How much Caster?
Discussion
steve_d said:
The urethane bushed suspension is not adjustable in caster only camber and toe-in.
Steve
Steve
I know that. But I still want to know the caster angle...
I want to increase caster to have a more possitive "steering return". The car feels kind of "dead" like it is now and you have to steer the car both in and out of turns. If you let go of the steering wheel in the midle of a corner the car will continue to turn. The big scrub angle in combination with more caster will for sure create roll steer (good or bad? I don't know...) and the changing camber will help.
gtr-tt said:
steve_d said:
The urethane bushed suspension is not adjustable in caster only camber and toe-in.
Steve
Steve
I know that. But I still want to know the caster angle...
I want to increase caster to have a more possitive "steering return". The car feels kind of "dead" like it is now and you have to steer the car both in and out of turns. If you let go of the steering wheel in the midle of a corner the car will continue to turn. The big scrub angle in combination with more caster will for sure create roll steer (good or bad? I don't know...) and the changing camber will help.
I find the steering is pretty quick for track use. I think that caster is OK almost you are going out for rallying.
srreck said:
gtr-tt said:
steve_d said:
The urethane bushed suspension is not adjustable in caster only camber and toe-in.
Steve
Steve
I know that. But I still want to know the caster angle...
I want to increase caster to have a more possitive "steering return". The car feels kind of "dead" like it is now and you have to steer the car both in and out of turns. If you let go of the steering wheel in the midle of a corner the car will continue to turn. The big scrub angle in combination with more caster will for sure create roll steer (good or bad? I don't know...) and the changing camber will help.
I find the steering is pretty quick for track use. I think that caster is OK almost you are going out for rallying.
Agreed! The steering is very quick for track use(imo). Caster is fine to for track purposes. The front pushes mid-corner. I think your chasing the wrong animal here. If the car feels dead, then you've more than likely got too much toe in. Depends on your goals actually. Where do you want the most steering performance. street driving? track days? 200+mph speed runs like schwartzyboy?
Still, I can't imagine someone's ultima feeling "dead" in the steering.
Maybe my English isn't refined enough to explain what I want to achieve... It’s not the steering entering a corner that is the problem. It’s when I exit a corner. I want the steering to return to straight by it self. Like it is now I need to “force” the car out of the turn. Or when the cars goes into over steer I just want to release the steering wheel and let the wheel counter steer by it self. Now I have to steer the car both in and out of corners.
I think the 5deg caster and 0 toe is very close to what I want. I looked at a few other cars at track and they where around 7 degrees caster and even a few where toe out…
I think the 5deg caster and 0 toe is very close to what I want. I looked at a few other cars at track and they where around 7 degrees caster and even a few where toe out…
Have a word with Z cars
www.zcars.org.uk
I went to brands at the weekend to Total Kit car Live. I was talking to the test driver for the 255BHP mini mote Carlo. They (Z cars) are the people that are developing the twin hyabusa engined 4WD Ultima. The test driver stated that the castor angle is all wrong on the sport and that they have re-designed the uprights and the wish bones for the car that they are working on. He tells me that the KPI (King Pin Inclination) is 5 degrees and should be around 15. Anyway, I am not convinced as the problems that he is stating that they have...he said you could not drive it one handed, serious tramlining when you pass over a white line etc etc, I do not agree with. I do not suffer the problems to the extent that they indicated. I have strapped a camera to my rear wing and can see that the nose of the car is stepping left and right ever so slightly at speed but I can not feel this in the cockpit. Maybe I have got used to this and do not notice. I can drive the GTR one handed, even in a corner at a reaonable speed. I do however suffer from horrendous bump steer on uneeven roads and end up fighting with the steering.
They also claimed that their mini mote carlo would out perform an Ultima on the track at Brands. Having been in the car, I have to say that it is seriously quick and was out breaking, cornering and lapping Caterham 7 copies, but i still do not believe that a well sorted GTR would lose.
Commet...
www.zcars.org.uk
I went to brands at the weekend to Total Kit car Live. I was talking to the test driver for the 255BHP mini mote Carlo. They (Z cars) are the people that are developing the twin hyabusa engined 4WD Ultima. The test driver stated that the castor angle is all wrong on the sport and that they have re-designed the uprights and the wish bones for the car that they are working on. He tells me that the KPI (King Pin Inclination) is 5 degrees and should be around 15. Anyway, I am not convinced as the problems that he is stating that they have...he said you could not drive it one handed, serious tramlining when you pass over a white line etc etc, I do not agree with. I do not suffer the problems to the extent that they indicated. I have strapped a camera to my rear wing and can see that the nose of the car is stepping left and right ever so slightly at speed but I can not feel this in the cockpit. Maybe I have got used to this and do not notice. I can drive the GTR one handed, even in a corner at a reaonable speed. I do however suffer from horrendous bump steer on uneeven roads and end up fighting with the steering.
They also claimed that their mini mote carlo would out perform an Ultima on the track at Brands. Having been in the car, I have to say that it is seriously quick and was out breaking, cornering and lapping Caterham 7 copies, but i still do not believe that a well sorted GTR would lose.
Commet...
gtr-tt said:
Maybe my English isn't refined enough to explain what I want to achieve... It’s not the steering entering a corner that is the problem. It’s when I exit a corner. I want the steering to return to straight by it self. Like it is now I need to “force” the car out of the turn. Or when the cars goes into over steer I just want to release the steering wheel and let the wheel counter steer by it self. Now I have to steer the car both in and out of corners.
I think the 5deg caster and 0 toe is very close to what I want. I looked at a few other cars at track and they where around 7 degrees caster and even a few where toe out…
I think the 5deg caster and 0 toe is very close to what I want. I looked at a few other cars at track and they where around 7 degrees caster and even a few where toe out…
Are you sure this problem is not due to turning into the corner too early?
I haven't had this problem. I've let a couple of scca pro drivers drive the car and they haven't said this either. The only comments were that the toe-in at front needed to be taken out to zero. Yes, some even go as far as toe-out on their cars at the track. The KPI. Well. That's something designed into the uprights. Impossible to change without redesigning them.
What about bump steer? You must zero this out also! World of difference. Is your corner bumpy mid-apex? hahahah. Just had to ask.
Now, the other problem, could be, that the car is "pushing" at the front mid-apex(which it does have a tendancy to do) and then you are having to make up for it by steering out of the turn. Sorry. Its early over here for me and I had to wake up my brain. Sometimes, you don't even realize it b/c your so caught up in the moment of the turn. When it became clear to me, I was following a race prepared mustang on DOT slicks through a 50mph corner. I was right behind this guy, same speed, same line, and watched as he held the line and my front pushed out mid-apex and I had to steer back on corner exit(as you describe). I'm now looking into wider fronts and some more mods.
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