Question about gearing, 3.70vs.3.90vs.4.11vs.4.44

[superu]

3.54 yay yay bump 3.54

 

teehee

[WoodsWagon]

What he really meant by "that's it" is the R&P setup process. Changing the gears to another set is trivial (open case, put in gears!) by comparison to what must be done after they are in the case - setting the clearances between the two is not something that most people are trained to do or really have the time/patience/equipment to undertake.

 

GD

I think he was being sarcastic. But really, swapping the ring and pinion is not rocket science. There's no custom machine work involved, and you don't have to match ratios on the 1-5 gears because they aren't attached to the pinion shaft like Gloyale had said.

 

Oh, and there's no 3.54 front ring and pinion sets available. The wrx's that had 3.54 rear diffs had 3.9 front diffs, and 1.1:1 rear transfer gear sets, so it was effectively 3.9 all round.

Edited May 27, 2011 by WoodsWagon

[987687]

I think he was being sarcastic. But really, swapping the ring and pinion is not rocket science. There's no custom machine work involved, and you don't have to match ratios on the 1-5 gears because they aren't attached to the pinion shaft like Gloyale had said.

 

Oh, and there's no 3.54 front ring and pinion sets available. The wrx's that had 3.54 rear diffs had 3.9 front diffs, and 1.1:1 rear transfer gear sets, so it was effectively 3.9 all round.

 

I thought the SVX had 3.54 all the way around? Or did it have a non-1:1 center ratio?

[superu]

I think he was being sarcastic.

 

right!

 

quote=91Loyale;1020159]

Oh, and there's no 3.54 front ring and pinion sets available. The wrx's that had 3.54 rear diffs had 3.9 front diffs, and 1.1:1 rear transfer gear sets, so it was effectively 3.9 all round.

 

that was bugeye WRX or all of them? I kind of remember that WRX's had a different front:rear split from NA 5MTs... the different gearing would explain it like you said then.

 

didn't the SVX have some weird FD ratio too? and they were all autos too. "luxury coupe" and all

[987687]

right!

 

quote=91Loyale;1020159]

Oh, and there's no 3.54 front ring and pinion sets available. The wrx's that had 3.54 rear diffs had 3.9 front diffs, and 1.1:1 rear transfer gear sets, so it was effectively 3.9 all round.

 

 

didn't the SVX have some weird FD ratio too? and they were all autos too. "luxury coupe" and all

As I said right above, some of the SVXs had 3.54 ratio. And since it's an auto I seriously doubt the center wasn't 1:1. That would mean they have to have a 3.54 front diff too.

[renob123]

As I said right above, some of the SVXs had 3.54 ratio. And since it's an auto I seriously doubt the center wasn't 1:1. That would mean they have to have a 3.54 front diff too.

 

I'm pretty sure you're correct. I thought for the longest time that the FWD SVXs had the 3.54 FD, so they wouldn't have a center ratio. I think a few years of STIs had the 1.1:1 ratio (including mine, maybe). There was a lot of misinformation out there during the first couple years they were released here, and that happens to be when I was doing the most research. However, as I've said before, FD is a moot point when you have the 6-speed gear ratios:slobber:

 

Jacob

[987687]

I'm pretty sure you're correct. I thought for the longest time that the FWD SVXs had the 3.54 FD, so they wouldn't have a center ratio. I think a few years of STIs had the 1.1:1 ratio (including mine, maybe). There was a lot of misinformation out there during the first couple years they were released here, and that happens to be when I was doing the most research. However, as I've said before, FD is a moot point when you have the 6-speed gear ratios:slobber:

 

Jacob

 

The only 6MT that has a 1.1:1 ratio (according to the spreadsheet of gear ratios I have) is:

UK/Europe/NZ Impreza WRX STi MY02-04

[renob123]

The only 6MT that has a 1.1:1 ratio (according to the spreadsheet of gear ratios I have) is:

UK/Europe/NZ Impreza WRX STi MY02-04

 

Yeah, see, it depends on when the spreadsheet was made and which information they chose to use. I read stuff a month ago or so that said a USDM '06 STI actually has a 1.1:1 as well.

 

Jacob

[987687]

I have this chart. Only goes to 05. But I've never heard the 06 having anything besides a 3.9

[superu]

Yeah, see, it depends on when the spreadsheet was made and which information they chose to use. I read stuff a month ago or so that said a USDM '06 STI actually has a 1.1:1 as well.

 

Jacob

 

So, how does or does that account for the VCCD (if those are the right letter?) variable center diff. STIs had that "dial-a-center ratio" right, but not WRXs?

[987687]

Only the 6speed has DCCD, the center diff control. WRX does not have 6speed.

 

I've never heard talk about 3.54 and STi trannies, but I don't have any hard information, so I'm not going to say they do or don't have 1:1 centers after 06.

[renob123]

So, how does or does that account for the VCCD (if those are the right letter?) variable center diff. STIs had that "dial-a-center ratio" right, but not WRXs?

 

That's in the same pile of misconception. It's not an adjustable ratio. The hard, metal gears are in a 1:1 or 1.1:1 ratio, and they're stuck like that. You can't dial the wheel and add/remove metal teeth from those gears. The DCCD adjusts the slipping of the center differential. You can lock it or leave it to slip, or some amounts in between. I leave mine on Auto mode, because the computer is smarter/faster than I am. In product brochures and a ton of other Subaru materials, they said that the bias is adjustable. It's not the ratio, it's the center differential clutch bias.

 

Make sense?

 

Jacob

[superu]

That's in the same pile of misconception. It's not an adjustable ratio. The hard, metal gears are in a 1:1 or 1.1:1 ratio, and they're stuck like that. You can't dial the wheel and add/remove metal teeth from those gears. The DCCD adjusts the slipping of the center differential. You can lock it or leave it to slip, or some amounts in between. I leave mine on Auto mode, because the computer is smarter/faster than I am. In product brochures and a ton of other Subaru materials, they said that the bias is adjustable. It's not the ratio, it's the center differential clutch bias.

 

Make sense?

 

Jacob

 

Ahh yes.

So then it's electronically controlled and not viscous?

So, while the RX had a locking center diff (covet covet), and all other FT AWDs are Viscous center diffs, the DCCD is electronically controlled and made for race use/abuse and therefore wouldn't be an economically viable or functionally good center diff "lock" option for off road use, right?

[987687]

Ahh yes.

So then it's electronically controlled and not viscous?

So, while the RX had a locking center diff (covet covet), and all other FT AWDs are Viscous center diffs, the DCCD is electronically controlled and made for race use/abuse and therefore wouldn't be an economically viable or functionally good center diff "lock" option for off road use, right?

 

No, you get a full 100% lock.

Bratman had a 6speed put in his fozzy, and I wired in an aftermarket DCCD box.

Taking tight turns on pavement if you slide the wheel all the way to lock the car jerks and bucks. It's total lock up.

[renob123]

It depends on what kind of off-road abuse you're referring to. I'd say that having the adjustability of DCCD is overkill for wheeling. You just want locked and unlocked modes, I assume.

 

And yes, it's not cheap.

 

Jacob

[WoodsWagon]

As I said right above, some of the SVXs had 3.54 ratio. And since it's an auto I seriously doubt the center wasn't 1:1. That would mean they have to have a 3.54 front diff too.

 

Yeah, the SVX auto's had them, but you can't use an auto ring and pinion in a manual trans so they're not much use. Unless you're running an auto that is. Could get good gas mileage with a 1.8 running it as a FWD in a stripped imp maybe?

[superu]

Yeah, the SVX auto's had them, but you can't use an auto ring and pinion in a manual trans so they're not much use. Unless you're running an auto that is. Could get good gas mileage with a 1.8 running it as a FWD in a stripped imp maybe?

 

Hmm, an interesting idea.

That actually sounds like a fun project..

1.8L FWD IMP with 4EAT running SVX 3.54 ring and pinion...

34+ MPG anyone?

[alaskanjer]

Yeah, the SVX auto's had them, but you can't use an auto ring and pinion in a manual trans so they're not much use. Unless you're running an auto that is. Could get good gas mileage with a 1.8 running it as a FWD in a stripped imp maybe?

 

If you are REALLY motivated you can. Check out this 3 minute video where a guy put a 4.44 out of an auto into 5mt.

[subaru360]

If you are REALLY motivated you can. Check out this 3 minute video where a guy put a 4.44 out of an auto into 5mt.

 

That guy is a hack. He was trying to sell that car on ebay and the rollcage was built out of black iron plumbing pipe.

[alaskanjer]

bummer... I was hoping for reasonably priced 4.44 gearing in my 5 speed someday.

[987687]

bummer... I was hoping for reasonably priced 4.44 gearing in my 5 speed someday.

 

The forester XT 5speed is 4.44.

[WoodsWagon]

If you're on good terms with a Subaru dealer parts dept, you can get a front 5mt 4.44 ring and pinion set for $300. I'd do that before I went through the trouble of dissasembling a 4eat, welding up and machining a shaft. Plus I'm not a fan of his annealing step. Seems like a good way to end up having the pinion twist off the shaft.

[el_freddo]

Ok, a bit late on the up take of this thread - just read it all.

 

so by "that's it", you mean to swap FD ratios you "just" open the box (transmission main case) and get the ring gear and it's pinion gear out of the front diff?

 

Likewise one "could" change any diff's final drive by swapping the ring and pinon gears, but in practicality why do that when you could swap diffs (axle issues aside)?

 

Part of the reason for keeping your original front diff centre when changing the diff ratio (meaning the ring and pinion gears) is that you don't have to screw around with the carrier bearing loads. Plus if you've got a front LSD you'd want to retain it. There are torsen units available on ebay for ~$400 which d_generate I think is running in the front of his dual range WRX offroader

 

swapping the ring and pinion is not rocket science. There's no custom machine work involved, and you don't have to match ratios on the 1-5 gears because they aren't attached to the pinion shaft like Gloyale had said.

 

Totally agree. Here's a pic of the pinion shaft with two lower gearsets on the bench in the background. We were swapping the lower gearset in this case to replace a dead 1st gear that had a chipped tooth - easier to replace the gearsets than press off/on one gear!

 

 

If you were to individually select each gear ratio 1st to 5th you would have to really do your math and research. The idea of running 27's then changing your diff ratio is to use the final drive (diff) of 4.11 to offset the change in gearing from the oversized 27 inch tyres. This will effectively pull your gearing back to stock when running the 27's.

 

While EA's were less powerful the gearbox strength and design basically remained the same. You can use EA forward gear ratios (1st to 5th) but you need to press them off the pinion shaft first, then press them onto the lower gearset "tube" of the AWD gearbox. Really not worth it.

 

The way you have done the diff ratio change with your original gearsets is the way to go in my opinion. This is what I will be doing with my gearbox build.

 

When you get the dual range EJ gearbox you will need to shave the crown wheel a little bit to allow clearance between the L series low range gearing and the crown wheel, otherwise it won't work. The factory dual range 4.11 ratio forester gearboxes from the EJ20 line up work because the low range isn't as low as the L's 1.59:1 reduction. I think the factory foz dual range (2L only) is 1.44:1 meaning smaller gears to allow for the larger 4.11 crown wheel on the diff.

 

Another thing I was going to add - the diff output shaft can be changed to the desired spline count when the gearbox is open for surgery - you just need to remove this circlip, pull the output stub and replace the desired output stub. There are two spline counts that I know of - 23 and 25. 25 being the most common on the EJ series at least over here all AWD gearboxes are 25 spline output. Here's a pic of the circlip:

 

 

If anyone is really desperate for AWD dual range in your EJ subi you can make them with an L series PT gearbox, EJ AWD gearbox, a press, time, blood sweat and tears and the EJ/EA adaptor. If anyone wants to hear more on this theory let me know and I'll write it up

 

So then it's electronically controlled and not viscous?

So, while the RX had a locking center diff (covet covet), and all other FT AWDs are Viscous center diffs, the DCCD is electronically controlled and made for race use/abuse and therefore wouldn't be an economically viable or functionally good center diff "lock" option for off road use, right?

 

Guyph on ausubi (and here occasionally) is building an EJ DR AWD with the DCCD centre for offroading. He's been canned by a few people who say that the user manual says that it is not designed for full lock for offroading - but with that said I don't think the majority of our vehicles were envisioned to be offroading the way we do.

Either way it should be a good project, I'll be keen to see the results anyway.

 

Cost of the DCCD? Well that depends if you're in the right place at the right time...

 

Cheers

 

Bennie

[WoodsWagon]

If anyone is really desperate for AWD dual range in your EJ subi you can make them with an L series PT gearbox, EJ AWD gearbox, a press, time, blood sweat and tears and the EJ/EA adaptor. If anyone wants to hear more on this theory let me know and I'll write it up

A write up with pics would be great. EJ dual ranges were never sold in north america because Subaru figured people were too stupid to work an extra lever, and the bigger motors would make up for the lack of gearing.

 

So the only way to get an EJ d/r box is to import it from NZ or AU, and most people won't pull and export transmissions because the buyers here flake out on the sale. It's a damn shame really.

[el_freddo]

If anyone is really desperate for AWD dual range in your EJ subi you can make them with an L series PT gearbox, EJ AWD gearbox, a press, time, blood sweat and tears and the EJ/EA adaptor. If anyone wants to hear more on this theory let me know and I'll write it up

 

A write up with pics would be great. EJ dual ranges were never sold in north america because Subaru figured people were too stupid to work an extra lever, and the bigger motors would make up for the lack of gearing.

 

I realise you guys didn't get the EJ dual range AWD. ***I would like to note that I have NOT built this gearbox before*** But it would be doable as subarus work like lego, you just have to nut it out.

 

What you'll need:

 

A press suitable for pressing off gears.

L series dual range gearbox, flywheel and clutch

EJ single range gearbox with the desired gear ratios, diff ratio can be swapped out for the one you're after same as what superu has done in this thread.

EJ/EA adaptor plate, EA start motor.

 

What you need to do is split both gearboxes so that they look like this:

 

L series PT4wd Dual Range gearbox:

 

 

The idea here is to use the L series' input shaft to gain the use of the dual range gearing that is located above the front diff.

 

To get your EJ gearing for your model of vehicle you will need to press off the gears from the top gearsets - keep track of what goes where as you'll need the EJ gearset to press back onto the L series' input/top gearset shaft.

 

Bascially once you've got this step complete you remove the L series lower gearset, reverse gear and front diff, drop in the EJ lower gearset, reverse gear and front diff. MAKE SURE you have the 25 spline output stubs on the diff, otherwise you'll have to stuff around with your drive shafts! They're a simply circlip to deal with

 

IF you will be running 4.11 or 4.44 ratio diffs these will foul on the L series low range. You WILL NEED to shave the crown wheel to gain the necessary clearance to make it all work without interference.

 

Once you've got this done you can then re-assemble. Make sure you correctly adjust your preload and backlash on the diff for correct installation.

 

The rear housing that has the centre diff will simply bolt back on to the EA front casings. Once you have it all back together you have an EA cased EJ dual range gearbox - as close as you'll get to a factory unit like we have over here.

 

To bolt it to your EJ engine you will need to us the EA flywheel with the elongated crank bolt holes as well as the EJ/EA adaptor plate. Bolt in the EA starter motor to get your EJ started. The gearbox will bolt in using the stock EJ gear shifter.

 

You will have to get creative with the low range lever as you cannot use the EA unit. The factory EJ low range selector uses a cable and a small lever mounted near the coin tray in the console. A solenoid could solve the problem with a button on the dash - this will be trial and error I'm sorry!

 

Hope this helps you out, not only do you get AWD advantages, you also get the best low range that subaru offered.

 

The RX AWD dual range gearbox will do the same but you will need a custom gearbox crossmember, prop shaft and most likely shifter linkages again.

 

Any Q's fire away!

 

Cheers

 

Bennie