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Zeitgeist 13
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Joined: March 05, 2009
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Location: Port Manteau
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 Posted: Mon Oct 22, 2012 2:04 pm Post subject: |
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In case anyone is having trouble imagining what I'm contemplating, here's a visual depiction rendered by my awesome MS Paint skillz:
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
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hans j
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Joined: May 06, 2006
Posts: 2741
Location: Salt Lake City UT
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| Posted: Mon Oct 22, 2012 2:13 pm Post subject: |
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| Zeitgeist 13 wrote: |
| I'm going to cannibalize my own thread with an off the wall "what if" question. Taking gear ratios out of the equation, would it be possible to place a transverse front wheel drive VW drivetrain mid-mounted (about where the trans normally sits) in a T3 chassis, but in a longitudinal configuration, with the drive axles running fore/aft to two separate differentials. You'd essentially have a center diff, perhaps even locking, with then two axle diffs, also perhaps locking. If the center diff were open, you'd probably want the drive axle output sent to the rear. Has anyone contemplated such an abomination, or am I missing a fatal flaw in the ointment? |
I would run a torque biasing diff in the trans and then what ever you want in the front/rear diff. I would think those would have to be close to 1:1 to keep the ratio from the trans to the tires correct?
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1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181 |
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Zeitgeist 13
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Joined: March 05, 2009
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Location: Port Manteau
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| Posted: Mon Oct 22, 2012 2:26 pm Post subject: |
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While I'm sure you want to keep the center/axle diff ratios within reasonable limits, wouldn't separate diff ratios just be similar to running portal-style reduction boxes? In other words, like I said before, the center diff just sets the output shaft(s) speed, but the axle diffs set the wheel speed. Perhaps I'm being naive and simplistic, but I think you can run just about any (matched) axle diff ratio you want, irrespective of the center diff (final drive). Could make for some interesting mix n' match scenarios
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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D Clymer
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Joined: December 22, 2005
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Location: Issaquah, WA
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| Posted: Mon Oct 22, 2012 2:36 pm Post subject: |
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| Zeitgeist 13 wrote: |
| While I'm sure you want to keep the center/axle diff ratios within reasonable limits, wouldn't separate diff ratios just be similar to running portal-style reduction boxes? In other words, like I said before, the center diff just sets the output shaft(s) speed, but the axle diffs set the wheel speed. Perhaps I'm being naive and simplistic, but I think you can run just about any (matched) axle diff ratio you want, irrespective of the center diff (final drive). Could make for some interesting mix n' match scenarios |
I'm pressed for time right now, so I haven't read the last few posts, but in regards to gearing, the final drive ratio in the transaxle would need to be changed to 1:1. Then the front and rear axle differentials would just need to be matched. You could choose whatever suits the application: 4.11, 3.89, etc. IRS differentials from rear drive cars would probably be the best components for this.
I actually like this idea. I think clearance of the halfshaft under the engine would be the only tricky packaging issue.
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Zeitgeist 13
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Location: Port Manteau
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| Posted: Wed Oct 24, 2012 9:44 am Post subject: |
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It's raining again, but it's still blue sky Wednesday here in Cascadia...
I'm certainly not a powertrain engineer, but I like to pretend I am here on the interwebs, so please indulge my silly little fantasy. Because I'm mostly ignorant and stoopid stubborn, I'm still not convinced that the center diff in this hypothetical arrangement needs to be either 1:1 or exactly match the axle diffs, but I'm open to being convinced. With that in mind, I'll forge ahead with more blue skying
The obvious choice for fr/rr axle differentials would be the early Quattro locking diffs in 4.11 trim, but they're really big, getting more scarce and may not be amenable to flipping end over end as would be need for the front axle. Another option I'm entertaining is the MB early 4Matic diffs in 3.27 trim. The intriguing thing about these is that they use a hydraulic locking arrangement that cinches down on each axle flange to progressively lock that axle. MB sets it up to lock both at the same time, but you could theoretically switch between locking both or single axles for something like a steering brake. 3.27 isn't exactly rock-crawling material, but it's an intriguing concept nonetheless. A simple little electro/hydraulic pump, switchover valves and a Syncro dash pod with push/pull switches and you've got locking differentials, just like a Syncro.
Complicated? pffft, we're blue-skying this thing
Here's a list of VW transmissions and their respective ratios for reference
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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D Clymer
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Joined: December 22, 2005
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| Posted: Wed Oct 24, 2012 9:57 am Post subject: |
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The front and rear diff ratios would definitely need to be matched. If you want a 4.11 in the front you would need to run a 4.11 at the back.
The reason you would need a 1:1 in the "center diff" position is to maintain a reasonable overall ratio. It's true, in practice you could run a stock ratio in the "center diff" position, but the overall ratio would be really low.
Fun to think about.
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Zeitgeist 13
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Joined: March 05, 2009
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Location: Port Manteau
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| Posted: Wed Oct 24, 2012 10:13 am Post subject: |
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Yes, this is for fun and brain candy. I'm completely on board with matching front/rear diff ratios...it would be a train wreck otherwise.
So, do the combined center and axle diff ratios get compounded, e.g.
Center diff: 3.389
+
Axle diffs: 2.65
=
Combined final drive: 6.039
If so, now we have created a rock crawler
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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D Clymer
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Joined: December 22, 2005
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Location: Issaquah, WA
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| Posted: Wed Oct 24, 2012 10:59 am Post subject: |
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| Zeitgeist 13 wrote: |
Yes, this is for fun and brain candy. I'm completely on board with matching front/rear diff ratios...it would be a train wreck otherwise.
So, do the combined center and axle diff ratios get compounded, e.g.
Center diff: 3.389
+
Axle diffs: 2.65
=
Combined final drive: 6.039
If so, now we have created a rock crawler |
You would actually multiply the two final drives. It's the same relation as having a low range transfer case factored into the equation. So yes, using a stock final drive in the "center diff" would make a rock crawler. Going throught a 1:1 "center diff" would create a good road vehicle.
Like I said, I like the idea. But I would modify the layout in your diagram so that the engine is as far back as possible. Then the rear diff could be beside it like it is at the front on some rear drive cars that have been modified for AWD.
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Zeitgeist 13
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Location: Port Manteau
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| Posted: Wed Oct 24, 2012 11:27 am Post subject: |
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Yikes, multiplying ratios? The lowest final drive combo I could find was 7.591...which would be pretty interesting for an offroad vehicle like Mike Ghia's lightweight SWB project
Ok, you've convinced me that the center diff needs to be 1:1, but I don't think the engine can be moved much further back unless the axle and part of the flange run through the oil pan, which is how it's done on the aforementioned MB 4Matic. Possible, but not very practical.
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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D Clymer
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| Posted: Wed Oct 24, 2012 11:40 am Post subject: |
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Yeah, but moving the engine back would allow it to sit in the engine bay, which I think is important. If it was further forward it would interfere with the rear seat. I don't think going through the oil pan is out of the question. After all, it's been done with numerous vehicles. It should be possible to do it with a VW inline four.
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Zeitgeist 13
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| Posted: Tue Aug 20, 2013 4:42 pm Post subject: |
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| Zeitgeist 13 wrote: |
Since Dave's excellent 5spd build thread has culminated in what appears to an excellent trans swap, I thought I'd resurrect this thread which is devoted to the pursuit of other options to consider. Maybe this will spawn a build thread...
I see several others have been pursuing Audi options like the 012, which appears to have some following amongst the kit car crowd. I think this is the trans we've seen in another thread that's been flipped over with the five cyl. TDI swap. As I've mentioned before, I'd like to see how that configuration holds up over time. If it does, that could be a very attractive option.
I'm presently contemplating the part out of my C4 Quattro which has a ZF 4HP 18 4spd automatic. This trans was installed in a wide variety of cars (incl. Dodge/Eagle/Renault) for about a decade, and is pretty robust. I'm very curious to see if it can be modified to run in a rear configuration with a pinion "redirect", as opposed to a ring gear swap.
Assuming this can be accomplished, it could technically be possible to run the remaining Quattro drivetrain, which could create a rather nice AWD vehicle for the road, rather than rock-crawling. Imagine if Audi had produced an upmarket version of the T3 back in the late '80's.
EDIT: That second to last pic appears to be an 016 trans |
I sorta hijacked Flint's reversed 1.8t thread with a question about the 012 trans which have had their bell-housings sliced off and re-welded 180 degrees from their stock orientation. Please provide any up to date info about these arrangements, so we can further the discussion regarding whether they are holding up in real world situations.
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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xoo00oox
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Joined: February 11, 2010
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| Posted: Tue Aug 20, 2013 5:39 pm Post subject: |
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| I believe there is an engine adapter made (UK?) to bolt the engine at 50° to a flipped trans. |
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Zeitgeist 13
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Location: Port Manteau
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| Posted: Tue Aug 20, 2013 5:47 pm Post subject: |
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So, they're no longer slicing the bell-housings? Seems like a variety of degree adapter options would be pretty cool, like 15, 22 and 50
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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xoo00oox
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Zeitgeist 13
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Joined: March 05, 2009
Posts: 12168
Location: Port Manteau
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| Posted: Wed Aug 21, 2013 8:20 am Post subject: |
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Here's a pic I cribbed from an Irish diesel Split build thread.
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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insyncro
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| Posted: Wed Aug 21, 2013 8:23 am Post subject: |
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| 930s and a slammed suspension looks to be the ticket. |
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svenakela
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Location: Ekerö
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| Posted: Wed Aug 21, 2013 8:44 am Post subject: |
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I have posted in before, but here goes...
If anyone is interested in the 012 swap, I have a list of almost all gearbox codes.
http://bit.ly/1f2nlWn
I also made a calc sheet where you can add the ratio's to compare with a Vanagon tranny directly, namely the AAP.
http://bit.ly/183EsmT
EHV is in the calc sheet as default because that is what I have. |
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Zeitgeist 13
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Joined: March 05, 2009
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Location: Port Manteau
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| Posted: Wed Aug 21, 2013 9:08 am Post subject: |
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Has anyone made an adapter plate commercially available? I might be convinced to keep my TDI swap a manual trans, if an option like this opened up as a viable inexpensive non can of worms. My local PnP has an 012 sitting in an A4 for really cheap.
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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svenakela
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Joined: July 19, 2006
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Location: Ekerö
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| Posted: Wed Aug 21, 2013 9:38 am Post subject: |
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| Zeitgeist 13 wrote: |
| Has anyone made an adapter plate commercially available? I might be convinced to keep my TDI swap a manual trans, if an option like this opened up as a viable inexpensive non can of worms. My local PnP has an 012 sitting in an A4 for really cheap. |
Yes, Tim has everything you need. Adapter, spacers for the CV's, shifter adapter (if not going the wire route), and a well proven method how to prepare the tranny for the flip side. The parts aren't listed on the web site but you find him here:
http://www.ultimate-engineering.co.uk/ |
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Zeitgeist 13
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| Posted: Wed Aug 21, 2013 10:04 am Post subject: |
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Thank you, sir!
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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