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Moving EA81 to rear suspension (custom fab)
Posted 28 June 2004 - 11:22 AM
I want to kick out the motorcycle engine and rear diff, and replace it with a EA-81 and DR 4 speed. This would make it a mid-engine buggy, pick up some horsepower, and give me a reverse gear. The low range would let me run monster sand paddles (no wheel wells to get in the way) and the high range would let me keep up with the Pinto-powered rails on the straight-aways.
I want to keep the rear torsion suspension, and drop in the tranny & engine. I have tested the fit of the rear axles onto the transaxle, and the holes for the pins don't quite line up.
Has anyone fit the inner CV from the front axle onto the rear axle?
This would solve the roll pin fit problem.
Are all rear axles the same? For this to work, I need to mount the
engine and transaxle higher so the oil pan clears the top of the
torsion tube. I can shorten the oil pan by 3" if needed.
But this requires the DOJ to be at its maximum angle. Can I get
a DOJ with the 83 spline that will allow a larger angle?
Posted 28 June 2004 - 11:28 AM
Posted 28 June 2004 - 12:46 PM
all rear axles and most front axles are 23 splines, and a 4spd is 23 splines also
you may be able to use a front axle doj on the inner side of the rear axles
Posted 28 June 2004 - 01:39 PM
If you can widen the track of your rig, you could use the EA82 rear axles that have an outer CV instead of a DOJ - the CV would allow for a steeper angle.
Posted 28 June 2004 - 02:57 PM
It sounds like I may have done the test fit of the rear axle to the tranny with the wrong end of the axle. I'll check that tonight. Hopefully the holes will line right up. When I did the test it was a half hole off. I assume that you are talking about the length lining up, not a rotation problem. Thanks for the tip Miles.
GD - I'll check to see how much shorter the 5 speed is. Ideally I would want a DR 2WD, if it existed. I suppose I could use the rear output for a PTO.
I like the idea of keeping the engine and tranny identical to my wagon, so spare parts can be shared and I can test out repairs by putting the engine or tranny on my car. I also like the abundance of EA81 and 4sp DR transaxles in this area.
Posted 28 June 2004 - 03:17 PM
The yards here consist almost entirely of EA82's, and now a few legacies, and the occasional impreza. EA81's are difficult to find - the local u-pull-it's here currently have 1 (tigard), 3 (foster), and 2 (damascus). And there was a gen 1 Brat at the damascus yard, but it might be crushed now...
Posted 10 February 2005 - 01:41 AM
More pics at:
Posted 10 February 2005 - 01:59 AM
Also, I would be careful about the rear CV angles, they look to be nearly at the max just at ride height. lifting a wheel could equal boom in midair or on landing.
Also I see you are welding to the hardened axle shafts. I would be wary of that, I did that on my lifted wagon, and had them snap the first time I went up an obstacle in double-low range. They are hardened, and so welding weakens them greatly.
You say that an improved version is in the works. Is a tube bender going to be involved in the next version by any chance? It could use it.
Just some constructive criticism, overall I think its cool, its definitely got some wheels turning in my head now. I have a dune buggy frame lying around that I've wanted to 4wd.
Posted 10 February 2005 - 03:11 AM
1. Why toyota ? EA82t would have been heaps easier in hindsight, but i had the toyota sitting there, it needed a home, and i had the running gear without a subie motor so i put 2 and 2 together so to speak. Next time round will involve an EJ20t.
2. Ive positioned the max/min rear travel to ensure the rear cvs are about 1/2" off max downward travel at their absolute limit. Its close but it hasnt come a cropper (yet).
3. The axles are case hardened yes... Im not so sure myself on the exact metallurgy of what is going on in there but ive seen welded axles work ok on many things and theres only one way to find out whats gonna happen. I only had to shorten it by around 3/4", the front diff is a fraction wider than the rear, and i must have got the gearbox slightly off-centre because the rh axle squeezed in ok. I made a real nice job of shortening the axle, cept i made it too short and had to make another. The second one, as you can see, isnt so tidy. Its butt welded, and then sleeved, and has handled 'abuse' on tarmac during the early testing. It also has to move a relatively lightweight vehicle, so im hopeful it will survive.
4. Improved version will indeed make much use of a tube bender, this one has been chopped and changed so many times its a mis mash of bits of steel. You can see transistions from large tube to square to small tube depending on my thoughts at the time. Now i have a fair idea of dimensions, spacing and ideals i can build another model with a fair idea of what shape each length needs to be. Below is a pic of my previous 4wd buggy built off a subaru domigo, which had a much neater appearance, but the 997cc engine gave rather boring performance with the level of traction it had. It kept me happy for 3 years, undergoing gradual improvements until now it is virtually impossible to get stuck. I sold it a couple of months ago.
5. Constructive criticism is all good, i was rather doubtful my chain and driveshaft would hold up and i really was expecting to have to modify it, or fix breakages. But i came home from the sand after the first trip very pleased, relieved, and with a short list of improvements, the first is to replace the SR 5spd with the DR 5spd ASAP becuase that toyota motor likes the 5000-7500 rev range.. and the SR gearing dont. The next biggest issue is the urethane bushes in the shifter linkage get quite sticky and need regular lube.
6. Build on, subaru is the best lightweight 4wd gear to play with. I wanted to see if a mid-engined 4wd was doable just for the sake of it, with the fall-back i could make it rwd only if it turned to custard. Now i want to start again, but now i have a full-scale model to measure off, eyes on an EJ20t, and i see if i can jig the clutch-pack 4wd-on-demand out of an auto box into a DR 5-spd.
Posted 10 February 2005 - 12:02 PM
Posted 10 February 2005 - 02:24 PM
That is the most creative use for a steering knuckle I have seen yet. When I originally found this website, that was the project I had in mind, and setting it up exactly the way you have in the mid-engine configuration, with a chain drive to run the driveshaft to the front. Unlike yours however, mine never materialized.
Welding a case hardened steel won't create any particularly horrible weakness in and of itself, basically it only anneals it...
The knuckle made me laugh. Its pretty redneck, but It works, and like you say its a prototype.
I mig welded a washer around my rear axles to keep my outer DOJ from sliding around on the shaft. I went up a muddy bank at idle in double low, lifted one wheel off the ground and 'ping' the other side's axle snapped like glass right at the weld. I never quenched it, I let it air-cool in warm weather in the sun. I fixed that side, tried the hill and the other side went 'ping' exactly the same. I've tried a new solution and now have no problems dumping the clutch in double low on rock or even dusty pavement.
Posted 11 February 2005 - 11:03 AM
What Did you use for coils on your struts in the front...? Rear's look stock, but fronts Look custom or Borrowed rear Coils...??
Love the design.....Does the chain drive give you any grief with trying to walk out of the tranny...???
I Love the use of the Hub assembly.....as a carrier.....
Fab On Man....
Posted 11 February 2005 - 01:42 PM
Couple questions for Mikie,
Where'd you get them Subaru ATV rims?
Are you running a 6 ply tire?
How long are your tires lasting?
I'm running on custom rims with Dirt Devil 6 ply's. Up front I'm already noticing some wear? Of course I've only been on pavement so far...
Posted 11 February 2005 - 04:28 PM
Subaru atv rims are Ford Econovan(Aka Mazda Bongo, E2000), which had a 12" dual wheel option during the 80's. They are the right stud pattern and pretty neat looking for steel, theres a set of 4 on the back of a wreck,and widening them 4" gives the right offset to clear a subaru caliper + take a 25-10-12 atv trye. They are offset outwards about 4" more than normal leone rims. By widening my back rims 6" using a larger diameter band i can get them to fit over the rear caliper as well. Tyres are just what i could get at the time, and i have only been out once so i cant report on wear yet. I will trry to keep off pavement thou. I set tyre pressure by measuring rim height from the ground to try to get an equal rolling diameter front and rear, no idea what pressure.
^^ Front struts are plain EA82, with spring cups ground off and a piece of threaded tube dropped over it. Spring is EA82 rear, but these seem a bit firm so im on the lookout for springs off a lighter vehicle. Daihatsu looks good. Rear struts are from something Honda, both struts and springs. Mounted further forward than normal to get 10" travel. The extra shocks mounted in the normal position prived to be far too much, so ive removed them and may refit them in front of the springs working at a reduced leverage.
I was expecting the chaindrive system to twist and prove unreliable, the rubber mounted centre driveshaft section to try to rip off, or at the very least bad viabration. So far its been fine and my first test drive was without rear driveshafts, using the front wheels only. Spinning up both front wheels constantly on pavement without any bad noises, viabration or ill effect put my fears to rest. The rear sprocket stays where its mean to (Using the tierod to ensure the hub runs parallel helps a lot i think) and the standard engineering sprockets drive a maza 323 front hub, axle is welded to a 1970s triumph 2500 rear axle to give a sliding spline, which is welded to 2x subaru centre driveshafts welded back to back to give a rubber mounted section with a flange at each end, which drives a normal subaru d/shaft section. Why? Dunno... but it works just fine. Id certainly do it different next time, theres weight to be saved and clearance to be gained. But the whole thing can be done cheaply and strongly enough without resorting to expensive engineering.
^^^ Rhino buggies look rather cool, and coincidently i am collecting larger 4wd vehicles with the intent of building a hummer replica. The mid-engine look is far nicer imho, the subaru buggy with the engine hanging out the front looks too nose heavy, and the 3 i know of locally look very nose heavy. My good friends one handles ok with a locked rear diff, but mine is more like a go-kart by comparision. If anyone here wants close up pics of anything just ask, or email me nyloc at inspire.net.nz, the more we put our collective minds together the more refined the concept will get. The biggest thig i would do differently next time is to use 2x front subframes. Mounting the engine, gearbox and rear suspension in one go, and using an EA82T leaves the left exhaust tunnel free for the forward d/shaft to tuck into. I also want to look into getting flanges laser-cut, and building my own rear gearbox section with internal transfer chain and 2wd/4wd select, making the rear shorter and neater.
Posted 15 October 2009 - 10:19 PM
Mikie do you visit these forums anymore? I see your last post was Jan/09
Edited by Little Bandit, 15 October 2009 - 10:20 PM.
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