great day at elvington, with Track Action

[joospeed]

Had a fantastic time at elvington today with the brilliant Graeme and his Track Action team (unreservedly recommended).

The V8 was perfect all day, driven to within an inch of it's life it never missed a beat, except for the fan belt coming off at the very end of the very last session .. oh well, I can forgive it that one little mistake!!

The new suspension settings work brilliantly for track day use with grippy SO2PP tyres (205 / 55 / 15 front, 235 / 45 / 16 rear).

I managed to pass a tuscan SP6 twice in one session, and the sight of it spining off behind me trying to keep up (with rude girl passengering in it at the time) is a sight I'll savour for a while!! The owner was a very decent likebale chap too ..

Only having about 200bhp is abit of a handicap on the straights especially as i only use 4500-5000 revs, but in the corners the S was simply brilliant .. slight corner entry understeer could be tamed with either wider front tyres or less low speed bump in the dampers, but at the moment the bump rate lets you lean on the outer tyre to give safe predictable corner entry.

If anything the new suspension settings give so much grip that the body roll is just starting to become a problem again (spring rates 500 front 375 rear) so a slight increase in spring rates and anti roll bar settings to dial out some roll without affecting traction too much would be nice, however the on track performance spoke for itself .. magic

all in all the best day at a track ive had since testing the nitron kit on the tuscan at bedford .. only an extra 160 bhp in the S would make up for that though !!

[greenv8s]

I tend to run the front dampers slightly on the soft side with relative high spring rates, to give transient oversteer (good turn-in) and steady state understeer. Then I balance the understeer with the throttle. You can tweak it to turn in more or less by varying the amount and timing of the engine braking on the approach but I do like to have a positive turn-in, nothing worse than starting your corner with a fight against understeer. Have to say the S series make extremely good track cars and the V8S is obviously the best of the bunch. Chuck in a decent power hike to bring it up to par with the later models in a straight line and it gets even better ...

[shnozz]

Jules, sounds a top day out mate. Will have to give you a shout about getting the noise levels on mine down enough to get her on the track.

[rude girl]

joospeed said:

I managed to pass a tuscan SP6 twice in one session, and the sight of it spining off behind me trying to keep up (with rude girl passengering in it at the time) is a sight I'll savour for a while!! The owner was a very decent likebale chap too ..

Joo - you didn't mention spinning off in front of us Not like you to miss a detail like that

[joospeed]

lol .. i thought you hadn't seen that .. hoho .. well if you dont spin you aren't trying and i only had the one all day .. hoho.

Peter .. I too favour high spring rates / low bump settings .. although on the AVOs you can't change the damper spec, but the cerbera dampersa ll round seem pretty good on this car, better than the proper avo S dampers in fact .. strange.! the stroke is too long but not a problem on my own car, but wouldn't do a customer car like that. jus ordered 600 front / 450 rear for playing with.

[rude girl]

joospeed said:

lol .. i thought you hadn't seen that .. hoho .. well if you dont spin you aren't trying and i only had the one all day .. hoho.

Blimming Heck - they're coming thick and fast now, aren't they?

He was a nice man though with the Tuscan, wasn't he?

[HarryW]

Most interesting Jools, I find the standard set up on mine waaaay too soft, particulary squat under acceleration (have a little more power than yours at the wheels ). That said it is very comfortable whilst pottering has has no vices.

I read with interest the 'not on a customer's car' what is differnet between the S and cerbie avo's , as I'm still saving for a replacement set up for all 4 corners now, actually have it in back pocket now but am just weighing up pro's and cons before parting with the hard earned . Could still be swayed by the nitron set up, but as an occassional track car the extra £400 for the nitron set up over the avo's could go towards something else .

Out of interest Peter what spring rates you using with the nitron set up and what would you recommend to a novice if the nitron route was taken in way of rates.

So many questions.....................so little time.

Harry

[greenv8s]

HarryW said:

Out of interest Peter what spring rates you using with the nitron set up and what would you recommend to a novice if the nitron route was taken in way of rates. So many questions.....................so little time. Harry

I'm currently using linear springs all round, 600 front / 400 rear, dampers specced to suit the springs (including non-standard lengths and bump stops) with fairly aggressive suspension geometry, slightly non-standard wheel sizes, stiffened arb and so on. These have been arrived at after years of testing and trial and error on track and off, and the end result suits me so well that it feels like I put the car on rather than get into it. I think the only reason I can get away with these spring rates on the road is that I'm using Nitrons, which do a superb job of absorbing road harshness compared to lesser dampers. I'm willing to compromise comfort on the road for handling on the track, but this is about as far as even I would want to go for a road car, and for most people I don't think it would be an acceptable compromise.

At the end of the day the only thing that matters is what do *you* want from the car, it needs to be set up to suit you. And the best way to find this is probably to start with the best dampers you can afford, spec them to cope with a range of springs from say 300 to 600 lbs, and start playing with spring rates and geometry. Best to make lots of small changes rather than a few bigger ones because as you change one thing you will need to adjust others to match, if you make too big adjustments you can easily get lost and end up with an evil handling bar steward.

(edited to add the bit about bump stops, which is important)

>> Edited by greenv8s on Monday 12th January 15:37

[HarryW]

Cheers Peter, I notice that the front/rear rate ratio of your springs is slightly different to Joolz, is that due to the thick arb on yours .
I have a feeling that I would as a starter may go for something along the lines of 450/325 or do you/joolz consider that too soft to get the full benefit of decent shocks.
I know it is asking a lot, but not being a total track monster I don't suppose I will change the spring rates from that specified unless it was seriously wrong in the first instant so wnat to get it right(ish) first time around.
I'm just trying to hedge my bets and rely on the fact I have adjustable dampers to fine tune the car.
Is your stiffer arb bespoke , as I have a feeling (unfounded btw ) that this may help resolve a lot of the S series trait of wollowing into the corner on initial turn in . Perhaps it may even be Joolz's problem as in the first post i.e. the current rates 500/375 with a thicker arb may help, or even be the way for me to go .
So many questions............

Harry

[greenv8s]

As you stiffen up the springs you need to stiffen the front relative to the rear because the contribution of the front arb becomes less significant. Mine uses the standard 7/8" arb but I've taken all the rubber out of the mounts and drop links, this increases the effective stiffness quite usefully.

[HarryW]

Thats interesting Peter, to replace the arb clamp rubber with a solid block is easy enough to manufacture, but exactly what did you do to the drop links too, as these obviously still swivel with the front wheel .
Out of interest, [suspension numptie alert mode on] , I assume that the front coilover being at a greater angle than the rear expains the different rates front and rear , what is the effective rate for both as even the rear are atan incline . I seem to recall that the arb is the equivilant of 70lbs on the springs is that correct .
[suspension numptie mode alert off]
Questions questions..................

harry

[GreenV8S]

HarryW said:

Thats interesting Peter, to replace the arb clamp rubber with a solid block is easy enough to manufacture, but exactly what did you do to the drop links too, as these obviously still swivel with the front wheel . Out of interest, [suspension numptie alert mode on] , I assume that the front coilover being at a greater angle than the rear expains the different rates front and rear , what is the effective rate for both as even the rear are atan incline . I seem to recall that the arb is the equivilant of 70lbs on the springs is that correct . [suspension numptie mode alert off] Questions questions.................. harry

The chassis mounts are actually pretty stiff, I tried pre-loading them to make them effectively rigid but it didn't make much difference. The big gains come from replacing the rubber bushed drop link with one using rod end bearings. You can buy the parts easily enough from Merlin Motorsport, you just need to add a spacer tube to stand the drop link away from the wishbone. Arb rate can't remember the exact rate without looking it up but you're in the right ball park. Spring rate versus wheel rate depends on the leverage squared but remember the rears connect to the middle of the trailing arms so have much less leverage than the front (1.7:1 versus 1.4:1). Hence front wheel rate is almost exactly half the front spring rate, rear wheel rate is almost exactly one third the rear spring rate.

[TimW]

GreenV8S said:

......... Spring rate versus wheel rate depends on the leverage squared but remember the rears connect to the middle of the trailing arms so have much less leverage than the front (1.7:1 versus 1.4:1). Hence front wheel rate is almost exactly half the front spring rate, rear wheel rate is almost exactly one third the rear spring rate.

Peter having a thicky holden moment here , if I understand this do you not want to get the front and rear wheel rates to be roughly the same so to balance the car .
Therefore, for your settings of 600/400, half the front spring rate would be a 300lb wheel rate and a third of the rear spring rate would be 130lb...........I think I don't understand this subject very well at present .

Again for the idiot please .

Harry

Edited to add it is harryW not TimW btw. just about to change log ins

>> Edited by TimW on Monday 12th January 22:54

[HarryW]

Thats better

[joospeed]

I'm going to run slightly higher rear rates than peter cos my car is about 70bhp down on peters and i dont have the luxury of oodles of torque to balance out the understeer.

[GreenV8S]

TimW aka HarryW said:

Peter having a thicky holden moment here , if I understand this do you not want to get the front and rear wheel rates to be roughly the same so to balance the car . Therefore, for your settings of 600/400, half the front spring rate would be a 300lb wheel rate and a third of the rear spring rate would be 130lb...........I think I don't understand this subject very well at present . Again for the idiot please . Harry

You're on the right lines, and other things being equal you'd go equal spring and damper rates all round to give neutral handling. The thing is, other things aren't really equal, because the front wheels are undriven and because of the weight transfer under acceleration/braking. [gross simplification] For various reasons, an important goal of the suspension setup is to give neutral handling under moderately hard acceleration out of a corner. Of course the definition of 'moderately hard' varies depending how much power you have, so the more power you are trying to put down the harder you need to make the front suspension and the softer you make the rear, to give more traction and less oversteer. The more power you have the harder this compromise is because of course you aren't always accelerating hard out of a corner, and it can lead to more and more understeer in other situations. [/gross simplification]

Each time I've added more power to the V8S I've had to tweak the suspension to give more traction and more understeer, and this has also meant changing my driving style further and further towards late apex/early acceleration rather than maximising speed carried through the corner. The mods come from a combination of spring rates, damper rates, geometry and driving style - its a continuous learning game and sometimes I over do it and end up with some lurid power slides, its a lousy job but somebody's got to do it!