Hot-rodding the Toyota MGR

[e*clipse]

Somehow, I thought this was inevitable.

Well, If you're so busy, and would be "bored" actually finding out the background to a problem. . .

Perhaps you can save of your precious time by not attempting to give everyone "advice" about stuff that has the level of consideration a high-school student would give to something.

I mean, this as an example, is the first thing that came to me as I unpacked the motors. After some consultation with folks who actually MAKE drivelines, I was convinced it was a bad idea, for reasons that would probably "bore" you.

Have you ever really DONE something, like perhaps a motor swap?? Or do you just troll around online giving shallow "advice" that is always so vague as to always be correct?

Originally Posted by P-hack

Not interested in reading all your posts, probably never will be that bored, but I do wonder why you don't mate some shafts from the source vehicle: "The vehicles were available from 2006 to 2010, and the drives were also called "Q211" by Toyota, and can also be found by looking for "rear differential" and "rear differential carrier."

Splicing two kinds of shafts is very common and probably any driveshaft shop can do it if you find some yokes/shafts that fit your motor, and some shafts that fit your hubs.

[P-hack]

I'm sure you have found a way to make it more complicated than necessary, so have fun with that. If you talked yourself out of using junk yard shafts on your junk yard motor, I don't know what you are thinking (and don't care) you made a mistake somewhere.

[pearl62]

Wow... why bother to post something like that at all?

I enjoyed reading every post in this thread (until yours). This builder is obviously trying to put together the best quality build he can. What could possibly be wrong with that?

[P-hack]

You have avoided the topic at hand, if "ultimate quality" is the goal, then why start with a $400 oddball motor and complain about lack of standards in shafts? Your enjoyment isn't a concern, engineering and practicality and costs don't care about your feels.

[AlexanderB]

I did see a video of a machine welding 2 shafts together, but they were pre-heated and slow-cooled and re-hardened after, if you just MIG it at home, they break right next to the weld. (Seen that happen so many times..)

(Machined from blank steel-) Custom shafts are not cheap, but theres companies that make them, some examples are already in this topic. its the best way if you have the money.

I'll be facing this dillemma soon, as my diesel gearbox will probably not survive long with the added torque a turbo, there's however a drop-in replacement gearbox that matches the engine bolts, clutch, flywheel, everything, but theres no axles that'll match my car to that gearbox. I heard rumors that certain axles would fit if I take the wheel hubs from that car and have them machined so they'll fit my wheel bearings.. We'll see.

But that brings me back on topic, the splines on the MGR side are not just the same ones Toyota puts on everything? that would make it somewhat easier perhaps, to find the correct length shafts. Machining down a set of Toyota wheel hubs to fit your wheel bearings is probably cheaper than custom shafts.

[pearl62]

Originally Posted by P-hack

You have avoided the topic at hand, if "ultimate quality" is the goal, then why start with a $400 oddball motor and complain about lack of standards in shafts? Your enjoyment isn't a concern, engineering and practicality and costs don't care about your feels.

There's nothing oddball about it... It's a great little motor that could suit some needs perfectly. You can't find anything packaged any better anywhere else.

If you don't like it why are you posting? You're not contributing anything other than your opinion. Maybe you just enjoy trolling, or maybe you're just miserable for other reasons and love taking it out on others... who knows.

Good thing my "enjoyment isn't a concern", because you are removing any joy from this thread.

e*clipse, please continue... I see some real potential in this tightly integrated little motor/generator/gear reduction.

[e*clipse]

For those who are interested in the details of making quality parts, I HIGHLY recomment Carrol Smith's books. "Engineer to Win" specifically addresses the metalurgy aspects of this axle problem.
www.CarrollSmith.com -- The Official Internet Site for Carroll Smith Books

There are some excellent examples - photos, etc of both catastrophic and fatigue failure of half-shafts. These **were** top-notch halfshafts used in high dollar race cars. They don't screw around with this stuff, yet failures happen anyway.

I guess I should qualify my "joining two different axles" statement. Yes, it's frequently done by OE's, who seem to have all manner of technology available. I don't.

In our case, taking two OE shafts from different vehicles would require:
a) tempering the shafts from the *** unknown *** heat treat state
b) making a possibly dual inner diameter sleave to join them - don't screw around here and start with something like a welded steel tube!!! You must exactly know the stress you will be dealing with and start with material that doesn't have a built-in stress riser like a welded joint.
c) welding the sleaves to the tempered axle stubs
quadruple checking your weld quality - have a certified welder do the job in the first place, then use various means to determine if there are voids, inclusions, etc. An inclusion or void due to incomplete weld penatration are perfect stress risers, and are the place where a fatigue failure is most likely to start.
d) retemper the weld joints
e) heat treat the assembly back to the point where the OE splines and the weld won't be the failure point.
f) have a driveshaft shop balance the new axle

I've welded a few moderately stressed parts, the motor mounts on my truck's engine swap for example. However, they were specifically designed NOT to be highly stressed critical parts like halfshafts are.

- E*clipse

[e*clipse]

I think I've narrowed my possibilites down to getting custome driveshafts made.

I was originally talking with the local driveshaft shop about making a custom Tripod joint housing with a 6-bolt flange that is compatible with the type-2 VW (100mm CV) CV joint. This might work; in fact there are some made for Formula Atlantic class open wheel racecars. However, my thought is that this is a wear item - and custom machined and hardened wear items seem expensive in the long run.

Instead, if I eat the cost, I can get a pair of driveshafts that hold up to drag racing Eclipses - a more or less "stardard" commercial off-the shelf product. There will be a small change of using a 100mm CV on the inboard side rather than the standard Eclipse tripod joint. I'm getting quotes for that right now. The beauty of this setup is I'll probably never break the axles, and I have a source for quality replacement parts. If I manage to hot-rod the MGR to the point that the axles, break there will be about two levels of upgrade axles already made that I can upgrade to.

Regarding the differential spline - sorry, this doesn't match any commonly available spline in a 'Yota pickup differentials. I've looked at all the stuff for pickups and asked around for that- hoping to fine a rock crawler spool or something. They're all bigger. If the ones used on a Supra or MR2 are similar, that would be great to know!

I have designed a spool/driveshaft/output flange for the MGR - it passes all the design requirement of "Engineer to Win" and I've done a FEA analysis of all the parts. It looks like it should have an infinite fatigue live when subjected to 1000 ft-lbs of torque. That's about 1.5 times the rated output of the MGR. I'm going to check costs tomorrow on that.

E*clipse

Originally Posted by AlexanderB

I did see a video of a machine welding 2 shafts together, but they were pre-heated and slow-cooled and re-hardened after, if you just MIG it at home, they break right next to the weld. (Seen that happen so many times..)

(Machined from blank steel-) Custom shafts are not cheap, but theres companies that make them, some examples are already in this topic. its the best way if you have the money.

I'll be facing this dillemma soon, as my diesel gearbox will probably not survive long with the added torque a turbo, there's however a drop-in replacement gearbox that matches the engine bolts, clutch, flywheel, everything, but theres no axles that'll match my car to that gearbox. I heard rumors that certain axles would fit if I take the wheel hubs from that car and have them machined so they'll fit my wheel bearings.. We'll see.

But that brings me back on topic, the splines on the MGR side are not just the same ones Toyota puts on everything? that would make it somewhat easier perhaps, to find the correct length shafts. Machining down a set of Toyota wheel hubs to fit your wheel bearings is probably cheaper than custom shafts.

[P-hack]

I am rooting for you, belive it or not I think getting it demonstrably rolling would have tremendous value for the EV community as these things are sitting out in the elements (and being scrapped) and plenty of people would be very pleased with the stock hp levels at the $400 price point. So it is your basic "the great is the enemy of the good" kinda thing IMHO.

Also 650 volts, despite the benefits, is kinda nuts in a DIY, nothing will charge it that I know of ('cept multiple isolated). Even the best dragsters aren't much over 400v. Maybe some of those connecting red/yellow/blue wires can be brought together to parallel some of the coils and cut the voltage requirements in half.

Also there is some question as to how much you can actually overamp the magnetics, as well as if the differential itself is a limiting factor in beyond stock power delivery. I wouldn't expect any miracles from a differential designed for 60hp.

[pearl62]

Originally Posted by P-hack

I am rooting for you, belive it or not ...
Also 650 volts, despite the benefits, is kinda nuts in a DIY, nothing will charge it that I know of ('cept multiple isolated). Even the best dragsters aren't much over 400v. Maybe some of those connecting red/yellow/blue wires can be brought together to parallel some of the coils and cut the voltage requirements in half...

I thought the Highlander PHEV pack was 288V, and there is voltage doubler in the motor controller inverter... What motor controller is going to be used inn this application?