simon's learning what to do with the polo thread

[sambb]

I've seen some early ford fiesta hillclimb specials on british hillclimb sites using that mumford linkage. Interesting stuff.

[Sydneykid]

I've seen some early ford fiesta hillclimb specials on british hillclimb sites using that mumford linkage. Interesting stuff.

Yep, they are also popular with clubman style RWD cars, Mallocks, Westfields etc that work better with a lower RC than a watts link (or panhard rod) will physically allow.

Cheers
Gary

[simon k]

Audi 8L S3 rear track is 1503mm, Polo rear track is 1425mm - I'm sure I'd be able to find 30-40mm to cut out of each side...

[sambb]

Simon, my guard lip to centre hub measurements are F 345: R 317.5 mm

[simon k]

Sweet, thanks Sam. The front might be close to that now actually, it's 320 from the guard lip to the top edge of the (missing) wheel centre cap. I might take the grinder to the rear springs

[sambb]

My rears are all the way down on the collars. I can remove the collars and get a bit lower but I'd then have problems with the springs not being captive with the helper springs at full droop so I've left it where it is. It'd look seriously weird if I went lower on the rear.

[simon k]

Going back to the first page of this thread Sam suggested a set of front subframe caster/camber adjustment sleeves - basically VW have designed the mounts to let a wheel aligner slacken them off and be able to wiggle the subframes around just a little bit to even things up - there is adjustment built in to the mounting points but they can quite easily adjust themselves, and getting the maximum amount of caster/camber out of them and making them consistent on both sides isn't feasible

Eddy is responsible for the idea of putting sleeves in the holes and the bolts through that, making repeatable adjustment possible. Since I like to do as much as I can by myself, and I'm reasonably OK at it, I CADed them up and made some myself... he's right, big difference, definitely a good bang-for-buck improvement.



I still haven't measured my caster properly, but can feel the difference - more direct, better turn in, less vagueness

[sambb]

I recently had my subframes dropped so that I could go back to the standard FARB. I removed the eccentrics and and on their hex heads marked them so that I could see when underneath the car what the narrowest and fattest part of them were. That way if I ever have them out again I know exactly where to set them to for repeatable maximum caster. I set the front ones in a position to pull the subframe as forward as possible and then the back ones so that the subframes are kicked out as wide as possible laterally. I don't have caster adjustable tops so in my situation I needed to get my caster at the bottom. Lucky for me when I went to the aligners afterwards they were bang on side to side so I then marked the chassis rails to correspond to those marks. All repeatable if subframes are removed. I've had lots of jobs that I needed/wanted to do that I hung off on because I knew it was a biggy to reset the subframes afterwards eg, FARB swap, steering rack bush, underbody brace fitup. Marking it all for repeatability once you know its all where you want it made that a lot easier.
Simon what sort of geometry did you chase - did you set the front and rear of your subframes outward aiming for max track or go for even more caster? Well done on reproducing them. Nice job.

[simon k]

Simon what sort of geometry did you chase - did you set the front and rear of your subframes outward aiming for max track or go for even more caster?

I put them in for more caster, just pushing the subframes forward - I was in a bit of a hurry to put the car back on the ground - I shoved them in, did a quick stringline, took some toe out of it then had to run out

Setting them up the way you did is the right thing to do.... I'll do the same when I have a little bit of time to set it up cos I'll have to take a bit of camber out of it at the top too.

[sambb]

With 215/50/15's and 195/55/15's, running the subframes as far forward and out as they go is the limit for un rolled guards at least at my ride height and with the rear LCA offset bushes set to the outward caster position. Tyres a long way forward in the arches - just something to be mindful of if you don't need to actually do that as you have the adjustable tops.