Building a car - looking for a kit

[Robby]

Evening all.

Next year I'm planning on building a kit car. In particular, I want to build a Lotus type 20

Now I can't find a kit for this. Does anyone know of a company that does plans for a kit?

If not, I'll design the chassis myself, and borrow as much as possible from a Locost - suspension, steering etc. To keep the rear engined ness I'll probably use a mk1 mr2 engine, gearbox, drivershafts, hubs, and suspension.

For any purists - I'm not trying to make a faithful recreating of a type 20, I just like that style. It will also be made road legal.

and yes, I will have a lot of time and money at my disposal, and I'll try to keep a build diary to interest the techies. or at least to interest marje and stinkwheel.

[Kickstart]

Hi

Would think an MR2 enigne would be far too wide to look even vaguely right. An inline fwd engine / gearbox would be more useable. To keep it low maybe an old Alfa 33 engine which is an inline flat 4 (would require some effort sorting out the gear change linkage).

Not seen any kit cars like that Lotus. Might well be one. There are a few vaguely race car styled models.

https://www.roadrazer.com/?pid=26

https://www.furorecars.co.uk/

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Robby]

Funnily enough, I was just looking at alfa transaxles. The few copies I've seen have used a ford/cosworth inline 4 lounted longitudinally, with a transaxle bolted to the back of it.

Alfa flat 4 sounds tempting though, keep the weight nice and low.

I think routing the gearchange linkage is going to be the least of my problems. Going to have to work out ratios too, because I want to use tall narrow tyres.

[Kickstart]

Hi

Alfa transaxle is heavy, and designed for a front mounted engine. Might work but they are very long.

The Alfa flat 4 is available in loads of different versions (and there were kits to take the 1.7 16V out to 2L). The last gearboxes in the early 145/6 might be better as they use a cable operated gear linkage which might be easier to extend / reroute. On the other hand you might prefer to use a Sud gearbox so you can use the inboard disks (and at least on a car designed like you have show you can get at the buggers to change the handbrake cable and adjust them).

Gearbox ratios are here:-

https://www.alfa-pages.co.uk/?go_to=gear

You should be able to mix and match some of those gear components to get the box you want.

I have a Sud engine and box in the garage I can measure up at some point if you want.

Biggest difference between the Sud and 33 box is the Sud has the mounts for inboard disks, and the Sud box has a cable speedo while the 33 has an electronic speedo drive (and the late sprint had a cable speedo drive without the mounts for inboard disks).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Robby]

The problem with using a engine/box combination from a front drive car is that I want to get the engine forward of the gearbox, to try and get the weight towards the middle. I'm quite tired, but I'm pretty sure that if I try this with a front wheel driver setup - engine forward of the box - I'll end up with 5 reverse gears.

Still, just done my first solidworks tutorial. Looks like its going to take me a while to design it with that, think I'll be dragging thre drawing board out tomorrow for the drafting work.

I'm not planning on starting the build until next year in about april, when I move back in with my parents. Until then its all just designing on paper.

for reference, here's a close up of the engine and box in a lotus clone. Very pretty it is too.

[ms51ves3]

Ever thought of a motorbike engine?

Maybe have a look at Tiger Cars

[Kickstart]

Hi

The MR2 engine / gearbox is a setup from a fwd car, just mounted in the middle of the MR2. Most inline fwd power plants will have the gearbox behind the engines (certainly the case with the Alfa flat 4), so no problem having 5 forward gears.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[plugger147]

The Renault 21 uses a front drive with a transaxle, seen them used in quite a few kit cars with a few different engines. They do look a bit big though.


Useful ratio table for the different models here:
https://www.lamboreplica.co.uk/gearbox.html
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Tristan the wrote: just whipped off my trousers to find a big bruise on my arse, caused by matt rear ending me...

[Kickstart]

[owdamer]

Good kit on ebay at the mo, i'd be surprised if you see another on the road.
Clicky

[Robby]

I won't be using a bike engine. There are many reasons why, one of them is that they go pop so often. The main reason is getting the drive to the rear wheels. Very few elegant solutions are available here, so I would either need to mount the engine transversely - which I don't want to do - and use a chain driven diff - which costs and arm and a leg.
Or, pikey way, weld a driveshaft to the output sprocket. Still leaves me with totally wrong diff gearing and a major headache.

So I'm following keith's advice and looking at longitudinally mounted engines driving the front wheel. Saab 900s use them, as do audi a4s, renault 21s, and a few other cars. The pipe dream would be to use a Toyota 4-AGE (mk1 MR2 engine) running a decent transaxle that allows me to mount the engine longitudinally. I would have to cut and weld 2 bellhousings together and hope for the best though.

Thinking out loud here - are there any decent engines under 1.5 litres? Would be a bonus to slot this thing into the lower tax category. I don't want to go down the forced induction route, I can see it being enough of a handful as it is without a turbo poking me, and I want to keep the wiring as simple as possible, whilst retaining fuel injection. This is a lot of the toyota 4-AGE appeal, it does have fuel injection, but its very basic.

[MarJay]

What about a 911 or (more bum basic) a Beetle transmission?
You could potentially marry a modern boxer four to a beetle or 911 box to keep the boxer six weight down...

That gives you a good choice of Subaru engines. With big turbos.

Would also be one of the worlds most tail happy cars though because you'd have to mount the wheels somewhere near the centre of the engine... a true Rear engine rather than the ideal RMR layout.

Just thinking aloud... Imprezas are good handlers because the engine is further back and lower in the chassis. Perhaps you could get a FWD impreza engine and spin it around to use the transaxle....

Another brainwave, why not buy something rear wheel drive and seriously shorten the driveshaft so the engine is RMR mounted rather than rear mounted? I think a rear mounted engine in a car like that would be a deathtrap. To be honest I'm thinking RWD car would be the best bet. You could get an old MK1 or MK2 escort or something from a scrappy, and shorten the shaft. The smallest you might get is a 1.6 though I expect.
You may need to add some sort of CV joint to allow for the sharper angle of the shaft, but I don't see this being an issue because the car will be so low to the floor anyway. You could also potentially mount the engine at a slightly canted angle, but this isn't ideal for C of G.

See attached diagram.

Good project, I hope it goes the distance!!
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

Just had another brainwave. Trying to think of smaller engined relatively modern RWD cars...

MX5?

You could even use the steering and suspension components from our friend the 5... build a nice spaceframe chassis, shorten the drive shaft, mount the lump low in the chassis. Should be childs play in comparison to tarting about with a Renault 21 engine...

Edit:

https://cgi.ebay.co.uk/mazda-mx5-eunos-salvage_W0QQitemZ310009666372QQihZ021QQcategoryZ18211QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Kickstart]

Hi

Think using a rwd drive train would cause a problem. Would likely be too long to work effectively (after all, when designing a rwd transmission, keeping the length down is hardly an issue). And would likely be even worse to sort out a gear change linkage for.

Beetle or 911 would give you a rear engine position.

The Alfa flat 4 is available as a 1490 producing a claimed 105hp in green cloverleaf spec. For more power you can play around fitting the 16V heads from the 1.7 16v engine but probably not worth it.

Old Saab 900 unit would probably be an easy way of getting a pokey engine, as you can use a turbo spec engine with several choices of power.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[MarJay]

[Kickstart]

[Kickstart]

[MarJay]

It seems there is already a Scooby engined RMR kit car, its called the Saker Sprint...

https://www.sakereurope.com/7/Models/default.ecms

Doesn't look like a Lotus 20, but could possibly be made to look like a lotus 20...

There is also a Blast, which looks damn hideous. However, it claims to be mid engined and looks very rear engined to me...

https://www.blastautomotive.com/photos.html
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

Sorry I was getting confused yesterday. The Subaru is supposed to have the engine mounted further back so most of its mass is behind the front wheels. This lead me to believe that the drive was transferred forward of the engine (somehow).

On reflection I can't see how this is the case. In which case, a 1.6l FWD subaru engine would probably be as close to perfect as you are going to get...

I think a longditudinal inline four would definately be too long, and gear shift linkage is really the most major hassle on the flat (boxer or H four) engine. Exhaust silencing might also be a problem, but I think that can be worked out. I think it would make the car look nice too, as you'll have two side mounted two into one pipes on a very low engine silhouette.

https://www.tigerracing.com/catalogue/index.php?cPath=51&sort=2a&page=3

There are some lotus 20 type cars for sale, but they appear to be race only. I'm guessing that if you built this car, it would need mudguards and loads of other stuff to pass a SVA test.

I think the most fun way of doing this would be to marry a FWD Subaru gearbox to a turbocharged Impreza or Legacy engine... You can easily get 300 horses out of one of those. Obviously fuel consumption wouldn't be great, and it would be a bit of a handful for a homebuilt...
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

Or you could take a 4wd Subaru, make the rear drive shaft a bit shorter and build this monster:










... Or maybe not!
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

https://www.forix.com/8w/sixwheelers/pat-clancy-special-2.jpg
https://artmodeling.com/hobby_shop/images/Photo/fw08bb.jpg
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Kickstart]

[Robby]

I don't want 300hp. The MR2, which weighs twice as much as this is going to, is a handful to keep in a straight line.

I'm leaning more and more towards the small alfa flat 4. Impreza stuff puts me off because its expensive, and has more wiring than I want. I'm going to keep my eye out for an knackered alfa with this setup - keith, is it from the alfa 33? presumably I'm looking for a rotten alfa 33 1.4 cloverleaf?

I want to have a setup similar to the one in the pic - certainly not rear engined, I want as close to 50/50 weight distribution as possible. This will means having me relatively far forward, and up front I'll have the fuel tank, rad, battery (although it will be a bike battery).

I will have to make some style sacrifices to get it through the SVA. Lights will be fitted, althogh I'll keep either make a couple of bulges at the front of the bonnett and mount them in there, or I'll put them up on stalks, 50s style. Numberplate will be a sticker on the bonnet and a proper one on the back. Mudguards will either be as small as is legal, or silly big droopy things, like on a 50s style cruiser (think vn800 drifter).

I had a look at suspension stuff last night, and the locost stuff is a fairly simple double wishbone setup, so I'll be using that. Keith - does the alfa use equal length driveshafts? If not, can I get away with using two of the same length, like 2 short ones. I want the track to be a bit narrower than a normal car, althought I suppose the track on a small alfa won't be too wide.

[MarJay]

Didn't realise the engine construction would be different. Assumed all H fours would be built in the Subaru manner.

Found 1 alfa 33 for sale, but its a 1.7...

https://search.autotrader.co.uk/es-uk/www/cars/ALFA+ROMEO+33/Ne-2-4-5-6-7-8-27-44-49-53-61-64-67-103-133-146,N-4294952169-4294967222/advert.action?R=200748299745098&distance=
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Robby]

I won't be buying the donor until next year, about march. Until then its all designing.

Solidworks is a cunt to use. Drawing board and pencil FTW.