Understeer on initial turn in

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Understeer on initial turn in

Postby james001 » Mon Sep 19, 2016 3:06 pm

Hi Brian.

I have an NC2 with progress tech springs, koni shock and racing beat sways. I do not drive my car on the track
james001
 
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Re: Understeer on initial turn in

Postby james001 » Mon Sep 19, 2016 3:11 pm

But I notice under steer on slow corners when I initiall turn in. I do not believe I am going fast enough that it should induce Understeer. The front bar is set outer hole and the rear bar to closest hole to the bar.

I have the stock bump stops. Is my car contacting the front stops too early and effectively increasing the front Spring rate and causing me to Understeer?

If you could give me some guidance that would be great.
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Re: Understeer on initial turn in

Postby Brian » Mon Sep 19, 2016 5:39 pm

What alignment numbers?
Shock settings?
Tires same size all around? Pressures?
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Re: Understeer on initial turn in

Postby james001 » Tue Sep 20, 2016 2:21 am

Hi Brian,

Removed front shock tower brace to check koni Shock settings.

Front and rear shocks set to full soft.
Alignment numbers: camber can't remember if -1 or -1.5 front, 5 castor and 1/16" toe in. Rear -1.5 camber 1/16" toe in.

Stock size 17 205 45 tyres

Have to check tyre pressure.

I decided to drive the car without the stock front shock tower brace now that I had removed it. Sooooo much better. Whilst the front feels softer, the initial push is definitely gone.

Should I put back on and change something else? The front doesn't feel as rigid but turn in is better? Should I leave off and increase front sway stiffness to middle hole? What will increasing the the stiffness on the konis do?

Thanks for your help :)
james001
 
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Re: Understeer on initial turn in

Postby james001 » Tue Sep 20, 2016 3:02 am

hmmmmm, there are a lot more creaks and noises now without the brace
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Re: Understeer on initial turn in

Postby Brian » Tue Sep 20, 2016 9:47 am

The brace really does not make much difference in balance, a number of factors here that could easily be playing a bigger role. My guess is the alignment is real issue and you might try toe zero up front and caster of 6.
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Re: Understeer on initial turn in

Postby james001 » Tue Sep 20, 2016 3:14 pm

Thanks for the response Brian,

I dont think I can get a castor of 6 without giving up some negative camber? I told them max caster they could get with camber of either -1 or -1.5 (cant remember which one). What does more castor do?

Will zero toe up front make the car follow the road too much for daily driving?

I was hoping to change balance first before playing with a more aggressive wheel alignment.

Thanks again
james001
 
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Re: Understeer on initial turn in

Postby Brian » Tue Sep 20, 2016 3:22 pm

Heights? Grab a yardstick and measure center of wheel up to fender lip.
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Re: Understeer on initial turn in

Postby james001 » Thu Sep 22, 2016 1:28 am

Hi Brian,

I measured 355mm up front and 360mm at the rear. Centre of wheel to fender.

This appears to be normal to me?
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Re: Understeer on initial turn in

Postby Brian » Thu Sep 22, 2016 6:48 am

Sitting a bit higher than I would expect with those springs and the koni shocks, which explains why you are not getting as much camber as you could use. Might just be your method of doing the measurement but were the install instructions followed, particularly the part about the suspension bolts not being locked with suspension fully extended? Typically with the KONI in there most customers are at least half an inch lower than you are, which allows quite a bit more camber up front, which takes out that initial understeer.
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