low range gears

Transmissions, Transfer Boxes, Axles, Drive Shafts
User avatar
davidvdm
Senior Member
Senior Member
Posts: 459
Joined: 13 Sep 2011 15:47
Full Name: David vd Merwe
Nickname: David - Hillbilly
Home Town: Carletonville
Current 4x4: 1997 2.7TD Nissan Sani Mk3 4x4 SFA (SAFANI)
Home Language: English/Afrikaans
Has thanked: 3 times
Been thanked: 14 times

Re: low range gears

Post by davidvdm » 22 Sep 2017 06:49

Even on 35's it looks like the standard Patrol TC Ratio achieves what you are saying Peter. Looking at an engine RPM of 2000 it falls right between 2nd and 3rd gears in low range compared to the speed at 2000 RPM in 1st High, at around 18km/h.
David - Bfreesani
1997 Nissan Sani MK3 2.7TD - Hillbilly (SAFANI)
MQ C200 SFA
MQ H260 LSD Rear
MQ Transfer as second low range
5" Lift
33"x12.5x15" tires on 8.5J rims - Want 35's
DIY rock sliders
DIY Snorkel
Madman EMS

User avatar
ricster
Patrolman 1000+
Patrolman 1000+
Posts: 5773
Joined: 13 Jan 2010 11:16
Full Name: Cedric Warner
Nickname: Cedric
Home Town: Alberton Gauteng
Current 4x4: '99 Nissan Patrol 4.2 Turbo Diesel
Home Language: English
Location: LA..... No not Los Angles ..... Lower Alberton, Gauteng
Has thanked: 214 times
Been thanked: 237 times

Re: low range gears

Post by ricster » 22 Sep 2017 09:02

I don't mean to be a stick in the mud here, but why does want to lower the ratios even with 33" tyres?

In my opinion sand or dune driving is just that... driving. On the river trip I was mostly in 4H and was fully loaded. Juice (Greg) found that 4L worked better for him. The difference was mine is a 4.2 diesel ( turbo ), and Juice has the 3.0 diesel. Ok, the diesels do have a very different feel to the petrol motor in the sand, that we know as petrol loves sand.

In my mind the real benefit in changing the T/C ratio will be when one is at an obstacle and a rocky one at that. Many petrol patrols go up obstacles in 2nd 4L, which gives you a certain speed at which you climb out of an obstacle. In my 4.2 diesel I love to put it in 1st 4L and literally idle up out of an obstacle with my revs at between 900 and 1300 rpm. This is a very slow speed, as i'm sure a few of you guys have seen when I go through an obstacle. If I changed the T/C ratios I would probably still use 1st 4L and same rev range but I could probably get out of the Patrol and walk next to it to check my line while the vehicle is still moving.....hahaha.... it will just be even slower, which in turn gives you more control.

There will be times that you need more momentum to get up an obstacle. More momentum = more speed. to me this negates the need for different T/C ratios, as you don't need the wheels to turn slower, but rather faster.

This is how I see it for a diesel motor based on the diesel motor characteristics. I do understand that the petrol motor may behave differently, and if with an auto g/box the will also be significant behavior differences.

Its a LOT of money for something that could rather go towards something else on a vehicle..... unless you are building an extreme 5+ rated obstacle eater, in which case I would probably just get a front difflock and an extra inch suspension lift and body lift.
Regards
Cedric
Nissan Patrol GL 4.2 Diesel Turbo (Iron Maiden)
Nissan SANI 3.0 V6 4x4 (SOLD)
Isuzu KB 280 DT 2x4 ('ol Smokey) - SOLD
Suzuki TL 1000R "V twin" (Growler) - SOLD

User avatar
Peter Connan
Moderator
Posts: 5268
Joined: 10 Sep 2010 07:21
Full Name: Peter Connan
Nickname: Piet
Home Town: Kempton Park
Current 4x4: 1996 Patrol 4.5SGL
Home Language: Afrikaans
Location: Kempton Park
Has thanked: 244 times
Been thanked: 328 times

Re: low range gears

Post by Peter Connan » 22 Sep 2017 09:55

Cedric, i think something has gotten lost in translation here.

I want lower T/C ratios to be able to go slower in extreme rock crawling. Just as you say, idling in first gear. Slow enough to get out and check my line.

If you saw the two jeeps going up Koos se Klim this weekend, you will understand just why. Lower speed means less loss of traction due to the wheels keeping a steadier pressure on the ground.

But i want approximately the same ratio as i currently have in 2l for dune driving.
So that i can retain the same torque/speed relationship, as the current over-all ratio in 2l is just about ideal for that. I don't mind what gear that is, whether it's 3rd, 4th or 5th, that's immaterial.
Mag ons ons kenniskry met lekkerkry aanhoukry.

User avatar
davidvdm
Senior Member
Senior Member
Posts: 459
Joined: 13 Sep 2011 15:47
Full Name: David vd Merwe
Nickname: David - Hillbilly
Home Town: Carletonville
Current 4x4: 1997 2.7TD Nissan Sani Mk3 4x4 SFA (SAFANI)
Home Language: English/Afrikaans
Has thanked: 3 times
Been thanked: 14 times

Re: low range gears

Post by davidvdm » 22 Sep 2017 10:07

I have also done things as slow as possible.. Basically just keep the revs high enough so I don't stall the little 2.7td. Then when you go from 29" up to 35" tyres, things get faster than you would like. So crawler gears is something I have always wanted. But you have to be realistic and see what you are going to need for sand. I will end up with the perfect setup, with two low ranges, giving me 10 low range gears and 5 high range.

Whats the cost comparison to rather add a second TC and replace two proshafts to the Patrol?
David - Bfreesani
1997 Nissan Sani MK3 2.7TD - Hillbilly (SAFANI)
MQ C200 SFA
MQ H260 LSD Rear
MQ Transfer as second low range
5" Lift
33"x12.5x15" tires on 8.5J rims - Want 35's
DIY rock sliders
DIY Snorkel
Madman EMS

Mystical_Beast
Senior Member
Senior Member
Posts: 112
Joined: 26 Sep 2015 23:03
Full Name: Julian Hilder
Nickname: none
Home Town: Edenvale
Current 4x4: 2008 Patrol 4.8
2007 RRS 4.4 V8
Home Language: English
Has thanked: 7 times
Been thanked: 14 times

Re: low range gears

Post by Mystical_Beast » 22 Sep 2017 10:51

I am inclined to agree with David and Cedric but still being mindful of Peter’s needs.
The above comments tie in with my gut feel.
Peter’s standard ratios are so good already.

I also have looked at it from just above idle RPM to see what one would get in that scenario.

The 4.2 Petrol Patrol standard trf box provides the same ratio in 1st gear LR as the 4.8 were it fitted with a 2.86 reduction box.
In looking at the calculations its easy to see that the 4.2 standard ratios are the best of the lot for serious off-road and the 4.5 Auto ratios are the worst.
(Which makes me question the need for such a large reduction – Peter specifically)

It further showed me that the ratio options from Marks 4WD have little to do with application but are rather very much vehicle specific.

After doing the calculations in the attached spread-sheet it again confirms my feeling that the 2.86 reduction would be the better choice all round

From a technical aspect, reduction and longevity are inversely proportional.
The smallest of gears in trf case will be working that much harder.
Something to think about?

Finally the difference between the 3.743 reduction ratio and the 2.86 reduction ratio is less than 300mm travelled distance per second in 1st gear on any vehicle configuration.
Im not sure that for less than 300mm/second travel distance its woth going to the extreme end of the scale.

Personally it makes no difference what your choice is.
My objective is too see if one could establish a one size fits all and I believe the 2.86 comes closest to that.
The objective being to have as many sets as possible to make them as cheaply as possible.
My thinking is still between 15 to 20 k for 10 sets, but it could actually be way less once I do an actual costing. Which I will upon receipt of Transfer box.

But I’m not going down the road for anything less than 10 sets.
Far too many manufacturing processes involved.
But I would manufacture 10 sets even if I received confirmation for only 8.
If those who are interested could reach consensus as to what it is they want one can take this further.

But if not its been interesting to look at nevertheless.
Attachments
Patrol Selection.xlsx
(10.59 KiB) Downloaded 27 times

User avatar
hugejp
Patrolman 1000+
Patrolman 1000+
Posts: 1434
Joined: 21 Oct 2014 21:01
Full Name: JP Viviers
Nickname: Oupoot
Home Town: JHB
Current 4x4: PATROL COLLECTION
2004 4.8 GRX "Tinkerbell"
2003 4.2 tdi GRX "The Coal Roller"
Home Language: Half & Half
Has thanked: 101 times
Been thanked: 71 times

Re: low range gears

Post by hugejp » 22 Sep 2017 10:57

Thank you for all the effort guys!!!
----------------------------------------------------------------------

You CAN with a NISSAN!

Jy KAN met 'n DATSUN!

Mystical_Beast
Senior Member
Senior Member
Posts: 112
Joined: 26 Sep 2015 23:03
Full Name: Julian Hilder
Nickname: none
Home Town: Edenvale
Current 4x4: 2008 Patrol 4.8
2007 RRS 4.4 V8
Home Language: English
Has thanked: 7 times
Been thanked: 14 times

Re: low range gears

Post by Mystical_Beast » 22 Sep 2017 13:43

Dear Peter

I have been back and looked and looked at your calculated total ratio and when one looks at that I understand why you feel the 3.743 (or 3.5 which is an unknown), is what is going to work for you.

However, based on your statement earlier as quoted below any ratio above 2nd High but lower than 1st High should work for you

‘’Now in these cars, 2nd low is the only gear that works for sand. 1st high is too low, and 2nd high is too high.

I attempt in the attached table then to show why a ratio of 2.86 would be more beneficial to you within those very same parameters.
The same table will then also show why 3.743 would be a step backwards for you.

In conclusion, the 2.86 ratio will improve your progress in that you will go slightly faster on the same RPM in a higher gear and still keep within Torque parameters that the vehicle is capable of.

The 3.743 Ratio, for all intent will mean at a one up higher gear, you will now go slower than what you used to be able too, standard.

Cheers
Attachments
Peter Conan Ratio Comparisons.xlsx
(9.97 KiB) Downloaded 22 times

User avatar
TijmenvdS
Senior Member
Senior Member
Posts: 219
Joined: 23 Nov 2016 06:25
Full Name: Tijmen van der Steenhoven
Nickname: Tijmen
Home Town: Pretoria
Current 4x4: 1997 Patrol TD42 GQ ST
Chevrolet 1974 K10 402 V8
Home Language: Afrikaans
Has thanked: 16 times
Been thanked: 28 times

Re: low range gears

Post by TijmenvdS » 26 Sep 2017 06:56

Ek het nou lekker gespeel mat daardie spreadsheet en omdat ek 35" op het sal die 3.743 ratio tog die beste vir my werk. Op die duine trip het Michael met sy diesel die lang duine in 3de begin en dan af gegear as ek reg ontou. So ek sou graag daardie as my maximum wil hê. Op 3.743 is 5de gelykstaande aan standaard lowrange 3de op 33". 4de Rat sal dan gelykstaande wees aan my huidige 1ste high range. Ek glo nie ek wil graag n vinniger ratio wil hê nie. Indien ek 33" op gehad het sou ek die selfde ingevoer het en sekerlik die 2.86 ratio gekies het. Ongelukkig gaan ek nie commit vir n vinniger een nie.
Matthew 6:33 Seek the Kingdom of God above ALL else, and live righteously, and he will give you everything you need.

My Build Thread: http://patrol4x4.co.za/viewtopic.php?f=43&t=7110

User avatar
hugejp
Patrolman 1000+
Patrolman 1000+
Posts: 1434
Joined: 21 Oct 2014 21:01
Full Name: JP Viviers
Nickname: Oupoot
Home Town: JHB
Current 4x4: PATROL COLLECTION
2004 4.8 GRX "Tinkerbell"
2003 4.2 tdi GRX "The Coal Roller"
Home Language: Half & Half
Has thanked: 101 times
Been thanked: 71 times

Re: low range gears

Post by hugejp » 13 Dec 2017 15:09

Does anyone on the forum have the imported low range gears in their vehicle?

I would be keen to hear first hand accounts of how well they work.
----------------------------------------------------------------------

You CAN with a NISSAN!

Jy KAN met 'n DATSUN!

User avatar
hugejp
Patrolman 1000+
Patrolman 1000+
Posts: 1434
Joined: 21 Oct 2014 21:01
Full Name: JP Viviers
Nickname: Oupoot
Home Town: JHB
Current 4x4: PATROL COLLECTION
2004 4.8 GRX "Tinkerbell"
2003 4.2 tdi GRX "The Coal Roller"
Home Language: Half & Half
Has thanked: 101 times
Been thanked: 71 times

Re: low range gears

Post by hugejp » 18 Dec 2017 22:59

hugejp wrote:
13 Dec 2017 15:09
Does anyone on the forum have the imported low range gears in their vehicle?

I would be keen to hear first hand accounts of how well they work.
Anybody with the Marks4wd gears???
----------------------------------------------------------------------

You CAN with a NISSAN!

Jy KAN met 'n DATSUN!

Post Reply

Return to “10. Drivetrain”

Who is online

Users browsing this forum: No registered users and 6 guests