View Full Version : 4x4 gearbox options for mk1?
TbarTurbo
05-12-2007, 23:37
What 4x4 gearbox options, if any do we have for the mk1? ideally keeping engine in the same position, but may consider 90degree rotation of engine if i have to.
Ive just realised i havent been very brutal this year with any cars, and feel i should make up for it next year!
Would also be intrested to hear any thoughts on how a 4x4 mk1 would handle.
Hmmmm, this was something we looked at with the pug 205's and the conclusion we came to is it'd be easiest to get a 4wd floor plan from another car and put the shell ontop.
Maybe the GT4 floor plan?
There is the centre tunnel which you could use for a propshaft if you moved the fuel tank.
It'd be a very custom setup though and tbh i dunno if it'd be worthewhile. Don't get me wrong, i'd love to see it done but it'd take away from what makes the Mr2 so much fun to drive and the is the Mid Rear bit of it. Well to me anyways.
Are you thinking permanent 4wd or rear biased only using the front when needed?
TbarTurbo
06-12-2007, 00:23
The 205 would be quite easy to make 4x4, only let down being the weak tx to gearbox shaft on the bx 4x4 and mi16 4x4. rear trailing arms can be modified to fit 106 hubs and bearings for the rwd. T16 gearboxes are rare and big $$$ so that left only the cossie/calibra turbo route... the 309 had a few 4x4 conversions iirc, and also in france you can find a 1.4 4x4 205... none any use for high power!
I have played with the sierra floorpan to convert a mk4 escort, but thats a lot of work so would try to avoid that route personally.
Back to the mr2, im thinking a viscouse tx box like that on a cally turbo, but permenant.It will put best part of the power to the rear wheels and only load the fronts up should the rears slip, ie in hard launching and cornering... i think.
Im thinking the added wieght of the diff in the front and the prop would be good for keeping the nose end down aswell. i dont think physicly fitting front transmission parts will be the biggest hurdle, cut the frunk floor and build a suitible subframe, im sure hubs and shafts ect can be source from other cars and shortened if need be.
i dont really fancy using a porche box though unless i cant find something cheeper. and i need a box that will drive the right way! the diff can be reversed to run the right way at the front though.
weegaz22
06-12-2007, 00:53
would be pointless imo, all that extra weight is gonna affect handling, if you want 4x4 buy a scooby or a GT4, you have the best layout possible in the mr2, mid engined, rwd, itll be a better circuit car than something with 4wd
lodgeman
06-12-2007, 07:04
have a look through this thread. it was discussed in depth some time ago, maybe it can be tried? never say never on twobrutal!!!:idea:
http://forums.twobrutal.com/showthread.php?t=206&highlight=wheel+drive
Paul Woods
06-12-2007, 07:04
ive looked at this for years and always come to the same conclusion that it would be easier to achieve 4wd in a mk1 by putting another 4a-ge in the front,but that too isnt exactly easy....but it would double the power output as well as a side effect....not sure what it would do to the handling and it would need a 6R4-esque bonnet but id love to see someone have a go at this.
or...Ive even had a little think about it too...surprise surprise....
a 1uz should fit over the top of the steering rack...and under the bonnet line...
from there into an arristo trans back too a soarer rear diff....
might need too make some kind of drop box/allignment box too get the drive back too the front axle centers...and use GT4 front hubs...
or...just put the GT4 setup in the back....and divert the rear trans feed forward too the other diff...no reason you cant mate the v6 too that trans either....
Paul Woods
06-12-2007, 07:23
how would you divert the gt4 rear trans feed forward though sketch? its pointing towards the rear if we stuck that in a mk1 no?
Same if you used a cally Turbo 'box - the transfer box fits into the back of the gearbox ( bitter experience swapping Cally txb's in the past )
Paul Woods
06-12-2007, 07:41
im confused here,whats a cally box? if a gt4 box was fitted into the rear of an mr2 the output shaft for the celica rear wheel drive would be pointing towards the mr2s rear bumper? how do we get that drive forward?
ive thaught about this and i came up with put a 1uzfe in the back faceing backwards then fit an audi quatro gearbox to it inverted, only thing is with this setup would be the weight further back so not good, would have the same problems with oversteer a porsche does
if you can recall the dirty old mini trans..youll know what I was thinking;)
build a box with a 1:1 drive ratio..drive in and out of the front face..rear output from trans goes in one side...comes out the other, joins onto the prop shaft for the front diff...goes under the sump...and through the fuel tank space
millentubby
06-12-2007, 10:48
Cally Turbo - Calibra Turbo?
Cally Turbo - Calibra Turbo?
Yep :thumbsup:
ive thaught about this and i came up with put a 1uzfe in the back faceing backwards then fit an audi quatro gearbox to it inverted
I know your not afraid of the grinder...stop thinking mechanical...
start thinking brutal...cut the rear off the car....and move it back;)
if SARD can do it....so can you!
http://www.twobrutal.co.uk/forum/images/recovered/2007/12/96.jpg
millentubby
06-12-2007, 10:59
I has winnar :D Off to celebrate by working on the camry :D
What about getting hold of a rolled or smashed GT4 and going from there?
Paul Woods
06-12-2007, 13:13
i still think another 4a-ge up front would be the better way and double the power output.... or twin 3s-gte's,anyone? :)
It woudnt be AWD but it will be 4x4 when you wanted too.
But maybe you could use one of those Toyota corolla AE94 or AE95 Boxes?
Juist another random 4x4 box they may work:)
Given the length of the engine, belhousing, and gearbox, wouldn't you end up with the longitudinal propshaft well offset onto the passenger side?
Paul Woods
06-12-2007, 18:10
not wishing to put a downer on an otherwise smashing idea,but i think that trans is far too long to mount transversely in an mr2 bay,take a look at podges v8 and audi trans,the end casing is almost touching the rear panel and thats with the front wall chopped out.Its 42" from standard front firewall to rear panel in the boot and only 36" between the frame rails in the engine bay so i dont think that will fit....however its the prefect solution if we can find a trans thats short enough to use with a v6.
TbarTurbo
06-12-2007, 18:11
I actually thought about a lenthened mk1 chassis, so as to fit the rear wheel axle behind the engine to retain mid engine and avoid the porche handling issues. would probably be a bit too much to take on myself, and i dont think it would look too clever either imo.
Twin engines, i thought there was some new laws to prevent twin engined cars driving on the road now? if i was to go this route id seriously consider bike engines, but obviously the cost will rocket...
im sure the key to rear engine 4x4 would be some kind of modded or custom tx box/gearbox combo to send the prop under the tank tunnel.
Paul Woods
06-12-2007, 18:16
i agree,but sadly it usually means the prop ends up turning the wrong direction.... i dotn think running a gt4 box upside down would work either,im pretty sure there's an oil pump inside those that needs orientating the right way,i might be wrong though
Na ya right paul it does have a pump and pick up pipe that needs to be at the bottom .
TbarTurbo
06-12-2007, 18:51
the front to rear prop can run whichever direction it likes... u can reverse the front diff to make the wheels turn the correct way... i only know this as i saw it on scrapheap challenge last week lol!
schumacher
05-04-2008, 05:46
Forgive me for my interruption, but you guys are forgetting that the Audis also had FWD option called Front-trac. The engines were still longitudinally mounted in the Front-trac cars, so the transmissions are exactly the same other than the fact that the massive transfer case / centre differential is not there (the black part in the picture). You wouldn't need the centre differential anyhow if you were going to use the transmission to send outout to the front LSD and the rear LSD using two propshafts. You would definitely want LSD in the transmission though, otherwise the power wheel go to whichever sets of wheels that have the most traction.
would have the same problems with oversteer a porsche does
No probs with Porker oversteer here fella - urban myth. All they do is understeer :D Just had mine out for a 150 mile run in the soaking wet. Like s**t to a blanket :thumbsup:
avoid the porche handling issues.
Grrr - lol
GregHoon
12-09-2008, 22:29
Hey guys,
This is probably a dead thread now but it just sounds so interesting as it is pure twobrutal stuff.
I remember a fifth gear episode where they had a kitcar with two engines. One driving the front and one driving the back. I think they were front mounted (a la lotus 7 shaped car).
The thing that interested me was that rather than have both engines engage the same gear simultaneously the gear lever was split in half and indeed both engines could be placed in different gears. I don't know the exact reason as to why but the machine was i think designed to break the world record 0-60 time of the time.
If you mounted an engine in front and one in back aside from doubling of the power could you then also make the rear engine produce more power than the front to keep a rear wheel bias etc? Just thinking that with that setup and compuer controlled throttle (i have no idea what work this would entail) the amount of power balance and bias could be controlled more so than on any other production car.
It would be a an awesome car and the dual control would mean the setup could be be adjusted by the driver whilst driving to see the effect rather than after ramping up. The car could drive with a rear wheel bias when accelerating in a straight line then more equal sharing of front rear power at high speeds. Somewhat like the R34 skyline.
I guess i only have to wait around a few months before someone does it on here anyway haha. A great community of nutters we have here. I love it.
TbarTurbo
12-09-2008, 22:41
To get the power bias , ive seen it done through the gears and clutch systems, where the rear engine is in a lower gear.i remember a twin engine nova running 600bhp this way. id not consider a computer controlled throttle, but then anything is possible these days :)
And im no further to getting anywhere with a 4x4 myself... :(
Marksman
13-09-2008, 00:43
Sounds like a good idea but our government in their infinite wisdom have banned twin engined cars I believe. Bugger!
Owen.
TbarTurbo
13-09-2008, 08:11
Yep, to pass the mot/sva you only need to switch on the rear engine ;)
Sounds like a good idea but our government in their infinite wisdom have banned twin engined cars I believe. Bugger!
Owen.
Do tell more.....
GregHoon
13-09-2008, 23:01
Cheers Tbar i understand why they use that system now.
If the two engined approach is just too difficult to achieve or infact no longer legal as marksman is suggesting then you are back to the same problem of fabricating a suitable 4 wheel drive shaft and setup. And it seems the hardest problem here is being able to fit the system into an existing Mk1 chassis.
One way to circumvent this problem could to fabricate the underpinning system entirely seperately from the chassis. If anyone has seen the Z cars montecarlo mini. The engine, steering and suspention even are mounted upon a space frame and then the shell (which in their version is seemingly more asthetic than actually a part of the car) is placed onto the frame. Now whether the result could really be called a mini. Well somewhat of a gray area.
Now could a rear engined, four-wheel-drive sytem be fabricated, with the steering system already assembled and attached to the frame. Obviously in the configuration of an existing mk1 with all the components in exactly the same position. Then a heavily lightened and bored out shell be attatched ontop of it. The result would be very light weight and the other problems of component placing is cured by the fact that they are all connected to the underpinning frame rather than the chassis. A completely hollowed out shell would give lots of space within which the fuel tank, cooling systems etc can be placed for perfect weight distibution.
Ok it is probaly a ridiculous idea and i don't know if you would really be able to class the resulting vehicle as a mr2. But once one it is fabricated it could be copied again and again reducing relative production costs by anyone wanting to say fit in a v8, bike engine, dual engine (if they are still actually legal) etc much easier as it has to only attach directly to the frame and not chassis.
Marksman
13-09-2008, 23:21
Tis a good idea for sure :thumbsup: My personal view is that the result would not be an MR2 but we're all different and any project should be supported. Much as I like the MK1 if I'd gone to the trouble of a 4wd spaceframed chassis, which is great, I'd probably not put a MK1 body on it. RS200 or Stratos maybe? Then again they've been done so why not the MK1, or a cut and paste of different styles with an individual twist thrown in.
Bottom line if you want one and you've either got the skills, know someone to help who has, or have the capability to learn as you go along, then build one. :praise2:
Good luck,
Owen.
GregHoon
14-09-2008, 22:38
Hehe i think that might be a little much for me Owen. I just liked the idea of someone putting a four wheel drive system into a mr2 and wanted to put my 2 pence in incase it helped at all. Throw some ideas around etc. Hey but never say never i guess :)
Greg
Marksman
14-09-2008, 23:27
Hell yeah.
Pre-TB I couldn't weld, was confused by engines, and though building cars was for other people. Now I seem to have two project cars, a full workshop and very nearly a parts business, and am giving serious thought to throwing in the day job. So who knows?
Owen.
The big issue with twin engine imo is power transfer. It can work for 1/4 mile but if the engines are completely separate you have a very loose connection front to back. It's not like a skyline with a connected diff constantly varying.
Anyway, I have now hopefully bought an ST185 GT4 awaiting confirmation and have this project in mind. I was going to start my own thread, but this looks like a good place to post for the time being. I won't be getting the car until November so a bit of planning to start with.
I've concluded that the best way will be to reverse the gearbox, if the engine is rotated to inline a scooby g/box could be used, or carrera 4 maybe. I'm going to go with the GT4 set up though as it's a cheap starter and no losses if I can't work it and break the lot.
The Major problems I expect with the gearbox are:- Oil pump and thrust reversal. The rest is just fabrication and fitting. I've yet to see an oil pump in reality. From the service manual it doesn't look like there's much room to work with re-directing the flow. As there are angular contact bearings at each end of the output shaft that should be ok... I hope.
For power I see 2 options, the rather large task of reversing a 3s-gte or using a vtec. Since I'll have a couple of spare 3s-gte's and all the stand alone gear I need I'm going to give that a shot also. I don't really expect the result to be reliable though :(
Handling wise, being a rear engined 4wd it's going to be awkward. Not enough weight over the front should leave it very willing to push under, and dialing that out could leave it very nervous and twitchy. Still, I don't spend much time at home so that would probably be at least 2 years down the line and hence not worth worrying about :D
I'd like to hear opinion on the gearbox though, that's my major worry..
TbarTurbo
25-09-2008, 21:49
So you mean to reverse the gearboxes output shaft direction? im sure running an engine backwards has been discussed elsewhere and not an option. the honda engine would be good to see.
What about a 4x4 honda box of some description? is there one?!
Start a new project thread as soon as u like... :)
I'll start a thread as soon as I've payed for the donor car, otherwise it's going to be put off by another few months.
I know it's not going to be easy to reverse the engine, but it is possible. How long it lasts is anyones guess though. I'm looking forward to getting stuck in.
Yep - getting a 3S to run backwards wuld require you to get new camshafts ground with the lobe positions reversed, ignition timing would need major work, the oilpump may need looking at to see if it would operate backwards, etc, etc. VTEC engine sounds like the best bet if you can get it to mate to a suitable gearbox/transfer box.
I'm not familiar with the GT4 gearbox, but I've done a fair bit of work on 4x4 Calibras in the past, and I think you'll find it very difficult to fit it all in the MR2 engine bay.
Of course there are a couple of mid-engined 4x4s out there you could use as donors - though I doubt that your budget will stretch to even a wrecked Gallardo:hidesbehi
Can we list all the posibilities for M4WD?
Gallardo
205 T16
Carrera 4 (ok R4WD but would work)
RS200
What we're building these Brutal Two's for, in my opinion, is more a Lamborghini of old. Almost too much power, wild as fuck, RWD, not the quickest point to point but getting there with a huge fucking grin and in style.
If you're gonna go to all the expense and hard work of making a M4WD car, as said before, put it in something properly special.
Do you want the quickest car point to point, is that what it's about for you? A serious question here.
TbarTurbo
25-09-2008, 23:41
that list is expensive... :(
That's the thing, it's not a cheap setup. Doubt it ever will be.
Spend the money making it a RWD monster that handles perfectly. Much more fun than 4WD autopilotism. :mrgreen:
See that's the epitomy of why?
It's 4WD, it's so easy to drive it makes journos think they're driving gods, you can't hear the engine properly, there's no drama, it's numb, it does the job and leaves you empty.
And don't get me started on the fairy lights.
Maybe i'm just stuck in the old school but where's the driver achievement?
LOL, I think a V10 would be a tight fit.
The GT4 box is a MK2 box with a transfer box on the side. It'll go in no bother if it'll run right.
What box is usually used on RS200 replicas? I've seen a couple of cosworth powered ones but didn't look too much into it at the time.
I don't think for a second we're going to get scooby/evo handling out of one of these.. Unless you go wild with the set up I reckon it's going to be more Delta S4 than anything else, ie terrifying :D
Oh and as for why do you want to do it.. How do you know what it'll be like until you try! For me it's going to be a project to work on in the background when there's nothing I can do on the Mk2 and want to get out into the garage. It's also going to be done for minimal cost.
getting a 3S to run backwards wuld require you to get new camshafts ground with the lobe positions reversed, ignition timing would need major work, the oilpump may need looking at to see if it would operate backwards, etc, etc.
Ignition timing, Already got a link ECU and coil packs sitting there, that also pretty much takes care of trigger points. Oil pump, pretty sure this won't be easy to reverse the flow. You can run it backward on the stock cams, just not well. That's the first step, once it's proved possible and run then things like custom cams can be bought and make it work properly. Up until that point the costs aren't that huge. There's going to be a few major stumbling points that's for sure, worry about that when they pop up though!
TbarTurbo
26-09-2008, 08:01
i wonder how long before crank pulley and cam pulley bolts come undone from spinning the wrong way...
:thumbsup: Not difficult to solve but I'd not thought of that.
I'll put a thread up later with a list to see what pops up :)
i wonder how long before crank pulley and cam pulley bolts come undone from spinning the wrong way...
Should be OK, as the torque to the pulley is transmitted by a woodruff key in the case of the crank, and from memory by a pin for the camshafts, so there shouldn't be any force trying to undo the bolts.
The cam timing is the real biggie - I've worked on engines that reverse ( big marine diesels - and I mean big - 900mm bore and 1550mm stroke ) and when going into reverse you move over to different cam timing. If you can source blank camshafts and get them professionally ground then you should be fine - but I suspect that getting the blanks will be difficult enough. Existing shafts can't be reground to give the correct timing, unless you can get the lobes built up by welding to give sufficient metal in the right place, and of course then you're into trying to get the right hardness etc.
With that you're doing injection and exhaust from one camshaft, and the cam profile is designed specifically to match maximum torque and power at the same rpm but keeping the duration just long enough to allow reversing.
With a 4stroke twin cam the problems are completely different, injection is electronic, so sorted straight away. Inlet and exhaust cams can be rotated by different values so that when reversed the cycle is not reversed also. The only issue I see with this is the ramp angles being too steep on closing and causing valve bounce early. This can be adjusted by re-profiling stock cams if the project gets that far.
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