gear. This is why XRR is still slower than FZR in accelerations, too much time lost with the current ignition cut (it'd be much faster to just give it the regular lift-type sequential, and yes, it would outweigh any disadvantages of losing some boost for a split second).

2. Having the option of autoclutch only on downshifts in cars with sequential gearboxes (ign. cut and regular), because that's how shifting is done in 98 % of the cases of dog-boxes in real life, making it a lot easier to blip the throttle (without chancing a miss-shift or riding the throttle as many idiots do).

3. Gearbox damage. Stresses on gear teeth and dog rings can be calculated pretty easily and a wear model could be introduced, this would be especially handy in endurance racing and it would force people to learn how to take care of their cars (and not skip blipping the throttle).

4. Clutch heating/wearing model re-done. Currently you can still flatshift in a 500 hp car during the whole 1-hour stint and not have your clutch temp go into the red area, and this is ok, racing clutches made of C/SiC don't really care about being slipped or their temperature, but what they do care about is being constantly stressed with impulses during flatshifts (and not only the clutch, but the whole drivetrain). This is another area where a vibration/stress model would be benefitial (especially for flatshifting in road cars).

5. As yaper said above, dog H boxes on racy slower cars (FWD GTR, FZR). Maybe even a DSG transmission for the never-coming Scirocco.

Quote from Degats :

Originally, LFS stopped you getting out of gear unless the clutch was depressed, but it was changed to allow the box to go into neutral without pressing the clutch pedal.

This was largely done to stop people cheating by putting the physical shifter into the next position early, then briefly mashing the clutch at the right time to change gear much faster and more reliably.

Short of FFB shifters, I'm not sure how this issue could be solved.

Yes, this problem is the biggest issue with present model in iR. In H dog box you can pre-set next gear while being on full throttle, and then just lift for a split second to have this gear engaged.
My idea to bring it back to LFS is to allow H pattern box to select next gear only in case when registered-physical position of the lever is on neutral position.
In other words:

• When you are on 2nd, LFS is registering current lever position, and you can only get out of gear in that case.
  
• When LFS will find out that you put stick into neutral position it will try to go out of gear. If transmission will be unloaded (lift, blip, or clutch depending on situation) it will go out to N and register that. If transmission still will be loaded, 2nd gear will still be registered.
  
• Next, the driver will push the lever into 3rd gear. Now LFS will check which gear is registered. If 2nd gear is registered (failed getting out of the gear) then it will switch to N (keeping the gear still registered until user will select N). If neutral was registered, LFS will continue to engage selected gear.
  

This will require to go through N in the process of gear changing.

Quote from Degats :

I know that would add a little realism, but would there really be any situation in LFS where you would want to turn on the ignition and *not* the engine?

Currently LFS simulates all the ignition stages that matter (stalling keeps ignition on and you have to reset to start the engine; pushing while on turns it off; pushing while off turns it on.

In the past (right before engine stalling was implemented IIRC) the starter actually engaged with the engine for a little while, and it was possible to move the car with the starter. I'm not entirely sure why that was removed. Ed: I suppose it's possible that the starter hasn't got enough torque to move the car

I was suggesting that just to remove need to double press of button to restart the engine in case of stalling it.

BTW.
You can still move the car with the starter.

Quote from scipy :

Imo, the only things to fix in LFS transmission modeling are:
[...]
3. Gearbox damage. Stresses on gear teeth and dog rings can be calculated pretty easily and a wear model could be introduced, this would be especially handy in endurance racing and it would force people to learn how to take care of their cars (and not skip blipping the throttle).

Sure, this is the item which has to be done. This will extort the driver to threat the gerbox more like in RL.

Good ideas yaper & scipy.

Quote from yaper :

When you are on 2nd, LFS is registering current lever position, and you can only get out of gear in that case.

• When LFS will find out that you put stick into neutral position it will try to go out of gear. If transmission will be unloaded (lift, blip, or clutch depending on situation) it will go out to N and register that. If transmission still will be loaded, 2nd gear will still be registered.
  

But IRL you can get take it out of gear, without clutch and it doesnt damage the gearbox. So why should this "sim" be anyway different?

Other than that i love your suggestions

Quote from Feffe85 :

But IRL you can get take it out of gear, without clutch and it doesnt damage the gearbox. So why should this "sim" be anyway different?

I wanted to say you can only get out of the gear, but not go into another gear in that step.