Ok, I have had the thought of a tubular subframe for a MK2 Golf in my mind for some time now, the reason being that it will be a great wy to save weight, allow for easy use of spherical joints and if designed rightly will give more strength. I remember that a US based rally team built one and posted the pics, it was a lovely bit of kit and I have found the pics still on the net they are below. If you were designing one, what or how would you go about doing it? I think I would push the front wheel forward in the arch to give for caster and keep more engine weight inbetween the axels, I think I would also ditch the std engine mounts and use a low dog bone at the bottom and top of the engine, bottom one linked to the subframe. Raise the rack to work with ball joint spacers? Is there room?
Time and effort, I have plenty of. Reward, if I could save 5kg + I would be happy, add then increased caster etc Cost is not a problem, we are only talking raw materials. It's more about the challenge of designing and making it, so if I decided I would make one I would enjoy the process.
I would probably add a brace in the front, however, this would possibly need to be removable so that the engine old be removed without contact.
Another thing worth checking while your playing, is checking the bump steer effects which has a lot to do with everything!
I see why it looks appealing from an engine mount point of view but otherwise I'm not sure its worth the effort? How much weight would it save? I'd say if you're going to the effort of doing that why go space-frame on the whole front end and be done with. Suspension geometry on a golf is awful so if I was doing all that fabrication I'd be tempted to go the whole hog and cut out everything bulk head forward and do Double wishbone and one piece fibreglass front end.
Hi Tom, Raising the subframe has the same effect on geometry as balljoint extenders. The roll center gets lifted back up into a more desirable area. As it also lifts the steering rack, this negates the requirement to flip tie rod ends too. You would need to shorten the steering UJ though. Gurds
^^ As long as you don't raise the engine (and therefore the centre of gravity) in the process. Do you think there's any scope to drop the engine down a bit while you're at it?
this rally guy is keeping it std below. the static/transient forces that go thro this during a rally would worry me hugely
Not adding an extra one as well as the standard subby then Jon? The girders you built round the front of the Mk1 hold it together pretty well!
Ibiza f2 rally car had tubular subframe like that pictured and that won multiple world rally champs. Got a pic somewhere will dig out.
And if they bent one on a stage, their team of mechanics would one of the spares ones out of their service barge in 15 mins probably. Laser checked on custom built jigs, out of unobtanium. At the other end of the spectrum, there's me...
Can't see the engine mounts on that one on top? I had my subframe off, don't remember it being that heavy. Quite fancy a go
I think moving the steering rack/subframe height up would cause many other problems such as exhaust mani issues, and engine sump to subframe distance, steering uj etc... However, adjusting the hubs (or off the shelf forged Ali hubs from the new generation of cars) is always possible, however, making the wishbones/hubs to suit the subframe geo setup would be easier. Making the engine sit lower is very real and separate engine mounts would be needed anyway with a subframe like this. But this could easily make its own thread. Now, how low can you go with the engine? People running dry sumps will be able to get the most benefit, however, this will mean adjustments to exhaust manifolds and resultant high costs for the dry sump system.
