Notice: We request that you don't just set up a new account at this time if you are a previous user.
If you used to be one of our moderators, please feel free to reach out to Chris via the facebook Outerlimits4x4 group and he will get you set back up with access should he need you.
Recovery:If you cannot access your old email address and don't remember your password, please click here to log a change of email address so you can do a password reset.

Transfer reduction gears

Tech Talk for Suzuki owners.

Moderators: lay80n, sierrajim

Post Reply
Posts: 8
Joined: Sun May 17, 2009 6:36 pm
Location: Emu Plains

Transfer reduction gears

Post by pgib2724 »

I am not that sure of the workings of the transfer case but but I want to know if it is possible to gear down low range with rockhopper gears and leave high range untouched?

In high I can only do 95kph at 3500rpm on standard 27 inch tyres.

Looking at 30' or 31' tires which will give me some more highway speed but my low range is already not geared low enough as it is.
Posts: 918
Joined: Sun Aug 20, 2006 11:46 am
Location: Western Brisbane

Re: Transfer reduction gears

Post by Highway-Star »

pgib2724 wrote:I am not that sure of the workings of the transfer case but but I want to know if it is possible to gear down low range with rockhopper gears and leave high range untouched?

In high I can only do 95kph at 3500rpm on standard 27 inch tyres.

Looking at 30' or 31' tires which will give me some more highway speed but my low range is already not geared low enough as it is.

With a Sierra, no. All gearing changes will effect high range (transfer or diffs). Making it higher geared will lose you highway speed. Suzuki motors need to rev to get power, and hence maintain speed.
When mine ran 27" tyres and stock drive train, it would go over 110 if I wasn't watching myself. I added 4.9 transfer gears and 31" tyres which made it effectively higher geared in high range (only a little), and it had a bit less up high, though the tyres tread pattern probably accounted for most of that. If your having trouble holding 100 in stocko form, I'd say your motor is either not tuned right, or is getting very tired.
Wheeling on completely wicked angles, without even looking stable.
God Of Emo
Posts: 7350
Joined: Sun Aug 24, 2003 7:04 pm
Location: Newy, home of the ZOOK (Rockin the 'diff)

Post by lay80n »

I would look at why you have trouble getting to 100km/h. When you increase your tyres diamiter, you want to alter your high gearing by approx the same percentage to offset the increase in tyre rolling circumference. If you dont, you motor will be working out of its efficiency range and will most likley strugle to reach the same speeds you are at now.

As said above ^^^ the aftermarket gear sets all alter the high and low range. But this is a good thing.


Layto....
[quote="v840"]Just between me and you, I actually really dig the Megatwon, but if anyone asks, I'm going to shitcan it as much as possible! :D[/quote]
Posts: 8
Joined: Sun May 17, 2009 6:36 pm
Location: Emu Plains

Post by pgib2724 »

I am running a corolla 1.6 with a T50 gearbox and the 5th gear has lower gearing than the suzuki box.

I have plenty of power and it will do 100 just that it is almost redlining.

I guess I could do this
I added 4.9 transfer gears and 31" tyres which made it effectively higher geared in high range (only a little).
It would give me a little more speed but I really wanted to try and get it doing 110 at about 2900.

The only way I can think of doing it is to put in higher diff ratios and then putting in the reduction gears.
Suzuki Sierra 1987 LWB, Corolla 1.6, 2' spring, extended shackles
Posts: 2585
Joined: Fri Mar 28, 2008 4:45 pm
Location: SYDNEY

Post by thehanko »

We have been busting our brains on this one.

the t50 5th gear is .86 ratio while the sierra 5th gear is about .79.

so the problem is exagerated by 6% with the corolla engine / gearbox swap. but even with std zuk set ups they rev their guts out.

Highway star, your car must have been pushing 3900 rpm to do 110, do sierra drivers just live with this?

On paper 31's only increase 14% which is close to but still lower gearing with the 4.9 gears which reduce it by 16%.

Who has done transfer gears and how is it for normal driving? what speed do you sit on on the hwy?

16 - 20% reduction in high range is huge.

On paper 31's only increase 14% which is close to but still lower gearing with the 4.9 gears which reduce it by 16%.

Has anyone ever bolted an external overdrive on?

do WT 3.9 centers fit into NT 4.1 housings? as this would give phil 5% increase (cancelling out his t50 gear box)

:x
*there's a rock, drive over it :) there's a bigger rock, drive over it :twisted: there's an even bigger rock, oops broke it :oops: Upgrade broken bit :bad-words:
Goto *
Posts: 918
Joined: Sun Aug 20, 2006 11:46 am
Location: Western Brisbane

Post by Highway-Star »

pgib2724 wrote:I am running a corolla 1.6 with a T50 gearbox and the 5th gear has lower gearing than the suzuki box.

I have plenty of power and it will do 100 just that it is almost redlining.

I guess I could do this
I added 4.9 transfer gears and 31" tyres which made it effectively higher geared in high range (only a little).
It would give me a little more speed but I really wanted to try and get it doing 110 at about 2900.

The only way I can think of doing it is to put in higher diff ratios and then putting in the reduction gears.

If its the '87 LWB in your sig, then you should have 3.9 diffs already. the highest diffs you can get are 3.7, probably not worth the effort, for such a small change.

I don't know much about corolla motors, so wont comment on what you should do with it.
Wheeling on completely wicked angles, without even looking stable.
Posts: 918
Joined: Sun Aug 20, 2006 11:46 am
Location: Western Brisbane

Post by Highway-Star »

thehanko wrote:We have been busting our brains on this one.

the t50 5th gear is .86 ratio while the sierra 5th gear is about .79.

so the problem is exagerated by 6% with the corolla engine / gearbox swap. but even with std zuk set ups they rev their guts out.

Highway star, your car must have been pushing 3900 rpm to do 110, do sierra drivers just live with this?

On paper 31's only increase 14% which is close to but still lower gearing with the 4.9 gears which reduce it by 16%.

Who has done transfer gears and how is it for normal driving? what speed do you sit on on the hwy?

16 - 20% reduction in high range is huge.

On paper 31's only increase 14% which is close to but still lower gearing with the 4.9 gears which reduce it by 16%.

Has anyone ever bolted an external overdrive on?

do WT 3.9 centers fit into NT 4.1 housings? as this would give phil 5% increase (cancelling out his t50 gear box)

:x

Standard Sierra Wide track with 3.7 diffs does 3570rpm at 100km/h in 5th gear. Widetrack has 0.864:1 in 5th also.

Standard Sierra Narrow Track with 3.9 diffs does 3470rpm at 100km/h in 5th gear. Narrow track has the 0.795:1 5th gear.

My setup is widetrack 5th gear, 4.9 transfer gears, with 3.7 diffs. This gives me 3510rpm at 100km/h in 5th gear.
This is about perfect with the G16 Grand Vitara EFI motor I now have. With the stocko G13 is could have revved a bit more just so I could of used 5th gear a bit more. Now with the 1.6, I could easily break any speed limit.
My car is daily driven and I love the gearing. Drove it on 31's with standard gearing, and it sucked cosmically. Even worse in low range.
A Suzuki project I am starting to gear up for (lol bad pun) at the moment, will be setup to do about 3750rpm in 5th gear at 100km/h, that should be quite nice I think.

Are you sure this suzuki wasn't originally a 1 litre? sounds like you may have 4.1 1 litre diffs and a 1L transfer case... :?:
Wheeling on completely wicked angles, without even looking stable.
Posts: 2585
Joined: Fri Mar 28, 2008 4:45 pm
Location: SYDNEY

Post by thehanko »

brain freeze! I meant from 3.9 NT centers to 3.7 WT.

was a factory 1.3 5 speed AFAIK

so do WT centers fit into NT housings?
*there's a rock, drive over it :) there's a bigger rock, drive over it :twisted: there's an even bigger rock, oops broke it :oops: Upgrade broken bit :bad-words:
Goto *
Posts: 918
Joined: Sun Aug 20, 2006 11:46 am
Location: Western Brisbane

Post by Highway-Star »

thehanko wrote:brain freeze! I meant from 3.9 NT centers to 3.7 WT.

was a factory 1.3 5 speed AFAIK

so do WT centers fit into NT housings?

LOL, fair enough.
Yes. straight swap apart from the tailshaft flanges are different. But they can be swapped. but front will have to swap for front, and back will have to swap for back. They cannot interchange front to rear unless you go chromos, but you'll also need widetrack housings for that.
You shouldn't have a hard time finding someone who'll gladly swap their 3.7s for a set of 3.9s :)
Wheeling on completely wicked angles, without even looking stable.
Posts: 8
Joined: Sun May 17, 2009 6:36 pm
Location: Emu Plains

Post by pgib2724 »

This sounds like a pretty good solution.
Will have to see how I go.
Thanks for the tips
Suzuki Sierra 1987 LWB, Corolla 1.6, 2' spring, extended shackles
Posts: 17
Joined: Fri Nov 02, 2007 7:03 pm
Location: brisbane

Post by chazza »

I think I may suffer from this the most, i haven't got a tachometer but my ears hurt that much u can guess what the revs are doing. I have the 1.6 also but the ze, t50 box, 1ltr tcase, and then I was cocky and put 5.12 diffs in! Also have 33's and to scared to put my smaller ones on. If I was to guess it would be doing arround 5g at 100 :( so does anyone want some 5.12 for some 3.9? I also need some tcase gears coz I like to crawl
Posts: 7345
Joined: Wed Jun 02, 2004 3:29 pm
Location: Melbourne

Post by Gwagensteve »

Chazza, you are revving 4319 rpm @ 100 if your tyres are actually 33. If they are actually 32, (more likely) you're at 4454.

That's way to high for a motor with that much torque.

You need widetrack 3.7's in the diffs and 4.9:1 transfer gears -

That will give you 3216 rpm @ 100 with the "33" 32's on and 63:1 crawl ratio (or so - not sure on you're first gear ratio)

Pretty sweet I reckon on and off road.

Steve.
[quote="greg"] some say he is a man without happy dreams, or that he sees silver linings on clouds and wonders why they are not platinum... all we know, is he's called the stevie.[/quote]
Posts: 904
Joined: Mon Feb 19, 2007 6:10 pm
Location: Perth

Post by mrRocky »

i dont want a tacho in mine as i know its screaming at 80km/phr
1ltr, 4 spd g/box, 6:5 t-case gears, and 4.1 diffs
I estimate mine is doing 4750rpm @ 85 km/phr but i just put around town and idle up hills :)
Posts: 18
Joined: Mon Apr 20, 2009 3:46 pm
Location: Melbourne

Post by jdk81 »

I have similiar issues when using stock tyres.

bog standard engine, gearbox, diff ratios. WT

Only change is series 4 rockhopper.

The little engine is at 4100 doing 100, much higher doing 110.

When I put the muddies on 32" pedes so 33.4" it gets back close to stock standard gearing in high range.

My solution will be to increase the diam of my road tyres, however trying to find 30-31" cheese cutter type road tyres on 15" rims is difficult.

Have I got any other cheap options to improve road driving.
Posts: 904
Joined: Mon Feb 19, 2007 6:10 pm
Location: Perth

Post by mrRocky »

drive slower :armsup:
Posts: 7345
Joined: Wed Jun 02, 2004 3:29 pm
Location: Melbourne

Post by Gwagensteve »

It's diffcult to find "cheese cutter" tyres for 15" rims, because there aren't any.

You need a 16" rim to run a tall narrow tyre. Sierra commercial rims- 16X4.5" LJ rims (also 16X4.5) and GV rims (16X7) are all options to run a narrow tyre in the 32" range.

Steve.
[quote="greg"] some say he is a man without happy dreams, or that he sees silver linings on clouds and wonders why they are not platinum... all we know, is he's called the stevie.[/quote]
Posts: 265
Joined: Wed Jan 09, 2008 3:18 pm
Location: Mt Evelyn.Vic

Post by BOGFROG »

Never been good with workin this out, Mine is running Barina 1.3 with 1.3 sierra box and 1 litre transfer (the one with the 4x4 switch) with WT 3.7 Diffs and 29.9" tyres can someone help me work out what I would be revving to at?

60km in 4th:
80km in 4th:
100km in 5th:
Top Speed in 5th:
I only have a tacho as my speedo reads wrong with the tyres.

and also what changes I should make? I do have 3.9 ring and pinions, should I use these with these tyres?

Also been lookin at 33"s down the track with this same set up with 5:12 diff gears do you think this is the way to go?

Cheers Robb.
Suzuki Sierra: half the size, half the weight, half the cost & twice the fun :lol: why would you drive anything else?
Frog Build up:
http://www.outerlimits4x4.com/ftopic145665.php&highlight=frog
Posts: 918
Joined: Sun Aug 20, 2006 11:46 am
Location: Western Brisbane

Post by Highway-Star »

BOGFROG wrote:Never been good with workin this out, Mine is running Barina 1.3 with 1.3 sierra box and 1 litre transfer (the one with the 4x4 switch) with WT 3.7 Diffs and 29.9" tyres can someone help me work out what I would be revving to at?

60km in 4th:
80km in 4th:
100km in 5th:
Top Speed in 5th:
I only have a tacho as my speedo reads wrong with the tyres.

and also what changes I should make? I do have 3.9 ring and pinions, should I use these with these tyres?

Also been lookin at 33"s down the track with this same set up with 5:12 diff gears do you think this is the way to go?

Cheers Robb.

your setup with 3.7 diffs:
60km in 4th: 2450rpm
80km in 4th: 3266rpm
100km in 5th: 3528rpm

your setup with 3.9 diffs:
60km in 4th: 2582rpm
80km in 4th: 3443rpm
100km in 5th: 3719rpm

33's and 5.12s:

33's, 5.12s, 1Litre case:
60km in 4th: 3072rpm
80km in 4th: 4096rpm
100km in 5th: 4423rpm

33's, 5.12s, 1.3Litre case:
60km in 4th: 2739rpm
80km in 4th: 3652rpm
100km in 5th: 3944rpm


OK some numbers there for you Robb. I think 33's 5.12's and the 1L case is a bit too much in high range personally. It's coming tolerable with the 1L case removed and replaced by a 1.3.
I have assumed the 0.86 5th gear in the gearbox; the 0.79 5th would probably make it quite nice. I wouldn't bother putting your 3.9s in if your thinking of going 5.12's, I dont think the difference between 3.7 and 3.9 is enough to bother when it come to low range gearing, and your highr range isn't too bad ATM.
Thats why I like my transfer gears, you can get a good difference between high range and low range, which cannot be achieved with the standard components (short of going dual transfer, a pretty epic operation).
Wheeling on completely wicked angles, without even looking stable.
Posts: 265
Joined: Wed Jan 09, 2008 3:18 pm
Location: Mt Evelyn.Vic

Post by BOGFROG »

Thanks Highway Star that gives me more to go off and a little more to think about Cheers Robb.
Suzuki Sierra: half the size, half the weight, half the cost & twice the fun :lol: why would you drive anything else?
Frog Build up:
http://www.outerlimits4x4.com/ftopic145665.php&highlight=frog
Post Reply

Who is online

Users browsing this forum: No registered users and 38 guests