The suspension saga continues - Bilstein Escort Cup ?

[appletonn]

Thanks Patrick - I did come across some calculations on a couple of the US sites and was doubting my rear combined figures. So that means my rear end is actually running at what combined stiffness?? Is it 42% of the total lbs/in of the t/b and coils?

Yes, I gather that the Cup cars were running circa 375 lbs/in on the front, so no wonder mine is so reluctant to turn in!

I've just spoken to Phil at Tech 9 in Liverpool, who used to race these cars in the UK and he has advised that I go with a 300lbs/in front spring - once I let him know the length and internal diameter (2.25" ID I think, but waiting for Lindsay racing to confirm both), then he says he has plenty of them from their racing days that I can choose from. He told me that they always used to set their cars up fairly soft at the front end to try and remove the understeer and then use thicker anti-roll bars at the front to balance things.

So, once I have the info I need from LR, I'm off to Tech 9 to get me some new springs!

Thanks again

 

[sawood12]

Well by quoting a TB rate as x lb/inch it all depends upon at what radius is assumed. 1 inch vertical deflection at 2 foot radius will generate more force in the TB than 1 inch vertical deflection at 1 foot radius as it will twist the TB though more degrees of arc.

Also TB's act as sort of progressive rate springs. Because if you raise the wheel by 1 inch vertically it will twist the TB a certain number of degrees. If you then raise the wheel by a further inch vertically it will twist the TB by more degrees than the first inch therefore you effectively have a progressive rate spring.

If I recall correctly I think with KWv3 the fronts are about 330lb and the rears are about 220lb.

 

[appletonn]

ORIGINAL: sawood12

Well by quoting a TB rate as x lb/inch it all depends upon at what radius is assumed. 1 inch vertical deflection at 2 foot radius will generate more force in the TB than 1 inch vertical deflection at 1 foot radius as it will twist the TB though more degrees of arc.

Also TB's act as sort of progressive rate springs. Because if you raise the wheel by 1 inch vertically it will twist the TB a certain number of degrees. If you then raise the wheel by a further inch vertically it will twist the TB by more degrees than the first inch therefore you effectively have a progressive rate spring.

If I recall correctly I think with KWv3 the fronts are about 330lb and the rears are about 220lb.

Well, according to the Clarkes site, where they quote equivalent wheel spring rates for the rear t/bars, the 25.5mm ones fitted to mine equate to 175lbs/in at the wheel which I guess then takes into account the length of the suspension arm etc?

http://www.clarks-garage.com/shop-manual/susp-15.htm

I rang KW to try and get some comparative spring rates and they quoted me these - Fr 50 N/m , R 16 N/m, not sure how that compares in old money though?!!

I'm going to give the 300 lb/in front springs a go - they are almost twice as stiff as the standard ones, so should still give me enough roll resistance for the track, whilst giving me back the front end bite that I crave so much![]

 

[Tam Lin]

ORIGINAL: appletonn

ORIGINAL: sawood12


If I recall correctly I think with KWv3 the fronts are about 330lb and the rears are about 220lb.

I rang KW to try and get some comparative spring rates and they quoted me these - Fr 50 N/m , R 16 N/m, not sure how that compares in old money though?!!

I think the main springs are 342 lb rising rate front, and about 190 lb rr rear for KW3 v3, though since both have helper springs, the absolute rates are a bit beyond my competence to work out

 

[appletonn]

ORIGINAL: Tam Lin

ORIGINAL: appletonn

ORIGINAL: sawood12


If I recall correctly I think with KWv3 the fronts are about 330lb and the rears are about 220lb.

I rang KW to try and get some comparative spring rates and they quoted me these - Fr 50 N/m , R 16 N/m, not sure how that compares in old money though?!!

I think the main springs are 342 lb rising rate front, and about 190 lb rr rear for KW3 v3, though since both have helper springs, the absolute rates are a bit beyond my competence to work out

Hmm, mine too....[8|][]

 

[appletonn]

OK, after further research, using this link amongst others http://www.tech-session.com/kb/index.php?article=39 , and taking on board Patrick's knowledge on the subject, I now believe that my rear combined effective spring rate is 315lbs/in, which was never going to provide anything other than understeer when combined with a front end as stiff as 450lbs/in.....[8|]

It can only be down to my 'Driving God' status that it went round corners at all....[][][]

 

[mike220]

Don't know about anyone else Nick, but I never once thought it could be any other reason ? . . . . . . . . . . . . . . . []

Mike

 

[Diver944]

ORIGINAL: appletonn

I now believe that my rear combined effective spring rate is 315lbs/in, which was never going to provide anything other than understeer when combined with a front end as stiff as 450lbs/in.....[8|]

Sounds like you need to put 550's on the rear then and make a block booking with your dentist

......and the rears are easier to change and won't require a realignment afterwards.

 

[appletonn]

ORIGINAL: Diver944

ORIGINAL: appletonn

I now believe that my rear combined effective spring rate is 315lbs/in, which was never going to provide anything other than understeer when combined with a front end as stiff as 450lbs/in.....[8|]

Sounds like you need to put 550's on the rear then and make a block booking with your dentist

......and the rears are easier to change and won't require a realignment afterwards.

It did cross my mind...

..but then the thought of a spinal block every time I went for a drive, persuaded me otherwise[]

 

[appletonn]

ORIGINAL: mike220

Don't know about anyone else Nick, but I never once thought it could be any other reason ? . . . . . . . . . . . . . . . []

Mike

 

[appletonn]

Update - had the 300lbs/in front springs fitted today in lieu of the 450lbs/in ones. Despite the monsoon-like weather in my neck of the woods today, I could immediately feel the difference in the way the front of the car turned into sodden roundabouts and how the front tyres felt so much more keyed into the tarmac. Need to try it in dry conditions but already have much more confidence in the car's handling.

Roll on Donnington![]

 

[Diver944]

Result! []

I love it when a plan comes together

 

[Fen]

Excellent! Now you just need a glass-out respray in any other colour and you're sorted []

 

[appletonn]

ORIGINAL: Fen

Excellent! Now you just need a glass-out respray in any other colour and you're sorted []

M u s t n o t b i t e . . . . [][]

BTW Fen, I agree with your comments elsewhere about LR - quite why they would supply the PO with such an ill matched suspension set up is beyond me, although I do know that 'rock hard' suspension = 'sporty' in the US?!

They have been very helpful, but I'm not convinced about some of their stuff