[race_prep] Guernsey Hillclimb 205 Build

[wardy18 33 1 Cars]

It was just in the hope to reduce a bit more body roll as at the moment pressures in the fronts lower than 27psi im running on the side walls round corners

Edited September 17, 2012 by wardy18

[Cameron 16]

Give it a try and see how it goes, but glad to see you're getting on better with more front camber! Also it looks like you found the limit of effectiveness at around 1.5Deg, so at least that shows the advice you've been given is consistent!

 

Edit: How old are your tyres, out of interest? And how do you protect / store them between races?

Edited September 17, 2012 by Cameron

[wardy18 33 1 Cars]

Tyres were bought march this year so are ok but certainly not at soft as new anymore!! Out of winter I just keep them in the back of the car in my garage, if I try to keep them for the start of the following years racing I'll store them in the house over winter (without the wife knowing!!!!)

[andy0075 9 1 Cars]

..........I'll store them in the house over winter (without the wife knowing!!!!)

 

So, I'am not the only one

 

On a frontwheeldriven car you increase understeer with an ARB and the thicker it is the more

understeer you will get. -> NO ARB!

But you will see it yourself on your next race with the thicker ARB.

 

Did you ever meassured the tyretemp ( inside- middle - outside ) after a race ?

Should be around 60°C. Because i think, and i wrote you that before, that the A15

on the front is way too soft! This also causes understeer. A53 or A11 is much better.

 

Andy

[wardy18 33 1 Cars]

Even with just 375lb springs? Still dont think the front is stuff enough causing body roll hence tyre roll hence understeer, if i wasnt getting body roll then yeh i would agree.... please correct if wrong?

 

No havent measured tyre temps yet, was going to stretch the budget for the ARB before my next event, tyre pyrometer was going to be on the xmas list.

 

I am intrigued about your theory of A15 on the front being too soft but its an expensive test at almost 250 a tyre?? So if tyre temps over 60deg then thats too hot for A15, is that what you are saying?? I might make a call to Avon (not BMTR)

[andy0075 9 1 Cars]

With 375lb springs i think it will be too soft, but give it a try anyway. You only have to disconnect one droplink and

that only means 5min work. If it does not function reconnect the ARB. But i would not try the 309GTI ARB.

 

I don't know what airtemperature you have at your races but here we have something between 25-35°C.

Last year i even overheated a A53 tyre on the front! After a 1min racelap i had over 90°C on the tyre tread

and the colour turned from black to blue!

 

Andy

[wardy18 33 1 Cars]

Finally someone sent me a link to a youtube video of the 205 at the Alderney Hillclimb, let me know what you think of the handling??

 

Hopefully some more to follow

 

[wardy18 33 1 Cars]

And another with the Traction Control, my startline RPM's were way too low hence the big bog down and technique all wrong so have much to try on the next event (Thanks Sandy) but still im happy with a 2.34 0-64ft time!!

 

[Cameron 16]

Looks like it turns in well!

 

Edit - first vid, difficult to see on the 2nd. 1st vid looks like it yaws well on turn-in and the back end comes around nicely.

Edited September 17, 2012 by Cameron

[andy0075 9 1 Cars]

First i have to say : Very, very nice car!!! Like it really much. Real nice sound. How high did

you rev the engine in this video ?

 

Second : Don't cut corners with slicks They don't like stones.

 

Third point : Yes, i think you have too much body roll. Make the front end stiffer and

maybe you can drop the hight (roll center) of the car somehow.

 

Andy

[wardy18 33 1 Cars]

Coming into that corner on the 1st video i was pulling approx 6800-7000 rpm in 4th gear

 

Everytime i came into that corner i was determined not to clip the grass but i kept on doing it!!!

 

If i went for say 450lb springs but in a 6" spring, i am on 7" springs at the moment and cant lower anymore on the coilovers.

[wardy18 33 1 Cars]

And another head on....

 

[wardy18 33 1 Cars]

Some still shots of the Hillclimb, the first is amazing, big front and rear left wheel lift.....still some tyre roll too though as you will see!!

 

http://www.guernseymotorsport.com/alderney-hill2012car-15

 

http://www.guernseymotorsport.com/alderney-hill2012car-36

 

http://www.guernseymotorsport.com/alderney-hill2012car-89

 

http://www.guernseymotorsport.com/alderney-hill2012car-165

 

http://www.guernseymotorsport.com/alderney-hill2012car-181

[wardy18 33 1 Cars]

More pics from the Alderney Hillclimb:

 

http://www.guernseymotorsport.com/alderney-hill2012car-274

 

Check the front tyre roll on this one........

http://www.guernseymotorsport.com/alderney-hill2012car-282

[Cameron 16]

It looks like your tyres have a slight stretch, which may accentuate any rolling of the sidewalls.. what size rim and tyre are you using?

 

Also.. I have a feeling your ride height is deceptively high, and your bodykit makes it look lower than it really is. Looking at the rear end it doesn't look that low at all.

Edited September 20, 2012 by Cameron

[wardy18 33 1 Cars]

Rims are 9" at the front and tyres are 8.7" as recommend by BMTR and Colin/Sandy run the same configuration with no issues.

 

I am going to move up to 450 or 500lb springs (HAVEN'T DECIDED YET) so when i do i am going to go for 6" free length rather than 7" so i can further lower the CG keeping damper travel in mind which i should have plenty off with Gaz having short bodies which i have had shortened by the further 20mm!!

 

The rear is 8 to 10mm higher than the front

[Sandy 191]

You've almost reached double the front spring rates Colin runs!

[stu8v 68 1 Cars]

You've almost reached double the front spring rates Colin runs!

 

Sounds like you know something he doesnt :-)

[wardy18 33 1 Cars]

I have spoken at length with Colin who is baffled at my tyre roll issues but many thanks to him to taking the time to discuss, however Colin has his self developed subframe with a much preferred roll centre ie not below ground level as with std lowering techniques!! Ability which is much desired!!

Edited September 22, 2012 by wardy18

[Cameron 16]

Yep, unfortunately it's not always as simple as just copying someone else's setup.

[Batfink 201]

You have to also remember that theres not a one size fits all setup. Colin may prefer a softer sprung car. From video footage of his events and the video of yours the cornish hills are slower speed.

On the 205 rallye we ran a stiffer rear spring setup to what colin uses, despite using the same suspension design...

 

I cannot remember how your car is setup at the front regarding wishbones but if Colins track width is wider then the effective spring rate is different. I'm not totally sure how its all worked out - whether its based on wishbone/hub width or overall track width. Colin used to run 0 offset front wheels but I don't know what this is now with the 9" wheels on the new setup.

[Sandy 191]

To be fair, you've not seen much of what Colin's done; many events are much higher speeds, especially the circuit based sprints and he doesn't want for high speed stability. The main issue is the geometry and instability of a modified standard chassis; it's a regular thing for people to try and solve those issues with spring rates that simply kill travel to stiffen the car to the point of being a kart chassis basically and ARBs that try to correct the problems further. Colin Chapman among others, established a long time ago that getting the geometry right, means you can run more travel, keep the tyres on the ground for more of the time and hence get more grip and traction, particularly on bad surfaces, which are typical of hillclimbs, sprints and tarmac rallies alike, even some circuits like Castle Combe, where the bumps define the entry and exits.

Views of what typical spring rates should be, are frequently skewed by advice based on poor chassis geometry, kerb hopping or in some cases downforce. You have to work from the basics and get them right. It's clear that knowing the basic geometry is right and consistent (not distorted by chassis and component flex); is the most fundamental element and we strongly suspect Simon's up against those issues. Colin wasn't born with the set up he now uses, he's tried alot and we still see alot of cars running modified standard chassis like this; in the rollers I can feel the difference, so it must be really limiting on an uneven road surface!

[Cameron 16]

Spot on - a high roll centre gives a fair amount of roll stiffness so there isn't the same need to control it so much with stiff springs and ARB's, also your / Colin's car has a lower CoG due to dropping the engine down which will also help things.

 

The problem is that unless Simon fits one of your special front subframes he's going to have to combat roll the conventional way and sacrifice a small amount of traction in doing so; and even if he did fit one, it would mean starting at square 1 again with the spring rates as there's no chance his and your cars will be similar enough to run the same rates.

[Sandy 191]

Even with what Simon has, it's unlikely spring rates that high are going to give the best results on variable surfaces. Colin and I strongly suspect that a proper square one session to make sure all aspects of the current chassis are in the right place, is needed.

[Cameron 16]

Yeah I'm not entirely convinced by running such high rates on hillclimbs.. 350-400lb/in is plenty stiff enough. Maybe on a circuit or a very smooth hillclimb, but how many courses are going to be smooth enough.