50 replies to this topic

[swast4]

Hi Chris,
Thank you for the time to reply, I did forget to attach the geo, so please find it attached now.

I've only done Cadwell 3 times but still know it pretty well and Oulton & Donny I've done 50 ish times, yeah I probably am driving it too hard but Chris (Chilli) had a passenger ride about a year odd ago and thought it was a bit soft, I've since put a 1" ARB on but I think it is capable of more.

Ideally I would like to meet more VXs on track to compare how they get on and what they have done but there doesn't seem to be that many doing track days. The national would be ideal but the last 2 I've been on my rostered shifts that I couldn't get out of.

I haven't done any vids for ages as I've just been enjoying the car (or hating it when I had my P1515 fault, which is now fixed)

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[chris_uk]

its hard to say for sure based on numbers, however, based on all that i would say its not too far off, the front camber is a little low (imo) i would suggest copying the 340R Road geo settings straight over as a starting point, slightly more camber all round and some toe tweaks, after it will feel a little more direct on steering input which will help on initial turn in. 

 

once you get the shocks back, get them setup, the way i personally do it is set the rears to 50% soft/hard then do some aggressive starts, if the car just squats and bogs down then it needs to be harder, if it just wheelspins without squatting then it needs softening up. your aiming for the car to squat enough to bite with minimum to no wheelspin.. once your happy dial in the front for under and oversteer. softer for oversteer, harder for understeer. when you are happy with that you are down to the finer tweaking. 

 

tyre pressures, everyone has their own opinions on them, for me..i understand it as each tyre make/brand/type has an ideal operating range, say 60c - 70c as long as all tyres are within that threshold you cant go far wrong, the problem is how do you know, well unless you have live data you don't so using psi as an cheaper way to roughly get an idea.. Cold tyre pressures are for the most part irrelevant, all we want to know if the hot pressure.. so i set the tyres in 2 stages.. 1, go out until all 4 corners are at an equal target PSI (30psi as a rule of thumb)..then if its required, just like the shocks i tweak them to suit under/oversteer.

 

you can use the tyre temperature over the tyre to dial in your camber more accurately, ideally, you want to be somewhere within 10C across the tyre, usually you will find the inner and middle are close with the outer being slightly cooler..if you have too little camber the tyres will roll and the outers becomes hotter, if you have too much the inner and middle will often be very hot and the outer miles away..  sometimes tho, if you are struggling to get heat (because that's what is paramount to) into the tyres you could increase camber / toe to drive the temps up.. obviously they wear the tyre out faster. 

 

when i had 888R's i aimed for 30psi hot all round, when i used ZZR i aimed for 28psi hot all round.

 

this is how i have always setup my vx and its always worked well and i think if you spend the time doing the same, i dont think you will be far off problem is, once you start pushing more and more, everything changes again and you have to go through it all again.

[swast4]

Thanks Chris,
Great advice, I look for forward to seeing the results and having an experiment.
I do remember that on the last geo I was at max neg camber, so they said if I want more, I will need them machined down or put the lotus light weight version's on.

I do find I have lots of tyre tread left on my rears (888s) with 99% track use compared to inners

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[Exmantaa]

Some pics of your Intrax shocks here I think?

http://www.vx220.org...1k2-suspension/

I see no helper springs fitted there on the shocks, so they must have pretty softish springs fitted. But going 750lb/800lb rears 625lb/675lb front is seriously hard.

(Although with a big wing + splitter and driving it very low on track I can see you may need these in race mode.)

 

Geo you can shave some off the steering arms for more camber. You removed the ABS shims already? (or buy aftermarket. the Spitfire ones that give you some more tuning options) You can also give it a bit toe out front for better turn in.

Then increase the rear a bit too...

 

 

But it is a rear engined car with no weight in the front wheels so a different track driving approach than the Escort...

 

[swast4]

Cheers for finding the advert for my shocks

Yet it does seem like a big leap in spring rate increase, but feel that I want to commit to full track set up.

Unfortunately I have no wing or splitter. I realise that having no weight at the front is a big issue with getting front end grip, but wouldn't a rear wing makr this worse? I have a front splitter but I'm sure it's more aesthetic. I remember reading nev did some experiments with front splitters saying that the front needs to be about 7cm off the floor or less for it to work. Which mine currently isn't.

I could lower the front further but would give loads of rake, as I have 16s front, should I go for a splitter as well?

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[Exmantaa]

I thought Cobra's car had a wing fitted (+ splitter), but that was on his 2nd VX attempt I think??

(On a track-only car with enough power to compensate the extra drag I would seriously consider that...)

 

But without aero mods those springs are pretty hefty. Not sure if that makes for an easy driving, as you want some compliance to feel what the car is doing.

Do you need to drive it to the track, or on a trailer? (low ride height + splitter don't do very well with speedbumps... )

 

 

[Rosssco]

Some pics of your Intrax shocks here I think?

http://www.vx220.org...1k2-suspension/

 

 

They were great dampers. I only used them on the road for a short time, and they were a decent improvement over the usual Nitron 1-way / Quantum Zero / Gaz dampers I've used previously. Probably a little soft for track use though (hence why I loved them on the road ). Same sort of compliance as Exige Bilsteins, but better damping.

[swast4]

The car is always trailered, as you never know what could go wrong......

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[PaulCP]

Ideally I would like to meet more VXs on track to compare how they get on and what they have done but there doesn't seem to be that many doing track days.

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Still a few VXers regularly attending track days but most do the LoT days, including Euro ones, where track discipline is much better than those which attract the FWD Chav brigade.

Edited by PaulCP, 20 August 2019 - 09:53 AM.

[Exmantaa]

Yep. Still a few places left @ LOT Zandvoort to test the handling of your car at speed.  

[Madmitch]

If I remove my drop links, thus removing my ARB, are you saying my car will handle better?
 

 

To answer your question -

 

If you disconnect the ARB this will allow the car to roll much more on it's suspension, you will get more feel and info from the car and it will feel easier to drive.  It will however be slower through the corners as the suspension will be extended or compressed much more affecting wheel angles, roll centres etc.  What the ARB does is to keep the variables, like wheel camber angles and roll centres, within limits defined by the stiffness of the ARB so that, stiffer = quicker but less easy to drive toward the limit and softer is slower but easier.  That said, just stiffening the ARB in isolation will increase understeer so, to improve the turn in you will need to look at both ends of the car, tyre pressures, spring and damper rates and geo, all of which affect how the car behaves.  

[Nev]

Some context:

 

The OEM FARB has (when new) a 50 lb/inch transfer, which is pretty weedy really, but very deliberately so, setup by people with far more handling understanding than you or I. Don't be fooled into thinking Dave Minter and Lotus made a mistake by doing that. However, once the drop links and bushes get tired, I found on mine that raising the suspension on one side took approx 1" to even start to raise the other side. This is something that many of our tired cars might suffer from. Another is people doing up the bolts too tightly on the top + bottom of the the coilovers, as this can add resistance.

 

These 1" FARBs that everyone seems to have with the 4 settings are 140 Lb, 165Lb, 200Lb, 250 Lb per inch. So you are effectively trippling to cinqtupling the transfer. Making that sort of change with making significant other changes is bound to make the car worse. A lot of people don't even realise that by putting these powerful 1" bars on the front, that the rear springs need far more delta (ie difference to the fronts) needs to be to compensate. So when you see people with something like 350f/450r springs but on these stiff FARBs, the dynamic spring poundage on a corner when your 2" heeled over would be 350 + 280 on the front but still 450 on the rear. Considering the front axle only has circa 40% of the car's weight on it, clearly having 630 lb of resistance is nuts (when the rear only has 450 lbs of resistance). And that's with the min setting of the FAB, if you use the higher Lb'age settings the delta will be even more! That will most certainly lead to understeer.

 

Which is why I made my suggestion to the OP to temporarily detach your FARB, I think you will suddenly realise that less can be more. I don't know you f/r delta, but I suspect it may be incorrect for your FARB. At the end of the day it's an easy test and if your f/r delta isn't right, this test will indicate that to you by giving you much more neutral steer (and maybe even oversteer possibly). I've done it myself and am going back to the OEM FARB (when I can be arsed to instal it!), for this very reason. ie, I don't want to be forced into installing circa 600 Lb rear springs to suit the stiff FARB (on my car for the type of road driving I do).

 

HTH.

Edited by Nev, 20 August 2019 - 01:41 PM.

[Madmitch]

Agree with all that, OP should find uncoupling the front ARB illuminating! 

[Exmantaa]

Hmm, on the road maybe, but on track a stiffer ARB prevents the front from excessive rollover on turn-in/trail braking that can/will cause a heap of other issues. (Roll/ bumpsteer to name one. Lifting the inside rear is another)

Although on my own car I did found the 1" a bit too much and switched back this year to my 7/8" version. But I'm now dialing that one back to almost full stiff, as on long sweeping corners my inner rear starts to spin a bit.. (yes, it has enough droop!)  Maybe will go back to 1", but on softer setting.

 

(I normally do not use the ARB on a full-soft or full-hard setting, as I don't like the extreme angle the drop links have in those positions.)

 

Where is Scuffers when you need him?

[swast4]

Thank you for all your input, there is still lots to think about, but also exciting 😁

I will speak to the guys doing my geo about what I was experiencing and what I'm after.

I am tempted to put an additional splitter on the car as its got one at the moment but I don't think it's big enough. Maybe I can add a composite aluminium one? Do you think a 3mm vision will be strong enough? (check out a pic of my current splitter) How low do I need to go to make it effective? Also I run my car with the engine undertray off as I prefer the extra cooling and access, but I still have the rear diffuser on.

I also have a, friend in work with a heavily modified 350z and he said when he put a lot of camber on the front it was like night and day with the turn in.



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[Exmantaa]

Yes, but don't overdo the camber, as it reduces tire area under braking.

Also try a bit toe-out front

 

DIY splitters (extensions) are made from simple plywood (sacrificial...), but read that also ~8-9mm cheap black polypropylene sheet was used.

[swast4]

I keep on forgetting to at attach the photos

Also I do love the LoT events but a lot are to far for me. I was due to do the double hdr at theend of Oct but the kids holidays are late this year so had to cancel for family holiday...

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[swast4]

OK cool, I'll have a l OK at that too

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[chris_uk]

ideally you want to have the undertray on, not using the flat floor is silly imo.. also, if you do put a splitter on you don't need one larger than 150mm, mine is about 100mm. 

 

 

 

 

 

 

[swast4]

Wow, that's low, how far does it sit off the floor at the front?

Do you think I can just attach an additional splitter to mine that sticks out about 100mm?

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