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prom8n
Samba Member
Joined: April 01, 2005
Posts: 60
Location: Pinckney, Michigan
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 Posted: Tue Oct 02, 2007 8:42 am Post subject: Dumb Question: Just what IS a "Super-Diff"? |
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Rebuilding my '73 Thing, pulled the trans last weekend. Checked the info here on transmissions, and I have the correct "AV" coded unit. I'm debating the benefits of installing a Super-Diff, but I realized that I don't really know what one is. I did a couple of searches, but didn't find any real answer. Lotsa talk about them, but not much on actual function.
So, oh wise ones, just what is this mystical device anyway? What's it do? Any benefit to installing one in a daily driver trans? Will a standard Thing gearbox see any real improvement? |
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Ian Epperson
Samba Member
Joined: January 12, 2005
Posts: 2262
Location: Alameda, CA
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prom8n
Samba Member
Joined: April 01, 2005
Posts: 60
Location: Pinckney, Michigan
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| Posted: Tue Oct 02, 2007 9:40 am Post subject: It's a bird, it's a plane, it's a ... Thing? |
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Ok, I asked for that one. Stepped right in it. But thanks for the info and the links.
As far as the engine goes, there's still the 1600DP over there in the corner, but I have a 1800 T-4 laying around, and I find the efforts of Mr. Jake Raby very interesting; perhaps I'll convert it. I wonder what extra stress this would place on the gearbox.... |
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Ace
Samba Member
Joined: July 07, 2003
Posts: 1903
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| Posted: Tue Oct 02, 2007 9:52 am Post subject: |
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| A super diff is basically a diff with 2 more spider gears. Doubles the strength of the diff. The aftermarket super diffs usually have a beefed up housing too. |
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Thingggg
Samba Member
Joined: June 30, 2004
Posts: 353
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spaeth
Samba Member
Joined: January 05, 2005
Posts: 355
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| Posted: Wed Oct 03, 2007 9:45 pm Post subject: |
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"I wonder what extra stress this would place on the gearbox...."
That is not a matter of how much power you have but how you use it. A stock 1600 can work over a stock tranny pretty well if you rev it up and drop the clutch at every start. The bigger motor you get the more power you have available to do damage, but if you apply that power accordingly you should be OK. If you want to do drag race starts or go off roading, where wheels are lifted, spin, and then catch, the Super diff is needed. If you just want more power on the hills etc... you can get away with a stock tranny.
Craig |
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prom8n
Samba Member
Joined: April 01, 2005
Posts: 60
Location: Pinckney, Michigan
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| Posted: Thu Oct 04, 2007 5:32 am Post subject: Trans choices |
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Thanks Craig. I intend to rebuild this Thing for long-term use. Had one when I was a kid, and beat the bleep out of it. Now that I'm pushing 50, I want to do it right (for a change) and make this one last (so my sons can beat the bleap out of it when I'm gone!). The research I've done over the last few days indicates that the standard AV-code trans in the Thing is a pretty sturdy unit to start with, and since I'm not using it for hill climbs or drag racing, I'll clean it out and keep it.
The extra power and torque of a T-4 will bend the frame forks down if I don't add a mustache bar behind the engine, so I'll see about installing mounts for this on the body if I go that route. I'd like to run a stock 1800 T-4, DTM fan conversion, dual carbs and a nice header, but we'll see.
Let the antics ensue. |
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Jake Raby
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Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Thu Oct 04, 2007 10:05 am Post subject: |
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Going to a moderately prepped TIV does not necessitate a super diff or other efforts at strengthening the frame horns unless the driver plans on driving the car very hard doing clutch drops and etc.
Going to TIV power is best when matched to taller gearing, the TIV has the excellent cooling capability as well as much hiher torque at a much lower RPM, both mandating gearing swaps for total vehicle optimization. |
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Ian Epperson
Samba Member
Joined: January 12, 2005
Posts: 2262
Location: Alameda, CA
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| Posted: Thu Oct 04, 2007 10:58 am Post subject: Re: Trans choices |
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| prom8n wrote: |
The extra power and torque of a T-4 will bend the frame forks down if I don't add a mustache bar behind the engine, so I'll see about installing mounts for this on the body if I go that route. I'd like to run a stock 1800 T-4, DTM fan conversion, dual carbs and a nice header, but we'll see.
Let the antics ensue. |
There are other ways of dealing with the torque without the rear hanger "mustache bar". I went with a Kafer-type setup with some mods to make it all fit properly:
Also welded the frame horn seams and added an intermediary trans mount.
_________________
VW-181 shirts and stickers.
http://ian.epperson.com/vw |
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prom8n
Samba Member
Joined: April 01, 2005
Posts: 60
Location: Pinckney, Michigan
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| Posted: Fri Oct 05, 2007 8:03 am Post subject: Trans bracing |
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Very nice work Ian. I've also perused your website, and I commend you on all the useful info there. Lots of good reading!
Do you prefer the diagonal brace from the rear trans mount to the shock tower over the mustache bar? I'd need to mount that to the sheet metal at the rear of the engine compartment somewhere, and I'm concerned that no matter how much this is re-enforced, it will still not handle the stress. The engine I'm considering came out of a '75 Bus, and has the bar and fresh rubber mounts, but there's no frame at the rear of the Thing to bolt it to. Fabrication is no problem, metal fatigue is.
What say you? |
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