Suggest a donor

[singlecoil]

The vast majority of kit cars require a donor production vehicle to provide most of the main mechanical items required, and the first choice a manufacturer has to make is- which donor is he going to use?

At the moment it's mostly the Ford Sierra, the differential and driveshafts, gearbox, sometimes the engine and the front uprights, steering column etc are popular and widely used.

More recently we are starting to see cars using other donors such as the MX5 and BMW, and MEV use the Ford Focus for some of their cars.

How about some suggestions as to what else could be used? It would be good if these suggestions were supported with some thoughts on the type of car to be produced, and how the inevitable problems would be overcome.

I'll start, with the Porsche Boxster for a mid-engined, open or closed sportscar. Examples can be had for £5,000 for a car in good working order, and considering the amount of very usable parts, that could be a good deal for the builder, especially as he would be entitled to a 'Powered by Porsche' sticker!

The front suspension on the donor uses struts which would probably spoil the bonnet line of a lower car, but they look as if they could be converted to double wishbone in the same manner as is often done with Sierra uprights. No other particular problems that I can see.

Any other suggestions?

[Busa_Rush]

I wouldn't use a Porsche as a donor, the idea is to have something that's not expensive to fix and modify and a Boxter, when it goes wrong, isn't going to be cheap.


I'd look at an MR2 . . . I bet you could build a cracking Ferrari using an old MR2 . . .

[singlecoil]

Busa_Rush said:

I wouldn't use a Porsche as a donor, the idea is to have something that's not expensive to fix and modify and a Boxter, when it goes wrong, isn't going to be cheap.

But look at the overall cost, and it's not so bad compared to many of the alternatives.

[Roman]

MGF - cheap & abundant with lightweight drivetrain, brakes & suspension, good wheels, cheap & plentiful spares. Perfect donor for a budget mid engined track day car.

You also have an opportunity to shorten the cooling circuit, add a 'low coolant warning' sensor and fit an uprated HG during the build.

I know some don't like the engine but it is proven in plenty of kit car applications, makes the donors very cheap and if your going to be building a car surely the thought of replacing a HG shouldn't be too daunting?

Or:

I like the Tomacat concept of a 'Locost' Bowler Wildcat too. Use a cheap & plentiful Disco, RR or Defender and as parts are mostly utilitarian & fabricated, development & production costs could be simpler and less than for a normal kit car. I don't think they need to be SVA'd either do they?

[Busa_Rush]

singlecoil said:

Busa_Rush said:

I wouldn't use a Porsche as a donor, the idea is to have something that's not expensive to fix and modify and a Boxter, when it goes wrong, isn't going to be cheap.

But look at the overall cost, and it's not so bad compared to many of the alternatives.

Depends on the alternatives but it's going to be a lot more expensive than a Focus, Mondeo, Sierra or MGF.

Tuning/upgrade parts for Porsche cost a lot more than for the K series and if a gearbox or crank seal fails on a Porsche, unless you fancy fixing it yourself, it's not cheap.


Edit: I think I might prefer a Porsche anyway rather than a kit car based on a Porsche.

Edited by Busa_Rush on Friday 11th June 09:57

[singlecoil]

Busa_Rush said:

singlecoil said:

Busa_Rush said:

I wouldn't use a Porsche as a donor, the idea is to have something that's not expensive to fix and modify and a Boxter, when it goes wrong, isn't going to be cheap.

But look at the overall cost, and it's not so bad compared to many of the alternatives.

Depends on the alternatives but it's going to be a lot more expensive than a Focus, Mondeo, Sierra or MGF.

Good stuff usually is more expensive than mediocre stuff. The question is whether it's worth the extra.

Busa_Rush said:

Tuning/upgrade parts for Porsche cost a lot more than for the K series and if a gearbox or crank seal fails on a Porsche, unless you fancy fixing it yourself, it's not cheap.

Well, you start with 204 bhp, so a new exhaust (which you are going to need on amy kit car) and induction kit and maybe a chip/RR session should see you with 230-250bhp even with the smallest (2.5) engine, and plenty of torque

Busa_Rush said:

Edit: I think I might prefer a Porsche anyway rather than a kit car based on a Porsche.

Well I daresay, but you can buy a decent Boxster for less than £5K and you'll have a job to find a decent kit at that price, so I reckon you might be in the minority (as far as this particular discussion goes) there

[Roman]

I didn't realise Boxters could be had that cheap.

Even so it would have to be a very nice looking and high quality kit to make me chop up a Boxter, but I think a nice 904 or 906 replica would do it!

[Busa_Rush]

singlecoil said:

Busa_Rush said:

singlecoil said:

Busa_Rush said:

I wouldn't use a Porsche as a donor, the idea is to have something that's not expensive to fix and modify and a Boxter, when it goes wrong, isn't going to be cheap.

But look at the overall cost, and it's not so bad compared to many of the alternatives.

Depends on the alternatives but it's going to be a lot more expensive than a Focus, Mondeo, Sierra or MGF.

Good stuff usually is more expensive than mediocre stuff. The question is whether it's worth the extra.

Busa_Rush said:

Tuning/upgrade parts for Porsche cost a lot more than for the K series and if a gearbox or crank seal fails on a Porsche, unless you fancy fixing it yourself, it's not cheap.

Well, you start with 204 bhp, so a new exhaust (which you are going to need on amy kit car) and induction kit and maybe a chip/RR session should see you with 230-250bhp even with the smallest (2.5) engine, and plenty of torque

Busa_Rush said:

Edit: I think I might prefer a Porsche anyway rather than a kit car based on a Porsche.

Well I daresay, but you can buy a decent Boxster for less than £5K and you'll have a job to find a decent kit at that price, so I reckon you might be in the minority (as far as this particular discussion goes) there

You're not going to get 50bhp by changing the exhaust and a chip swap or even a remap. The engine has been designed for low noise, low emissions and good economy. If that's what you want in your kit then leave as much of it as stock . . . 200 bhp isn't going to be too slow unless you make the kit from old railway lines

But upgrading an engine to get anything sensible from it takes a lot more than an exhaust and an induction kit, unless you start with a Saxo 1.1 in which case you can get an immediate increase in the region of 80 bhp

You need to make internal changes to the engine to make it more powerful, so that means probably pistons and four cams and 2 x combustion chamber work, maybe valves and you're then needing new gaskets, valve springs, the odd bearing, honing etc, it's all starting to add up and you still don't have your expensive exhaust and induction kit and you've still got the standard clutch, flywheel, gearbox etc. Add an ECU which you'd need unless you can remap the existing box and it's all looking really expensive. And all that on a 100,000 mile engine which has a reputation for not being the most reliable in the first place.

Choose a Ford Duratec for example, if you can't get one second hand with some work already done, the parts are much cheaper, there are 4 or 5 companies who can supply parts and knowledge and even new crate engines are only £1k. You can have a nice 250bhp in a reliable package which is used by 100's of other people with off-the-shelf replacement parts for not a lot of cash.

And say you pay £5k for your Porsche, you strip out the engine and gearbox, ancillary parts and maybe the brakes if you want some heavy calipers, then what do you do with the rest ? Sell the parts on eBay and hope you get back £3k or so ? What's an old Boxter shell worth given there are Boxter shells available with an engine and gbox for £5k ?

I suspect it's a route for a very expensive, if nice engine. There are much better options.

How about the Lexus LS400 ? The engines are as reliable as they come these days. Whole car for £1200 with a lovely creamy V8 that already makes 250bhp. Mates to a Supra flywheel, clutch and gearbox if you don't want the auto that it comes with. You could even use the dash with the rather neat lighting it comes with

[singlecoil]

Busa_Rush said:

Lots of opinions about why he absolutely hates the idea of a Boxster as a donor

Wow, I never expected the Spanish Inquisition! Funny how an argument can appear out of nowhere.

Anyway, instead of trying to pull my suggestion apart, why not make a proper one of your own? (MR2 bodykits don't count BTW, and if you were gong to use the LS400 engine you couldn't use much else, the auto gearbox is controlled by the ecu, and the dashboard is tied into it as well)

[slomax]

Id like to see Pumas as a donor. There are lots of rusty ones around that are mechanically sound and a nice nippy motor. I bet there were a lot of Pumas given in for the £1000 off a new car and it is an absolute sin as they are cracking little cars.

[singlecoil]

slomax said:

Id like to see Pumas as a donor. There are lots of rusty ones around that are mechanically sound and a nice nippy motor. I bet there were a lot of Pumas given in for the £1000 off a new car and it is an absolute sin as they are cracking little cars.

In what sort of car, are you thinking FWD as in the cheap and cheerful thread?

[Busa_Rush]

singlecoil said:

Busa_Rush said:

Lots of opinions about why he absolutely hates the idea of a Boxster as a donor

Wow, I never expected the Spanish Inquisition! Funny how an argument can appear out of nowhere.

Anyway, instead of trying to pull my suggestion apart, why not make a proper one of your own? (MR2 bodykits don't count BTW, and if you were gong to use the LS400 engine you couldn't use much else, the auto gearbox is controlled by the ecu, and the dashboard is tied into it as well)

You made a suggestion and asked for comment . . . and then refused to accept somebody else's opinion ! It's a discussion forum . . . if you don't want a discussion then don't ask for it ! Simples

There is a way of swapping gearboxes, you don't need to use the auto, lots of people have done this.

I quite like the Boxter, nothing against it or its engine but . . . .

I was joking about the MR2, I thought that was obvious

How about the V6 Alfa 75 as a donor ? Most of the 75's are now more rust than metal so you could even say you're saving "heritage", they are cheap and the engines and gearboxes are easily repairable and there's a reasonable supply of parts.

[slomax]

singlecoil said:

slomax said:

Id like to see Pumas as a donor. There are lots of rusty ones around that are mechanically sound and a nice nippy motor. I bet there were a lot of Pumas given in for the £1000 off a new car and it is an absolute sin as they are cracking little cars.

In what sort of car, are you thinking FWD as in the cheap and cheerful thread?

or turned around like a GTM or MEV or Mojo. But FWD is the obvious option, yes.

[singlecoil]

Busa_Rush said:

You made a suggestion and asked for comment . . . and then refused to accept somebody else's opinion ! It's a discussion forum . . . if you don't want a discussion then don't ask for it ! Simples

Actually, if we are going to be pin point accurate, and why would we not want to be, I didn't ask for comments on my suggestion, I asked for other suggestions, and I didn't say I didn't accept your opinion either, I just said IOW I disagreed with it, which ios OK on forums, simplers still

Busa_Rush said:

There is a way of swapping gearboxes, you don't need to use the auto, lots of people have done this.

I quite like the Boxter, nothing against it or its engine but . . . .

I was joking about the MR2, I thought that was obvious

How about the V6 Alfa 75 as a donor ? Most of the 75's are now more rust than metal so you could even say you're saving "heritage", they are cheap and the engines and gearboxes are easily repairable and there's a reasonable supply of parts.

I did realise that you were joking abut the MR2, but they still don't count

Your other suggestions seem to be about engines, and possibly gearboxes, but little else. We still need front and maybe rear uprights, differentials steering columns etc.

[Busa_Rush]

singlecoil said:

Your other suggestions seem to be about engines, and possibly gearboxes, but little else. We still need front and maybe rear uprights, differentials steering columns etc.

Make them as part of the kit then you don't have to compromise. My Dax has Dax designed and manufactured suspension, only the bushes, springs and dampers are bought in.

Steering column, well, plenty around from Mondeo/Focus etc, same as basic brakes, Mondeo 1.8 has good enough brakes for a light road car unless you go racing or want a bit of bling. Or use the Alfa parts ?

The Alfa 75 comes with its own gearbox and diff in one housing

[singlecoil]

I'm afraid I don't know much about Alfas, so I looked up the 75 and I agree, there is much that is usable including the transaxle and probably the De Dion rear, I esxpect the instruments and steering column would be ok too. I hadn't realised they were so old, finished in 92, though. Good thing from the emissions point of view, no catalysts required.

Not many of them about, 3 on PH and 2 on Autotrader, so maybe not so good if a manufacturer were thinking of doing a fair few........

[jason61c]

e36/46 is the common easy one, not sure about in a middy though!

[spyder dryver]

Might I suggest the Mk2 MR2 but strictly as a donor in the usual sense, not as a panel kit.
The 3SGE engine is very strong and comes ready configured for a middy set up.
The Rev3 engine makes 173 bhp and there are also VVTi versions available which make 210bhp, not to mention the turbo 3SGTE variant which can make a lot more.
I am not sure about the front suspension arrangement, it might be struts, but as previously stated these can be adapted for dual wishbone set ups.
Cheap enough to buy I would have thought and plentiful in supply.



Geoff.

[cymtriks]

Mazda MX5
Double wisbones
Rear wheel drive

BMW
Lots of engines
Rear wheel drive

The above will be the future of Sevens. There is no other realistic choice. Ford RWD is now circa 17 years out of production.

Porsche Boxster
Lovely engine, you don't need the whole car, there are plenty of engines for sale now.
Too expensive? Just design for a Subaru 4 or 6 aswell.
Suddenly there are lots of engines from a Subaru 1.6 to a Porsche 3.8 that fit nearly the same space, have a very low CoG and are ideal for a mid engined car.
This is my choice if I ever get to build my own car.

Ford/Vauxhall small car
Any of them in production today.
This is the future for any mass market cheaper kit.
Plenty around, long term spares, not so obscure as to ruin the business case.

[CDP]

Roman said:

MGF - cheap & abundant with lightweight drivetrain, brakes & suspension, good wheels, cheap & plentiful spares. Perfect donor for a budget mid engined track day car.

The engine and transmission of the MGF is exactly the same as the front wheel drive K-series Rovers. The same goes for MR2s; the engine has been moved to the back. So there's no particular reason for starting with a transverse mid engine car as you'll just pay extra.

At an Autosport show Ford had a little mid engine space frame car build with Ford Ka components. What was interesting was the gearbox came from a Focus and it's linkage cable looked like a large co-ax but with multiple links inside. This made moving the engine to the back much simpler than some of the other FWD designs where there may be more than one cable. Ford bits are very cheap too and they're even quite happy to talk to and advise home builders.

Alternatively there's always the Honda Civic type R.

For front suspension I'd just base the design on that a Locost or Caterfield type car and possibly buy in the wishbones and steering components from the existing manufacturers.

The other car that interests me as a donor is the VW Passat that just went out of production and it's FWD Audi counterpart. As they have longitudinal engines and FWD they're ideal as donors for bigger mid engined cars. Also Audi do some fairly powerful engines that will bolt straight on. The biggest issue is that linkage cable.

BMWs are more readily available than MX5s for a front engine, rear drive car and the range of engines is excellent. People have adapted Locosts to take the parts.