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Post by kcswimrac on Feb 17, 2016 17:55:28 GMT -5
okay so the first project is definitely not the best welding i have done, but i finally got it done. Second project is a torsen limited slip differential carrier. It will look something like this when i'm done.
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Post by gearheadeh on Feb 17, 2016 20:04:48 GMT -5
okay so the first project is definitely not the best welding i have done, but i finally got it done. Second project is a torsen limited slip differential carrier. It will look something like this when i'm done. There is only one pic showing, which is a shame- this sounds really good. Do tell us more?
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Post by kcswimrac on Feb 18, 2016 13:23:09 GMT -5
I think I fixed it..
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Post by madmatt on Feb 18, 2016 15:09:03 GMT -5
GTFO!!!!!
Dude...
What the...
Oh man..
So sexy...
FAWK...
Oh and I'm planning on a lathe purchase on my return... that looks like a mill/lathe combo... what is it? I've heard scary stories, but mostly from folks doing big production work. and maybe something like that fits my needs (I'm no machinist!)
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Post by madmatt on Feb 18, 2016 15:12:41 GMT -5
okay so the first project is definitely not the best welding i have done, but i finally got it done. Curious your rational on such short runners? what you got planned?
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Post by gearheadeh on Feb 18, 2016 15:39:40 GMT -5
Yes indeed, this will be EPIC!
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Post by justine on Feb 18, 2016 23:28:32 GMT -5
Oooh that diff. what are your overall plans for the car?
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Post by jasin on Feb 19, 2016 5:36:07 GMT -5
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Post by kcswimrac on Feb 19, 2016 12:56:05 GMT -5
Matt, all the turning was done on a lathe, in the setup in the picture it is actually on a vertical mill, with a dividing head so cut out the area where the gears will reside. And the rational for the shorts headers is, 1) they're not much shorter that the factory cast manifold 2) Turbo.. lol
I've got a new Garrett G1544 turbo waiting to be installed. It's a little small even for a Justy, but talking to Garrett, I should be able to hit peak boost of only about 7 psi at around 2000 rpm @ expected 120 lb.ft of torque, and peak power right around 120 hp at around 5250 rpm. (yea I know, right now gas mileage is going to hurt, constantly being in boost on highway, but I should be able to have a highway tune on the mega squirt where I dump most of the boost/just leave the waste gate open at cruise.)
Justine, one day I hope to use it as a rally car, not caring too much about what class I'd end up in with all the additions to it. But for now I use it as an exploring car, driving on forest roads, and getting around all the big truck in the snow, and a car to just try to challenge myself on by modifying. I've already rebuilt the engine, and gone from the '89 carb to a '91 fuel injected manifold all currently running on a megasquirt 3 with individual coil on plug and individual injector control rather than batch fire. And if the front diff functions well i'll be making one for the rear.
Jasin, I'll have to take some more screen shots for you, it's actually using the gear set from an Audi Quattro center differential, I have to finish the internal milling, then i'll be cutting involute splines on the carrier and the inverse splines on the inside of the OEM input gear so they slot together.
Also I stole an idea from Matt, I believe, I have an early 2wd transmission that i'm going to take the gear set out of and install in my late 4wd gear box.
Like I said, too many projects... lol Also i'll get more photos up soon.
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Post by kcswimrac on Feb 19, 2016 13:01:36 GMT -5
torsen.info/fsae/fsaefaq.htmHere's all the info on the original audi diff, torsen actually sells the whole center differential to the college SAE formula teams for use in their cars.
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Post by madmatt on Feb 19, 2016 13:41:19 GMT -5
That was my assumption he he he looks tres bon!
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Post by kcswimrac on Mar 1, 2016 20:55:22 GMT -5
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Post by Armageddous on Mar 1, 2016 21:50:07 GMT -5
The lighting makes it appear brass. That's gorgeous tho, very nice work. If it works you might have to start production Terry
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Post by kcswimrac on Mar 2, 2016 23:14:22 GMT -5
I might have to redesign it for quicker production if that happens. But I really like the idea of a LSD front and rear. I've got a few more ideas I've added to the list. I'm thinking wheel speed sensors, arduino, and LEDs in the 4wd indicator, that change from Green to red based on faster spinning wheels. Also trying to do some design work to add a granny gear on the end of the transmission shafts, thinking a low gear of 12:1 should be doable with simple dog engagement, would put me around 2 mph @ 2000rpm and about 7mph @ 5500 rpm. Should be low enough for the forest exploring I do. I think I have the space issue worked out, I just have to do some calculations to see if the output shaft of the transmission could hold up to that kind of torque multiplication. Other idea is an electronic wet clutch pack inline of the prop shaft, I already have the clutch pack, and clutch driving units, I would just have to figure out a method of electronically applying clamping pressure (probably pneumatic), cut some adaptor splined shafts, and a housing to hold it all together. Also I would have to get a custom shorted prop shaft, and figure out if the steeper angle is something regular u-joints will handle. I'd imagine so, the Justy doesn't have much drive shaft angle. End goal being crude and for the streets, and still lockable off road. Similar style set up as the 90's automatic awd subarus.
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Post by Armageddous on Mar 2, 2016 23:32:11 GMT -5
Sadly, an Arduino is not going to quite cut the mustard for your wheel sensor idea. They simple don't have the speed (mhz).
Running wheel decoders on 4 interrupt routines, while writing pins, will make it run too slow to be reliable or even functional.
Terry
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Post by wittgensteinsergeant on Mar 2, 2016 23:32:19 GMT -5
OP, you are completely batshit insane. AND I LOVE IT! Torsen LSD on a Justy? Oh yeah. Low Range a-la the Legacies? F yeah!
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Post by kcswimrac on Mar 3, 2016 10:25:44 GMT -5
Well in that case, I I'll have to start playing around with my raspberry pi again, I know it should be up to the task. I might be crazy, but I told myself that I'm going to try to do one project at a time, so I'm sure it will be slow going. But I intend to get them all done!!!
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Post by kcswimrac on Mar 4, 2016 15:28:05 GMT -5
Ran some Finite Element Analysis this morning on a crude justy transmission output shaft assuming the lowest quality steel it could be is 10xx alloy steel, and if I made 120 lb ft of torque with a 12:1 super low gear puts me at 1440 lbft of torque max on the output shaft (which it will never see, the wheels will spin or something else will give way first).
I ran the calculation at 1500lbft and arrived at a factor of safety of 1.3. In other words the failure point is around 2000lbft. I think the next step is to design some gears, and a housing for my limited available space.
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Post by justine on Mar 4, 2016 16:16:46 GMT -5
What is it that you do for a living that gives you access to all your resources and tools? Very good information your putting out here Thank you!
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Post by kcswimrac on Mar 4, 2016 19:13:28 GMT -5
I'm just a college student, but i like trying to make the best use of everything available to me currently. Because I know once I graduate this stuff will be harder to come by.
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