How stiff do you like it?

323ian · Post by **323ian** » Sun Jul 01, 2007 9:56 pm

That does not make sense, surely if i am getting oversteer sensation then the rear is not getting enough grip, not the other way around!?

sdminus · Post by **sdminus** » Sun Jul 01, 2007 10:02 pm

Testing is the only way to find out. Have you thought the problem could also be related to the front end grip ?

To diagnose the condition you need to understand where it does it.

is it turn in , apex, exit.

it could be that you are using too much throttle and the front is griping far too much. I am trying to get you to think here. the answer is in the set up but by applying simple logic to it you can improve most situations with minor alterations that can be track tuned to the weather and temp

Scott

323ian · Post by **323ian** » Sun Jul 01, 2007 10:05 pm

I think the only way for me to go before i try anything drastic is to get my car set up properly on a laser jig like autotest at norwich. I think the best way to get this oversteer sensation out is to dial in a bit of toe in at the rear?

It just feels a bit oversteer happy on constant throttle all the way around a corner really, sometimes on the road as well as track so not always doing high speed.

duncan · Post by **duncan** » Sun Jul 01, 2007 10:13 pm

COG = centre of gravity

F! and BTCC set up geometry for specific tracks with toe-in/out / camber and caster angles set for specific track and condition without even touching on tyres pressures, compounds, spring rates, damper rates, rebound rates, compression rates.

The best we can hope for in our shopping cars is a good compromise that we can live with

Rear stepping out - has it done it? It might just be a sensation rather than a reality or could be a driving style that is doing it rather than a problem with the car set up.

Altering geometry or at least knowing what it is would be the first step in my book (and was) and what changes work. I have set toe out on my understeer barge to get it to be a bit more pointy in corners. This makes it turn in better but can make for a lively drive

Thicker anti roll bars can make the car feel lifeless and stop the weight transferrance that actually helps cars on essentially road tyres work.

It is such a black art Ian that I doubt whether any one of us 'really' knows what we are talking about and most of it is down to personal preference anyway.

sdminus · Post by **sdminus** » Sun Jul 01, 2007 10:17 pm

Back to what stu wanted to know :

Front. Going to a stiffer spring (higher spring rate) will increase understeer
going to a softer spring (lower spring rate) will reduce the roll resistance of the front end but move the cornering balance away from under steer.

Rear. going stiffer will increase the tendancy toward over steer while a softer one will go in the opposite direction tending to under steer.

323ian · Post by **323ian** » Sun Jul 01, 2007 10:17 pm

dynamix wrote: It is such a black art Ian that I doubt whether any one of us 'really' knows what we are talking about and most of it is down to personal preference anyway.

That is one of the best statements i have heard in a long long time. Absolute gospel truth. 8) :lol:

I think i will have to let another responsible Skyline driver have a go in my car on the track and see what they think, trouble is there is not many of them about!! :lol:

duncan · Post by **duncan** » Sun Jul 01, 2007 10:18 pm

very succinct Scott :thumb:

Just tilt your heaad a bit stu and it wont look like it is leaning

slaphead · Post by **slaphead** » Sun Jul 01, 2007 10:24 pm

323ian wrote:
dynamix wrote: It is such a black art Ian that I doubt whether any one of us 'really' knows what we are talking about and most of it is down to personal preference anyway.
That is one of the best statements i have heard in a long long time. Absolute gospel truth. 8) :lol:

I think i will have to let another responsible Skyline driver have a go in my car on the track and see what they think, trouble is there is not many of them about!! :lol:

Can I volunteer Ian [-o< and being an old fart an all, I drive like a granny Honest :lol: (I suspect Ian has died of fright by this piont)

~Mark

duncan · Post by **duncan** » Sat Jul 14, 2007 7:01 am

Some useful info here Stu:

http://www.wtrscca.org/tech.htm

Post by **Stuart** » Sat Jul 14, 2007 8:32 am

To be honest, I think I should have explained myself better. I know and understand all of the principles that have been brought up here (thanks all the same though) . It was more about trying to learn about what other people are using on their cars and trying to draw parallels with their car and mine bearing in mind approx weight, weight distribution, tyre choices etc.

I am happy with the turn in, the balance of the car is fine in fast sweeping bends (eg I am just starting to get oversteer/4 wheel drift in the dry at 95-100 around the last part of Corum, comfortably tidying things up for the entry to Russells) The only area of improvement I seek to fix is the transfer of weight between left and right handers or vice versa (ie chicanes) like the Esses at Snett or Donington. The body roll at these points is pronounced and although it looks flat -ish I feel it could be tidier. I do not want more understeer though, so I'll have to get Cadwell out of the way and then consider swapping springs around for a spot of trial and error.

Thanks for your input chaps.