(Solved) Clutch strength and "realistic" take-offs

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flyboy463
Posts: 38
Joined: 12 Jun 2016 07:34

(Solved) Clutch strength and "realistic" take-offs

#1 Post by flyboy463 » 29 May 2017 09:50

As anyone who drives a tractor-trailer (or just a regular home tractor) knows, the clutches and transmissions in these vehicles are STRONG. I've given myself a jolt many times just by lifting up on the clutch for a 3 cylinder gas tractor too fast in second gear, taking the front wheels off the ground. Going to a CDL school range and watching the newbies lurch the trucks and shake the hell out of them shows me that it's possible to do almost the same thing in big rigs.

So my question is; Is it possible to dump the clutch in game in a relatively tall starting gear (3lo) and not make the truck stall?

I've tried fiddling with the transmission factors in the physics file and the only thing that gets close to this is the (manual_)clutch_connected_viscosity_factor line. Changing this to a lower value, like 0.5 allows the clutch to be dumped without stalling, but introduces the problem of "RPM lag." By RPM lag I mean that the RPMs can increase by about 2 hundred before the road speed starts to increase.

The easiest way I can think to remedy this is to make another variable like the connected clutch viscosity, but make the viscosity strength relative to engine RPMs, and have it hit 100% strength at about 600 RPMs, similar to how an automatic transmission's torque converter locks up at a certain speed/gear/RPM/however it works. But, since something like that doesn't exist for the clutch in this game as far as I know, I'm looking for other ways to do this.
Last edited by flyboy463 on 04 Jun 2017 07:02, edited 1 time in total.
TheHire99
Posts: 3
Joined: 15 Jun 2016 22:31
Location: New Jersey, USA

Re: Clutch strength and "realistic" take-offs

#2 Post by TheHire99 » 04 Jun 2017 04:00

What kind of pedal set are you using? I found changing the dead-zone on my clutch axis to improve the clutch response. Initally the clutch was grabbing too low down and I increased the dead-zone to have it grab more towards the middle of the pedal travel. Made a world of difference.
marcf
Posts: 326
Joined: 11 Jul 2015 22:23
Location: Townsville, Australia

Re: Clutch strength and "realistic" take-offs

#3 Post by marcf » 04 Jun 2017 05:18

I think flyboy is right, I've only done a handful of lessons in a prime mover (Western star 4800 with 15L Cat engine and 18 speed)
No trailer, starting off and 3L and not needing to use any throttle to get it moving, so much torque at idle that I have never stalled it taking off, told by the instructor not to use any throttle starting off empty
In ATS you can get moving in 1L or 2L if you let the clutch out very gently, but it takes several seconds before you're moving half a mile per hour to get started.
Very difficult to get moving with even a light trailer without throttle

Perhaps this could be addressed in the torque curve around 500-700rpm?
flyboy463
Posts: 38
Joined: 12 Jun 2016 07:34

Re: Clutch strength and "realistic" take-offs

#4 Post by flyboy463 » 04 Jun 2017 06:31

TheHire99 - I have a stock G27 setup with the SKRS, the clutch deadzone is almost all the way down, sensitivity is also pretty low, around 1/5 of max. This makes it easier on me to "pretend" I have dead air and a clutch brake, as well as quicker double clutching, but does make feathering the clutch a bit difficult.

As it turns out my problem was the realistic engines and sounds mod. The engines didn't take too kindly when the clutch is dropped, and stalled even in the lowest gear in any manual transmission. I played with the stock engines, and they are much more forgiving with this. In fact, I could drop the clutch in 3rd in a 13 speed with a 4.33 differential with the second base SCS engine. I believe I could drop the clutch in 5L with the top of the line stock SCS engine with an 18 speed with a 3.55 differential and still not stall. (Edit: Both times I didn't have a trailer and didn't use the accelerator at all, but I do remember I could still dump in 3rd or 4th with a load no problem with the best engine and 18 speed.)

I've found the solution to my question, now to figure out why the realistic engines don't hold much low end torque when compared to the base game engines.
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