FlaFFy_91
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Registered: 30th Sep 08
Location: Formby, Merseyside
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Understeer in cars.
This isnt a help me my cars understerring thread
Its a general chat about understeer and what you think is the best way to get rid of it in a car
Lets take a fwd civic for example. The handling on them are realy good as standard. Lowered, tyres and some arbs and its going to be a winner. But when you put too much power into them they understeer more
I know you can go into things like damper rates and spring rates but i dont realy know alot about them
more damper means less understeer or the otherway round and more spring rate means less understeer or again is it the other way around?
And does a stiffer front end (stiffer or thicker arb) mean less understeer too?
Basicly if theres and track boffins out there who can go into a daft amount of detail feel free 
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Jake
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Registered: 24th Jan 05
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flexible front end reduces understeer i reckon
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Neo
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Registered: 20th Feb 07
Location: Essex
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Soften front springs and remove ARB if it has one
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Graham88
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Registered: 16th Apr 07
Location: South East Kent Drives: E46 M3
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Stiffer front end makes the understeer worse. I was just bouncing around some corners at Silverstone trying to put the power down, slacked off the dampers on the coilovers to competely soft, drove like a different car, but did make it bumpier at high speed
All I know about it really is that stiffer on the front isn't good, which is why alot of people take front ARB's out on some cars. But spring rates etc is out of my knowledge
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antnee
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Registered: 30th Dec 07
Location: Cov Drives: Clio 197
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Generally, the rear will be set harder than the front on a FWD car.
Its all about balance, you can't just say a stiffer front is better. For a really good handling car on semi slicks, it can be a lot stiffer all round over the standard setup.
When people take front ARB's off, I think its probably cos the rear isn't stiff enough.
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FlaFFy_91
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Registered: 30th Sep 08
Location: Formby, Merseyside
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so basicly a stifferfront end is more understeer realy?
i do get what you mean antee every car is different and you do have to balance between front and rear but in generalities a front end that is softer is better
i would of thought a softer front end but with a higher spring rate to keep the wheels down onto the track would be better?
what about rear and 4 wheel drive cars, same sort of deal?
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antnee
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Registered: 30th Dec 07
Location: Cov Drives: Clio 197
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But softer than what? Standard?
If the front is too stiff it will understeer.
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AK
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Registered: 5th Jul 00
Location: Aberdeen City
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Understeer....
Tyre pressures too high (tyres too hot?)
Susp too firm.... (springs or do firm dampning)
too firm from ARB
A stiffer front end is good IF you have tyres and geometry to cope with it! i.e you'll just get understeer if you are running 0 camber and softsidewalled tyres. The tyres will flex and roll over
Add as much CASTOR as you can to give more camber where you need it (on corners). Healty amounts of static camber will help too.
Springs and dampers. The spring is what holds the cars weight... the damper just controls its transfer. If its too soft the car will just wallow/bounce on the spring (assuming 1 way adjustment for compression/rebound). If its too firm the tyres will take more of the load. The tyres can only take so much, esp when your asking them to turn and accelerate.
[Edited on 17-10-2011 by AK]
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AK
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Registered: 5th Jul 00
Location: Aberdeen City
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adding a rear ARB will also help turn in (reduce understeer) but increase rear twitchyness.
quote:
would of thought a softer front end but with a higher spring rate to keep the wheels down onto the track would be better?
a higher spring rate would make it a stiffer front end. If you soften off the dampning on a stiffer spring the car will just skip about. You need decent amounts of dampning to allow the car to lean onto the tyres gradually, but you also need quick enough rebound to keep the tyre in contact with the ground on bumps. Its always a bit of a compromise on 1way adjustable dampers..... even 2way!
You dont need high spring rates to push the wheels back down. Gravity helps out even the softest sprung suspension. On 1way adjustable suspension if you increase it the rebound gets slower (wheels hang in the air longer). 2 way you can adjust compression and rebound - so the car car lean slowly into high speed corners for stability but have slightly quicker rebound to help keep wheels on the ground. 3way you have hi speed rebound and lo speed - (kerbs etc = high speed).
[Edited on 17-10-2011 by AK]
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Nick-S
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Registered: 3rd Mar 04
Location: Leigh. Drives: RS Megane 230 F1 Team R26
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Always though 3 way was hi and low speed compression and rebound. Ie, low speed sqwat, dive and role. Hi speed, bumps and kerbs and rebound?
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sand-eel
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Registered: 15th Mar 07
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Also if you have thicker ARBs, there is no need for majorly negative camber anymore as the car obviously won't roll as much.
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Nick-S
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Registered: 3rd Mar 04
Location: Leigh. Drives: RS Megane 230 F1 Team R26
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Also am not convinced about removal of FARB. Surely that will make it unstable at high speeds.
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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It does...yes, its a stupid thing to do.
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Alex_Rally
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Registered: 6th Sep 09
Location: Tyne and Wear, gateshead
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would a welded in roll cage stiffen everything up ??
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Eck
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Registered: 17th Apr 06
Location: Lundin Links, Fife
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If you're speaking strictly of a FWD (as per example), I've found it's not really understeery unless I'm being a proper tool. The back is really stiff (more so than the front) so I'm guessing by the above that this helps!
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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It stiffens the shell up, meaning the suspension does its job better.
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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Ideally a FWD should have higher poundage springs than the front.
Eg corsa with redtop conversion - 250-275lb/mm front 500-600 lb/mm back.
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Alex_Rally
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Registered: 6th Sep 09
Location: Tyne and Wear, gateshead
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quote:
Originally posted by sand-eel
It stiffens the shell up, meaning the suspension does its job better.
i hoped so , cos mines about 95% in there now lol , twat of a job lol
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sand-eel
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Registered: 15th Mar 07
Location: carluke/braidwood--IRNBRULAND
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quote:
Originally posted by sand-eel
Ideally a FWD should have higher poundage springs than the front.
Eg corsa with redtop conversion - 250-275lb/mm front 500-600 lb/mm back.
^^^ oh this would be very good on a track not so good on shit uk roads.
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Mieran
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Registered: 28th Jan 08
Location: Newcastle upon Tyne
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quote:
Originally posted by Nick-S
Also am not convinced about removal of FARB. Surely that will make it unstable at high speeds.
I wouldn't take a front anti roll bar off unless its a shit design like the Nova/Corsa/Tigra ones which are designed to make the car understeer!
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0775kieran
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Registered: 28th Apr 10
Location: Bolton, Greater Manchester
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When i have taken the front arb off it has made for a better turn in and less understeer, but has made it unstable at higher speeds, if its a road car just leave it on.
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AK
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Registered: 5th Jul 00
Location: Aberdeen City
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quote:
Originally posted by Nick-S
Always though 3 way was hi and low speed compression and rebound. Ie, low speed sqwat, dive and role. Hi speed, bumps and kerbs and rebound?
that would either be 2 or 4 way then 
Front ARB (on corsa)
If wet trackday, remove it. Test it on round-abouts - constant raduis with a bit of power. I always found you'd get more power down without the ARB.
Rear ARB:
Our GTR (not fwd) is very RWD biased and has been struggling for rear traction this year. We've gone from an adjustable thick blade ARB, to a thinner one and now nothing!
[Edited on 18-10-2011 by AK]
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Mike GSi
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Registered: 3rd Jan 07
Location: Ipswich, Suffolk Drives:Astra VXR
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When i removed my FARB on my Let corsa with coilovers it was much better on smooth tight long bends, but on a gradual shit country road bend at anything over 70mph you could feel on the steering wheel the slow rebound time.
As said. For track conditions no FARB, for a daily driver on uk roads FARB is a must imho.
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Rob B
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Registered: 8th Jan 04
Location: Area Motorsport Drives: Race EP3
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quote:
Originally posted by sand-eel
Ideally a FWD should have higher poundage springs than the front.
Eg corsa with redtop conversion - 250-275lb/mm front 500-600 lb/mm back.
Entirely depends on the motion ratio front to rear?
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AK
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Registered: 5th Jul 00
Location: Aberdeen City
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quote:
Originally posted by Mike GSi
When i removed my FARB on my Let corsa with coilovers it was much better on smooth tight long bends, but on a gradual shit country road bend at anything over 70mph you could feel on the steering wheel the slow rebound time.
As said. For track conditions no FARB, for a daily driver on uk roads FARB is a must imho.
Not arguing or anything.... BUT removing an ARB will promote FASTER rebound, i.e your car will have have less tendancy to 'pickup' a wheel at the corner under hard cornering. Without the ARB the car will lean on the springs more.
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