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Handling issues in autocross: understeer and steering pump catch

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Old May 18, 2010, 09:24 PM
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Handling issues in autocross: understeer and steering pump catch

I recently went to a test & tune event that consisted of a skidpad, slalom, figure 8 and short autocross course.

I have another car that I've dialed in for good autocross performance and was a little disappointed with my stock Ralliart Sportback.

Grip was rather low as expected from the various reviews out there, and there was also a lot of steady understeer. It loosens up a lot in the transitions which probably means any rear bar addition will likely make it quite tail happy in the transitions.

Worse yet is that there's pretty bad p/s pump catch when I try to toss it. That was rather annoying, not to mention sore on my arms after a while. The front tires are really quite chewed up. I think the first mod for me would be better tires along with more negative front camber, if nothing just to even out tire wear in even normal driving. I was running 38/35 psi pressures as I wanted to evaluate the car close to stock design.

Overall roll control is good, and no premature ABS interventions. I even ran with stability control on initially to see where the limits on that system were, and it's pretty unintrusive until the slip angles get large.

Are there any good camber shim options (would like to stay away from camber plates/mounts if I can). Has anyone looked into power steering pump upgrades?

Thanks.
Old May 18, 2010, 10:07 PM
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I've run my car through some twisties and didn't have a problem with the p/s pump.

The tires are a must for your first upgrade if you are going to autox the car.Stockers just plain suck.
Old May 18, 2010, 11:41 PM
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Originally Posted by sith_killer_99
I've run my car through some twisties and didn't have a problem with the p/s pump.
Perhaps there is some minor build variation among the pumps. But as I try to increase the steering wheel rate (if I'm late for a slalom cone for example), the pump runs out of flow and the steering wheel refuses to turn further for a split second which messes the line up even more. I've driven other cars with this issue but didn't expect to get it on this car.
Old May 19, 2010, 04:04 AM
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The first thing I did was to change my stock tyres to Falken 452s and never regretted it. Less understeer now and the ride is a bit softer too.

I'm getting coilovers put in in a couple of weeks so I'll let you know how I go with that.
Old May 19, 2010, 09:21 AM
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I've noticed the power steering pump catch as well, very annoying.
Old May 19, 2010, 10:47 AM
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havent experienced the p/s pump catch yet, but i have installed the ingalls front camber bolts and running -2* up front and -1.5 in the rear (thanks to drop springs, no camber adjust in rear) and it has made a huge difference. definitely looking to address the understeer issue further though, a rear swaybar upgrade is in my future for sure
Old May 19, 2010, 01:20 PM
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Originally Posted by stfuad
I've noticed the power steering pump catch as well, very annoying.
Do you know if the Evo steering pump/gear exhibits this issue too?
Old May 19, 2010, 01:23 PM
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Originally Posted by 03chi-town0Z
havent experienced the p/s pump catch yet, but i have installed the ingalls front camber bolts and running -2* up front and -1.5 in the rear (thanks to drop springs, no camber adjust in rear) and it has made a huge difference. definitely looking to address the understeer issue further though, a rear swaybar upgrade is in my future for sure
Can you tell me more about the camber bolts? Is it an eccentric bolt to replace one of the strut-to-knuckle bolts? Is it variable or just two orientations like the Evo? -2* might be a bit too much for me but I'm not running aftermarket springs so it might be a little closer to -1.5* in my scenario. Thanks.
Old May 19, 2010, 09:08 PM
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it's a variable placement bolt, full 360* articulation of the eccentric bolt to achieve specs +/- 1* of what is capable with stock adjustments. (stock spec is already supposed to be -1 with +/- 0.5* adjustability) part number is 35420, i ordered a pair on e-bay and it ended up being like 25 or 30 bucks including shipping, well worth it.
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