Which 4WD or RWD setup would you go for?

[marine boy]

I am starting to design a space framed car suitable for road, trackday and occasional hillclimb use and am a little undeceided on which route to go for.

My plan at the moment is to buy a complete car and use the engine, box, diff and loom as the basis for the engine and drivetrain package.

My target is for a reliable useable 300-350bhp with good low down torque with relatively low gearing for a vmax of around 125mph. The total car weight will be 900-1000kgs and I am aiming for as close to a 50:50 weight distribution as practically possible.

My two preferred routes are front engined 4WD and front engine RWD as my budget of £5k for a full running engine, box and diff probably makes a rear mid-engine set up out of reach.

In the 4WD corner my favourites at the moment are a Subaru Impreza STi Ra or a Mitsubishi Evo 4, 5 or 6. I like the idea of the subaru boxer layout as the centre of gravity is low but the front/rear weight ditribution is not ideal.

In the 2WD corner is the good old tried and tested Cosworth 2WD set up or a slightly more modern and zingy Honda S2000 set up. With the engine set behind the front axle centreline a 50:50 weight distribution is achievable but on the other hand I do like the idea of the extra grip from the 4WD option.

To get the optimum package I would be happy to consider a mix and match approach as I will need to have custom driveshafts and propshaft made to package everything under what will be a rather unconventional bodyshell.

Hopefully you guys can advise me on what choice you would go for.

[GreenV8S]

My first thought is that 300 bhp per ton is not enough to require 4wd to put the power down, so unless there's something unusual making traction a particular issue I'd stick with the simplicity and lightness or rwd.

Does it really need to be that heavy, btw?

[cbcbcb]

There must be a suitable Audi 4WD set up you could use. IIRC you can get 300bhp out of a Audi 1.8T with a bit of work.

How about Toyota Supra running gear for RWD?

You mention budgetary reasons for not going mid-engined; have you discounted mounting a FWD engine+box as a mid-engined RWD? (Same trick as the MGF and others)

[Snake the Sniper]

If you're happy with a 900-100kg vehicle, then you won't need 4WD. Which means that you can use pretty much whatever you drive train you like. If you have £5K to play with, then I would go for a V8 of some description, probably something American. Or do you want something a little bit different? You could always use an Alfa 3.2 V6 and supercharge it for example, or turbo an RV8.
Personally, at 1000kgs, I think the car sounds heavy for what you want to do with it. Does it need to have a roof, 'leccy windows, full doors, air con etc? If not, then you should be able to do what you want with something like a 7, or a 7 inspired/chassised vehicle and get weight down to 500-600 kgs if you try.
As has been said, a cheaper option could well be something like the VAG 1.8T engine and box in the back of something, making it mid engined. Easy to do too, as it requires no mods to the drive train, bar a different exhaust.

[chuntington101]

Here is a scooby based kit car you might want to look at....

http://adrenalinemotorsport.co.uk/

Also have a look in this months PPC. a guy recons a Sccoby flat four will fit in a 205 fornt end! should result in a sub 1000KG 4wheel drive car!

Chris.

[marine boy]

I think I may not have been ambitious enough on my target weight so can I start again with a leaner 600-700kgs with a 4WD set up and as Snake rightly suggested 500-600kg with a 2WD set up. This would get me up into the +500bhp/ton territory which sounds a lot more exciting.

I do like the idea of a Audi 1.8T with 4WD suggestion as the donar vehicle I have planned is probaby a little smaller than a TT.

The donor vehicle is a little on the different side and not something you would expect in your wildest dreams to keep up with modern sports cars which is part of the appeal of the project for me. I would like people initial reaction to be WTF!

The wheel base will only be 2300-2350mm with a track width around 1400mm with quite a forward seating position so trying to shoe horn in a V8 or V6 will be difficult but not impossible.

I would prefer 4wd and it is more in keeping with the theme of the car so really like the Subaru kit car which I will look at in a bit more detail, good suggestion Chun.

The classic 2WD Caterham type set up is very apealing as it will probably give me the best handling package due to the lowest weight and best weight distribution.

Thanks again and keep the suggestions coming.

[stevieturbo]

Subaru STI RA would be ideal. It has very short gearing, and parts would be readily available at sensible money from breakers.

Complete cars are also available to buy quite cheaply too.

[cbcbcb]

marine boy said:

The donor vehicle is a little on the different side and not something you would expect in your wildest dreams to keep up with modern sports cars which is part of the appeal of the project for me.

Oh go on, tell us more!

[Snake the Sniper]

If the car is to be quite short, you may struggle a bit with the scooby stuff, as the front drive shafts exit the gearbox behind the engine, and as such would need to run forwards at a possibly crazy angle. You may not, but only you know what you have in mind so it's something to bear in mind. If you want the seating position to be quite far forward, then that lends itself quite nicely to the idea of a mid engined car, which then lets you use pretty much any FWD engine and box.

[marine boy]

I was hoping I had dropped enough hints of what donor vehicle I want to use is but as I said it's not a conventional choice. The picture is not the actual Land Rover I will use but it would be the same vintage as the Land Rover Series 2 pictured.



I can't really take full credit or depending on your point of view blamed for the choice as some madman in the states is already building a drag/autotest Land Rover by slotting in a Porsche 356 motor with torsion bar suspension. I thought it was such a cool project and thought it would be good fun to push the concept on a bit further with more power, better handling and stopping performance.

You really have to use your imagination to picture what the end product will look like, but if you can visualise it very generously lowered, the body widened by 4" and the roof with a mild chop. It would also be cool to keep all the farmer dents in the bodywork but somehow with the amount of bodywork alterations that it will require I can see a full repaint in one of the classic Land Rover colours happening.

I think 4WD is more in keeping hence me steering towards a Subaru STi Ra but I like the idea of the simplicity of a good front engine RWD set up.

Apologies to any classic Land Rover purists but I have one life and want to live it!

[GreenV8S]

Are you planning to keep the original bodywork? If so the result is going to weigh tonnes, which seems like an odd approach when you seemed to be describing a high performance track car.

[offroading.net]

Bodywork isn't that heavy, if you can ditch the steel bulkhead the rest is lightweight. Do away with the cab & screen, go with 1/2 doors and use pickup points on a spaceframe to do away with the bulkhead.

I'd go mid engine RWD, 3.2 Alfa would be nice

Edited by offroading.net on Thursday 3rd September 22:12

[chuntington101]

I have got it mate! LS engine with a pair of turbos!

Seriously though dont laugh to hard. a guy on here called eliot has a Dakar based of a randy/range rover with a SBC (Small Block Chevy) 350 V8 and twin turbos! last i heard he was using the LandRover auto box but a TH400 would be a much better choice as it can be built to take SH!T loads of power.

Cheers

Chris.

[annodomini2]

Sylva??

Mid rear

http://www.sylva.co.uk/

[beejay]

Some inspiration perhaps?

(specs on page 2, not much to be fair but I'm sure there's a few more threads about it on there)

[marine boy]

Stevie turbo, for the reasons you pointed out a STi Ra is still my prefered choice but the size and weight of the rear diff I think could be reduced but I am not sure from what. Maybe a Sierra Cosworth aluminium diff casing with the same ratio as the Subaru might work.

GreenV8S you are spot on sir, what I am attempting to describe is exactly as you say a high performance track car but with added twist of very low performance look.

As offroading.net describes I would ditch the heavy steel bulkhead, probably keep the screen so as not to eat bugs everytime I want to go for a spin. As I would like to widen the bodywork it would probably end up a mixture of original aluminium panels and new dib and dob carbon panels to keep weight to a minimum.

chunington101 I don't really want to go the V8 route as I want to play overtake on the corners and keep up on the straights than overtake on the straights white knuckles on the corners. I think that would be more suprising to other startled track day drivers in their sports cars which would be more fun for me.

I do like the sound of a mid mounted RWD 3.2 Alfa engine but part of the whole package for me would be a very slick gear change which I am not sure would be easy to get right with a custom gear linkage or cables to an FWD gearbox.

beejay many thanks for that link, that slammedrover looks so wrong but so right, it really has given me the inspiration I need to start to getting serious with this project. I just need to get back to work and get started laying it all out on CAD (obviously in me lunchtimes only)

Keep the great ides coming and thanks again

[GreenV8S]

marine boy said:

GreenV8S you are spot on sir, what I am attempting to describe is exactly as you say a high performance track car but with added twist of very low performance look.

Sounds as if you describing a real Q car, although I wonder how far you could lower/widen it before you give the game away. It would certainly surprise a few people. As I'm visualising it, it won't be very streamlined so high speed performance might be compromised. Would you consider dropping a more streamlined shell on your spaceframe once the 'Q' novelty has worn off?

Some of the comp safari cars are very cute indeed, and although they're designed for off-road use I reckon they would be huge fun on the road too, if you take that route. I know somebody who built a very lightweight version powered by a turbo Mazda rotary that had superb power-to-weight, and apart from the ride height and suspension travel that's basically what you're describing.