Hey all, just wondering if anyone can shed some light on how adjustments affect the diff.
I know on a rwd that a lower decal reduces lift-throttle overstretched and reducing accel helps reduce corner exit oversteer from too much throttle.
But how does it work with Awd cars? What are some good starting points and what adjustments do you make to fix various issues. The tuning guide doesn’t have much in it on the diff so just wondering if anyone could shed some light, maybe get the guide updated for awd diffs. Cheers in advance.
I treat the rear differential the same on AWD as I do on RWD cars. Reducing the accel helps reduce on-throttle oversteer and reducing the decel does reduce lift-throttle oversteer. I tend to run a little higher on the decel setting because a higher decel setting helps slow the car down when you take your finger off the gas and so you can slow down more without having to brake which helps lap times.
As for the front, I don’t know too much as this game I’ve done mainly RWD racing. I would operate under the same premise as above. Do to the front what you would do to a FWD car.
Then, use the torque split to help push the torque to the rear, I find settings between 60 and 85% are good. IF you’re going to put 100% torque to the rear wheels you may as well do the build with RWD*.
- Unless the build must be AWD for whatever you are entering
I treat the rear diff as I do on RWD cars, and the front diff I do on FWD cars.
Think you have the decel wrong if I understand your wording.
Lower decel (towards the left) on a rwd car increases its turning ability off throttle but go too far left and you may get lift-off oversteer.
With AWD it works the same at both ends but because the car often has understeer tendencies you may need to tune elsehwere or be a little more adventurous with your diff settings.
eg try 0 decel at both ends and tweak it up from there if needed. Try high accell and try shifting more torque to rear wheels.
I thought lowering the rear decel setting reduced lift throttle oversteer.
Increasing decel diff reduces lift throttle oversteer.
EDIT:
Taken from TG Wormburners stickied tuning guide:
“On deceleration when you lift off of the throttle one tire locks faster than the other. This can cause the back end to want to kick out over the locked tire in extreme settings (under 15%). A lower setting does help things and the further apart the accel and decel are on the same differential the more unstable the car seems to get in my experience.”
Note his second sentence which means the lower you go, (under 15%) in his quote, the more likely the back end will kick out.
His third sentence means it is good to go as low as possible (decel) but there will be a point where the instability gets too much. In short find that point and then close the gap (between accel and decel) until you get enough turning ability with as much stability as you need. On some cars that may still be a large gap but on others it may mean a smaller gap.
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I did some reading a while back but this is what I got from experimentation with the Lotus E21.
Rear Differential Decel set to 100. Drive pretty fast in 5th gear and let off the gas completely. The car slows down pretty fast and drops lots of seed without needing to brake maintaining the current balance.
Rear Differential Decel set to 0. Drive pretty fast in 5th gear and let off the gas completely. The car slows down but it maintains speed rather well. You will need to brake to achieve the same reduction in speed over an equal distance to the above example.
Now, obviously, there are some stability issues and traits with this as well that need to be balanced out with your build. I usually start my decel setting (rear diff, RWD) around 25 and go from there based on feel. On some cars like the lotus build a super low decel setting of 8 is good. On the Lotus E21 which is already super stable I use a rear decel setting of 75 - 90.
My latest tune has a decel setting of 8 and there are no problems. Is this perhaps because they can be tuned out elsewhere?
It could mean that 8 is right for that car. It could mean that 8 works with the rest of the tune. It could mean you like or are used to single digit decel diff.
Most of my front engine, rwd cars have decel that low. As weight shifts back my decel diff goes up. I don’t understand why but that is what works for me. So my Rufs have decel diff around 50 or higher.
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Try this setting on 4wd …Good starting point.
Front betwee 65-70 accel…0 decel
Rear between 75-80 accel…15 decel
58 % centre diff towards the rear…
This is just a starting point and will need to be adjusted depending on the Car/Class…
have to keep that in mind for next tune, cheers for that. Was just racing you on nurburg GP A class rivals, still 3 seconds behind but 2:08:4 in an auto isnt too bad I think.