Volkswagenist
Ozko the eccentrics on our cars are used on the subframes. They're not crash bolts on strut legs. The subframes like almost all the subframed VAG cars are notorious for shifting around. The eccentrics are used as a set and forget. Any tuning changes after that are made at the strut top. I basically put my subframes as far forward as they'd go on the front hole and as far out as they'd go on the back hole to maximise caster. In doing this the eccentrics didnt bind one iota because obviously everything isn't an interference fit under there. I believe the ones we use on the Polo offset each bolt relative to the frame by 2mm so there is nothing extreme going on there. As long as you use common sense ie not try to move the front eccentric forward and the back one back, and move them in complimentary ways so that they're not fighting one another, then there's no functional problem. The main benefit is that you can go some way to accurately squaring up any left/right discrepancies and once you've done it you lock it down and you know it'll never move again, unlike the factory situation where you're putting a 10mm bolt in a gaping hole that no matter how many times you spec torque it with new factory stretch bolts it WILL move again.
Volkswagen Fanatic
And I still would not use eccentrics but thanks for the explanation, the best thing that can be said for them is they are a crude cheap device. I am involved in prototyping some adjusters on another vehicle at the moment to replace the eccentrics that are currently used and my dislike for eccentrics has grown as I get further into the project.Originally Posted by sambb
Volkswagenist
we are just as much using the eccentrics to anchor the subframe as we are using them for alignment reasons. In terms of the anchoring side of things go, yeah it would be much better if the subframes had tight tolerances with the bolts and were even dowelled/keyed into the body. Then for one you'd not even need to look there for a possible solution to an alignment problem and also you'd know that regardless of position that they'd stay put. There might be better ways to fix the subframes but after lots of km's, track work and a solid front end collision later, the subframes havent budged with the eccentrics whereas they were all over the place without them. Its pretty commonly accepted on the VW's that fitting subframe sleeves to fill the void between bolt and subframe hole will help in rigidly anchoring the subframe. I'll be honest with you I cant figure out how an eccentric (provided its not binding and putting sheer forces through its bolt) is any different to a basic sleeve. To the bolt, it just sees the lip on the eccentric adjuster as a washer doesnt it and puts the same clamping force down through the subframe as if it were acting directly on it? I'm happy to be schooled though if that's not the case. As an adjuster, yeah for sure they are finicky to setup if you are looking to adjust in just one plane without affecting the other. On our subframes if you think of them as a base adjustment to get you close to square before you zero in with your other adjustments, then they suffice - or if the car is basically stock (no ball joint or strut top adjustment available), and has say a significant mismatch left to right then it gives you probably the only adjustable way of remedying that.
The method you are prototyping - is it to replace subframe eccentrics with slots, or to replace eccentrics in their various uses in general? If its to do with VW subframe adjustment then I'd be super curious to see what you are working on.
Volkswagenist
These are yours yeah? and this is the drivers side. It looks like the slider section is biased towards one side of the strut top eg the inside two bolts in this pic. So you've oriented the tops north/south which looks like it might even add a bit of camber if you are trying to add caster which sux. Normally you'd line up the slider axis with the inside back bolt (for caster and camber) but it looks like your slider channel wont extend far in the desired direction if you do that.
Easiest fix would most likely be running different strut tops that line up the slider channel differently so you can angle them in and back. Apparently nissan S15 strut tops (check with Simon) have our bolt pattern. Maxpeeding do cheapies and these one position Whiteline ones would get you max camber/caster in a fixed position style......but then to dial it in you'd have to eccentric the subframe.
Couldnt tell you if S15 ones use the same bolt sizes or if your strut would fit into them without a sleeve/mod etc though.
This is my passenger side top looking back towards the firewall. They were east/west but I was able to change the orientation so the channel ran towards the inside back bolt. These are MCA tops but you should be able to find an S15 alternative that will give you that orientation with more range than your ones will give you.
While the eccentric designed to fit more or less into the existing subframes holes are quite good at maximising caster they dont seem to have as much impact on camber. My eccentric only needed the slightest ream for them to go in. In terms of lateral movement, front hole of subframes does camber, rear hole does caster. I think Simon floated this at one stage but for your situation possibly you could drill out the front bolt hole on the subframes so that an oversized eccentric could go in there allowing you to get say 3-4mm of lateral shift in the front of the subframes. Run them with superpro offset caster rear LCA bushes so you dont give away any caster and that may be enough to get you an extra 0.75 degree. Other than that modding wishbones to accept an alternative ball joint or balljoint position would most likely be the answer.
Volkswagen Enthusiast
Nissan strut tops have the same bolt pattern, but rotated 180 degrees (or swapped side to side). Maybe try to find some with a longer channel, one that goes all the way across like Sam's. Those tops in Sam's picture would work, but they look pretty big, you'd have to cut the whole of the dome off - does that weaken the tower too much?
Volkswagen Fanatic
Sam, unfortunately for all sorts of reasons I can't go into the work we are doing but is for alignment and adjustment reasons and not subframe stuff like you are dealing with. I have never been involved with setting up any VW but a lot of people do not understand the problems that eccentrics cause in alignment and suspension setting until it is explained to them. Apart from the adjustment in two planes problem they generally as a rule have very limited adjustment capacity as introducing more makes the two plane mixture even worse. My intent on putting my 2c worth in was to alert others who may not be aware of the problems this style of adjuster has and they can then make their own decisions on using them, a heads up really and nothing more.
Volkswagenist
Thats cool. I'm no eccentrics fan boy by any stretch. When you mentioned their drawbacks and using them myself on the subframes I was a mixture of curious and wondering what I might be missing if there was a major issue. I do understand their limitations. For instance I wouldnt use them on hubs where the strut bolts on. I've spoken to a guy whose eccentrics repeatedly let go on turn 1 at eastern creek and helped a competitor with the eccentrics on his HSV Clubsport that let go run after run at a hillclimb (both retailed parts, not DIY).
Volkswagenist
Pardon to interrupt the discussion.
What are the eccentric bolts/inserts you guys are talking about?
Google shows there are eccentric washers for bolts but only for MK5 platform.
Got a link?
Sent from my iPhone using Tapatalk
Volkswagen Enthusiast
I posted a link back in post #9..
Volkswagen Fan
Yeah, unfortunately they are biased towards one side, so need to prioritise either caster or camber.
These are yours yeah?
That was drivers side. This is how they are setup now...
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Last edited by teamshaw; 13-12-2020 at 03:42 PM.
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