transaxle upgrade's

Duk
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Re: transaxle upgrade's

Post by Duk » Wed Nov 23, 2016 9:19 pm

An alloy steel bearing plate???

Or find out if vacuum infusing a laminated a carbon fiber component that is 30+mm thick is doable and then machine the CF to suit?
Maybe would want bronze inserts for the shift rods?

You could also look at making the the areas around the 2 bearings thicker on the input shaft side and just have the plate relieved around the gears that make up 5th gear (literally a counter-bore for gear clearance), secector shafts and outer flange thickness as required.
And use a thick machined alloy steel bearing retainer that is also relieved clear the (4th) gears.

At the end of the day, the weight penaly of making the bearing plate from a decent alloy steel would actually be quite low. The weight is also very low and quite central to the car. So performance wise it would be of a very low impact. Strength wise it should give a huge improvement to bearing plate rigidity. Especially if you can add even more material to it so if can better resist flexing.
Last edited by Duk on Sat Feb 03, 2018 9:33 pm, edited 1 time in total.
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75evo
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Re: transaxle upgrade's

Post by 75evo » Fri Nov 25, 2016 10:15 pm

GTV-racer,

Any chance you could design a flange setup for all 3 giubos so it uses a single BMW type giubo? If you have a design ready I can print it using my 3D printer and mail it to you. In fact if you have any part you need printed just email me the stl file and I can print it for you.

Actually the French guys did a nice adapter but I could not convince them to share the design. Willing to pay of course.

I hope you can make the aluminum plate design available.
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Re: transaxle upgrade's

Post by gtv-racer » Mon Nov 28, 2016 1:11 pm

That's a nice offer! What kind of materials can you print?
Then again i don't have any donut problems since i replaced the middle one with the bmw part. If i do get problems i'll look into that if it's low milage related. I driven 4000km's so far and i recently inspected them. No sign of wear yet.

There's also a problem with the front one because the bmw part has to fit the flywheel picht bolt patern.

@duck
If youwant more then 37.5% improvement i'd go for the steel plate. Simple,robust .
The extra thick one's, with relieves for the gears and other stuff, still have the weak spot where they go to the 30mm thickness but it should be a next step.
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75evo
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Re: transaxle upgrade's

Post by 75evo » Mon Nov 28, 2016 1:26 pm

I can print on PLA only, no ABS. I will ship to you free.

I'd like this mod because the Alfa units are made with varying quality and some have known to explode prematurely. They're not cheap either. May as well go with a single style easy to obtain giubo.
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Re: transaxle upgrade's

Post by Duk » Tue Nov 29, 2016 2:12 am

From Kevin's thread on the 75 IMSA car viewtopic.php?f=21&t=4115, a rather non-aluminium bearing plate in the middle of the gearbox.
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75 gearbox 3.jpg
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Re: transaxle upgrade's

Post by gtv-racer » Tue Nov 29, 2016 11:32 am

Nice to see the idea backuped by the pros!
Would like to know or this gearbox has a needle bearing in the font box part for the secondary axle instead of a bronze bush....? That also will help secondary axle flex because of the play in the bronze bush.
The bush was worn out badly in my transaxle when i overhauld it only in the flex direction.
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Re: transaxle upgrade's

Post by gtv-racer » Fri Jan 27, 2017 1:07 pm

Took some measurements today. I saw we can have a 4mm space for an extra bearing if we move gears...That looks like verry limmited space but i'll discuss it with our engineer.
Bought cooling stuff for the transaxle last month. Oil cooler,fully controlled thermostat,inline filter and a pump.
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Giuliettaevo2
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Re: transaxle upgrade's

Post by Giuliettaevo2 » Sat Jan 28, 2017 2:42 am

Are you only going to circulate the oil to cool it or will you spray it onto a certain location?
Drive it like you stole it...
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Re: transaxle upgrade's

Post by gtv-racer » Sat Jan 28, 2017 11:29 am

Think i only circulate it. My good guess is that the oilflow in the box is so turbulant it will mix up just fine.
But inject the oil in the back and suck it out upfront so you get a nice oilflow. I'll make these connections when i pull the box for the bearing plate upgrade. For now i just use the oil filler pllug and the drian.
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Re: transaxle upgrade's

Post by gtv-racer » Fri Mar 17, 2017 10:37 am

Installed the transaxle oil cooler.

Heat exchanger with ducting:

Image


Overview:

Image

A 0.06mm filter is fitted with a magnet inside.

The fully controlable thermostat:

Image
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Re: transaxle upgrade's

Post by gtv-racer » Fri Dec 08, 2017 12:13 pm

Finaly finished the gearbox.

New ugraded 50% stiffer gearbox bearing flange installed with mildly lightend 5th gear and reverse:

Image

Needle bearing install instead of bronze bush wich wears out quicly and causes extra axle flex:

Image

The brace wich keeps the gearbox halves together with preload screws:

Image

Image

Image

Hope it is now ready for an other power mod :mrgreen:
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Re: transaxle upgrade's

Post by Duk » Fri Dec 08, 2017 8:38 pm

Excellent!
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Re: transaxle upgrade's

Post by 75evo » Sun Dec 10, 2017 3:53 pm

Nice one bud. Can we buy the design from you? Can CNC it locally.
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Re: transaxle upgrade's

Post by gtv-racer » Tue Dec 12, 2017 8:29 am

I think i'll produce a small serie for sale. That's if enough people want them.
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Re: transaxle upgrade's

Post by maxiboy » Tue Dec 12, 2017 2:31 pm

gtv-racer wrote:I think i'll produce a small serie for sale. That's if enough people want them.
Amazing work.. loving this thread
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