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quicky1980

VR6 Dropped Spindles/hub

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Bonus points to those who know how to use vernier calipers (and have a pair!) :D

 

I've got 12" and 24" digimatic vernier calipers and I know how to use them. I've also got a spare set of bearing carriers with BJ's fitted and I'll be swapping out the wishbones for refurbed items soon. Let me know if I can help out.

 

Dave

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Yes :D

 

let's all meet in Oxford. I hear there's an ultra rare purple C there that needs a bit of hands on work...

 

We also have the oldest Coffee house in all of England!

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Over the weekend, I patched up the two models a little (hub and lbj). I'm going to try and calculate the kpi from the corrado chassis dimensions I have, although it won't be that easy as the castor will have to be accounted for to realise the true 3D position of the hub, and subsequently the balljoint.

 

I'm going to play around with ideas of shortening the hub (make a new model) and also offset the shocker mount points to add in a little widetrack perhaps. It's easy to play with on the computer and doesn't cost anything so i'll see what I can come up with.

 

---------- Post added at 09:06 AM ---------- Previous post was at 08:50 AM ----------

 

Good thread based on Mk2 Golf GTi - I can't imagine Corrogated VR6 si too much different.

 

Scrub radius, and offset importance

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I had a look under my car last night while I was tinkering and the wishbones are absolutely dead level. So you can base your start point on that.

 

Jay

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mr monkey, are you stealing my find? I already highlighted that link on the previous page.

 

Joking aside, nice work. I'm hoping to make it to the stealth rr. would be a good chance to talk about this a little more.

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:lol: sorry. Didn't mean to steal your glory *gives glory back*

 

I've been doing searches on "corrado kpi" on the goog, although I have had a disturbingly high amount of hits for 'key performance indicators'. It seems an early purple 16v with a blown engine doesn't meet their requirements :lol:

 

Jay, I will start on the angled movement thing then and see where I get to :D

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I'm hoping to make it to the stealth rr. would be a good chance to talk about this a little more.

 

Yep, don't forget your lab coats and clipboards boys :D

 

scientists.jpg

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Looks fantastic so far :) Might also be worth considering that the SR has a large effect on torque steer too, as in the larger the SR the more of a tendency the wheel has to want to pivot towards the back of the car under power. Any slight difference in geometry from side to side (in particular castor) will increase the possibility of torque steer so I think its worth trying to maintain standard geometry as much as possible.

 

I'm useless with CAD/computery stuff but spent quite a long time experimenting with suspension geometry on my Vauxhall-engined Mini and in the end after a lot of experimentation with different length top/bottom arms, KPA's, wheel offsets and castor angles I was able to get it to put 130bhp to the ground through 6x10" wheels without a hint of torque steer. However I didn't have to design anything as radical as a new hub as the Mini uses a proper dual wishbone setup on the front so adjustability was easy to build in - none of this Macpherson strut nonsense ;)

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i've seen a few of those old red topped minis! Must be fun :D

 

I'm sure we can sort something out with this design. We can work to fractions of mm on the computer, and even in manufacture I'm sure +- 0.5mm would be feasible from the companies i've worked with in the past. Atm im just trying to find time to work on it.

 

I'm actually thinking of coming up to the Stealth RR day just to put some faces to names (about 40 miles from me), and talk this through some more (although it's the day after my birthday so someone better buy me a burger! :lol:)

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Cheers :D Just a few assembly pics/renders not a major update. Does it look right to you guys? Obviously the balljoint is static in this model, and as such I can't rotate it round to mount properly into the bottom of the hub. But I just want to check the angles are right. I developed some mating planes based on features I know to be flat (for example, the surface of the LBJ bolt holes is at 90deg to the hub face which the disc sits on) although I guess this is an assumption.

 

assem1.jpg

 

assem2.jpg

 

assem3.jpg

 

 

Seems to me that the LBJ base plate is off 90deg side to side (i.e. front to back of vehicle when in position) and also at approx 70 deg between balljoint and base plate with the hex end of the balljoint pointing inboard.

 

Anyways let me know what you think. I'm in the process of mocking up basic representations of wishbones and struts to put this all together and measure how the hub and balljoint position change at 20/40/60/'scene' millimetres of lowering.

 

If any of you other CAD users know how to better manipulate IGES data (perhaps import as surface sketches and re-3d it myself?) I'm more than happy to chat :D After all, all of us have input in this to some extent :salute:

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Good work Jon, so here's what we know so far....

 

1.The suspension damper is attached to the upright through the two holes. Going from what pictures I have, the holes in the damper are evenly spaced from its centreline. This means that the strut is parallel to a line drawn between the two holes on the upright. So this is the direction the upright travels in when the suspension moves.

 

2. We know the factory camber setting (well I don't but I'm sure others on here do!) , this will give you the angle to set the hub flange up at. You do not need to take into account the caster, as it's only the relationship between the upright and the swing of the wishbone that we are changing.

 

3. The radius of the wishbone swing is 355mm

 

Now if you lower the car 30mm then the wishbone moves up by 30mm and also inwards by 1.27mm (if they start off flat as Jay said). So all you need to do is move the balljoint down by 30mm (along the centreline of the strut) and then outwards by the 1.27mm and you'll have maintained the original position.

 

 

However...... I've been scanning through a few old pics of mine (my Corrado isn't to hand as it's under wraps and my old mans house) and it may just be that you'll just have to move it vertically downwards to avoid it hitting the backing plates. So what would the effect of this be? Well you would reduce the KPI which would also cause the camber to go in the positive direction, so to correct that you would have to move it back negative again, which then moves the scrub in the positive direction (the bottom of the wheel outwards away from the KPI)which means more steering feel but harder steering and more torque steer. ..But I'd be amazed if anyone could notice the difference if it was left as was, you'd be talking about 2mm change in scrub or something. I would suspect that the Corrado has marginal negative scrub as standard, most fwd do.

 

Here are some pics for reference. If you wan't me to do the modelling then i'm happy to do it pal, but you'll need to look under a few c's at the rr day and check it all out!

Edited by KipVR

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Cheers Kip, that's some great input and help! :D I'll deffo take all of that into account and hopefully get some more of it sorted this weekend.

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Two thoughts,

 

the scrub radius will be impacted anyway by those of us with non stand width or offset wheels

 

is the backing plate required, if so maybe a laser cut backing plate/splash guard would over come the possible clash issues

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Yeah you should really have the backing plates on a road car, if anything to protect the lbj ruber from the disc heat. Laser cutting one won't solve the problem though as the current one is close to the disc anyhow.

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Davo, if you could take those measurements about backing plate location on your hubs or at least get some pics up so we can see what the deal is that would be good.

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