Reply With QuoteYou got it. A little too much droop on the front is not a bad thing, maybe keep that inside wheel on the ground a little more.
Cheers
Gary
Volkswagenist
So Gary to convert that 64mm (including travel into the bump stop) of shaft travel to wheel travel, I leave leverage ratio out of it and just go 64mm / 0.9 (motion ratio) yeah? That means I've got 71mm wheel bump travel which is close enough hopefully. Lots of droop though. 55mm wheel x 0.9 = 49.5mm at the shaft. Josh said I should have no less than 45mm wheel droop with these particular shocks so hopefully 55mm isn't majorly excessive. Add 49.5mm shaft droop + 64mm shaft travel = 113mm. I'm using 12.6mm of bump stop. That leaves approx 100mm on the shaft alone (not including the bump stop) which is exactly how the damper comes out of the box, so it looks like all the calcs are correct and the car does indeed have a 0.9 motion ratio.
Alright so the drivers side is set up now for a 33.75cm ride height (hub centre to arch). I'll do the passengers side tomorrow hopefully. Its spring is less compressed to hold ride height cos that side of the car is lighter so setting up the travel wont be such a close run thing like it has been on the drivers side and I should fly through it. Then I can drive the thing!!
Last edited by sambb; 08-06-2018 at 02:26 AM.
Volkswagen Enthusiast
You got it. A little too much droop on the front is not a bad thing, maybe keep that inside wheel on the ground a little more.
Cheers
Gary
Golf Mk7.5 R, Volvo S60 Polestar, Skyline R32GTST
Volkswagenist
actually thinking about it, i'll have to set up the damper strokes the same on the passenger side as on the drivers side yeah? If I had different damper strokes ie gave the passenger side more bump travel because its spring had more travel, then wouldn't I be preloading the bar when one side went to full droop or full compression and had a little more or less travel than the other side. It should just be the spring preload which will vary side to side.
Volkswagen Enthusiast
This is common when corner weighting, that's why we use adjustable length links on the swaybars.Originally Posted by sambb
Cheers
Gary
Golf Mk7.5 R, Volvo S60 Polestar, Skyline R32GTST
Volkswagenist
I do have adjustable droplinks on the front anti roll bar. If the ride heights are the same but the strut tubes droplink mounts are in slightly different positions I can account for that and not pre load the bar with the adjustable drop links.
Whats confusing me though is if I have more available bump stroke on the passenger side, do I take it, or do I match its stroke to the shorter sides? eg If I set the P/S to have more bump travel (because it can before spring bind is an issue) and then I say hit an equal two wheel bump (drainage depression across the road) which takes the D/S to full compression, wouldn't everything suddenly become asymetric as the P/S might be able to keep going another 10mm?
Volkswagen Enthusiast
If there is 10 mm difference across the front then something is wrong, it would need around 80 kgs of weight difference to make 10 mm difference in spring preload. Roughly an 80 kgs driver will add around 20 kgs to the RF, 10 kgs to the LF, 35 kgs to the RR and 10 kgs to the LR. So the difference across the front when the driver is added should be around 10 kgs, a long way from the 80 kgs necessary to make 10 mm difference.
If it is in fact 10 mm then it's most likely going to be chassis twist. In which case you should look at fitting a spacer on the low side, above the top spring seat, between it and the chassis, so you don't have a difference in spring preload.
My scales are off in the US being serviced at the moment, but when they come back we should arrange a suitable time and corner weight your Polo.
Cheers
Gary
Golf Mk7.5 R, Volvo S60 Polestar, Skyline R32GTST
Volkswagenist
OMG that gave me a heart attack when you mentioned twisted chassis etc I went back through my notes and it was only about 5 mm difference from left to right. Now having gotten the new 200mm springs in, its barely even a discernible difference - both at 155mm more or less. phew!
I'm going a bit higher on the ride height this time too. It needs to be at least 34.5cm hub to arch before you can measurably see that the control arms are higher on the inner pivots, so I'll try it there which will be 10mm higher than I'd had it previously. Steering actually feels nicer over bumps but handling wise I probably wont be able to tell until the next track outing. It definitely looks more bum down now.
Volkswagenist
Ok I finished the fitment of the 200mm springs and setting them up. Spring preload ended up being more or less identical on both sides. Its quite a process getting the base heights for the damper stroke set up and then the ride height separately but I got there in the end. The FARB links went straight in with no need to adjust them so nothing was pre loaded compared to how it had been. The car is 10mm higher at the front than previously just to see if the better geometry can be felt. I measured the toe at 2mm total toe out so i'll set that out further when I get time and then the car will be ready for the next round.
I fitted the replacement MCA rear damper and at the same time race taped the threads on the adjusters and drilled out the adjuster base so that any water that gets in there can drain out (they were half full of water when I removed them). I re fitted the rear bar with the normal whiteline drop links. I made a new set of spherical drop links but figured there's no point them running around on the road between events as they sit so low and just pick up crud and grit which ruins them too quickly.
Timing belt kit inc water pump is on the way and so is a cam cover gasket as I have an oil leak dripping down onto the compressor housing from there which I need to get onto. I should have those two things addressed by mid July you'd think which is the next hillclimb state round i'll go to at my home track, but as is the way with things I'll be pushed for time again I'm sure.
Volkswagenist
The timing belt, water pump and tensioner was done
3yrs ago if I recall correctly. Do I recall correctly you saying there was a leak or am I getting confused? Should be in the log book anyway.
The cam cover gasket is straightforward, though also worth doing the half moon bit which is the sucky part of the job. Need a tool to take the tension off the cams to lift them. Had to do the gasket on the red polo as the half moon was leaking.
Volkswagenist
Yeah it was actually when we were at the track when I got under it and was relieved to see that the source of my no power was a boost hose off. But that was follwed by 'why the f%%$^ is there so much coolant everywhere' ha ha. Its dribbling out that little hole at the bottom of the bottom timing belt cover so definitely a water pump. No biggy and definitely not on you. I did the timing bet on my first car myself. It was bought at 23,000km but was 8 years on the original belt so got it and the pump done right away - paid for that one as didn't have the free time chasing two babies around. The dam water pump started leaking by 60,000km so did the next one myself which was still good at 90,000km when that tool crashed into me. So my experience is that water pumps leaking early isn't such a big surprise.
Yeah I'm still not sure about whether I should do that bit below the cam timing solenoid. I wiped every bit of oil away from those areas and its clean as a whistle but is dribbling off the back right corner where its only the rocker gasket in that spot so I'll chance it and just do the cover gasket now. Also it might be that I get in there and find that the chain guide is worn and needs replacing in which case I'd have to get back in there at a later date anyway to replace that - but don't really want to go buying all those parts just on suspicion at this point. When the half moon leaked on yours was the oil going down the back or was it tracking rearward along the step on the side of the head below the solenoid?
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