Interesting thread...... There are plenty of cars that convert to wide track - most of S1600 cars - kits can be bought from TAS for eg. for Nova's. They do this by lengthening the bottom wishbone and usually by using a spacer between the std upright and std strut or a new upright with more offset from hub to strut attachment (both so they can maintain sensible camber given that the top of the strut stays approx in std position). The increase in spring rate needed with the increased leverage is easy to sort out with stronger springs. If you restore std ride height with the stronger springs, I dont see that roll center is an issue. KPI will be same. But the scrub radius changes since the top of the strut has not been moved........and these cars are fine. I dont understand how this can have such a major influence.....please explain further Thanks Rob Edited by: RobT
There's more to the Reeve's Mk1 suspension geometry than simple extended wishbones.. Look at the hubs
Bill, Daz/motorhead hads done it but the exact parts etc probably needs a pm to motorhead. reeves run a lower bottom ball joint that sorts out the roll centre issue i intend to run mk3 VR front suspension on the mk2 which is approx 1" wider each side, as fitting an 02m with wider diff i need all the driveshaft length i can get on the short side i'm pretty sure the mk3 bearing carriers are a different geometry to the mk2 ones, but no idea of whether the bottom ball joint is lower or of other changes but i can measure them up, using ET45 wheels too also i intended to use TAS top mounts to allow the centre of the topmounts to be offset outwards, and i can mess with the caster etc it'll run at approx standard ride height see any obvious f'k ups in me plan Golden/Daz? Edited by: prof
The simple answer is, it doesnt. There are four areas you need to look at when widening the track. 1.You need keep the angle of the upright the same. 2.You need to keep the angle of the wishbone to the same. 3.You need to keep the scrub radius the same. 4.You need to keep the KPI or SAI the same. In your example you mention resolving 3 of the 4 areas to maintain the correct geometry. Although you say fitting stiffer springs would sort the roll centre, this would only be true if any adapters or offset hubs also brought the upright back to a normal angle. Without opening a huge can of worms, this thread (sorry again Tubs) drifted into talking about putting Passat wishbones on a MK2. Doing this leaves 3 areas screwed with only KPI unaffected. As an extra point, scrub radius, which Im infamous for banging on about, is critical. It effects turn in, tyre wear, self centring, steering feel and stability. Thats why I always mention it when people say large wheels dont work because in a vast number of cases the ET is below 35, screwing the scrub radius. Combine this with changing any of the 4 areas mentioned above and you can see why you hear people say large wheels are awful. Hope that answers your question Rob.
Prof, if I'm looking at the right things then the TAS offset mounts wont do it. You need something that looks like this. To get the upright angle back where it should be.
Lowering bottom ball joint is only an issue on a lowered car when the wishbone goes past parallel to the ground - if you uprate the springs on a car with longer wishbones this wont be required The Mk3 VR bearing carriers do have a lower bottom ball joint Cheers Rob
[/QUOTE] The simple answer is, it doesnt. There are four areas you need to look at when widening the track. 1.You need keep the angle of the upright the same. 2.You need to keep the angle of the wishbone to the same. 3.You need to keep the scrub radius the same. 4.You need to keep the KPI or SAI the same. In your example you mention resolving 3 of the 4 areas to maintain the correct geometry. Although you say fitting stiffer springs would sort the roll centre, this would only be true if any adapters or offset hubs also brought the upright back to a normal angle. Without opening a huge can of worms, this thread (sorry again Tubs) drifted into talking about putting Passat wishbones on a MK2. Doing this leaves 3 areas screwed with only KPI unaffected. As an extra point, scrub radius, which Im infamous for banging on about, is critical. It effects turn in, tyre wear, self centring, steering feel and stability. Thats why I always mention it when people say large wheels dont work because in a vast number of cases the ET is below 35, screwing the scrub radius. Combine this with changing any of the 4 areas mentioned above and you can see why you hear people say large wheels are awful. Hope that answers your question Rob. [/QUOTE] Not quite...... The angle referred to in (1) is angle as viewed from front of car I assume. If you bring the strut back to this std angle with spacers between the upright and the strut, the wheel itself will move outwards by the distance that the wishbone is lengthened (assuming flat ground parallel wishbones). The scrub radius will change - there is no getting around this without moving the top of the strut outwards by the same amount that the wishbone is lengthened - now this is fine if you only want to go out say 1" as this could perhaps be accomodated with the strut top mounts pictured, but if you wanted say 3" a side - like on a F2 Ibiza for example and also more than 1" on a kitcar or S1600, this will not be accomodated by this tactic. And if you use the top mounts pictured, you will not be able to get lots of castor on which is a major need of these cars. If we get back to our original question - what will change if you stick longer lower wishbones on a Mk2 - then I dont think the scrub radius will change since the relationship between the strut and the wheel remains constant - the camber will go very negative, the ride height will fall due to the effective change in spring rate (inc. roll / roll center issues etc). The issue comes when you try and restore the correct camber = change in scrub radius over stock because of strut angle change. Phew. Cheers Rob Edited by: RobT
so what do you think would be a good combination using standard parts, pretty sure TT used longer costom wishbones and offset topmounts on his turbosuperstapress wagon
Andy - if you did that experiment then you would need a car that had perefct weight distribution from left to right hand side - GOOD LUCK! And i'm sure that i posted about welding my wishbones up once upon a time....
With stock parts, You will be able to go wider by the amount that you can offset the center of the strut top from its original position - this is perhaps 10-20mm only but may be ok for you - you are simply moving the whole strut/wheel assembly outboard. If you address the need for stronger springs it should be fine IMO. (you will have to lengthen the steering arm but thre may be enough adjustment on this to cope). Me - I am trying to work on 3" a side........F2 Ibiza stylee Edited by: RobT
Rob, RSD are doing a wide-arch Ibiza at the moment. IIRC not proper F2 rally car but the same as the one displayed at the motor show several years ago, which the prepped. I'm keeping a close but distant eye, could be worth a shout if you want to jump in now.
Good couple of points there Rob. Regarding your first paragraph I can't really comment cos I'm not familiar with S1600 suspension but I'm assuming F2 suspension is bespoke to the car so with a clean sheet of paper it should be achievable. Next bit: That pic was the first one I found that showed what was needed. The trouble with the eccentric top mounts (which I assumed prof was on about) is that to get the strut angle back you'd compromise the castor. Your third paragraph I don't understand, you seem to answer your own question. You say that you don't think the scrub radius alters, which it doesn't if you don't move the upright/hub joint. Then go on to say it would once you corrected the camber, which is also true. Which I assumed you would do when I said the scrub radius would be thrown out. Sorry if I'm being thick Rob, are you just making a point in the third paragraph? Tub, sorry again I blame the lad singh....
right.... I'm interested in this here suspension theory y'all seem to talk aboot. You lot, Golden, Rob, Motorhead etc seem to know a thing or two, despite a few diferences of opinion. Recomend me a book that will get me thinking for my self (probably with calculator) I'm sure I'm not the only one who is interested...
Just like the good old days eh!! How many of you have actually TRIED differnet setups? eh? come on, how many of you have treid different combinations of wheels, tyres, wishbones, ARB's, and all that? well, i can tell you now that I have, in several cars as well as developing the smae car with different setups. I can tell you now that the wider track and welded wishbones ARE stronger and you can feel it too. Also, why such the big deal about moving away from manufacturing tolerances? who's to say VW got it right in the firsft place? don't forget the car was setup for the AVERAGE driver. it's up to you to tailor it to what YOU want. one size does not fit all..... Interstingly, my best track effort, which was a 3rd place at Kames last year, was in a mk2 VR6 (which don't handle apperently), with passat wishbones up front, wide track on 4 stud hubs, mk3 vr6 struts, TAS eccentric tops mounts set for more camber and castor (no idea how much, I'm not that anal about geometry) and shagged out monroe shockers on the narrow traack rear beam...........beat all but 22 cars on the day, in my 2nd ever track atempt.....
No sh1t Sherlock no I didnt get chance to look at the hubs but the lower arm mounts looked interesting Edited by: motorhead
Great reading guys - not only for the humour but there are some very interesting points made ! My experience of 17"'s ?? Went to bed afew nights ago and watched a video of me and paul at combe a few years back. Nothing amazing about that i know ( unless anyone knows what a sony GVD-800 is ...) but the car that chased me all the time was a lil red 4 door mk2, slammed to fck and a whopping great cage in it.... any ideas ? Caged used to post on here a lot, but went the mk4 route and has since left the fold, but that had 17"'s on it with a tuned 1.9. My at the time fairly standard 2.0 16v on 15"s couldn't leave him ... and he gained in the corners.
I'm not posting a CV boys, if you think I'm full of shit then don't read any posts with Golden in the left hand corner
