Understeer
Understeer
I do at least one event of Autocross per month. One of the problems that I need to perfect is understeer. Besides becoming a better driver, slow in- fast out, etc. what can I do to the car so I don't have that much understeer? Also what techniques are you guys using not to understeer?
I have the Tein springs, Dunlop Direzza Z1 tires.
I have the Tein springs, Dunlop Direzza Z1 tires.
I do at least one event of Autocross per month. One of the problems that I need to perfect is understeer. Besides becoming a better driver, slow in- fast out, etc. what can I do to the car so I don't have that much understeer? Also what techniques are you guys using not to understeer?
I have the Tein springs, Dunlop Direzza Z1 tires.
I have the Tein springs, Dunlop Direzza Z1 tires.
- Bigger rear sway bar or smaller front sway, if you feel like the front sway bar is too stiff.
- stickier tires
- Alignment tweaks
If you've got a budget in mind, the 1st place I would think about liquidating funds would be new springs. Coilovers would be great if you can afford them because of the adjustability you'll gain but if spending $1000 isn't an option right now then I'd start with new springs, then sway bars, and finally some stickier tires. PM me if you need anything.
I already have Tein-S springs( I know they are the best but they are ok) and coilovers are out of the picture since I can't afford that much right now(personal problems).
I know there is a thicker rear sway bar so I will look into getting it. The front sway bar is the stock one.
I know there is a thicker rear sway bar so I will look into getting it. The front sway bar is the stock one.
What do the rules of your class allow ?
Start there.
A rear sway bar if allowed is the way to go.
Experiment with tyre pressures.
On a previous car, 28 psi all around would have the car almost spinning like a top.
Drop to 26 psi in the rear and it was understeer.
27 psi on the back and I had an almost neutral car, but under and over steer were accessible on request.
Alignment wise, getting rid of front toe in reduces understeer too.
Driving wise, lifting off the gas just after you turn into the corner, trailing the brakes etc maybe helpful depending on if you are going fast enough to generate the forward weight transfer to sufficiently let the rear lose some grip. Flicking the car the opposite direction first, then using combinations of the above and the handbrake can influence turn in too.
Oh yeah, sometimes especially in low speed turns, any attempt to get on the gas pushes the front wide. Be quick to recognise when that is the case as there is jack all you can do about it.
Start there.
A rear sway bar if allowed is the way to go.
Experiment with tyre pressures.
On a previous car, 28 psi all around would have the car almost spinning like a top.
Drop to 26 psi in the rear and it was understeer.
27 psi on the back and I had an almost neutral car, but under and over steer were accessible on request.
Alignment wise, getting rid of front toe in reduces understeer too.
Driving wise, lifting off the gas just after you turn into the corner, trailing the brakes etc maybe helpful depending on if you are going fast enough to generate the forward weight transfer to sufficiently let the rear lose some grip. Flicking the car the opposite direction first, then using combinations of the above and the handbrake can influence turn in too.
Oh yeah, sometimes especially in low speed turns, any attempt to get on the gas pushes the front wide. Be quick to recognise when that is the case as there is jack all you can do about it.
Last edited by 2006_RA; Dec 12, 2011 at 04:00 PM.
+1 for the rear diff. the clutch pack in the diff is not correct from the factory.
Also upgrade the front swaybar, or the front and rear as a set. You can upgrade just the rear, but that is a bandaid solution.
As far as driver's improvement, this is the best area for the buck.
If you are getting understeer exiting the corners, then you are not using the brakes hard enough on corner entry. You also need to time the boost to the apex of the corner, not your throttle pedal input. Get on the boost too early, and it's understeer city... Get on the boost too late, and your run is trashed.
Also upgrade the front swaybar, or the front and rear as a set. You can upgrade just the rear, but that is a bandaid solution.
As far as driver's improvement, this is the best area for the buck.
If you are getting understeer exiting the corners, then you are not using the brakes hard enough on corner entry. You also need to time the boost to the apex of the corner, not your throttle pedal input. Get on the boost too early, and it's understeer city... Get on the boost too late, and your run is trashed.
I already have Tein-S springs( I know they are the best but they are ok) and coilovers are out of the picture since I can't afford that much right now(personal problems).
I know there is a thicker rear sway bar so I will look into getting it. The front sway bar is the stock one.
I know there is a thicker rear sway bar so I will look into getting it. The front sway bar is the stock one.
I didn't even think about the diff. Good call!
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Evo owners think everyone has turbos and rear differentials...
Honestly dude, the only thing that's going to fix understeer is very stiff, low riding suspension and an LSD...lateral structural braces will help, but the reason you get understeer is mostly due to the open diff...as soon as the inside tire is unloaded, and loses traction, it gets all the power, and the outside tire which is getting no power, will just slide sideways regardless of how you are steering the car will go in the direction of its inertia at the instance you lost traction...lowering your center of gravity and increasing the dampening force of the suspension will decrease the tendancy to lose traction on the inner tire, but again, FWD with an open diff does not corner well, no matter what else you do to the car...
P.S. our stock sway bars are fine, especially in auto cross, with close to stock power, you won't be accelerating enough between corners to exceed the capability of our sway bars in the corner...I've tracked a bunch of times since having the LSD, and just Tein S-techs...i'll tell the only thing i feel letting go in a high speed corner is my side walls...i have stock tire profile, and it's a bit mushy...
Honestly dude, the only thing that's going to fix understeer is very stiff, low riding suspension and an LSD...lateral structural braces will help, but the reason you get understeer is mostly due to the open diff...as soon as the inside tire is unloaded, and loses traction, it gets all the power, and the outside tire which is getting no power, will just slide sideways regardless of how you are steering the car will go in the direction of its inertia at the instance you lost traction...lowering your center of gravity and increasing the dampening force of the suspension will decrease the tendancy to lose traction on the inner tire, but again, FWD with an open diff does not corner well, no matter what else you do to the car...
P.S. our stock sway bars are fine, especially in auto cross, with close to stock power, you won't be accelerating enough between corners to exceed the capability of our sway bars in the corner...I've tracked a bunch of times since having the LSD, and just Tein S-techs...i'll tell the only thing i feel letting go in a high speed corner is my side walls...i have stock tire profile, and it's a bit mushy...
Last edited by CrAnSwIcK; Dec 12, 2011 at 07:29 PM.
I don't think anyone makes a front sway bar for our car and I think due to our car being fwd putting a larger rear sway bar will help lessen the understeer. RRM has the best price on the rear sway bar. The bar is made by progress but RRM sells some nice perches to go along with it so you don't tear your stock ones. I just picked up the bar as a Christmas present. I know that Otter said it was the most effective part purchased for his car that helped with understeer. Smike now owns his Ralliart and both of them autocross a ton. They would be the best source of info on Autocrossing a Ralliart.
Yeah Dacib I've told you before , the big "3" for the rear . Rear strut bar, rear tiebar, and rear swaybar with perches all made of solid metal, none of that perforated aluminum ones with nits to make it longer or shotter. Eclipse2lancer was a big autoX guy when he was here and he won multiple tournaments ,even 1st place at the end of the year in his class. He said removing the front sway bar helped the car in auto X. He sometimes pops back up but rarely. :mistu:
Dacib since we are running auto's Im not certain we can get the LSD. Ive heard people saying we can, and people saying we cant because we have a torque converter. Im not claiming to know either way because I'd love to have an LSD if we can. Just that we'd need more clarification and a bit of research before ordering anything.
Tire pressure is the best free mod possible. But unless someone has the exact same tires on the exact same car, I wouldn't blindly listen to their recommendations for tire pressures. In other words, the 26, 27, and 28 mentioned above are waaaay too low for me as I fill to between 32 and 34 cold, which then rises to 36 or more when hot.
In general though, higher pressures in back will mean less contact patch and a firmer sidewall which will mean it will be looser. Lower pressures in front will provide more contact patch and looser sidewall, making for more grip but less response.
I'd also look into an alignment. Not sure of prices where you are, or how much room the RA has to play with, but it should only cost ~$100 and will also do a lot to improve the front contact patch.
In general though, higher pressures in back will mean less contact patch and a firmer sidewall which will mean it will be looser. Lower pressures in front will provide more contact patch and looser sidewall, making for more grip but less response.
I'd also look into an alignment. Not sure of prices where you are, or how much room the RA has to play with, but it should only cost ~$100 and will also do a lot to improve the front contact patch.
Dacib since we are running auto's Im not certain we can get the LSD. Ive heard people saying we can, and people saying we cant because we have a torque converter. Im not claiming to know either way because I'd love to have an LSD if we can. Just that we'd need more clarification and a bit of research before ordering anything.