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What sort of power can the automatic gearbox can survive.

Posted: 08 Aug 2013, 10:40
by Zebedee
Does anyone know what sort of BHP and most importantly torque the automatic gearbox can survive?

Will 225 lb/ft be too much for it?

Re: What sort of power can the automatic gearbox can survive.

Posted: 08 Aug 2013, 17:56
by silverbullet
Autos are all massively strong as a rule, because the epicyclic gear assemblies can handle huge input torques. I was told that my supercharged MV used to be in an auto Caravelle Gl with all the toys inc. aircon and would still turn in a 0-60 in under 9 seconds :shock: So it was getting a fair bit of load put through it!
What engine are you thinking about that makes 225 lb.ft? That's 305 Nm or just about the ultimate limit for the manual transmission in a light T3, driven with respect...
I think that Mr Mule had an auto on an SVX but it might have been the Subaru trans with a special reversed r&p set.

Re: What sort of power can the automatic gearbox can survive.

Posted: 08 Aug 2013, 18:07
by Zebedee
My bad, its just a measly 184 lbf/ft not 225. :oops:

Its a 1.8t engine from a B5 passat.

Re: What sort of power can the automatic gearbox can survive.

Posted: 08 Aug 2013, 20:32
by silverbullet
OK so that's still 250 Nm, the auto will easily handle that but... there aren't many people doing engine swaps on autos so you'd be pioneering all the way. Plus that engine is designed for a modern 5(?) speed auto with the relevant ecu-controlled shifts, not the ancient wide-ratio 3-speed you find in our buses.
Good luck!

Re: What sort of power can the automatic gearbox can survive.

Posted: 09 Aug 2013, 11:04
by Zebedee
2.0 AGG would probably be easier. Its just the passat is currently sat in my local scrappy and it got me thinking. :oops:

I like the idea of an auto, just don't want to really go the scooby route and would rather keep it VW engined.

Re: What sort of power can the automatic gearbox can survive.

Posted: 10 Aug 2013, 09:24
by mm289
Pretty much as SB said, IIRC Mr Mule's one was a standard T3 auto but with a new ring and pinion - he had a limited production run done. The 1.9 Auto has a lower final drive which makes it unsuitable for anything with any power as it will just buzz th engine, the 2.1 is the one to go for but r&p's are none existent as parts. Have a look http://www.thesamba.com/vw/forum/viewto ... sc&start=0 for the full story.

The one thing I would do is increase the cooling capacity on the auto box, additional load = heat in an auto and heat = death :roll:

Cheers,

MM

Re: What sort of power can the automatic gearbox can survive.

Posted: 10 Aug 2013, 10:40
by Zebedee
So the 2.1 autobox is the one to use then?
Whatever engine i end up with the autobox is probably gonna get the VW cooler removed and a fan assisted mocal or similar with a thermostat fitted instead.