Rack and Pinion - one size fits all?

[funkyflynz]

Guys,

after some advice, im converting my Australian Valiant to rack and pinion, i know a subaru outback rack is the correct length for my application to help reduce bump steer.

My question is, would a rack from a 6cly outback with 205 tyres vehicle be ok for my v8 valiant (running a 6.1 hemi) with wider tyres (245)?

Im assuming the outback being 4wd and having a lot of its weight over the front wheels would have a reasonably decent rack?

Are there any concerns around racks and additional steering forces? Could i use a quick ratio Subaru WRX rack for instance?

Thanks

Lee

[pjs65]

I wouldn't have thought that anyone has done that conversion before , but there's a first time for everything . I do have a WRX and they were built for rallying which is a tough event , they are also well used for most forms of motorsport and can stand a fair bit of heavy use . A boosted up WRX with racing tyres can generate a lot of load on the tyres and the steering seems to cope with that ok , i personally wouldn't worry about the strenghth but more about the alignment and geometry . Give it a go if you think you can do it and i like a bit of mix and match engineering , my 69 Camaro has 540 BMW rear brakes. Pete

[funkyflynz]

Originally Posted by pjs65

I wouldn't have thought that anyone has done that conversion before , but there's a first time for everything . I do have a WRX and they were built for rallying which is a tough event , they are also well used for most forms of motorsport and can stand a fair bit of heavy use . A boosted up WRX with racing tyres can generate a lot of load on the tyres and the steering seems to cope with that ok , i personally wouldn't worry about the strenghth but more about the alignment and geometry . Give it a go if you think you can do it and i like a bit of mix and match engineering , my 69 Camaro has 540 BMW rear brakes. Pete

Thanks for your thoughts, much appreciated mate. Its a near perfect fit for my geometry

[Rhino]

There are a LOT of measurements that need to be compared prior to calling the rack a good match. Personally I haven't run across a single OEM rack I'd feel comfortable putting on the stock 1st gen sub without significant other changes.

How close is the inner ball joint to inner ball joint measurement of the rack compared to the frame side pivot points of your lower control arms?

[funkyflynz]

Originally Posted by Rhino

There are a LOT of measurements that need to be compared prior to calling the rack a good match. Personally I haven't run across a single OEM rack I'd feel comfortable putting on the stock 1st gen sub without significant other changes.

How close is the inner ball joint to inner ball joint measurement of the rack compared to the frame side pivot points of your lower control arms?

Its bang on the same distance, it would be nice if the rack was 5mm longer each end as the rack will sit about above the pivot points of the lower control arms so the tie rods stay parallel, but bump steer will be minimal. Im not going to worry too much about ackerman.

[pjs65]

Originally Posted by funkyflynz

Im not going to worry too much about ackerman.

I wouldn't totally ignore the Ackerman as it can have a noticable effect on the steering . My Camaro was hard work to get turned in to a corner and the tighter the corner the worse the turn in was . When i checked the Ackerman i found that the intersect point was out behind the rear bumper , so i put some spacers behind the steering arms to move them in which in turn moved the intersect point forward to the diff yolk . The turn in improvement was noticable at the very first turn and is way better than it used to be , it makes hairpins and 90 deg turns a lot better now . Pete