Ultimate Understeer. :/

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Oli192
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Ultimate Understeer. :/

Post by Oli192 »

I am just starting down the road to use my car for Autosolo, I had fun doing it in my MX5 last year but want to use the Stylus for it now.

To that end I have put a quick rack and an LSD on it (and lengthened the final drive ratio to make it nicer on the road)

Rob helped me loads with the handling last year with the handling and I appear to have undone all the good work.

Under low speed acceleration the front was lifting so much that the inside front wheel was lifting clear off the ground quite regularly.
I am really hoping this can be cured with change of front and rear heights and stiffening the dampers.

Has any else suffered with this? I knew the LSD would make the nose push on but a front wheel clear off the ground does not help much with steering!

These pics show the extent of the problem:

https://drive.google.com/open?id=0B02xE ... TJadnJXZWM

https://drive.google.com/open?id=0B02xE ... 0J6U1ZmMTg

https://drive.google.com/open?id=0B02xE ... UFxRVZzYUU

hearbear
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Re: Ultimate Understeer. :/

Post by hearbear »

In the last pic is the rod bent if so that isn't going to help.
Image

Oli192
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Re: Ultimate Understeer. :/

Post by Oli192 »

Indeed. :/

I bent that at Castle Combe last month. Not 100% sure what can be done about that either. I think I might have to start from scratch on it.

josephmoore
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Re: Ultimate Understeer. :/

Post by josephmoore »

Ah yes, Ben said about your ruined panhard rod :lol:

Maybe the rear springs are just a bit soft for two fully grown men?

Got any video of you driving? The thing I've found that had the biggest effect on getting rid of the understeer was being strict on getting it into 2nd gear and never accelerating/braking while turning.

stylussprinter
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Re: Ultimate Understeer. :/

Post by stylussprinter »

With two up your rear springs are simply inadequate for competition . What spring rates/lbs are you using front/rear. By the way , there's nothing inherently wrong with an inside front lifting , check out my Goodwood Chicane photo . You can set a car up for that particular competition without changing the springs , provided they are correct in the first place. Ideal would be an oversteery car , so's you can steer it on the throttle . Really sticky quality tyres up front (any soft compound TOYO YOKO AVON etc) with correct tyre pressure for max grip . Then tatty cheapo rear tyres slightly over inflated = bingo , turn wheel slightly plus lift off = sharpe turn . I drove a Caterhan setup this way and it was an absolute doddle to compete around cones etc.
I just love the Stylus but she keeps swallowing £££ !
Alfa Red 159 2.4 jtdm ti 260bhp 365lbft / BilsteinB12 + Adjustable Powerflex camber/castor bushes. Red STYLUS 2lt zetec 231bhp 185lbft Dunnell . RED 1972 Alfa 2lt GTAm replica 170bhp.

Oli192
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Re: Ultimate Understeer. :/

Post by Oli192 »

The suspension is all Protech, fronts are 12in open shocks with an 8in 300lb Spring and the rears are 15" open with a 10in 250lb spring. I do much prefer a loose rear end, I really hate fighting understeer.

No video to hand and that is probably for the best! :D I did one run in second and it did not make a lot of difference.

stylussprinter
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Re: Ultimate Understeer. :/

Post by stylussprinter »

Oli192 wrote:The suspension is all Protech, fronts are 12in open shocks with an 8in 300lb Spring and the rears are 15" open with a 10in 250lb spring. I do much prefer a loose rear end, I really hate fighting understeer.

No video to hand and that is probably for the best! :D I did one run in second and it did not make a lot of difference.
Have you got at least 10mm's of rake with you still in the car :?: Don't understand why there's a passenger in the car in competition though :o This will make it almost impossible not to understeer unless the rake is double or more , because the car is going to have '' back to front rake '' ie. front higher than rear :!:
If you still have the settings I gave you -- bump/rebound then set front tyres to 17psi if list 1B or 18psi if normal road tyres . Rears to 22 psi unless it's too much oversteer , in which case drop 1 psi at a time to arrive at your personal need.
I've never seen any competition with a passenger on board :roll:
I just love the Stylus but she keeps swallowing £££ !
Alfa Red 159 2.4 jtdm ti 260bhp 365lbft / BilsteinB12 + Adjustable Powerflex camber/castor bushes. Red STYLUS 2lt zetec 231bhp 185lbft Dunnell . RED 1972 Alfa 2lt GTAm replica 170bhp.

josephmoore
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Re: Ultimate Understeer. :/

Post by josephmoore »

No, car's definitely not eligible for a PCA so I'd kick that bloke out :lol:

hearbear
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Re: Ultimate Understeer. :/

Post by hearbear »

Just looking at the pictures again I think the front wheel is lifting so much due to the body moving side ways at the rear due to the bent panhard rod, if you look at the last pic the top of the wheel is well in the arch so I think as you are turning the rear of the body is moving and twisting round and that action is then lifting the front wheel. Before getting in to deep I would make a new rod and try again.
Image

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MattD
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Re: Ultimate Understeer. :/

Post by MattD »

hearbear wrote:Just looking at the pictures again I think the front wheel is lifting so much due to the body moving side ways at the rear due to the bent panhard rod, if you look at the last pic the top of the wheel is well in the arch so I think as you are turning the rear of the body is moving and twisting round and that action is then lifting the front wheel. Before getting in to deep I would make a new rod and try again.
Its all in the chassis.... Rear setup affects the Front & vice versa...... new beefier Panhard rod & a front ARB as a minimum.
And all that V6 torque prob means lots of axle tramp too - hence the bent rod ??
SSC Stylus Integrale Turbo16V
Kit 1999, OTR 2002, and still tweaking....

Oli192
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Re: Ultimate Understeer. :/

Post by Oli192 »

The rod is bent because it was hitting the diff when the car squats.

An ARB will have to be on the shopping list but if I stiffen the rear springs will I have to change the fronts as well? And what kind of Spring rate will I have to go for?

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