Diy Neg Camber On Front?

[sutol 0]

Anyone ever altered the front track by moving the wishbone locating holes in the front subframe.?

 

Been looking at it today and it dosen't seem that difficult to weld a piece in with the holes a couple of cms further out.

Edited March 2, 2008 by sutol

[ifcho 0]

this sounds interesting. I have a spare subframe, and after I finish my car.... I may try something like this :-)

[danpug 1]

If you can make the holes strong enough i can't see any reason why it wouldn't work, an interesting idea.

[nick 3]

I think for the time and effort it would take to do (accurately) it's not worth it when you can just stick 309 arms on for the same effect.

 

Nick

[sutol 0]

I was thinking of welding a piece in or using a thick washer and welding that at the chosen spot. this way I could shove the wheels out by 2cm or 5cm or whatever rather than being stuck with whatever the 309 arms shove them out by. If you look at it then the factory welding isn't really substantial and the more you look the easier it gets.

 

I have a spare subframe and will be looking at it seriously for my track day Gentry later on in the year.

 

[nick 3]

Once you get past the amount that a 309 arm will give your going to struggle with the driveshafts I would have thought (the same problem with using 205 shafts on 309 arms)

 

Nick

[sutol 0]

Once you get past the amount that a 309 arm will give your going to struggle with the driveshafts I would have thought (the same problem with using 205 shafts on 309 arms)

 

Nick

How many of those cm things does a 309 arm shove it out by then?

I was thinking to go 2 or 3

[tom_m 0]

if you've lowered you car you could even relocate the holes further up to go some way to correct the wishbone angle

 

and 309 wishbones are only 10mm longer

 

but you could look into 405 shafts if you run out of length on 309 shafts

Edited March 3, 2008 by tom_m

[sutol 0]

OOOOPs

getting mms and cms mixed up again.

 

What happened to imperial, I knew where I was with that.

 

10mm isn't a lot then so elongate the hole and weld a thick washer in and bobs your uncle.

or have I got it wrong again

[ifcho 0]

i have a friend with a 1.9 turbo who runs it with 309 arms and 205 shafts with no problems...almost 3 years so far..

 

this piece of metal that is going to be welded, needs to be quite strong. I have some 3mm sheets, but I do not think that they will be strong enough...may be we should think of some reinforcing, so that they do not move alot.

Edited March 3, 2008 by ifcho

[taylorspug 7]

if you've lowered you car you could even relocate the holes further up to go some way to correct the wishbone angle

 

You wouldnt go up far before the rear wishbone mount was hitting the chassis leg, so would either have to notch the leg, or go forwards slightly and up.

[GLPoomobile 958]

if you've lowered you car you could even relocate the holes further up to go some way to correct the wishbone angle

 

So I'm not the only one to have thought of that then. Damn! There I was thinking I had this ingenious thought LOL!

 

Sutol is right. I've just been looking at a spare subframe and the wishbone mounts are separate pieces of steel bent to shape and welded on to the subframe. They are about 3mm thick. Really not all that big a deal when you look at it!

 

I don't think the washer idea is a goer though. 10mm will put the hole too near the edge of the metal. If you are handy with metal work it should be straightforward to replicate these mounting sections but oversized to accomodate the new hole location. Just needs careful measurement and some sort of jig to maintain the wishbone geometry.

[paul205mi16 4]

I'm Sure this would have been tryed and tested before now, Possibly not reported on a forum though.

 

Seems fairly easy to do, What are the possible problems with extending the mounting points & relocating them?

 

Paul.

[GLPoomobile 958]

You wouldnt go up far before the rear wishbone mount was hitting the chassis leg, so would either have to notch the leg, or go forwards slightly and up.

 

Ahhhhhhhhhh, very good point Sir! See this is why you're an engineer and I'm just a bag of ideas that never see fruition (note to self - must consider all eventualities).

 

JUst looking at the pictures of a rebuild in this topic which illustrate the point quite well. I think the wishbone would also foul the upright section of the subframe.

 

Anyway, enough about this idea and back to Sutol's...............

Edited March 4, 2008 by GLPoomobile

[tom_m 0]

Just looking at the pictures of a rebuild in this topic which illustrate the point quite well. I think the wishbone would also foul the upright section of the subframe.

 

how far are you planning on moving wishbone! if you were going to look into it seriously you'd have to work out the revised geometry to make sure you're not going to turn it into a pig to drive anyway.

[jackherer 543]

how far are you planning on moving wishbone! if you were going to look into it seriously you'd have to work out the revised geometry to make sure you're not going to turn it into a pig to drive anyway.

 

I agree, the relationship between the arc the wishbone follows has to be closely matched by the trackrod to prevent bumpsteer. If you move one without moving the other you are asking for trouble. When adding 309 wishbones the trackrods are extended to match (by winding out the trackrod ends) so the geometry is maintained but if you move the mount of the wishbone then the trackrod (even if extended) will turn the hub slightly as the suspension compresses/extends as they will follow a different path.

 

If you do decide to do this its fairly easy to measure bumpsteer, all you need to do is jack the car, let the wheels droop fully and measure the toe, then jack each hub a fixed amount, say 10mm, then measure the toe again, repeat this until you have checked the toe at every height from full droop to full compression and the toe should be the same throughout, if it varies then the car will feel awful and you wont be in full control of it.

[Rippthrough 98]

Just done this on my 306 subframe actually, please be aware that if you put the wishbone in the wrong place you could end up with the roll centres completey out, bump steer,excessive roll/pitch or go the other way and have very little roll/pitch because the suspension is binding so it's very, very skittish.

 

I shifted mine following the wishbone arc from lowering to get the camber gain back, then tweaked that position and I've also moved the top mounts to get the right roll centre and some anti-dive up front.

 

As above, you need to modify the steering rack arms to cover a parallel arc in order to keep bumpsteer as standard.

[jackherer 543]

Just done this on my 306 subframe actually

 

 

Got any pics you'd be prepared to show us?

[welshpug 1,655]

I dont know any specific details but I read on Jeram's goodwood V6 thread that he had moved the arms forward by 30mm IIRC, would this have any unwanted effects?

 

I know that the litchfield Type 25 impreza has the front wishbones circa 25mm further forward than stock.

[GLPoomobile 958]

how far are you planning on moving wishbone! if you were going to look into it seriously you'd have to work out the revised geometry to make sure you're not going to turn it into a pig to drive anyway.

 

Yeah, but that's all engineering stuff!! Nothing ever goes beyond an idea in my brain

[Rippthrough 98]

Got any pics you'd be prepared to show us?

 

 

I'll get some if I remember

[sutol 0]

I dont know any specific details but I read on Jeram's goodwood V6 thread that he had moved the arms forward by 30mm IIRC, would this have any unwanted effects?

 

I know that the litchfield Type 25 impreza has the front wishbones circa 25mm further forward than stock.

Probably altering the castor to induce the required camber on turn in. That will give them more neg camber on the loaded wheel when cornering I think

[tom_m 0]

with the scoobies its all about trying to get rid of lift and trying to reduce that 4wd understeer thing

[Anton green 12 1 Cars]

Im digging this thread up a little, but there is some semi useful information to be had, plus I would like to hear of any results gained by people or possible adverse effects experienced after doing the conversion

 

I dont know any specific details but I read on Jeram's goodwood V6 thread that he had moved the arms forward by 30mm IIRC, would this have any unwanted effects?

 

The ackermann angles would be altered from standard, and I presume subaru set them like that for a reason.

 

There was a guy who moved the wishbone 5mm or so further forward a while ago, according to a magazine feature on a 205. It may have been jamie tonks with a blue T16 205 I believe I have seen that name on the forum somewhere. NB/ I remember seeing rose jointed wishbones on it, so the increase in wheelbase could have been achieved by altering the 'balljoint-hub' location relative to the subframe mounting points and not the mounting points themselves. Im sure if it is him he could give you some information about it however as he should know

 

OP

For the sake of at least an afternoon in the garage and under the car, just work an extra afternoon and go buy some 309 wishbones!

I remember from my RC car racing days that ganerally cars with longer wishbones handled better than shorter wishbone'd cars everything being the same. Don't know how relevant that is to a car with torsion bars on the rear end tho with the roll center on the ground -RC cars use coilovers front and rear

 

Hope this is of some use to people.

 

Rippthrough, do you have a couple of shots of your subframe knocking around?

 

cheers

[Rippthrough 98]

Rippthrough, do you have a couple of shots of your subframe knocking around?

 

cheers

 

 

No, but I'm doing another one next month for someone so I'll get some pictures.