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baz00ka
14-09-2015, 23:32
figured its a basic question and there are enough race car nuts here to answer :) road cars or at least modern road cars have rev limiter so say in 1st if you redline it and it hits rev limiter it stays there til you lift. works the same with in game road cars. race cars in game say McLaren 12c gt3 again in 1st if you redline it it hits the limiter then cuts completely on its own when throttle still fully open then goes back quickly to the limit then stays there. i assume its realistic representation so what its all about ? is it there to help with starts as it seems pretty efficient at that ? obviously i'm not a racing driver and not even decent amateur but in a road car i would never redline it in 1st instead i would get it somewhere high enough in rev range depending on a car and then slip into 2nd from there which burns the clutch but works out faster. this momentary cut thing seem to be working pretty efficient at least in game so i wonder if this is what its made for in the first place or there is a different reason for it.

AB_Attack
15-09-2015, 10:44
i assume its realistic representation so what its all about ? is it there to help with starts as it seems pretty efficient at that ?
I assume it is there to protect the engine. Nothing good comes out of overrevving anyway as far as I know.

What I wonder is why the RUF GT3 hits the limit before the marker?

madmax2069
15-09-2015, 11:07
The rev limiter/fuel/ignition cut off is there to protect the engine to keep you from over revving, thats its only reason.

baz00ka
15-09-2015, 11:17
that doesnt really make sense. if you take in game McLaren 12c road car which btw has more power than its gt3 race counterpart there you hit the rev limiter in 1st and its stays there on the rev limit til you lift, no cut happens at all. so why the cut in the race car, why not just standard rev limiter where it simply doesnt let it go beyond what the engine is designed for?

madmax2069
15-09-2015, 12:29
that doesnt really make sense. if you take in game McLaren 12c road car which btw has more power than its gt3 race counterpart there you hit the rev limiter in 1st and its stays there on the rev limit til you lift, no cut happens at all. so why the cut in the race car, why not just standard rev limiter where it simply doesnt let it go beyond what the engine is designed for?

How does that not make sense, the higher the revs the higher the rotating mass which means parts are under more stress, if you go far above that point something is going to break, and anything above redline produces less power as well.

Read this in its entirety then you might understand
https://en.m.wikipedia.org/wiki/Rev_limiter

Theres different forms of rev limiters as well, ignition cut off, fuel cutoff, and combination of both.

AB_Attack
15-09-2015, 13:12
No, he's asking why it drops revs instead of staying at max allowed. I agree that doesn't make sense much in a racecar. If that is what happens.

baz00ka
15-09-2015, 13:14
@madmax it does not make sense bc you clearly dunno the answer yet compelled to answer anyway as it often is on internet forums for some reason and throw some generic bs with wikipedia link explanation that does not address the question. let me split it into several questions, maybe it would be easier to comprehend what i'm after.

1. the cut only happens in 1st gear once from standing start. if its there only to protect the engine why does it only happen once and only in 1st and only from standing start ?

2. if you dont lift and keep on it after cut it allows the rpms to raise again and stay there so presumably it hits the actual limiter or 2nd limiter or whatever. if the initial cut is to protect the engine why it does not cut the second time ? if there is 2nd limiter why cut in the 1st place ?

3.. 12c and 12cgt3 both have the same engine. granted gt3 version is tuned for track and compliance. if its built and tuned to operate at higher rpms than the standard one why simply not raise the standard rev limiter range from the regular 12c, why cut the power off completely ?

thmxvr
15-09-2015, 14:50
It is probably physics related. The rev limiter cuts the spark (and sometimes fuel) for a small amount of time until the rpm gets down to a certain margin. So if you go from the limit to where the rev limiter enter in action to the limit where it deactivate and so on very quickly you will not perceive the fact that it is working intermittently, but it always is.

After that (depending on a lot of factors) you might be in a situation where you need more time without powering the engine to get back in the safe rpm range. This most likely because the inertia of the car made you go OVER the rev limit. The rev limiter have no effect over this phenomenon and your engine will suffer/fails. The race car and road car are totally different and comparing those expecting to perform equally is not a good idea. On the top of my head here are the settings that can change this phenomenon:

- Rev limiter hysteresis setting (at which rpm it enters in action at at which it deactivate). I expect road car rev limiter and race car rev limiter to have totally different settings.
- Engine responsiveness
- Inertia/weight of the transmission component
- Weight of the car
- Gearing. And this one is probably the one with the more effects. Road cars have very short 1st gear so much more engine brake when you lift off or the rev limiter enters in actions this brings you to a lower rpm quicker.
- ...

Yorkie065
15-09-2015, 15:26
Ah! See I had my eye on this thread earlier and had something in my mind as to what it could be but your break down of questions has confirmed my suspicions.

It's the auto clutch! I don't know why, but it's pretty poor on the GT cars. I know they have a huge amount of mechanical grip, so much so that there have been reports of drivers snapping drive-shafts if they try to launch the car too hard irl. But I think what it is the clutch moves to the biting point and holds for a split second then drops the clutch and it seems like there isn't enough power or there's too much grip to the spin the wheels so the revs just die out. Thats what I believe it is anyway, as other cars either have tyres that aren't great or more power than the tyres can handle, so they spin up and you can hold the revs better as you pull away.

Umer Ahmad
15-09-2015, 15:30
Yeah good point, test again with auto-clutch = OFF

Same behavior?

AB_Attack
15-09-2015, 18:35
Ah! See I had my eye on this thread earlier and had something in my mind as to what it could be but your break down of questions has confirmed my suspicions.

It's the auto clutch! I don't know why, but it's pretty poor on the GT cars. I know they have a huge amount of mechanical grip, so much so that there have been reports of drivers snapping drive-shafts if they try to launch the car too hard irl. But I think what it is the clutch moves to the biting point and holds for a split second then drops the clutch and it seems like there isn't enough power or there's too much grip to the spin the wheels so the revs just die out. Thats what I believe it is anyway, as other cars either have tyres that aren't great or more power than the tyres can handle, so they spin up and you can hold the revs better as you pull away.

Good stuff. This is very applicable to my thread on standing starts as well. http://forum.projectcarsgame.com/showthread.php?39151-Starts-getting-off-the-grid

baz00ka
15-09-2015, 21:56
Bingo Yorkie065! I did find an article about someone driving McLaren GT3 and it says it has sequential sans clutch shifter except for the 1st gear to start moving from stationary. This is the only time that car needs clutching. So the game when auto clutch is set just simulates the operator doing it. Without auto clutch set it behaves exactly the same like once there is significant enough bite on the clutch the revs drops dead and then build back up from there as it gains momentum. Must be to protect transmission parts (from what you are describing) as sudden kick like that has to go somewhere and if the car is glued it will find another way out thru transmission part breaking loose. As an experiment (in game) its is possible to start keeping at maximum rpms or close to it (without cut) by slowly burning the clutch in. Call me stupid but i'm pretty impressed by the level of modelling this game does on little details like this. Anyways, another mystery solved, thanks!



Ah! See I had my eye on this thread earlier and had something in my mind as to what it could be but your break down of questions has confirmed my suspicions.

It's the auto clutch! I don't know why, but it's pretty poor on the GT cars. I know they have a huge amount of mechanical grip, so much so that there have been reports of drivers snapping drive-shafts if they try to launch the car too hard irl. But I think what it is the clutch moves to the biting point and holds for a split second then drops the clutch and it seems like there isn't enough power or there's too much grip to the spin the wheels so the revs just die out. Thats what I believe it is anyway, as other cars either have tyres that aren't great or more power than the tyres can handle, so they spin up and you can hold the revs better as you pull away.

hkraft300
16-09-2015, 01:19
Yorkie65 got it. I hate the auto clutch but I'll use it til I get a wheel. Try the 2.84 1st gear in the Ruf GT3 the car bogs down bad. Also the RWD P30 if you have a tall gear ratio for first. The auto clutch modulates so the revs go up and down to keep the engine spinning.

Reading the OP I was thinking more along the lines of rev limiter- depending on the car's ecu calibration, you can apply different methods to have a smooth cut (where the engine reaches and stays at the rev limit) or a hard cut (where the RPM reaches the limit, ECU cuts fuel/ignition, revs drop then come back up) where you see the rev "bounce" on the limit.