Type 1 trans in an electric car

Discuss VW transaxles and transmissions. Gearheads wanted!

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Marc
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Re: Type 1 trans in an electric car

Post by Marc » Fri Jan 13, 2017 3:31 pm

That may be true, with no tachometer to go by it would probably take a while to master. My point is that as a rule electric motors don't have to deal with endthrust and therefore don't have bearings capable of standing up to what amounts to an attempt to eject the shaft out the back.

Maybe the ultimate shift-on-the fly trans for an EV would need to be based on an Auto Stick? Naah, I doubt that little clutch could hold that much torque.

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Re: Type 1 trans in an electric car

Post by Jadewombat » Fri Jan 13, 2017 4:44 pm

Yeah, I agree. Putting $50K into an old VW is an absolute waste of money in that you'll never see that again. Unless you get $50K of fun worth out of it...not likely.

More along the lines of this???

http://www.diyelectriccar.com/forums/sh ... 82159.html

It'll probably twist the car in half eventually from all that torque, but an "E" for effort though.

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Re: Type 1 trans in an electric car

Post by Marc » Fri Jan 13, 2017 6:39 pm

https://youtu.be/9ODDp-DOhj4

This guy's got the worst sense of time in the world (and apparently is unaware that there's a clock on the video player). Doesn't matter how many times he says that's two seconds, it's more like 8 or 9 - to where he claims 50 MPH. :roll:

The ratios Bruce has chosen should be good for traipsing around-town (sub-40 MPH) in third or highway travel in fourth. I've never run a third shorter than 1.65 so I don't know how valid Pablo's concern about the 1.84's strength is - presumably you'd want to weld the synchro hubs on both gears but I suppose you could skip that on third to make it the weak link which would hopefully prevent tooth breakage.

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Re: Type 1 trans in an electric car

Post by Bruce2 » Tue Feb 14, 2017 2:21 am

Pablo2 wrote:I would be very hesitant to use any aftermarket gear (and especially such a low ratio 3rd) against a torquey electric motor.
I sent a question to Weddle asking about the durability of the 1.84 in an electric car. Their response:

That 3rd gear does get a little bit weaker than the taller gears next to it. Since the gear has to get smaller to essentially work with that ratio, there is less material between the root of the gear tooth and the bearing bore of the gear, which can cause them to crack under high stress applications. In a street car that is not being driven super hard, you may be just fine, but I cannot guarantee that it would work perfectly fine. I would certainly try to use the 1.78 3rd gear as it does get a bit stronger.

My customer has approved the use of a 1.78, although they did say the car would be slower.

A way to compensate would be to go with a 4.37 R&P instead of a 4.12. Then use a .82 in high gear.

Old:
1.84 x 4.12 = 7.59
.89 x 4.12 = 3.67

new:
1.78 x 4.12 = 7.34

Alternate:
1.78 x 4.37 = 7.79
.82 x 4.37 = 3.59

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:06 pm

In the months since I started this topic, my customer had a few questions spread around. Then about 4 weeks ago they pulled the trigger and ordered the custom gears from Weddle.
We must have forgotten the choice of a 1.78 3rd because we bought a 1.84. High gear is 0.89. Both on a 4.37 R&P since they didn't think the finished car would be able to go much more than about 80mph.

While I started the trans project, they started cutting up the reproduction speedster to take the batteries. The car they started with was originally set up with a full automatic gearbox, so for the two speed, they had to sort out pedals, shifter and shift rod to the back. They had a dummy 4 speed to mock up the motor mounts while I built the gearbox.

Here's the assembled pinion shaft:
Image
Last edited by Bruce2 on Sat Sep 09, 2017 8:13 pm, edited 1 time in total.

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:09 pm

A couple of months ago I opened up a core and found one with the teeth on 1st gear cleaned off, so it made the perfect mainshaft for the 2 speed. I spent a bit of time on the bench grinder to make it look good. I also cut away part of 2nd gear's teeth.
Image

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:16 pm

Here are the shafts in the gear carrier with the fork:
Image

And installed in the fixture:
Image
Image
Image

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:18 pm

This pic shows the plate I welded onto the end of the 3-4 shift rod to contain the tip of the hockey stick.
Image

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:21 pm

This pic was taken minutes before installing the gear carrier and shafts. It sure went in easy when you don't have to play around with the reverse idler gear.
Image

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:26 pm

One liability concern I told them about was that this car would be able to go backwards at 80mph! Their cars are normally setup to take a late Beetle 3 bolt nose cone, so I suggested that I could install one that had a neutral switch, and that I could modify the hockey stick so the car couldn't reverse in high gear. But that would only limit the top speed in reverse to about 50mph.
Instead, we did a modification we normally do to Subaru powered cars. Here is a stock Beetle CV flange with an extra ring welded on. Then they screw a bolt into the radial holes. The extra long studs are for a bracket to hold a speed sensor. Through the "engine management" system, they can speed limit the car to any speed they want in reverse.
Image

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Re: Type 1 trans in an electric car

Post by Bruce2 » Sat Sep 09, 2017 8:31 pm

I delivered this trans to them last Sunday. By Thursday they were driving the car! I stopped by their shop yesterday, but the car was already off to a local car show. I'll get a chance to drive the car in the next few weeks.

When I dropped it off, they said the only thing holding them up was the clutch. They needed a Stage 2 according to ???? I disagreed. The motor makes 120ftlbs of torque, and nobody is going to be drag racing this car, so they put in a Stage 1. Now that I read back at Marc's comment about the motor's ability to take thrust, this was a very good decision.

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