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MG Midget and Sprite Technical Bike engined Midget BBS discussion at MG-Cars.net
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MG Midget and Sprite Technical - Bike engined Midget
| Just impulse bought a 1972 midget - was looking to build up a tube frame bike engined Mini roadster but this came along at the right price. Was thinking of dropping a 600cc bike engine into the thing as-is if the shell isnt too crusty, or hacking the innards out and draping the shell over a tube frame if its shot. What, if anything, in terms of braking, steering, and suspension is worth keeping? What do people tend to do tho these first to make them stop, steer, and lay down power? The bike engines are around the 100hp mark and I wouldnt rely on any mechanical sympathy. |
| Marko |
| The body is to heavy for 600, it doesnt have enoungh grutt would to better with a Suzuki Hayabusa lump, even then I wouldnt expect great things:( |
| K Harris |
| I have a pal who built a mini with a busa engine, Marko go for it, it is awsome. I think someone posted a film on you tube when we were at north weald with it at an MG on Track day. The body is steel although I will admit the interior is pretty well stripped out. He also owns a DB-9 and openly states the Mini is the one he would never sell. |
| Lee Reed |
| Agree with comment above... the torque from a 600cc bike will be too low to make a decent street driver. There's a guy who competes in the MGCC Speed Champ with 1000/1200cc bike engine (Hayabusa??) - it's good for sprints, less good for hillclimbs and road use. It's low-down torque that makes an easy shifter; you'll soon be tired of buzzing everywhere at 8K+ rpm... I think you'd be better of with 1600-2000cc modern EFI ally lump from a car... IMO! Other answers: FL suspension, 11/16 arb, bigger disks, LSD, decent wheel/tyre combinaton... A |
| Anthony |
| A guy in the UK put a Kawazaki 1100cc which gave 150bhp into a 1971 Midget. It revved to 13000rpm in all 6 gears. He had to fit a Cobra bonnet scoop to clear the pipercross air filter. It had a Quaife bolt on reverse gearbox, so you got 6 reverse gears as well. 3.5:1 LSD. 2 custom made propshafts. Lots of suspension and braking upgrades. 0-60 in 4 to 5 seconds. Top speed 125mph est. I saw the car at a show a few years back. It was beautifully finished with grey leather interior. |
| Geoff Mears (1970 Midget) |
| When I saw Anthony and Russell at Curborough a few years ago ISTR there was a green bike engined Midget competing against Anthony. Quick and noisy but his times weren't as good as the Kmidget. Was that a 'Busa Ant? (Or as often the case have I got it wrong again?) Is there a sprint at Curborough this weekend? Rumours I hear, if so I may take a ride down there... |
| Bill |
| There is a sprint at Curborough this weekend and I am going. Good inspiration there to get on with the Midget! Carl |
| C Bintcliffe |
| The only bike-powered car I have actually seen was a busa-powered Westerfield 7. It did ok in the autocross (woulda done better with more experience on the driver's part), but it arrived by trailer because it is so bloddy awful on the road. The shortage of low-end torque, as indicated above, combined with the absence of a flywheel, make these a pain in stop and go driving. It is just too much finesse involved in transitioning from the Newtonian concept of "a body at rest" to "a body in motion" for it to be fun. A complete newbie in an Elise that he was babying (not yet fully broken in) stomped all over his best times. This project is a "toy" and will never be a particularly usable road car, although it could be a blast for track days or empty (cameraless) country roads! Stock suspension works quite well when in good repair. Since you would be eliminating the rear axle (I hope), you will have a major project designing and implementing a new rear suspension. Frontline has some pricey options for updating the front. There are big-brake kits available as well. David "have fun!" Lieb |
| David Lieb |
| Hi Bill - yes, Steve Naish's MG, IIRC. Very nicely engineered, too. I hope to be at Curborough on Sunday too, assuming weather will be reasonable. A |
| Anthony |
| Customer of mine is putting a Ducati engine in a Frog. WHY?????? |
| Max T |
| 3 or 4 years ago there was a bike engined Midget at the MG show in Stoneleigh but I can't recall much of the details other that it seemed well executed. Obviously didn't see/hear it running. I'm hoping to get along to Curborough on Sunday so hope to see some of you there! |
| Chris Hale |
| There was an article on a bike powered midget or sprite in Mascot a couple years ago. This guy build it for/with his son but when finished his son wasnt allowed to drive it because of insurance regulations due to extra BHP. Ill see if i can find the article. |
| Arie de Best |
| Im sort of sure this was the Curborough car But for all I know it could be a sewing machine motor behind those lumps of hightechery  |
| Bill |
| Bill - that's the one ... he was right next to BRB at Curb in 2003. We drove home in convoy; it was strange hearing but not seeing a bike... Eventually I popped BRB up to its normal cruise speed and left it behind... A |
| anthony |
| Update: Some history for the car. Used to be a mint MG Midget. Punk-ass dirty f**king hippie kid (TM) buy sit and decides to throw in an RX7 engine. Botches the job entirely, cooks the engine, has no time or money left to fix it so leaves it in his mother's garage until she moves and sells the thing. Bought a CBR 1000RR instead of the 600 - big enough to cruise with (no worse than a 948 anyhow), not so big as to chew the back axle, keeps the "screw the bo**ocks off of me goddammit" rev-happy vibe. Shell turned out to be far from crusty - seems like its true what they say about California cars! Fitting the Mazda engine and gearbox using a cold chisel has done more damage: http://www.cosic.org.uk/MarkoStuff/misc/stripping/ Suspension - agreed, frontline stuff looks nice. I think I can do better though, as I'm not restricted to bolt-ons. Front is easy, rear I'm not so sure on. Anybody have photographs of nice 3 or 4 link setups? I think I'd look do do a mumford linkage like the frontline kit, with three links for the other location. Steering - seems ok to me as std. Would like a collapsible column. Any examples? Brakes - how silly would it be just to throw standard parts back on? New everything, decent brand of (plain) disc and drum, Mintex 1144s or similar fade resisant pad. It'd be for road use rather than track - should work fine I think? Shell - where do I seam weld it/stiffen it? Transmission tunnel is going to get smaller (I don't need the width - as the transmission will all be in the front with the engine) and the sills will get deeper, but aside from this? |
| Marko |
| Took BRB to a very cold - sometimes sunny, but with snowflakes - Curborough yesterday; most competitors had a coat over their race-suit when not driving! Some great performances. I left before the end (the whole day was brought forward to advoid left afternoon snow forecast - as usual great organisation) to dodge the snow-showers on my journey s/w. A |
| Anthony |
| Ant, any pictures please? |
| Arie de Best |
| It was too cold to get my hands out of my pockets... but Helen Waddington took pics (on a much better camera than mine)... I will ask her! A |
| Anthony |
| Marko, a good deal of the structure is in the xmision tunnel - keep it if you can, there is quite a lot of room in the midget for legs as standard. The later cars had a collaposing column, but be careful to note the nylon pins - if they are now metal screws it isn't a colapseing column any more! Once you find one, be careful not to damage the pins on removal. Removal is two bols under the dash one on the pinch bolt and some hammering on the end with a drift. Don't put the engine too far forward or you'll ruin the handling. The stock axle will be fine with this kind of power, but you might consider stronger halfshafts - later halfshafts were stonger. |
| Will Munns |
| I stayed until the end at Curbourgh despite the cold. FTD by nearly 4 seconds went to an MGF with trick suspension but a standard vvc engine. Very impressive when you think that it was up against a WRX Impreza and a 4.6ltr slick shod MGB! It was nice to get back in the car out of the wind for the journey home. The sun was out and really warm through the glass despite the snow flurries. Strange weather! Cheers Carl |
| C Bintcliffe |
| How have I missed this thread until now! I recently put a k series engine in my midget, 170 bhp (135 lbft), I’d describe it as quick, certainly not blistering. In the search for more performance I’m half way through my next project - blackbird engined Reliant Kitten. The blade engine you have is probably good for 80-85lbft of torque, far more than any of the A series variants, yes you're going to have to rev it but that’s the whole point isn't it. As someone mentioned, the lack of flywheel mass will be annoying for an every day driver, but not more so than the extremely tall first gear. I knocked up a spreadsheet for my kitten gearing with the ratios of a blade (I initially started the project with a blade engine, had second thoughts and bought a blackbird) you'll probably want a 4.5 diff (depending on the wheels you're going to use) with standard 10" wheels and a 4.2 diff I’m geared for about 110. I anticipate that you'll need to lose some of the passenger footwell as the gearbox output is very much behind and below the engine as it is mounted in a bike. I’ve had to mount it towards the passenger side and tipped back slightly to try and get the output more inline. I've got round this problem mostly though by using a double propshaft. Honda exhaust manifolds are very handy in that the flanges aren’t fixed to the primaries, you can separate the primaries at the bottom, rotate them to any position and them bolt them up tight. Having said this you’re still going to have a fiddle getting them past the chassis. I'd suggest going for the biggest brakes you can on the front, I’ve had 1144 pads on 8" discs on my midget and they pretty much fade immediately. I'm in the process of fitting mondeo/cougar (different offset, four stud with no screw holes, exactly the same ID to locate on the midget hub - 63.5mm) 10.25" vented discs on the Mig, but I’ve got 14" wheels. You can buy adapters that go from bike output shaft spline to four bolt propshaft flange, they're about £60, see westfield website. Performance wise, my midget was 710kg with all steel panels and standard trim. You’re probably looking at about 220bhp/ton before you get in. A standard kitten is 510kg much like a seven but with no added luxuries like cornering stability and braking power. I’m all for it, look forward to seeing photo’s. |
| R T Jakeman |
| Do you want to sell the fenders? you might as well get a GRP front end with what you want to do.. Stefan |
| Stefan |
| Richard Despite being a keen advocate of the KSeries, I must defend the ASeries from you comment above: getting 80-85 lb-ft is quite easy with relatively simple mods, e.g. BV/HC head, big carb, LCB and road cam. I did it with a 1293; and if you're prepared for 1380 and more, 100 lb-ft is on the cards. And don't forget the turbo variant, which is good for 50% higher torque, depending on boost... A |
| Anthony |
| You're too late Ant, he's already bought a blade engine! But yeah good point. I was really thinking about the standard midget variants. Just trying to point out that he'll have as much torque as any standard midget to get 700kg going with, all be it at 9k rpm. I wasn't bad mouthing the A series, it’s a great engine. Richard. |
| R T Jakeman |
| Great stuff guys, thanks! WM - thanks for the tips on late model halfshafts and columns. I'm a MechE (local actually - spent the last four years hungover in trumpington street, you may have seen YVC 788K terrorising or broken down about various parts of town...) so will be sympathetic with the structure. Will probably complete the transmission tunnel where its currently open at the base and tie it into the frontend better whilst at it. RTJ - westie part looks the ticket, double props are going to be a must to keep the LH (drivers!) footwell a sensible size with the engine mounted far enough back. Will see how bad it is once it arrives. If the brakes are this bad then maybe I should redo the entire frontend with new brakes/upright/wishbones. Where do Frontline add their 2 degrees of negative camber? Presumably they change the kingpin inclination too in order to get this, as the spindle is fixed in the upright. How do they then do bump-steer correction, if at all? After the character more than the speed. It needs to be a riot to drive, be a drop-top, go fast enough to leave the bosses 1800 (VW) Dune Buggy in its tyresmoke, be slow enough not to attract the attention of the lads in the Ford Crown Vics, and cute enough to keep that 'adorable' tag. ;-) Torque at 2krpm on the blade engines is not dissimilar to a 948 at 2krpm, plus being EFi you can plant your foot at low rpm without stumbling or hunting/kangarooing, so much more driveable. If I like it I might build a hotter version - tube frame with a 'busa or ZX14 engine in the rear, Midget skin to keep it looking cute and innocent. For now the blade will do! |
| Marko |
| Marko, On my original design the 2 degrees negative was added by shortening the upper link by an amount to bring the kingpin top inwards and change the camber from 3/4 degree positive to 2 degree negative. As this is with a standard trunnion I expect FL still do it the same way. IIRC this had a benefit in reducing bump steer also. |
| David Billington |
| Marko, I particularly liked the announcement for residents of London :0) |
| G Lazarus |
| Can I just add more to the A series discussion (uh...oh). My car's motor: - 276 Cam - Ported, but otherwise totally standard head - 'Vizarded' HIF44 (it doesn't make much difference, but it does make SOME difference!) - Bored to 1330cc - CR of 10:5:1 Even before properly run in and without being fully strained was pulling over 105lbft torque on the rolling road, as shown here. http://www.flickr.com/photos/77673728@N00/1805532609/ It pulls like a train (Matt W's words, not mine) and is even quite a match for some modern cars when pulling away at speed. 3rd gear at 3.5k revs and above is the best fun ...! My main point, to follow Ant's, is that you really can do a lot with an A series even without a 1380 (or 1430!) bore. Although, this is coming from me who is itching to supercharge the engine...and wants a nice fancy head. |
| Rich Amos (1330cc Blaze Red '72) |
| Re FL bumpsteer - on my recent trip to BMH in BRB, I turned off the M5 (southern) at J11a. Part-way along the slip-road is a large dip on a long curve. I took this at speed and was watching out for the bump-steer (I travel this way in the TypeR at least once/week so am very familiar) - and was pleased to see not a hint of it over quite a severe bump. This is at least as good as and probably better than the std set-up. A |
| Anthony |
| Anthony. What a great exit that is, I love it in Lara, with no sign of bump steer as you say. When I first fitted the FL/David's design I reported that I can dash round a roundabout that notoriously used to throw me well off course via a very large pothole in the inner gutter. I just sail through the same roundabout now and come out on the course that I go in on. I have total confidence in it's design, thanks David. I did need to adjust the toe-in a little though, but that was more due to not having done it during the rebuild... :-( I know I will regret not having as much power as Toby and Gary on Saturday at the track, but in honesty with Lara dashing around freely at possible speeds in excess of 105 how much power would I need to have and keep my license? I certainly wont be on track every weekend. It would be a K or Zetec for me if I went "more powerful", the A is plenty good enough for now |
| Bill |
| You'll have more power than me (This time) but nice to see that the spec of my new engine will be similar to that of Rich's 1330 apart from the slightly higher copression ratio that it looks like I'll have. Now all I have to do is learn how to drive a car properly. |
| G Lazarus |
| Hmm, I dont mind you coming in the passenger door mate Just dont bring your Froggy in there too... ;-) I think I am going to be a little slower round this time, plus I want this engine to get me back to Le Mans one more time. I don't have a garage floor littered with spare injins. :-( |
| Bill |
| Bill, In my experience when you do test days and the like and get the suspension sorted so you get get round the corners quicker you soon get used to the engine power and need more to help join the corners up even quicker. |
| David Billington |
| David, that is of course my biggest fear. As with the last two I am bound to come away shouting MORE, MORE, GIMMEE MORE!!! Since my last one I have removed rubbery bushes every where (almost) and put my best tyres on the back of the car (so the portuguese/argentinians can get scrubbed away and I can justify the new ones that will come along very soon) With the K&Ns binned for a while and stub stack and sock installed I will be wandering around having major "getting used to it" fun. I kanardley wait! |
| Bill |
| Cheers DB, Ant! Any idea how high off the deck they set the rear rollcentre? What's the standard tyre diameter/ride height for a Midget - and a 'typical' ride height for say a moderately modified (but still roadgoing) one running 185/60R14s? I'll try plot the geometry virtually. Front/rear axle weights, front/rear unsprung weights, spring rates, and anti-roll bar lever arm length/motion ratios? |
| Marko |
| Found the article in Mascot(midget&spriteclub magazine) nr 243 2004 and another picture in mascot 251 2004. Red midget, grey leather seats and: Kawasaki ZZR 1100cc engine. 150bhp equals 266bhp per ton. 13.000 rpm in all 6 forward gears, 7000 rpm at 70 mph in top Quaife bolt on reverse gearbox. 3.5:1 LSD Take off engine speed 1000-2000 rpm, clutch not really required on sequential gearbox. Topspeed claimed 125mph. Sorry, but i have no facilitys to scan any pictures but i looks very nice and a great fit. Sounds like a great project your doing Marko. Good luck and keep us informed with lots of pictures! |
| Arie de Best |
| do you think this would work in the midget? http://www.networkupload.com/adsupported/motorcycletowing101/ rear engined? |
| Will Munns |
| Marko, As a standard 1/2 elliptic cart sprung axle the RC is in the centre of the axle at about the height of the spring fixing to the axle. |
| David Billington |
| Aye - I was after the RC where FL put it with their Mumford linkage though. Would somebody mind dropping a tpe measure from the large flat crossmember plate under the front of the car to the ground for me please? What should that be as standard/typically set to? |
| Marko |
| Marko I've read that the R/C for the mumford link / RTL is the point at which the main links would intersect (if projected). With correct geom, ISTRT it should remain a fixed point wrt chassis as the car suspension is deflected. A |
| Anthony |
| Marko, Are you planning to replacing the 1/2 elliptics with coil springs or something that doesn't provide axle location. If not then the RC should stay about where the 1/2 elliptics dictate or you will get contention with the Mumford, Watts, or Panhard. If you are going to use a Mumford as the sole axle locating mechanism then you can place the RC where you like even below ground level as the RC is virtual rather than physical like for a Watts linkage. |
| David Billington |
| Marko, See attached drawing for RC axis of my car. I'm not sure how much use it is for you, my car's lowered and on 185-55-14. Obtained this through measurement of the front geometry (as best I could) at ride height so accuracy is questionable. If you gave Tim Fenner a ring he might be forthcoming with data. I'm planning a double wishbone rear in the near future (Cant live with leaf springs or enormous unsprung mass any longer) so I’ll be revisiting this project with stronger intensions of accuracy. Unsprung mass front: 49kg (8" vented discs, alloy wheels) Unsprung mass rear: 83kg sprung mass: 579kg Mass total: 711kg mass split: 53-47 (front to rear) Bare in mind this is with a K series engine (lightish) + type 9 gearbox (heavyish) Springs: front: 400lbs/inch (standard is 260 I think?) rear: 80lbs/inch ARB: 11/16 inch, effective ARB blade length 115mm This gives me roll stiffnesses of Front 13493Nm/rad Rear 4710Nm/rad Richard  |
| R T Jakeman |
| Yes David - the plan was for coilovers all round. Richard - is it really 83kg? Blimey! Drawing and numbers are great, and they don't disagree wildly with my tape measure measurements... I like the way you think - and think you might like OptimumK: http://www.optimumg.com/ Have used WinGeo in a past life, but OpK is in a different league, especialyl if you're datalogging and running the real track data back through it. Not tempted to throw a di-dion setup at the back? K is 95kg IIRC, not usre on the type 9 but guessing around the 40kg mark. The bike motor/transmission is in the region of 65kg, looking to end up below 600kg when done with a few other bits on a diet. Whipped a front corner off tonight and took a look. What a mess - who on earth came up with this suspension system? There's no real way of doing the brakes/wishbones nicely without remaking the entire upright, so think for the sake of getting the show on teh road by the summer I'll just throw the front back together as standard, albeit with a whole front wishbone and telescopic damper running to a 'turret' mounted to the spring mount (which would then have a hole in) Keep the stock discs and just deal with teh fade until such a time as I design some proper uprights/wishbones/brakes. Then again, if I get that serious I might just buy another shell - and build the tube frame underneath it that I've always threatened to... |
| Marko |
| Richard very interesting analysis ... I'm at an early stage in IRS for BRB. I'm wanting to create a bolt-up system based on Sierra disk. Would be interested to share ideas. Marko I will also replace the king-pin / swivel-pin front suspension at some stage too; but agree the geometry does not easily lend itself to simple modification of existing parts if you want to retain the existing rotation axis (which is desirable...). A |
| anthony |
| Marko, if your car is getting lighter then 600Kg then watch out for take off when on speed! or just ordinary wind... LOL |
| Arie de Best |
| Marko, 83kg, looks bad on paper, feels worse when you drive it. Eg. When you drive over a ramp in the road there's a nice bumph as the front goes over with no drama. Then you get fired off the seat as the already light rear end + weak leaf springs + armstrong leaver-arms try to absorb the inertia of 83kg. Optimum K looks good, I’ve downloaded the trial but haven't had a chance to play yet. Generally I use Pro Engineer for geometry and kinematic analysis. It’s ok for a quarter car model but can’t do anything nearly as fancy as optimum K looks to do. If you can get down to 600kg, and there's no reason why you couldn't then this stands to be a pretty serious midget. Honda recon the engine you've got is good for 175 bhp...290bhp/ton, six speed sequential box… I like the way you think! I haven't given the Di Dion much thought, my plans are in their infancy really, I’m still thinking that if I go to all that effort then I may as well go for the optimum. Ant, Sierra is one option, I still haven't decided on a donor vehicle. I've been thinking mx5 but only a few models had LSD's. A bolt on setup would be nice, were you going for twin trailing arm? I need to model the underside of the car really and try out some ideas. I'll keep you up to date. Richard. |
| R T Jakeman |
| Richard The plan is to make a bolt-on mod that replaces all existing; that is, solid mount the diff to a frame that also has the twin wishbones (could be solid bushed if I wanted but most likely poly of some kind), hubs, & coil-overs. This sub-frame then bolts to the car (4 points 'upwards') to rear bulkhead and boot floor; 2 points to existing front spring hangers. All mounts to car body will be bushed. I will allow for optional ARB. This will allow me to make a very rigid (and reasonably light frame); all the suspension and drive forces will be absorbed into the frame. I can check the geometry off the car; and mod/repair off the car if needs be. First job, as you say, is understand the shape of the volume available. A |
| Anthony |
| Update: been busy at work, but managed to get the car completely stripped on Sunday. Good news: shell definitely has no rot, found that the car already has the collapsible column. Bad news: shell is definitely bent, looks like the frontend has met its bumpstops a few times too many, collapsed the collapsible column whilst removing it. Other news: damn these bike engines are big... ...or these midget engine bays are small. Plan B: there's an enormous amount of room where that rear axle goes! Lop the frontend off, build one in tube with proper suspension, steering and brakes Lop a hole in the hump behind the rear seats and build a nice cradle there to take a transverse mounted bike engine, quaife chain drive diff and all the gubbins to mount a di-dion backend (keep the non-independent rear character of the car) Tie the whole lot to the remnants of the car (really just the tub/exterior at this point) with a nice cage, fuel up front betwixt (larger!) footwells. Probably Golf, Civic or MX5 for anything not fabricated. Going to start me some new threads with specific questions... |
| Marko |
| Marko, I suggest a search on 'attack banana' to find a site with an SR20 turbo conversion using tube chassis, independent rear end and corvette front suspension. It will show how much work is involved and give an indication to available room. I'm part way through a N/A SR20 conversion myself - the most difficult parts are the gearbox length and engine head width (especially with intake/exhaust). Nothing that doesn't appear overcomeable though. What I've found is that the sprite rear end is one of the lightest solid axles around - alloy centre. |
| simon |
| I've seen the attack bananna site and am afriad that I'm not a huge fan. Super heavy and not particularly safe/stiff. Will throw some sketches of what I had in mind up once done. |
| Marko |
| Marko, the Midget frame at the front is not completely level with the floorpan, if you have seen a definite upward kink towards the front, it's supposed to be like that! |
| David Smith(davidDOTsmithATstonesDOTcom |
| As David says. If you're referring to a bend of a few degrees in the two "chassis legs" at the front then no need to worry, thats your caster! I'm sure you're not the first midget owner to see that and think ****! its ******. |
| R T Jakeman |
| Where's the "I'm such a doofus" smiley... :o ;) Cheers guys |
| Marko |
| Have you had a look at the z-cars site Marko? http://www.zcars.org.uk/mini/index.htm Quite impressive!! Carl |
| C Bintcliffe |
| Marko here's a shot of the bend being built in at the factory. This is the jig that imparts the notorious bend. No doofus smiley required, we all get it wrong first tim we come across it. Me? I made a straightening jig on my garage floor with every intention of straightening it out before it "clicked" and I looked at someone else's chassis... keep on keeping on!  |
| Bill |
| Indeed I have Carl - I had wanted to do a bike engined mini roadster at first. Something like this: http://www.spagweb.com/v8mini/v8fools/other_pics/701.jpg http://www.spagweb.com/v8mini/v8fools/other_pics/706.jpg Spaceframe, glass shell or epmty steel outer, keep it looking as close to a late-model cooper as possible except for the roof chop. Had to strike a balance between spending money on toys and paying off student loans though, and out on this side of the atlantic the classic minis are deeply fashionable and hugely expensive. :-( Pricing on the Z-cars stuff reflects this. Nice enough kit though by all accounts. Midgets however are ten a penny until such a time as Hollywood uses one, and have the advantage of coming sans roof from the factory! :-) Bill - glad you guys stopped me before I started making a jig out in the yard! |
| Marko |
| I agree with your thoughts on the attack banana... Hopefully mine will be much better. Interested in your sketches to compare against mine, although my sketches are only in my head! |
| Simon |
| Easy enough - imagine an old Elan: http://www.spydercars.co.uk/new_page_2.htm Now picture it with the engine in the ar*e - a bike engine transverse mounted (exhausts pointing backwards), driving a quaife LSD via chain/sprocket. Double wishbones up front, either double wishbones or a di-dion setup on the rear. Housemate just had his Subaru wrecked whilst parked, so could be tempted to try make something of the uprights on that, but they'll be hard to convert from macphearson strut to real suspension. Roll hoop = rear bulkhead = rear suspension mounts, brace rear hoop to the engine. Front hoop = front bulkhead = front suspension mounts, which is at the footwell and full height, not where the dashboard is. Footwell is one large affair, much like an elise is: http://www.elises.co.uk/components/s1/chassis/index.html Twin door diagonals tie these two bulkhead together and provide a modicum of impact protection. Floor, footwells made from honeycomb sandwich panels and act as stiffeners for the sills. Fuel tank and battery etc sit inside cockpit in the centre of the single large 'footwell'. Impact attenuators stuck at the front bulkhead and on the back of the engine. Radiator up front, exhaust under boot floor. Luggage space in the boot likely better than the original (it can be full depth). Chop away almost all of the original Midget shell, leaving just the outer panels in place, no need for inner wheelarches etc as the cockpit is full enclosed. If I were making an attack bananna, I'd follow the elan concept even more closely. Nice big torque tube/backbone, throw mazda miata/mx5 ends on it, chop the tunnel from the original floorpan and glue the floorpan to the new tunnel/chassis where it touches... (hopefully on the rear chassis rails, bulkhead behind seats, centre console and the ends of the footwells) |
| Marko |
| Marko If your friend is looking for something to do with his scooby he could always try this http://www.youtube.com/watch?v=awvNFJNLPb0 Carl |
| C Bintcliffe |
| Already earmarked for one of these... http://bp2.blogger.com/_6EK6R4bVYt4/R0p6s-JPktI/AAAAAAAANPw/vFdcPvraH9w/s1600-h/17.jpg |
| Marko |
| Having done some block models in CAD, there's no hope in hell of fitting a bike engine in the back of a midget without it ending up cantilevered off the end of the back axle like a VW - not keen. Nicest thing to do, if starting from scratch, would be to build am alloy honeycomb tub with a backbone, attach a tube steel subframe front and rear, then hang the shell over the top. Backbone links the subframes, tub gives you a modicum of crash protection and makes mounting steering/brakes/seats etc easy. If made with 1" thick/0.032" wall oanels (25.4mm, 0.8mm panels), overall width 48", tunnel 8" wide, 12" high, sides 24" high with 8" sills it'd weigh in around 70kg and be plenty stiff enough. Subframes 20kg apiece, engine/transmission 75kg, diff 20kg, corners 25kg apiece, complete glass shell 100kg etc - 500-550kg all up is achieveable. Unfortunately, pricing up all the pieces that I'd need to do this (essentially the entire car, bar the number palte/licence plate) puts this out of my league, so I'm going to have to scale back somewhat. Current plan - clean up shell, 3-link/watts-link/coilover the back axle; coilovers and new wishbones up front (attaching to a frame that carries the front end of the engine. Rollbar in the rear and clean/tidy and call it done, living with the crummy brakes/steering until the next project... |
| Marko |
This thread was discussed between 02/04/2008 and 24/04/2008
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