TheSamba.com :: View topic - Manual transmission rebuild

Fri Jan 07, 2011 9:31 am

I have the EJ22 with the stock trans, 215-75-15 tires. The stock ratios are pretty good. Ideally I'd have a slightly taller 3rd gear so I can cruise up hills at 60 MPH without flogging the engine so much. And a shorter 1st gear would be great for those infrequent times I find myself off-roading or towing something heavy. I would not change 4th gear.

With my rear anti-sway bar I find my rear tires spin all the time in the rain around turns. A better diff would be nice for sure, but I've never been stuck because of the open diff. I could not justify the price of the Peloquin.

Fri Jan 07, 2011 11:15 am

> !. I read the ratios are just fine if I use bigger tires (from the Suby-Vanagon list.) But just how big I never find out. What is the story here?

215x75x15 is the reasonable limit, but only if you need more ground clearance offroad and are willing to spend a lot of time in 3rd going uphill, they are 10% taller than stock

the tire size you are considering is 5% taller than stock.. I would not go bigger and I would not make the gears taller

> 2, Related to the above, do I want a different 4th gear like a 0.77? How is the gap 3rd to 4th? Do I want this or not?

NO

> Does it really make better mpgs?

absolutely NOT

> 3. Since we may go in the snow or sand a couple of times a year, maybe, do I want the limited slip? (BIG bux here.) Do I really need this as we just don't do it much, but once in a while, maybe?

NO, not for your driving needs

> 4. Locker? Costs like another grand or more on top of everything?

absolutely NOT, based on your driving needs

> With my rear anti-sway bar I find my rear tires spin all the time in the rain around turns.

time for new tires brother :-)

Fri Jan 07, 2011 11:26 am

Jon_slider wrote: > With my rear anti-sway bar I find my rear tires spin all the time in the rain around turns.

time for new tires brother :-)

How do you think my tires got that way? :wink:

Fri Jan 07, 2011 11:36 am

Jon_slider wrote: > With my rear anti-sway bar I find my rear tires spin all the time in the rain around turns.

time for new tires brother :-)

Rear anti-roll bars limit the downward travel/pressure of the inboard rear tire causing traction issues. The "loose" Vanagon differential allows that inboard tire to spin...even with brand new tires. I have been "stuck" in a few situations with a tire completely off the ground while traversing into/out of driveways with my rear anti-roll barred van.

Fri Jan 07, 2011 11:46 am

loogy wrote: Jon_slider wrote: > With my rear anti-sway bar I find my rear tires spin all the time in the rain around turns.

time for new tires brother :-)

Rear anti-roll bars limit the downward travel/pressure of the inboard rear tire causing traction issues. The "loose" Vanagon differential allows that inboard tire to spin...even with brand new tires. I have been "stuck" in a few situations with a tire completely off the ground while traversing into/out of driveways with my rear anti-roll barred van.

Drinking the same water again, I see Chris :) I was just about to post the same thing. A rear sway bar indeed cuts down on the already minimal amount of rear suspension articulation on the T3. At that point, tires don't matter. That dynamic consideration is what has kept me from ever installing a rear bar on my van.

David

Fri Jan 07, 2011 6:09 pm

I talked to the gear heads at Weddle. While .77 is too big a jump, there is a .82 gear (rare factory and $300 aftermarket.) Anybody care to play the numbers game with me?

The idea is to get the rpms down on the freeway. A quick pencil push indicates about 3600 RPM at 70 mph. I want to stare at the numbers and torque curve a bit before I step over to that ratio for 4th.

Fri Jan 07, 2011 6:46 pm

Just going purely by gear ratios I think the .82 would be fine, and it wouldn't create a huge gap between 3rd and 4th like the .77. In fact, the factory used the 1.26 to .82 3rd and 4th gear setup back in the early T3 1600 air cooled vans. However, on the flipside that's still $300 for a very minimal change in gearing. I would be tempted not to do and just rely on the upsized tires to raise the overall ratios of all the gears.

Another alternative that no one has mentioned is to fit a 4.57:1 final drive ratio to the transmission. This is a factory ratio used in some european transporters (not to be confused with the 4.57 final drive in our air cooled trannies that won't fit an 091/1). Using the 4.57:1 with the stock .85 4th would yield an overall 4th gear ratio of 3.88:1 as opposed to 3.96:1 for .82 x 4.83. It's a little more expensive. Winkler sells it for 410 euros on their website and Weddle probably can supply one. Using the 4.57 would allow you to keep tight gear spacing, it would raise all the gears usefully, and you wouldn't have to oversize the tires so much.

David

Sun Jan 09, 2011 11:12 pm

OK, I think I am set. Here's what is on the plate at Rancho to include in the rebuild:

Small Car bell housing
Weddle hardened 3/4 slider
Weddle machined end cap with hardened shaft holder
SA oil deflectors
0,82 4th gear (71mph @ 3500 rpm with my 27in 215/65-16 tires)

Tell me what you think.

I used the calculator at:
http://www.teammfactory.com/gearcalculator.php?kmh...on+1+%26+2
.

Mon Jan 10, 2011 12:08 am

I like it! looks like a good combo.

Mon Jan 10, 2011 12:00 pm

D Clymer wrote: Just going purely by gear ratios I think the .82 would be fine, and it wouldn't create a huge gap between 3rd and 4th like the .77. In fact, the factory used the 1.26 to .82 3rd and 4th gear setup back in the early T3 1600 air cooled vans. However, on the flipside that's still $300 for a very minimal change in gearing. I would be tempted not to do and just rely on the upsized tires to raise the overall ratios of all the gears.

Another alternative that no one has mentioned is to fit a 4.57:1 final drive ratio to the transmission. This is a factory ratio used in some european transporters (not to be confused with the 4.57 final drive in our air cooled trannies that won't fit an 091/1). Using the 4.57:1 with the stock .85 4th would yield an overall 4th gear ratio of 3.88:1 as opposed to 3.96:1 for .82 x 4.83. It's a little more expensive. Winkler sells it for 410 euros on their website and Weddle probably can supply one. Using the 4.57 would allow you to keep tight gear spacing, it would raise all the gears usefully, and you wouldn't have to oversize the tires so much.

David

I have been contemplating a transmission overhaul and re-qearing to better suite my Subie 2.5 install last year. Talking to Go-Westy they were recommending going to 1.18 for 3rd, .77 for 4th and then changing out the ring and pinion to 4.57:1 to raise the overall gearing of the transmission. I always thought 1st gear was too low. and my driving would be mostly highway so that appealed to me. To try and get my head around things (and because I'm such a nerd) I decided to try an graph RPMs vs MPH. I'm currently running a 84 Westy with stock 2.5L SOHC engine, code DU 4 speed and 205R65 x 15 tires (25.3 dia). Cruising with the current set up the engine really likes to run about 3500 which is about 62 mph. As a first estimate I'd thought if lower the gearing to get the engine turning 3500 at 75mph that would be good. My concern with that is that if you got into hilly country then you would have to down shift to third and would you be able to maintain highway speed with the RPMs being unreasonable.

I graphed RPM vs MPH for my current stock set up and the lower 3rd/4th and ring and pinion.

For a 2.2 Subaru installation with 20 less HP the higher overall ratio may not work if you drive in hilly terrain.

Of course the hot set up is using the Subaru 5 speed as I know you are working on Dave. I've included that in these graphs to show how it will perform. Any news on your 4.44:1R&P Dave?

Mon Jan 10, 2011 6:56 pm

What size tires is this based on?
Are the stock ratios for the DU of 3.78, 2.06, 1.26 and 0.853 with RP of 4.86?
What are the Suby ratios?
.

Mon Jan 10, 2011 8:17 pm

JPrato wrote:

Of course the hot set up is using the Subaru 5 speed as I know you are working on Dave. I've included that in these graphs to show how it will perform. Any news on your 4.44:1R&P Dave?

Hi J -

Yes, I created some graphs comparing the Subaru 5MT close ratio trans to various Vanagon 091 ratio combinations and it's pretty amazing how ideal the spread of gear ratios really is. I think it's going to bring a whole new dimension to these SubaruVanagons.

I heard from Todd Triebler last week and the trial gearset he had ordered from the new factory had been installed in the blue test buggy along with a WRX limited slip differential and were functioning beautifully under hard use. The next step now is order my set of gears. I need to touch base with Todd and find out if he has placed the order yet.

I am planning on producing and selling the conversion shift linkage, trans mount, and modified end housing to make this conversion a bolt in.

David

Mon Jan 10, 2011 8:20 pm

r39o wrote: W
What are the Suby ratios?

Walt,

The close ratio Subaru 5MT gear ratios are:

3.55:1
2.06:1
1.45:1
1.09:1
.78:1

There are a couple variations, but this is the typical setup.

The shortest available final drive is 4.44:1.

David

Mon Jan 10, 2011 8:44 pm

an unmodified USA model vanagon goes 71mph at 4000rpm

I dont recommend gearing faster than 76mph@4000rpm, because you will be spending a lot of time in 3rd gear above 5000rpm, which is not relaxing, even though the subaru can tolerate it

link to spreadsheet here:
http://www.thesamba.com/vw/forum/viewtopic.php?p=5043442#5043442

Mon Jan 10, 2011 10:11 pm

D Clymer wrote: I am planning on producing and selling the conversion shift linkage, trans mount, and modified end housing to make this conversion a bolt in.
I want to play. This monkeying around with the 4 speed and costs are not what I want. Too bad I am at this point now.

I guess now I have to search out some of those 5 speeds that were useless before....

Mon Jan 10, 2011 10:25 pm

Jon_slider wrote: an unmodified USA model vanagon goes 71mph at 4000rpm

I dont recommend gearing faster than 76mph@4000rpm, because you will be spending a lot of time in 3rd gear above 5000rpm, which is not relaxing, even though the subaru can tolerate it

link to spreadsheet here:
http://www.thesamba.com/vw/forum/viewtopic.php?p=5043442#5043442
What I propose is 83 mph at 4000 rpm.

The below calculator says to shift at about 4662 rpm.

Based on my torque curve above, I have over 100 footpounds of torque at the wheels from 2500 to 5000. If I shift into 4th at 3700 rpm I end up 2500 rpm, still well in the torque band.

I don't get why I "will be spending a lot of time in 3rd gear above 5000rpm?"

http://www.teammfactory.com/gearcalculator.php?kmh...on+1+%26+2

Mon Jan 10, 2011 10:31 pm

If you want to compare gear ratios and/or RPM with different tire sizes, I found this link to be very usefull. It lists all the different trannys and gear ratios and has built in work sheets to compute convert engine RPM to MPH There is a line to input custom gear ratios if you wanted to create the ultimate tranny

http://members.shaw.ca/vwdiesel/VanagonTransRatios.xls

Have fun, I've spent hours running different combos of gears and tire sizes

Hans

Mon Jan 10, 2011 11:23 pm

r39o wrote: D Clymer wrote: I am planning on producing and selling the conversion shift linkage, trans mount, and modified end housing to make this conversion a bolt in.
I want to play. This monkeying around with the 4 speed and costs are not what I want. Too bad I am at this point now.

I guess now I have to search out some of those 5 speeds that were useless before....

Yeah, I know. I didn't even want to mention the possibility of the Subaru tranny though since I know you need a tranny now and I'm still a little ways off with the conversion. You've made good choices with the trans you're building, though, and it will serve you well. You can always resell it if you do decide to go with the Subaru 5 speed at a later time.

BTW, thanks for posting the link to the ratio graphing website. I had been looking for a program like that and I had fun graphing different ratio comparisons last night :)

David

Mon Jan 10, 2011 11:45 pm

David,

Other people have told me that this item or that which I am using for my conversion was not available when they did theirs. The Subaru transmission is the one that is not available for my conversion. It is a evolving moving target.

Sometime down the road I may be switching engines or building that higher compression 2.5 with the 2.2 heads I have read about. So I could do it then. I suspect it is all more than a year away likely anyways for you.

I am about economy. Sure I would have loved a TDI. We drive two of them. I can not get my self to slaughter my 98 NB just yet. It is too cheap to drive it. But, just how much money do I want to spend in the name of economy anyways? The TDI is just too involved for my requirements and costing.

A cheaply build, more efficient 2.5L coupled to a better matched 5 speed with some LSD would be a step up. Or maybe even a Subaru diesel mated up to a Subaru 5 speed. All nice and if I can do it without breaking the bank, I will consider it. It would be cost effective. I would guess it would be more fuel efficient too.

In the mean time, I will go along with this setup unless I am convinced I am not making a prudent choice.

THANKS,
Walt...

Tue Jan 11, 2011 1:37 am

r39o wrote:

Based on my torque curve above, I have over 100 footpounds of torque at the wheels from 2500 to 5000. If I shift into 4th at 3700 rpm I end up 2500 rpm, still well in the torque band.

I don't get why I "will be spending a lot of time in 3rd gear above 5000rpm?"

Your torque at the wheels will change with a different ratio

Bear in mind that you are pushing a giant brick through the air - the faster you go, the more torque you require - and it's not linear, it's exponential!

The required engine torque increases as gearing gets taller. believe me - as mentioned above, if the gearing is just a bit too tall, every hill you get to, you'll find you HAVE to change down to maintain speed, so you end up doing even higher RPM than if you had a more conservative ratio.

Think of a bike. you can exert the same pressure on the pedal within a given pedal speed range. if you try to ride up a hill in top gear, you will stop. choose a lower gear, you can do it. remember, you are able to exert the same pressure on the pedal. The gearing makes the difference.

You will need to have more rpm than a subaru car at the same speed, to overcome the additional weight and wind resistance. The subaru gearing will be set generally for optimum fuel economy.

If you had 5 gears to play with, then 5th could be taller, because you can change down to 4th when ever you want, and leave it there. Since you only have 4 to play with, do you want to be in a situation when your only option is 3rd and what ever RPM that entails?

Allan.