13 replies to this topic

[NeilR]

This has been the ideal for feedback on tyre setup but has always been out of reach for most; so before the app is released (pun) there is this:

 

http://www.izzeracin...re-sensors.html

 

http://www.izzeracin...S_Datasheet.pdf

 

Can I just say I want some for the pretty colours to go with the G sensor!

Edited by NeilR, 13 July 2015 - 12:54.

[ivanalesi]

This is pretty damn cool also for driver training, not very expensive at all.

[Greg Locock]

Great find, I can't wait to see the tire temps during parking maneuvers, that should really allow us to optimise ackerman- typically at 100% ackerman at full lock the tires are fighting each other (somewhat), so we need less than 100% but more than 0%. We can model it, but low speed tire F&M data is not commonly available.

[Lee Nicolle]

Yeah, the driver has all the time in the world to be monitoring tyre temps! 

A cheap pyro is a handy gadget when testing and if you are quick when you come in from a race too. Again if quick to monitor brake temps too, something that influences tyre temps a lot.

[NeilR]

I personally would love it coupled to video of the drive as per the one on the site. Feedback is then a one person operation

[gruntguru]

Great video.

 

You could just about make a case for softer compound on the RHS for that track.

 

I'm no expert but the driver seems to be maintaining a pretty smooth pattern on the traction circle (for an amateur?)

[desmo]

Do road racers use laterally asymmetric compounds when allowed by the rules?  The demands on tires at a circuit track will always be asymmetric, using the same compound for all four tires isn't likely to be an optimal solution.

[Greg Locock]

I thought the taxicab racers regularly ran different compounds left to right, maybe just based on what they had left with rubber on.

[NeilR]

I have no idea if they do. I know GT's don't and all other racers I know of don't

[NeilR]

TC3000 I believe you are in Europe somewhere (forgive me I do not know), but the process you describe may be the case in european hillclimbs as they are so long. In the UK and Australia they are generally very short sprints (will post a vid) and new tyres from Avon etc are all that is used. 3 runs and they are 'old'.

[mariner]

Last month the 750 club had a very interesting talk from Russell Paddon of Multimatic on dampers and rig testing. He works for Dave Williams who has posted here and is , of course, the "father" of active suspension. 2 1/2 hours of excellent nformation well presented via diagrams and graphs but no maths!

 

A number of interesting points came out including that on road cars fitted with multi position dampers the "comfort" setting, not the "sport" or "track" setting gave the best overall mechanical grip results on the four post rig.

 

One point the lecture raised in my own mind was whether you could collect the tyre temperature data and automatically change the damper settings to react to the changes in tyre temperature?

[gruntguru]

A number of interesting points came out including that on road cars fitted with multi position dampers the "comfort" setting, not the "sport" or "track" setting gave the best overall mechanical grip results on the four post rig.

 

Whereas the car would undoubtedly lap faster on track using the "sport" or "track" setting.

 

Is this entirely due to the trade-off between steady-state grip and transient (steering) response or is there something else at play?

Edited by gruntguru, 16 July 2015 - 22:55.

[mariner]

I'm no rig expert so I will probably get this all wrong but here goes.

 

- The rig doesn't measure lareral forces per se as it can't - only vertical forces.

 

- On the Multimatic process the posts are driven at varying frequencies and stroke with at least four movement points measured- the tables ( road) , the hubs, the top damper fixings and  the chassis/body

 

- They calculate a "performance index" which they believe represents a single objective measure of overall grip. I think it is this they see as often  better with the softer setting because the softer dampers allow more total wheel contact and eveness of tyre load than harder ones.

 

- This is for a non-aero situation. For high DF cars the dampers are being used primarily to control pitch and underbody air gap. The mechanical grip may be  poor but nobody cares as long as the ground effects are  working.

 

- Remember they test lots of road cars where damper to chassis mountings  include bushings and sub frames which have designed-in compliance. I think what I took away from the talk was that your damper or spring , settings cannot be stiffer than the load path from damper top mount to body/.chassis or you just cause deflection in the mounting sytem and the dampers aren't actually pumping very much so no conrtol.

 

- A lot of emphasis was placed on that point and , apparently, F1 cars do not have the utterly rigid mounting paths to the main chassis you might expect!

 

- I think the point might be that if you design sufficient complinace into the damper to body mountings for normal ride comfort then tighening the dampers to " track" may not do what you think. Also harder settings may chuck the driver around more so he/she thinks they are going faster even if they are not!

Edited by mariner, 17 July 2015 - 08:45.

[Greg Locock]

Good summary

 

"I think the point might be that if you design sufficient complinace into the damper to body mountings for normal ride comfort..."

 

I think a good question is what do we think the isolators in the shock absorber are for? I can tell you now, it isn't primary ride. One reason is so that you don't hear the shock absorber sloshing and wheezing.  I'd guess there are very small amplitude road inputs we don't want to feel. I do know that making them stiffer can improve 'shake', but if they are too stiff it gets worse again. I last played with them 28 years ago. Incidentally one of my party tricks was to replace the subframe mounts with aluminium pucks, which is one reason why the Ford Falcon IRS doesn't have subframe mounts. Think about it-if we really needed subframe mounts for isolation from the road, how come virtually all front suspensions are mounted to rigidly mounted subframes or cross members?

Edited by Greg Locock, 17 July 2015 - 08:10.