4350 replies to this topic

[chris_uk]

Ride heights were raised 10mm all round to what it was then we re-did everything.. Question tho scuffs, why was it set to toe-in ? Rather than toe-out?

if your on about the front, it was not.   hence my point about ride heights (although 10mm is not enough of a change to do that).   (it was originally set to just toe out from parallel - within the bounds of practical measurement and suspension play)

Unfortunatly.. It was impossible for there to be any toe-out. We had to cut down the rack to get any toe-out. Even when we cut the new track rod ends to the identical size as the originals there was not enough adjustment to alter it enough. Any idea why?

[Scuffers]

didn't we re-do the geo at Brands?

I have no idea what happened to it after Cadwell.....

[turbotoaster]

looking at that, I can only assume the ride heights were somewhat different than it was originally set at.

 

rest of it looks about right to be honest (for what it was originally set at).

 

 

 

 

 

So you set it up to run more camber at the front than the rear? was that just this particular car or do you do that with all elise based race cars.

 

The reason i ask is, I asked Mike what camber he set his to and he told me 2.75/3.5 and jamie told me 3.5/4.5 so when i get to do a shake down at the track I was planning on starting with 2.5/3.5 and moving up from there but if I should maybe start with 3.5/3.5 then that would save me wasting laps if the car ive started with wrong camber angles in the first place

Edited by turbotoaster, 02 April 2014 - 02:08 PM.

[Scuffers]

 

looking at that, I can only assume the ride heights were somewhat different than it was originally set at.

 

rest of it looks about right to be honest (for what it was originally set at).

 

 

 

 

 

So you set it up to run more camber at the front than the rear? was that just this particular car or do you do that with all elise based race cars.

 

The reason i ask is, I asked Mike what camber he set his to and he told me 2.75/3.5 and jamie told me 3.5/4.5 so when i get to do a shake down at the track I was planning on starting with 2.5/3.5 and moving up from there but if I should maybe start with 3.5/3.5 then that would save me wasting laps if the car ive started with wrong camber angles in the first place

 

more a case of trying to get as much as I could all round.

 

the limit at the rear was about other stuff, that said, the wider the rear tyres you go, the less you can/want to get away with.

 

bear in mind what the car was originally setup to do and what we had to work with.

 

to put this in context, camber is very much tyre and car dependent as well as application, I have run cars with 6+ degree's of neg before, or as little as 1, really just depends on what your working with and the intended usage.

[chris_uk]

Completely dictated by tyre temps both core and across the tyre.

[Scuffers]

Completely dictated by tyre temps both core and across the tyre.

that's a rather large assumption, and far from right depending on the application.

 

think about it, if the car has to post 1 lap vs. one that's in a 1 hour race, the needs for the tyres are massively different.

[chris_uk]

Ok.. Apart from the obvious wear issues

[Scuffers]

Ok.. Apart from the obvious wear issues

nope - was not even thinking of that. (although it's another very valid consideration)

[chris_uk]

Well.. If. Tyre isnt working at the correct temps on as much of the tyre as possible then surely camber needs to be adjusted to suit that.. Otherwise it seems a bit pointless setting it.

[Scuffers]

Well.. If. Tyre isnt working at the correct temps on as much of the tyre as possible then surely camber needs to be adjusted to suit that.. Otherwise it seems a bit pointless setting it.

to a point yes, but consider this:

 

1) how do you get said tyre up to temp in the first place?

2) this ignores the handling effects of said tyre on the car, ie. it's often the case that you have to run a specific geo to encourage the car to handle in a specific way, like getting sharper turn-in, being more progressive on break-away, etc.

[chris_uk]

as far as i am concerned camber is there to make use of all tyre and on top of that make sure the temps were about equal across it.

 

1) as for temps, pressures.. this is predominantly what controls the temps..

 

2) as for handling, there are a number of other factors which you can mess with that alter the handling of the car..caster, toe, suspension bump/rebound, ARB's etc but ultimatly.. a propperly setup car should handle the way the driver wants it to whilst having equalish temps across the tyre and have acceptable tyre life (wear) obviously the longer the race the more tyre wear is a concern.

 

with all that said, the tracks dictate what the cambers should be on the car anyway, obvisouly drivers have an input too with driving styles but as long as the tyres are working at the correct temps and as much of the tyre is being used as much of the lap is possible other aspects should be used (like above) to make the car handle the way it needs to.

 

now tell me why we couldnt get any toe out on the front of mikes car without modifying the steering rack.

 

Edited by chris_uk, 02 April 2014 - 04:03 PM.

[Scuffers]

that's way too simplistic.

 

for example, how are you measuring the tyre temps? once back int he pit lane is not the same as on the cct going round a corner.

 

realistically, your looking for a temp spread, it's not the target to make it even.

 

Back to mikes car, I have no idea?  you tell me?

 

last time I had string round it, it was set to toe-out (all be it a nats whisker)

 

from what you have said, I would be looking to see if something is bent (like a ball joint) or a bush has moved/worn/etc.

 

without it being infront of me, I am just guessing.

[chris_uk]

does it really matter if its explained in a simplistic way.. ??

 

if the car was to come in from a hot lap, there is the distance from pit entry to the pit box for the tyres to start cooling down, now i know they can cool quite fast but its not how much it cools by, its what the differences are across the tyre..

 

lets just say the tyres run at an optimal surface temp at something like 60c and you get readings of something like the following:

 

          F

 

45/65/70       60/60/55

 

          R

 

30/45/80       75/70/40

 

 

from the face of that info it would say to me that 3 of the 4 corners needed less camber, that alteration can be done and then it can go back out to see whats happening then.. and you just keep altering it until its something like.. ideally in my head you want as much camber as you can without jepordising the amount of availible tyre you can use.

 

i know it can get very complex but the basic principle is there.. use the cambers to adjust the use of the tyre, use pressures to control the temps then use the other stuff to control how the car feels/handles.. this should give yo ua basic setup which is drivable then you tittivate it from there altering pressures, cambers as you need to fine tune the car.

 

anyway, we will see how the new settings work because we can practically compare directly the setup it had in the TA and the setup i have done on it by the lap times we get at croft. I will genuinly be interested in what results we get (just so im clear.. because i know how you get, im not saying that the setup i had done will be better than the setup you gave it for the TA season.. i just want to make that very clear)

 

as for mikes car, we had to chop 10mm from the steering rack so we had scope to adjust the toe out to where ever we wanted to put it.. nothing seemed bent, but that doesnt mean its not.. what could be bent which could cause it to mean we couldnt get any toe-out?.. with you being the boffin you are i wouldnt expect you to be able to identify a number of things we can look at to double check.. because obviously.. if you are adament there was toe-out on the front and from what we saw it was impossible there was ever any toe-out.. something is wrong somewhere and it needs to be checked.. wouldnt you agree?

[Scuffers]

Eh? Yes, something is either bent/moved or the like? From several hundred miles away, i don't know what. Back to basic setup, remember, i believe it's got to17 inch aims on it ne, it was originally setup with 16s. That makes quite difference... Front bump will need looking at again as you have change the hub height by at least 15mm just for starters, then whatever ride high change you then use? What i am trying to sayings that your coming at this from the wrong direction if you have a problem setting a sensible setup go look for the problem don't modified parts to make it fit the river sea is something wrong and you need to go and find it rather just chopping the end off things

[chris_uk]

what you mean Eh?

 

from your expertise.. what items would you check if the toe is no longer adjustable to toe-out.. you dont have to be sat next the car to tell me that..you mentioned changing from 16's to 17's. would that realistically alter the toe that much that we were no longer able to adjust to get any toe-out (infact the minimum we could get was 1.00 degree toe in.)

 

We checked the front bump and it was still pretty decent what do you aim for as acceptable front bump?, as for ride height we altered it by 10mm all round, so whatever it was on each corner we just upped it by 10mm. i called MB and he confirmed that it would technically make a difference but not enough to worry about it.. 

i understand and agree with you about not just modifying parts to make fit, but we looked at everything and nothing seemed out of place or damaged, the car once finished drove perfectly fine and actually felt quite nice.. obviously thats not to say something isnt damaged which is why im asking you for ideas for things to check..

[Scuffers]

Chris, Whatbare you trying to achieve with your posts on here? Its pretty clear there is something wrong, chopping the trackrod ends down to achieve a toe when it has been set before clearly shows something is wrong. Why do you think i am going to know what when i have not seen the car for well over 6 months? Stop picking a fight, and either workout what's wrong, or take it somewhere competent enough to work it out. Seriously, WTF are you on?

[turbotoaster]

I dont know if this is anything to do with anything but we have just bolted on the ep arms and rose joints, threaded them onto the steering rack rod to the same position as the old ones and we now have gone from a little toe out to about 15 degrees of toe in, I dont know yet if potentially I will have to cut the rod length down to get it correct(havent checked yet)

 

Maybe something like someone has adjusted the rose joints thinking it would be the same as there car etc?

[Goosenka]

Never knew suspension could be so emotive.

 

Bucket of your finest please young man.

[chris_uk]

Keep your hair on.. Im just asking for ideas as to what component damage would cause the changes in toe we see here.. You say it was toeing-out, i believe you.. now its (was) impossible to get less than 1degree toe-in by just altering the components which were on there. You mentioned going from 16's to 17's would alter it, but would it be enough to cause it to toe in by over a degree?? Stop trying to read between the lines there is nothing to read, just answer my questions..

[chris_uk]

I dont know if this is anything to do with anything but we have just bolted on the ep arms and rose joints, threaded them onto the steering rack rod to the same position as the old ones and we now have gone from a little toe out to about 15 degrees of toe in, I dont know yet if potentially I will have to cut the rod length down to get it correct(havent checked yet)   Maybe something like someone has adjusted the rose joints thinking it would be the same as there car etc?

Are the track rod ends longer in overall length than the previous?