Sam's build thread

[Sydneykid]

I use string (actually hat elastic is better) in the workshop to do the initial set up on all 4 wheels, it's the best / most accurate method. But once I have a base set up I use toe plates, they don't matter on the front (just turn the steering wheel) so I pretty much always use them. On the rear I make sure I adjust both sides equally when making a between sessions set up change. Obviously if I suspect movement or the car has a hit etc, I revert to the string lines. Once I have the settings marked on the toe adjuster and know the control arm length etc then I often don't even use toe plates at the race track during the day. One turn = 2 mm etc, just check it later to confirm, same with camber.

Keeping in mind that I'm not looking for ultimate accuracy as much as consistency in the measurements.


Cheers
Gary

[Sydneykid]

Thanks Gary, i'll go over your numbers based on your targets and make sure I was doing the conversions properly. In the mm to degrees/minutes conversion table, were you doing it for a 15'' rim?
Gary have you always used these shims or if they were staying in there long term would you not prefer the ones I linked above - steel.
thanks for the help

Yep, 15" rim.

I haven't had a car that uses shims for a long time, but when I did I used the Specialty Products shims. With 5 different thicknesses, 2 wheels plus one for toe and one for camber, the problem with the steel shims is we could need up to 5 x 2 x 2 = 20 to facilitate changing settings.

Glad to be able to help. It's actually good that you are prompting the memories as I'll have to do the Polo at some point.


Cheers
Gary

[sambb]

Gary I flicked you an email with a question that's a bit too wordy for here re the front end. Pretty stoked, my 8kg/mm rears arrived today so I'll bung them in tomorrow. Yeah the 6kg/mm rears weren't going to cut it. I put them in with the rear bar on full hard and it definitely needed more in the back so hopefully the 8kg/mm are the right step up and will allow me to use a few of the bar adjustments for once.

[sambb]

Hey Gary the Jan Racecar engineering landed on my door and has a good story on damper technology in F1 etc

[metalhead]

I agree the toe plates are excellent for front toe. I guess I'm a bit more focused on the rear toe than may be required here - I need to get the rear toe just right on my car, my old Corvette is twitchy enough (and has a terrible rear toe curve where it toes out under bump/compression...) without introducing any thrust issues too!

[sambb]

found this build of what looks to be a 9N3 to S2000 spec?
YouTube

[sambb]

best footage I've seen yet of a little Polo (6N but close to ours) that looks still like a real world car, not like the mega swiss hillclimb monster Polo's doing tarmac rally sprints on circuit and open road. A little three wheeling demon.
YouTube

[Sydneykid]

I agree the toe plates are excellent for front toe. I guess I'm a bit more focused on the rear toe than may be required here - I need to get the rear toe just right on my car, my old Corvette is twitchy enough (and has a terrible rear toe curve where it toes out under bump/compression...) without introducing any thrust issues too!

Yes, they have terrible bump steer almost as bad as a trailing arm Commodore
What model is yours?
If it's transverse rear leaf spring model (do they call that C4?), have you added to the additional rear spherical equipped links for toe and camber? They make a huge difference.

With them I used to count the turns per mm of adjustment on the toe links, from memory it was something like 1/2 a turn = 1 mm toe adjustment per side. So if I wanted, say, 2 mm more toe in (total) then I'd simply turn the link rods 1/2 a turn each side. Then check with the toe plates to confirm that I didn't turn the links the wrong way (done it more than once facing backwards and lying upside down in the pits rushing for the next race).

I'd then check it back in the workshop with the elastic lines.

Merry Xmas
Gary

[metalhead]

Yes, they have terrible bump steer almost as bad as a trailing arm Commodore
What model is yours?
If it's transverse rear leaf spring model (do they call that C4?), have you added to the additional rear spherical equipped links for toe and camber? They make a huge difference.

With them I used to count the turns per mm of adjustment on the toe links, from memory it was something like 1/2 a turn = 1 mm toe adjustment per side. So if I wanted, say, 2 mm more toe in (total) then I'd simply turn the link rods 1/2 a turn each side. Then check with the toe plates to confirm that I didn't turn the links the wrong way (done it more than once facing backwards and lying upside down in the pits rushing for the next race).

I'd then check it back in the workshop with the elastic lines.

Merry Xmas
Gary

Mine's nowhere near as good as a C4... I have a 1979 C3, which in turn has the same suspension as the C2, all the way back to 1963. It also uses a transverse leaf spring, but with a trailing arm, and using the half shaft as the upper suspension link. A terrible design! Rear toe is set with shim packs on either side of the trailing arm pivot bolt...

Merry Xmas to you too!

[sambb]

After finally getting all the bits sorted I've put the turbo back together and will hopefully install it before my track day in mid Jan. The core has been rebuilt with new journal bearing and seals and the shaft rebalanced. The compressor had been modified by having thesilencer canister cut off and a straight pipe a la K04 welded on instead. The wastegate actuator is a generic Turbosmart IWG75. I decided to fit the 7psi spring that I'd run last year. I don't want any issues with sustained high boost that the 10psi might bring at Wakefield so thought I'd be conservative on that one. The exhaust housing has had the wastegate port ported pretty extensively and has been ceramic coated.

Did a dummy fit with the exhaust manifold so that I don't get any nasty surprises when the car is in pieces. The exhaust manifold is the ported one and has been ceramic coated too. One thing I did do was modify the bolts for the turbo. The infamous turbo bolts coming undone thing with these turbos/manifolds was playing on my mind. I measured the VW bolts and it seemed ridiculous to me that they only went about 15mm into the turbo when there was double that in thread depth in the turbo available. So I ran a tap down to clear out the threads (would have done it anyway to clear out any ceramic coating in there) and the threads were fine all the way in. What I ended up doing was taking 12.9 cap head bolts with nice long shoulders on them and measuring them against the thread depth available and cutting them to size. Each of the three bolts is now bespoke for its position (and they are marked so I wont mix them up). So now i'll have nearly double the thread penetration, the same tensile and wider shoulders to take out as much slop as possible in the manifold bolt holes. They'll be secured also with some nice big Nordlock locking washers, so these suckers better not slip or i'll weld them on like eddy did!

Another possible solution to the loosening turbo bolt saga is to change the way the turbo/mani support is designed. The bolt hole in the turbo is 12mm but the bolt that goes through it is only 8mm. I ground off the welded on 8mm nut on the flange and drilled it out to accept a 12mm bolt, so maybe now the hole thing will be able to be bolted up rock solid and not move at all which I'm sure it could have done the other way.
Anyway so that's that. Armed with the correct torque figures thanks to Gav's upload I'm ready to go and just need to find the time to smash it out one night.