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ToOSk3tChY
17-05-2015, 12:37
I'm trying to tune the Ford Zakspeed.

The main problem I have is corner exit oversteer. The backend has a tendency to travel around, not sharply but it's quite annoying. I was testing at Donnington Park but ended up tuning for so much understeer that I was loosing turn in and it felt wrong and that I was heading in the wrong direction with the set up. I of course understand that driving comes into it but I'm not a bad driver. I just want to get this thing in to and out of corners confidently.

I use controller
No assists
I'd rather achieve the desired effect through suspension and dampers than alignment but at this point I just want to be able to put in a blinding lap, just one... Im not greedy lol.

theres very little neg rear camber available but I was thinking if I raised rear ride height and softer rear spring to increase the travel and have it arc more giving me more rear camber. Untested yet but anyway you can see my heads in it trying to work it out...

Any ideas?

Thanks
S

Umer Ahmad
17-05-2015, 12:38
Reduce (slide left) ACCEL diff lock

Left = safety and less performance
Right = more performance and less safety

JeyD02
17-05-2015, 12:41
I'm trying to tune the Ford Zakspeed.

The main problem I have is corner exit oversteer. The backend has a tendency to travel around, not sharply but it's quite annoying. I was testing at Donnington Park but ended up tuning for so much understeer that I was loosing turn in and it felt wrong and that I was heading in the wrong direction with the set up. I of course understand that driving comes into it but I'm not a bad driver. I just want to get this thing in to and out of corners confidently.

I use controller
No assists
I'd rather achieve the desired effect through suspension and dampers than alignment but at this point I just want to be able to put in a blinding lap, just one... Im not greedy lol.

theres very little neg rear camber available but I was thinking if I raised rear ride height and softer rear spring to increase the travel and have it arc more giving me more rear camber. Untested yet but anyway you can see my heads in it trying to work it out...

Any ideas?

Thanks
S

You start to oversteer when you pressing the gas or even without pressing gas.? Does it happens in all corners or just slow, is the entry corner not oversteer?

JeyD02
17-05-2015, 13:04
Reduce (slide left) ACCEL diff lock

Left = safety and less performance
Right = more performance and less safety

No no lol, I think you got it backwards. In this case you INCREASE ACCEL lock.

More = more traction, much propulsion but more understeer while on gas.
Less = way less understeer but less stable (lesser traction or too low radius steering degree )

ToOSk3tChY
17-05-2015, 13:46
The default accel is already quite high. I think it's a suspension issue. I've tried rear toe in, highest accel. Higher decel to keep a more stable entry. I wish I could give it more throttle. I happen with corners with elevation changes.

To describe my throttle it's moderate on entry until I feel I'm on exit and it's very subtle but it feels like there's an over abundance of front camber steering me round more or the rear is rotating too much(not skidding).

Umer Ahmad
17-05-2015, 13:51
More ACCEL lock typically gives me power oversteer in project cars.

Just try lowering it as a test.

JeyD02
17-05-2015, 15:33
The default accel is already quite high. I think it's a suspension issue. I've tried rear toe in, highest accel. Higher decel to keep a more stable entry. I wish I could give it more throttle. I happen with corners with elevation changes.

To describe my throttle it's moderate on entry until I feel I'm on exit and it's very subtle but it feels like there's an over abundance of front camber steering me round more or the rear is rotating too much(not skidding).

What type of corner is it? Slow, mid, chicanes, fast? In any case ACCEL slip lock is original not causes of oversteer, you control torque power with throttle footwork. So basically you want to have as much accel lock as you can without understeering while on gas.

Try these.

Stiffen front and soften rear suspension little by little.
Stiffen front slow rebound and soften slow rebound rear a little by little

In fast corner corner try increase rear dowmforce

donpost
17-05-2015, 17:15
No no lol, I think you got it backwards. In this case you INCREASE ACCEL lock.

More = more traction, much propulsion but more understeer while on gas.
Less = way less understeer but less stable (lesser traction or too low radius steering degree )

No he had it correct.

More accel = more traction before a wheel starts spinning, but when you overdo the throttle it'll be more of a snappy oversteer. (AKA more performance and less safety)
Less accel = easier to spin that inside wheel, but easier to save the car when you do. (AKA safety and less performance)

Also bear in mind,

More accel = more torque transferred from low grip wheel to high grip wheel = MORE rotation (the torque difference at the wheels creates a rotational force trying to rotate you into the turn)
Less accel = Less torque transferred therefore less rotation.

This second bit is true even in a FWD car, which is why the Clio's default accel is 100% - for the extra rotation.

JeyD02
17-05-2015, 17:57
No he had it correct.

More accel = more traction before a wheel starts spinning, but when you overdo the throttle it'll be more of a snappy oversteer. (AKA more performance and less safety)
Less accel = easier to spin that inside wheel, but easier to save the car when you do. (AKA safety and less performance)

Also bear in mind,

More accel = more torque transferred from low grip wheel to high grip wheel = MORE rotation (the torque difference at the wheels creates a rotational force trying to rotate you into the turn)
Less accel = Less torque transferred therefore less rotation.

This second bit is true even in a FWD car, which is why the Clio's default accel is 100% - for the extra rotation.

Yes I am aware hence my 2nd post after I explained the basis of accel; under good driving line and proper throttle control diff slip lock don't normally causes oversteer, much more so it causes understeer, but with a high accel it goes traction when wheel on straight line.. we have to understand that in general any setup with car can oversteer with an sudden angle turn while maintaining a high amount of acceleration. The case for the OP isn't this. Even with "moderste" throttle, deff not a primary reason, in my case. It could be depends on how one drives. ... ,

however he said that his car is kinda carrying a oversteer by turn exit, that to me sounds like much weigh in front and lack of traction on rear like Springs not transferring correctly or perhaps needs more aero on rear. Like in my previous post.

ToOSk3tChY
18-05-2015, 08:17
Lowering the accel helped a lot. I didn't think it would but it did so thank you. Now I just gotta get more turn in without destabilising the sensitive back end. :)

MDH PYRO
18-05-2015, 08:42
Reduce accel and soften up rear suspension slightly would be my suggestion

Rift Racer
18-05-2015, 13:48
Lowering the accel helped a lot. I didn't think it would but it did so thank you. Now I just gotta get more turn in without destabilising the sensitive back end. :)

Increase decel diff :)

JeyD02
18-05-2015, 14:13
Lowering the accel helped a lot. I didn't think it would but it did so thank you. Now I just gotta get more turn in without destabilising the sensitive back end. :)

Is it while breaking or lifting off gas and approaching turn in?

fitz the viking
20-05-2015, 01:41
mess with the diff like people have been saying, soften rear antiroll bar or stiffen front. mess with all 3.

Stag
20-05-2015, 11:05
Too much rear camber. Or increase rear downforce

Doug914
20-05-2015, 18:56
If the mid corner , once the car takes a set, is pretty balanced, then it's most likely the dampers. The slow dampers especially. They really affect the instant transitions more than any one item. ie the driver inputs. Try decreasing the rear slow damping and increasing the front slow damping. Also make sure the rear bumpstop isn't contacting under aceleration. Try shortening them if its possible..