306 replies to this topic

[Matthew Bentley Racing Ltd]

Yes your droopyness is no problem, but if your worried speak to a doctor?!

 

As for your car you could go stiffer springs, but not by loads with RSR's. I think we originally specced for road/trackday and for RSR's/R888's.

 

[Sticky]

Don't start with droop Matt, brings back some painful memories from a couple of years ago

[Matthew Bentley Racing Ltd]

Don't start with droop Matt, brings back some painful memories from a couple of years ago

 

Painful for us all.......

[Rosssco]

 

 

The tyre wear was caused by the car rolling too much in the corners or not running enough negative camber to account for the roll depending on how you look at it - the front camber was already pretty much maxed out though. The ARB has helped reduce roll and therefore tyre wear but has also moved the balance towards understeer. The way I see it, the ARB needs to be matched to the springs. At present it's too stiff for my springs, which isn't quite what scuffers said.

 

 

 

Yeah, that's what I'm getting at - the ARB prevents the from of the car from moving into the optimised geometry state (optimised for front end grip during the cornert phase, not tyre wear) therefore robbing you of some front end traction, but ultimately saving you on tyre wear. So perhaps you need to look at modifying the uprights for more camber.. Of course this may have negative side effects when not in the corner phase..

[MAXR]

I think that many of you who drive your car on the road still also expect to have a perfectly honed track weapon. I'm not sure if that's really possible. You'll have to decide on which is more important & that will inevitably be for road.

[Firthy]

I think that many of you who drive your car on the road still also expect to have a perfectly honed track weapon. I'm not sure if that's really possible. You'll have to decide on which is more important & that will inevitably be for road.

 

 

I was talking to Rob Boston about this a while back, he was saying when he raced MX5's a good quick race car could still sort of work on the road.

 

However if you want to have a setup to extract the maximum out of a s1 s2 vx on track its not going to be a lovely road car as well!

Edited by Firthy, 15 October 2015 - 08:56 AM.

[Firthy]

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]"The way I see it, the ARB needs to be matched to the springs. At present it's too stiff for my springs, which isn't quite what scuffers said."[/color]

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]Having tried this myself I don't agree with Scuffers either, there are a lot of quick people out there that don't agree as well.[/color]

 

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]ARB full stiff is not the solution for all setups... IMO[/color]

Edited by Firthy, 15 October 2015 - 09:08 AM.

[Scuffers]

 

Yeah, that's what I'm getting at - the ARB prevents the from of the car from moving into the optimised geometry state (optimised for front end grip during the cornert phase, not tyre wear) 

 

come again?

 

really? ARB changes geometry?

 

Please, try and think about this stuff before making claims like this...

[Rosssco]

 

 

Yeah, that's what I'm getting at - the ARB prevents the from of the car from moving into the optimised geometry state (optimised for front end grip during the cornert phase, not tyre wear) 

 

come again?

 

really? ARB changes geometry?

 

Please, try and think about this stuff before making claims like this...

 

 

No that's not what I said... The ARB resists the front end in roll during cornering right? So if his suspension geometry is set to optimise the tyre contact area during that corner, the stiffer ARB may partially prevent the tyre working correctly - is that not why "race" cars run often extreme camber, so that the outside tyre/s contact area is maximised during cornering?

[Captain Vimes]

I think that many of you who drive your car on the road still also expect to have a perfectly honed track weapon. I'm not sure if that's really possible. You'll have to decide on which is more important & that will inevitably be for road.

    I was talking to Rob Boston about this a while back, he was saying when he raced MX5's a good quick race car could still sort of work on the road.   However if you want to have a setup to extract the maximum out of a s1 s2 vx on track its not going to be a lovely road car as well!

I totally agree that suspension changes are always going to be a compromise. I rarely drive my vx on the road so am happy to accept that it will be a worse Road car if I want better track balance. The question I have is can I do that without spending another £2k on dampers? The answer may be NO in which case I have 3 options - suck it up and spend the cash - enjoy the car as it is - sell it and buy a race car & trailer I'm hoping that a change of spring with the current dampers will be enough to improve the track performance (with corresponding reduction in road comfort).

[SteveA]

- sell it and buy a race car & trailer  

 

You know it makes sense

[alexb]

option 4: drive a bit slower and enjoy the scenery

 

From the info you gave, it would make sense to go to higher rated springs. Something like 400-450F and 550-600R. One of the things this does is reduce the roll. With that kind of spring rate, you also get in the area the 1" ARB should work fine. BTW, you can always drill an extra hole in the arm of the ARB if I remember correctly. And, changing springs is easy and doesn't cost an arm and a leg. If you don't like it, you just put the old springs back and sell the new ones to me. (I drive at about half your speed, which doesn't keep me from endless tinkering with the stupid thing)

 

Dampers is a whole other nest of worms.

[smiley]

option 4: drive a bit slower and enjoy the scenery

 

You should have bought an mx5

[Captain Vimes]

- sell it and buy a race car & trailer  

  You know it makes sense

This supergrad is quite tempting: http://www.grs-cater.../cars-for-sale/

[MAXR]

The relatively low cost for uprated new springs makes it a no brainier as a next step. However, selling your existing dampers & putting the money towards a new set of Quantums with higher Spring rates with helper springs may prove to be a more cost effective long term option? Perhaps MBR could borrow a set of Quantums from EP & meet a few interested trackers for a track day at Bedford Autodrome or Snet & give genuinely interested people a chance to try them out, with any orders being placed through him??? I was converted after 1 lap! That's why I switched...

[Firthy]

I think that many of you who drive your car on the road still also expect to have a perfectly honed track weapon. I'm not sure if that's really possible. You'll have to decide on which is more important & that will inevitably be for road.

    I was talking to Rob Boston about this a while back, he was saying when he raced MX5's a good quick race car could still sort of work on the road.   However if you want to have a setup to extract the maximum out of a s1 s2 vx on track its not going to be a lovely road car as well!

I totally agree that suspension changes are always going to be a compromise. I rarely drive my vx on the road so am happy to accept that it will be a worse Road car if I want better track balance. The question I have is can I do that without spending another £2k on dampers? The answer may be NO in which case I have 3 options - suck it up and spend the cash - enjoy the car as it is - sell it and buy a race car & trailer I'm hoping that a change of spring with the current dampers will be enough to improve the track performance (with corresponding reduction in road comfort).

IMO - if you still want to have a pleasant road car as well as just enough stiffness on track 425 550 is a great balance! If you noticed the lighter silver exige parked next to mine, (it's usually attached to the back of my car on track) it's my best mate that I do all my track days with. He runs these rates and imo they represent the optimum balance for a road / track setup for our cars. You would notice a significant difference, if your damping on the streets can take it. Check the last vid I uploaded

Edited by Firthy, 15 October 2015 - 06:23 PM.

[Aerodynamic]

...   This is one of the reasons people reading books that say too stiff an ARB make a car understeer, and then try and relate this to the Elise/VX, well, yes the book is not wrong per say, but too stiff in the context of the VX would need a 2"+ think ARB at least, and even if you made one, the chassis mounts would flex rather than the ARB!   ...

  My experience of adding a 1" ARB to my car is that it has increased understeer. Here's a lap comparison before and after adding the ARB. The extra steering lock needed is clearly visible:     On the plus side, tyre wear has improved greatly..

Good film. What spring rates are you on? Br, Per

[909]

Finding a suspension compromise between road and track is always going to be a personal decision.  Each to there own preference.

 

The problem with heavy anti roll bars is they tend to remove the independent nature of independent suspension.  That is, the heavier the bar the more a bump on one side will impact on the other side.  As you increase stiffness at one end of the car the more that end will loose traction in corners.  i.e. a heavier front bar without any other suspension mods will tend the car to understeer more (or oversteer less).

 

Dedicated race cars will tend towards stiffer springs and softer anti-roll bars, while road cars tend toward stiffer anti-roll bars and softer springs.  Anti-roll bars on a race car will be tuned more for under/oversteer control, while on a road car are used more for roll control.

 

 

 

 

Edited by 909, 16 October 2015 - 07:33 AM.

[Captain Vimes]

Good film. What spring rates are you on? Br, Per

350f/450r

[Captain Vimes]

Good film. What spring rates are you on? Br, Per

350f/450r