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Figuring out transfer gearing
https://auszookers.com/forum/viewtopic.php?f=37&t=54963		 Page 1 of 1
Author:  Technotron101 [ Mon Jan 22, 2018 8:29 am ]
Post subject:  Figuring out transfer gearing
Hi all,

I've been trying to nut out what's going on with my transfer case for a while now, because I'm completely convinced I'm running a reduction without knowing it.

I'm running 225s, so about 28.3", and I have the 0.864 fifth gear, with the 1324cc motor (don't ask, nothing matches on the car haha). I'm 99% sure I'm running 3.7 diff gears, but will be checking all these figures later today.

At the moment I'm doing around 3750 at 90kph, which is awfully high, especially considering how loud things are when we crank it up to 110 :shocked:

I crunched some numbers in the gearing calculator, and it appears I have 4.9s... Does this sound completely out of the question?

I used to run a coily transfer (also, don't ask - I was the one who removed it, not installed it :lol: ), and the gearing felt very tall, especially on the highway, and even around town. The whole thing was a very sluggish affair. And as for lowrange - barely useful. Having installed this new-to-me transfer, I have excellent lowrange performance and zippy town performance, but my highway performance, while good, feels like I'm being very unfair to the little donk screaming away in front of me.

I have another transfer I can swap in, because my current one makes all sorts of noises, but then I think I'll lose my lowrange awesomeness :cry:


So, questions. TL;DR does 3750RPM at 90kph on ~28s seem like a reduction of some sort, whatever the ratio?

Also, when I yank the transfer out later today, how should I best go about counting it? Turn the input shaft ~5 times and see if that gets me close to one full turn of the outputs while in lowrange?

Thanks for the help guys, the community and knowledge here is unbeatable.

Cheers! :woohoo:
Author:  Technotron101 [ Mon Jan 22, 2018 8:31 am ]
Post subject:  Re: Figuring out transfer gearing
Also, attached is a screenshot of the gearing calculator.

It's giving me 60MPH at 3750, which translates to 90KPH, with 4.9s.
Author:  Gwagensteve [ Mon Jan 22, 2018 8:43 am ]
Post subject:  Re: Figuring out transfer gearing
You can easily check the ratios- you don’t need to pull the case.

Leave the hubs unlocked. Put the gearbox in neutral, transfer in low range. Jack one or both rear wheels off the ground. (Depending on your locker situation.) leave the handbrake off.

Mark a spot on the rear output flange of the transfer. Grab rear driveshaft and turn it one turn. Count the turns of the jackshaft.

Procedure is the same whether the case is in or out of the car- it’s just easier to do with the case out.

Don’t bother doing high range- the differences in ratio are small enough you could miss it. Once you know low range you automatically know high.

Yes, your revs imply transfer gears.
Author:  Technotron101 [ Mon Jan 22, 2018 10:09 am ]
Post subject:  Re: Figuring out transfer gearing
Ok so after counting, we've some interesting results.

I got a 2.5:1 in lowrange, and around 1.6:1 in highrange... Now according to the gearing calculator, standard is 2.268 and 1.409 respectively.

I've never heard of an aftermarket gearset for such a small difference, so I'm wondering perhaps is there more than one model of WT transfer? Or is this lining up with a 1L switched transfer?? It's a WT transfer, so I though, but I'm not familiar enough with them to be able to tell.

What do you make of it?
Author:  Technotron101 [ Mon Jan 22, 2018 10:16 am ]
Post subject:  Re: Figuring out transfer gearing
Diff is 3.7, just confirmed.
Author:  bumstein [ Mon Jan 22, 2018 10:30 am ]
Post subject:  Figuring out transfer gearing
What’s the full tyre size? 225/75R15?

Oh, and is your speed double checked with GPS?
Author:  Technotron101 [ Mon Jan 22, 2018 10:47 am ]
Post subject:  Re: Figuring out transfer gearing
Ok, just did some more measuring and research. My tire, physically stands at 26.7", which is a long shot from the supposed 28.3. this means my gearing calculations were being skewed.

I did some digging, and found some info from way back. Looks like I have a 1L transfer.

1L is 2.511 low, mine is ~2.5

1L is 1.58 high, mine is ~1.6

So turns out I thought I bought a standard WT case, and I ended up buying a switched 1L case.

With accurate measurements of tyre size, all my other calculations perfectly lined up.
Author:  Technotron101 [ Mon Jan 22, 2018 10:48 am ]
Post subject:  Re: Figuring out transfer gearing
225/70R15 bumstein, and my speedos all out so I've recalibrated myself to its new speeds, which are checked by GPS.
Author:  bumstein [ Mon Jan 22, 2018 10:49 am ]
Post subject:  Re: Figuring out transfer gearing
Ok popping a few numbers into my calc. Assuming the tyre size is 223/75R15 which makes the circumference 2.257 metres (which will likely vary depending on the manufacturer of the tyre somewhat) and your speedo is spot on.

Firstly the ratio’s you’ve given, at 90 in 5th your pumping along at 3187 RPM

Image

This might help narrow down the gearing as you can also see what low range revs are at any close speed intervals and gears etc

With a 1ltr TF case you’ll be doing 3357rpm at 90

Image

And with 4.9’s it will be around 3461rpm

Image
Author:  Technotron101 [ Mon Jan 22, 2018 11:29 am ]
Post subject:  Re: Figuring out transfer gearing
Ok so if my tyre height is 680mm and circumference is 2136.28mm, what sort of rpm would I looking at when at 90?

I do about 3750, and this lines up with other calculators I've used over the morning.
Author:  Technotron101 [ Mon Jan 22, 2018 11:38 am ]
Post subject:  Re: Figuring out transfer gearing
I've just counted turns on another spare transfer I have here but not fitted yet, and thankfully it is in fact a 1.3 WT transfer.

I should end up with a final setup that gives me 3550 at 100 using a WT case, my 0.864 fifth gear, and my 680mm tyres.

I should be happy with that, as when I was running the coily case, my revs were 3500 at 110, and it was too sluggish around town, and with the 1L case I was sitting on 3750 at only 90, so this should end up being a good compromise between highway driveability and around town driveability.

Almost like it was designed that way :lol:
Author:  Technotron101 [ Mon Jan 22, 2018 11:40 am ]
Post subject:  Re: Figuring out transfer gearing
How much of a difference would I be seeing between 1L low range and WT1.3 Lowrange? Will it be noticeably taller?

I instantly loved it after changing to the 1L case (unbeknownst to me that's what it was), but considering the WT1.3 case is closer to the coily in terms of ratio, it'll be back to where I started almost, won't it?
Author:  MrRocky [ Mon Jan 22, 2018 12:21 pm ]
Post subject:  Re: Figuring out transfer gearing
12% dif between 1ltr and 1.3 low range.
These motors are quite happy sitting on 4000-4200rpm at 100km phr. You will find economy and engine life is actually better at a higher rpm. With my 1.6 baleno motor, 4.1 diffs, 6.5 gears economy was 9ltrs per 100km and 13ltrs towing a camper trailer on and offroad at 110 with 32" tyres. These figures were with 2 different lwbs same gearing spread over 200,000+ kms Rpm at 100 was 4100rpm.
Author:  Technotron101 [ Mon Jan 22, 2018 12:59 pm ]
Post subject:  Re: Figuring out transfer gearing
Wow that's pretty impressive actually.

I've got no sound deadening, and so it's just generally really loud as you bring the revs up past 3800 ish.

Plus the 1.0L case I'm running now has noises, and isn't particularly healthy. I'd rather change over to my WT case (already own it, costs me nothing) and play it by ear from there. I may end up rebuilding the 1.0L case and using it down the track if I get bigger rubber, as a cheap (read: free) reduction.
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