74 replies to this topic

[ee601]

Do any of the wise folk here have any wisdom that can impart on this subject please? I've just come back from 2 days on track at Spa Francorchamps and we had an unexplainable off on day 2, putting the car into the wall backwards at Blanchimont. On day one the car was pretty sublime in dry and damp conditions (horrible on the OEM 17" wheels with Bridgestones but great on 16/17" combo with 888s). On day 2 which was more greasy and wet, but no standing water of note, the car oversteered at the top of Eau Rouge several times. This wasn't a serious problem but got our attention without doubt, but a little later it went into snap oversteer after straightening up out of Blanchimont. This happened suddenly without warning and on putting the power down after changing up to 4th gear and going straight having completed the corner and unloaded the suspension. It was as if the rear tyres had spun up with no grip, yet there was no standing water and the track condition was hardly different to the previous laps, at least no more different than several other laps. So, my question is - was this the famous "VX220 snap oversteer" or did something on the car break? Is the "snap oversteer" particular to the 17" wheels setup, as the car felt pretty undrivable on them, very unpredictable and snappy between understeer and oversteer. (We were on the 16/17 combo by then having dismissed the 17s for track use). The car runs Gaz Pro Golds, just reconditioned by Gaz, we had just replaced all the suspension bushes all round, and added the rear toe link kit. If any of you who race or time attack a VX have any ideas or wisdom to share I'd be most grateful. Thanks Ian

[Nelly Vx]

SSSSF

[chris_uk]

Got vids? Something could of broke like a toe link and just caused it to spin.

[Claws]

Sounds like a snapped toe link to me too, especially if you were giving it beans round Spa on sticky tyres. Unlucky

[Tony H]

Hub carrier bolts? How was the car?

[siztenboots]

I love Spa , but the difference driving it this year without the rear wing meant the car was doing some strange things on the approach to blanchimont 1 with the back snaking a bit, another member of the Spa bit me club.

[Mike (Cliffie)]

Sudden loss of traction on one of the rear wheels. Happened to me at Snett in a straight line as well.

 

Could be any number of reasons, damp, oil or coolant on the track, broken HCB or toe link or even loss of talent. Impossible to say but a video would help.

[Claws]

Examining the rear suspension would also help, provided that your "off" didn't land said corner into the barriers

[fiveoclock]

Turbo, NA or SC and what power? Anything broken on the car that you may have thought broke when it hit the wall (as someoine has already said toe link, hub bolts broken)? What pressure hot were you getting the rear tyres up to?

[ee601]

There is a vid from a Clio Cup car some way back but it only catches the end of the accident, after it bounces off the wall. Then the Clio just misses the vx as it's spinning backwards by going on the grass. The accident happened whilst going in a straight line, just after putting the power down in 4th. There was a slight "kerlonk" sound a couple of laps earlier but the feeling of the car didn't change at all. Haven't inspected the car fully yet so can't give a full report. The toe link bolt has snapped but that may have been caused by the impact Haven't checked the hub carrier bolts yet The toe link adjusting rod lock nuts were loose so the rod possibly could have been rotating through vibration giving the o/s/r wheel negative toe? The tyre pressures were getting up to around 27psi, and temperatures were nicely consistent over the width of the tyres. My main concern is that we've come across the mysterious vx snap oversteer scenario, so whatever we do to sort it this surprise might always be present. I can't find any definitive description of this phenomenon anywhere..? Oh, and it's s/c and putting out around 250 BHP.

[chris_uk]

My money is on the toe link. Question is.. Why didnt you come in to check the car after you heard the clunk sound..

[fiveoclock]

My money is on the toe link. Question is.. Why didnt you come in to check the car after you heard the clunk sound..

 Toe link. Are they standard or uprated?

Edited by fiveoclock, 13 October 2013 - 11:34 PM.

[Joss]

Sorry to hear this, you were going so well on Wednesday. Was there still any trace of the Lambo's coolant on the track?

[siztenboots]

plus the track tends to get quicker as it gets swept clean on the line and if you get slightly off line then you get noticeable less grip , especially if its been a wet start to the day

[Pidgeon]

There are many aspects of your post that appear unusual to me.  Firstly stating the car was 'horrible' on Bridgestone's.  I have started using them on track again (mainly because I am too tight to shell out for 888s all the time) and really enjoyed them.  They are true and predictable.  Don't have the outright grip of a semi slick, but other than that, a quality tyre.  If the car feels bad on them, there's something wrong with your set up, not the tyre.

 

Secondly the car oversteering at the top of Eau Rouge.  The first time I went to Spa, there was a clearly recognisable silhouette of a GT3 RS in the tyre bales on the right.  The combination of the painted kerb on the left, corrections to the line when you have sight of Kemel and (most significantly) the crest cause a lot of spins there.  Some oversteer is normal.

 

Finally, my recollection of Blanchimont is that it is a difficult balance to complete the corner before braking for the Bus Stop.  You're on the very edge all the way around and very minor changes in input or track conditions will cause the car to start to rotate.

 

When you get it back together, have the geo properly adjusted.  That's where my money would lie.  You can do it yourself easily enough.

 

It's also interesting that you sound like you were have issues with an Elise Parts style toe link kit.  When I first fitted mine one end became loose causing some interesting characteristics and it's still not right now.

 

Finally, don't propgate myths of 'famous VX220 snap oversteer'.  It does not exist.

[Mike (Cliffie)]

 

Finally, don't propgate myths of 'famous VX220 snap oversteer'.  It does not exist.

 

I have to agree. Any snap oversteer I have encountered can be traced to definite circumstance and not an inherent trait. 

[ee601]

Thanks for all the suggestions. It's hard to get across the actual circumstances in text, so I'll try and explain a little further and answer some of the questions. The Bridgestones were on all 17" wheels as per OEM (skinny fronts). The 888s were on 16" TDs. The run on the 17s was hairy. Unpredictable and lacking in confidence. 16s with 888s was night and day different... Toe link kit was fitted. After clonk, I don't know why he didn't come in - I think the car felt otherwise perfectly fine so it was put down to being just one of those things...could have been anything. It wasn't me driving at the time. Car was being driven by a multiple rally champion so I find it hard to believe he hit oil or ran out of talent. There was oil on the track from the previous day, but it was clear where that was and not noticeably different at Blanchimont. It was still evident at the Brussels hairpin, and the left hander before Pouhon, so you could either avoid it or drive through it and deal with the consequences. I chose the latter... Oversteer at Eau Rouge, yes, normal to have a few degrees of correction at the top, but I'm talking about instances of armfuls of lock, rather than a dab of oppo.. Car ended up in the wall backwards - bit of a hole in the clam, only cosmetic no chassis damage at all, and some minor (thankfully) suspension bits bent now. MMG rear diffuser would seem to have taken a lot of the impact and saved more clam damage.. Geo was done by Hangar111 just before the trip so should have been fine... Sizetenboots - does the wing make that much difference? What kind of wing? Must get one! Sorry, absolutely not trying to propogate any myths, just wanting to know if the rumours I'd heard have any substance. That was my main question - thanks for clearing that up. Good to know it was most likely something broke rather than a handling trait I'd have to deal with.

[Claws]

As said, never heard of a classic "VX snap oversteer" trait. The fact that there is a nut loose on a toe link points to a mechanical issue with the car, be it the geo wildly adjusting itself under stress or a failure

[Acidpopstar]

Sorry to hear your tale and hope you get it patched up OK. Ive never heard of any snap oversteer issues. I drove Spa earlier this year on standard bridgestones, suspension etc, no geo and loved it. Bridgestones are very predictable and give you lots of notice when they start to slip, if not a huge amount of actual grip compared to semis.

[ee601]

Sounds to me like the Bridgestone issue was probably more down to the 17s than the tyres maybe. The mix of that and Gaz Pro Golds perhaps - not standard suspension at all.