Help! Overloading outside front on track in our Mk1

^^ Also helps the F/R weight distribution, by the look of it

Nice of you to give away some trade secrets, Gurds!

 

Inspired from? !!

 

No secrets, just nobody ever asks

Gurds

 

Inside leg measurement pls!!

 

no more secrets Gurds

 

Wow!

Thats massive, how does it fit on, any piccies of it on the car?

Is it tempered or just a steel tube?

I`ll need to upgrade the engine or lick out any passengers to counter the weight.

 

Hi Hilux,

I think i saw your car at this track day [was admiring your neat job on losing spare wheel section/welded in plate] I was in the yellow Seat Leon and at one point followed you into hairpin before main straight and i did notice you cock a wheel

That corner and the tight one at end of pit straight/just passed garages are two corners that i thinkl to be fair that a certain amount of understeer is unavoidable in a FWD.
I know because i also noticeably suffered in these two places.I found it a bit frustrating having to scrub quite so much speed off on entry and having to be very patient on exit as i was keen to go quicker.A few times i found myself bouncing across track on entry or on exit struggling wih understeer.Once i had found the sweet spot it was fine but i find in a FWD car i feel i am capable of carrying much more speed into and out of the corner than the limit of sensible grip will allow.
Other than that much as mentioned i would say go track biased tyres,probably 26-28 psi hot in yours [equalise all once hot after runs],arbs front and rear but thicker on rear,personally i would keep spring settings similar front/rear,not too much camber and toe is personal preference but i prefer neutral.lowering front slightly in relation to rear can help with front grip a bit as well as it helps weight transfer.

 

http://www.clubgti.com/forum/showthread.php?t=164051&page=28 ...

 

Tube? No, it's a solid bar!! Have a look at my updates on my thread to see how it's made and mounted. I get very little understeer like this. You could watch one of my Bedford vids to see how it compares? Or next time I'm on track, jump in and see what you think.

Edit: James posted a link above. Cheers.

Gurds

 

Welcome to early front wheel drive suspension design.

The standard mk1 has a very basic design of front end suspension, developed at the beginning of the FWD era by VW. It was inherently designed to understeer for the general masses safe use on the open road.
This being the case there is only so much you can do with the standard parts before bespoke design is needed to make further improvements imo.
I struggled with understeer on my own Rocco (mk1 platform) trying many different things before throwing the lot away and making a hybrid setup using other VW parts and a few home made adaptors.

You rarely need camber in a straight line. Going round corners is when it generally comes into play.
Whacking on 3 deg of static negative camber to keep the outer tyre from going over on it's outside edge probably means you have 6 deg of positive camber on the inside tyre resulting in a loss of lateral grip and understeer.
This is because when running high static negative camber there is not enough castor in the OEM design to allow a significant camber change during cornering.

Gurds, your car is widetracked and has several extra tweaks and adjustments iirc? These result in it moving quite a way from the standard setup by some margin.

 

Yep. There are loads of changes made to most things.

Gurds

 

Erm... group buy?

I'm trying to work out where it bolts on - have you made some custom mounts for it on the trailing arms?

 

http://www.clubgti.com/forum/showthread.php?t=164051&page=28

696 / 697 ...

 

Hey................howdy do...................

I remember you my son knows your car and it is seriously quick. I recall you had a coupple of issues as I saw it on jacks and I believe ended up changing pads as you were testing brakes in the paddock?

We meant to have a chat as I am a nosy sod and my son has just sold his Seat but the day was a good `un and we ended up doing some serious miles on track.

That tight left hander before the main straight is a great bend to get right as you need to nail it asap to get a good terminal speed but you are right you have to exit fully before nailing it and the one at the end of the pit straight is a right bu**er and you need to get the line right.

I agree, I didnt leave braking too late with too much emphasis on the front weight transfer on those two bends as this increased the oversteer but in my 944T you left it until the absolute limit and threw it in but on the faster bends found a settling dab of brake transferred the weight enough to avoid a sudden transfer mid corner.

I`m not saying my car is cr*p at all just annoying us at the moment but it needs more power on the straights on a fast circuit like the GT as it hauled in some cars but couldnt always pass them and couldnt quite get to 120mph terminal on the main straight however its not a race and driver skills vary.

I have it 15mm lower at the front and tend to think you are right re pressures (but I will experiment) and think I will go for more track focused tyres and lose some unsprung weight with lighter wheels.

Next time we see each other it would be good to chat

Regards

 

Indeed be good to have a chat when our paths next cross. Do you normally do autometrix VW/Audi in July as have done that last two years and chance i may try and get along again this year?
On changing pads,thankfully it was nothing more than pads being totally shot.Knew they were getting low [hence i had spares] but had thought they might make it through the day.Forgot how hard it can be on brakes there as by third run they were well and trully finished.Other than quick spurt round pits i went out and just gave it the beans on new pads and thankfully it seemed to bed them in nicely

 

Never heard of it, what is it and where?

 

VAG trackday at Castle Combe, organised by Autometrix Publications ....

http://www.autometrix.co.uk/Volkswagen/current_issue.html

A great place to experiment with tyres, pressures & settings

 

All of the above is fairly well proven but different driving styles vary and so will the set up, all about testing. My car (MK1 Golf) came with the std 'Slick 50' set up as described by Sam above and worked fantastically on a track day but wasn't as good on the hillclimbs and sprints as I developed the car.

The spec of my car now is a real mix of all of the above so probably not of any interest in this thread but one thing that may help with the original issue, off side front tyre wear, that hasn't been mentioned is corner weights.

When I set my car up at the start of the season it always wants around 15mm more height on the off side front to get the weights correct across the diagonals. Now that might be my chassis, but despite its tatty look it's pretty straight when the geometry is checked. I'm no expert but I guess this reduces the weight on that corner and I would assume would put less stress [heat] in that tyre over an extended period on track.

The car came to me set like that as well and when I first started out racing I just assumed it was badly set up and leveled the suspension out, measuring off the floor to the chassis, couldn't tell you if it made a difference as I never did a back to back test and I continually develop the car. In my particular sport you don't get enough time in the car to really tell what the long term effects are as it's all pretty frantic and I've not done a track day for a few years but I'd wager that will help.

One point on turn in, run some toe out on the front, that will help however it will increase wear [heat]. I do it to get some heat in the tyres which again is important in my game. The circuit guys also run toe out on the rear as it induces oversteer and gets the car turned in fast again. Feels odd though and I've taken it out of mine as it's easier to drive a fairly neutral feeling car as you need to be on the pace from the first second on the hills and sprints but when you have time on a circuit you can dial it in and I'm told the fastest FWD cars run toe out on the rear. As my car is getting up there with the really quick cars (and with my limited driving ability I need all the help I can get) I'm looking at putting some toe out back in at the rear.

On ride heigh I run the car nose down by about 10mm as it increases the traction off the line and out of slow corners, again useful in my game, not so important on a circuit but I'd guess it helps turn in as well.

 

I know a very nice chap with corner weight scales and will be talking to him about it however its great with the driver only but add a passenger...................its probably very worth it as these cars are light at the back when fully stripped out.

BTW - I bought a Mk1 MX5 recently for peanuts for a bit of a larf and the wheels on it are seriously light and are 100 PCD

 

Good to see people picking up on this, i think it's a good practice to have, not so much on the golf's with sliders on the calipers, but comes from driving the leon supercopa with solid mounted calipers..