Correcting Understeer

[Quicksilver]

So, I started to get annoyed with my car's understeer last year and I want to improve the situation for the next AutoX season.

As far as I understand, stiffening the rear with a larger sway bar and/or changing the camber in the front will both help.

Any suggestions if either of these is more effective than the other?
Should I consider adjusting rear camber as well? (FWD car)
Any other things I can/should look at? Arrrrs are out - I am not a good enough driver yet to benefit from them (I think they would mask mistakes) and my RS2s are still quite healthy.

The main use (besides daily use) is AutoX. I might attend an event at Mecaglisse if we arrange one, but that will be about it for lapping. Can't afford to bend the car on a track...it's the only one I have. And since it's the DD, I can't go too nuts on the changes. So I'm looking for best bang for the buck, and things that won't mess it up too much for regular use.

Thanks!

[Robin2]

easiest and cheapest way is to adjust air pressures..... it's free...

what pressures were you running last year (front and rear)?

on my subaru impreza.... for stock sways bars, i had 19mm front and 13mm rear.. going to 20mm rear wrx sway bar made the car very balanced. I also can control the car with the coilovers (stiffness levels between the fronts and rear on the settings).

But tire pressures is the easiest... if you run pretty much the same tire pressures overall, I'd pump the rear ones a lot more...

example...
if you ran 42psi all around, I'd keep the fronts the same or even lower a bit (if they're not rolling over on the sidewall) 38-42psi and pump the rear ones higher to 48psi (and go from there)... if it's too tail happy, take some pressure out if, if it's still understeers, try a bit more air.

[sfong]

I'm going to assume that you're a beginner, so forgive me if some of this sounds condecending IMO, here is the checklist order to go through.

1) Driver technique
- If the understeer happens under acceleration, be gentler on the gas, only really put the hammer down when the front wheels are straightened out. It's FWD.
- If the understeer happens on corner entry, you're going too fast in and/or you're not blending the braking and turn in well to get weight transfer to the front tires to get more grip there.
- Change your driving line to cover up the understeer/FWD. Not sure on this one, not a FWD guy.

2) Tire pressure
- Each tire/suspension will have an optimum air pressure to get maximum grip. You have to figure that out yourself. Set tire pressure so there is maximum grip in front and then put a non-optimum pressure in the rear. You can get less grip by making the pressure less than optimum (to make the sidewalls bend, making a bad tire patch) or making the pressure more than optimum (to ballon the tire, shrinking the tire patch).

3) Alignment
- A good alignment is a good idea in general. As long as you don't go really radical, in general more negative camber gives more lateral grip, but you give up a little braking/accelerating grip. Toe also has a minor effect, but it's probably not worth youre time.

4) Stiffer rear swaybar/softer front swaybar
- The stiffer side transfers weight faster on that end which reduces grip there. This is the cheapest/easiest car mod do to tune static under/oversteer.
- Stiffer swaybar also reduces car roll, which can sometimes give more grip (which is opposite to what you would expect) if the reduction in car roll optimizes the the camber setting for the tire. This is typically not the case though.

5) Stiffer rear springs/softer front springs
- Same mechanism as the swaybars. Requires more work in the mod and also reduces ride quality more than the swaybars. Go too crazy with the change in spring rate, you'll also want retuned shocks.

6) Adjustable shocks
- This effects dynamic over/understeer when there is weight transfer happening. Not going to try to explain this as its complicated and you're probably not going to go this far if price is an issue.

7) Wider front tires/thinner rear tire - don't do this on a daily driver

8) Shift weight bias to the rear - don't do this on a daily driver

[craig]

Left-foot-braking and the handbrake!

[vwgolf2lwk]

If you are driving a EP3 Civic or RSX Mac strut type chassis and assuming you have some experience driving a front driver and are not simply over driving the car to begin with. Adding front neg camber is essential, I have 2.5 deg neg camber on mine and the car came alive this year (the car ships new with zero camber meaning that as soon as you get any body roll the tire contact patch begins to decrease = understeer). Also, depending on what your car came with from the factory for a rear sway, you can add a stiffer bar but beware, going too stiff makes the rear unpredictable at the limit on some cars. You are looking for a balance. Tire pressures should be used to "Tune" the set-up, but you need to understand what happens to the tire sidewall vs contact patch to get the best from this tuning tool.

[Jodie]

Left-foot-braking and the handbrake!

Don't forget the Scandinavian Flick.

[el_torpedo]

If all else fails - brake a little earlier!

[wing]

I know those german cars tend to Break, but Honda's like Braking.

Trail Braking will help for sure -- only drove the Mazda3 once at Auto-x that thing was so tailhappy with trailbraking it was fun!

[el_torpedo]

oops.
fixed

[WRC_VERNA]

only use one rear tire at any point.. half the traction!


hop in with me in the accent anytime, being someone who managed to spin out a fwd car a couple of times maybe i'll trade you a little oversteer for some understeer!

[Quicksilver]

Thanks all. Sounds like I'm on the right track. If there's a really fast lil' red Honda this summer, it's partially your fault.

[GoesFilled]

only use one rear tire at any point.. half the traction!


hop in with me in the accent anytime, being someone who managed to spin out a fwd car a couple of times maybe i'll trade you a little oversteer for some understeer!

Works for me too... especially on cold days and old RA1's.