Min ground clearance

[Coyoteboy]

So the rotting shell is still concerning me. While I have the kit and have cut patches to suit the sills and arch I know the end is only being postponed. So in the pipe-dream factory I'm toddling through a design strategy for the replacement, to be enacted when I get the car here and get chance to make more detailed measurements. Or rather the transplant. Things I'm thinking over.....

Minimum ground clearance - this brings questions of wheel sizes and cheap available tyre sizes, plus the minimum clearance I want from stray objects in the road, and bump clearance when the sus compresses.

Wheelbase - keep it as-is or modify to be a little shorter?

Target weight. I'd like to aim as light as possible but don't want to end up with matchstick wishbones and zero impact strength. I'd like to aim for a sub-700kg car, but with the full 4wd running gear that might be pushing the realms of the possible.

Shoe-horn into an existing kit chassis or deal with completely new chassis design and the paperwork that goes with it? This is an area I'm not 100% on, the legality side.

[ChrisW]

http://online.businesslink.gov.uk/Transport_files/IVA_Information_Guide_V2.0_with_links_FINAL_Oct_09.pdf

This page is pretty comprehensive on VOSA guidelines

[Coyoteboy]

It's actually as clear as mud Difficult to know if your car falls under an altered vehicle or a new vehicle, I think to get new vehicle it has to be mostly new parts, which means the IVA may not apply? What a royal pain. Anyway, heres the IVA test manual for M1s
http://www.transportoffice.gov.uk/crt/repository/IVA%20Inspection%20Manual%20for%20M1%20Passenger%20Cars%20April%2009.pdf

[ChrisW]

I started reading that up to the 'amateur built' part, then my head started to hurt lots I think classification will depend firstly on the new or existing chassis and if there is a comparative vehicle already listed?

[Coyoteboy]

Chassis will be new/built (which would suggest new car) but then it can't get a new reg is the majority of the parts are not new, so how does that work?!

No specs for groudn clearance. Don't have to comply to impact regulations. I suppose I'd want a minimum of speed-bump clearance, so 125mm (pavement height).

[ChrisW]

Would it go on a Q plate as a kit car? Cheap insurance

[Coyoteboy]

Yep, I think it would be a Q unless I could demonstrate mostly new parts. I like cheap insurance!

[Frikkin Evil]

I think this is a great plan, and I hope you're able to do it.

Just one thought from a layman... If you reduce the weight to that level (presumably with a space-frame design), will the engine need to be mid-mounted to maintain a balanced chassis?

[Coyoteboy]

I've books on chassis and suspension design coming out of my ears at the moment!

That's a reasonable question and I did think hard on whether to modify the driveline to de-couple the front shaft location from the gearbox but I think it would be so much extra work I'm just kinda hoping I can make the front end relatively short and keep the seating, tank, battery and maybe rad at the rear. It is an aweful lot of weight up front and while its C of G does sit slightly behind the front wheels in stock form, I was pondering the idea of lying the engine over a bit more at the very least.

I'd be re-using pretty much the whole driveline (maybe shortening the prop, but I like the length as-is if I don't have overhangs?), hubs, hub carriers and some of the rear sus links like the front-rear tie rods. This removes the need for most of the custom parts that would cost a fortune to make like uprights (maccy struts will be easily modified to double unequal length A arms and I might go with pushrods to keep the shocks inboard and under-cover.

[Coyoteboy]

Something along the lines of a dax rush quadra, if you fancy a youtubing.