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Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

2010 Defender 90 Puma 2.4 SW Alpine White

pardon my ignorance, but that do the 1.2/1.3/1.4 ratio refer to?

I have a BAS remap & Alive intercooler and sometimes I find myself wanting a 7th gear - would a lower ratio then be a recommended mod?

Does this mod change the Low Range or only the High?

thanks --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

24th Jun 2019 7:51am

JOW240725

Member Since: 04 May 2015
Location: Suffolk
Posts: 7906

2012 Defender 110 Puma 2.2 XS CSW Orkney Grey

I'm not expert so wait to be corrected but this ratio is the transfer box gearing. Early Defenders run 1.4 but the Pumas already run 1.2. The ratio is both low and high.

I've not heard of an overdrive for a Puma? James
MY2012 110 2.2TDCi XS SW Orkney Grey - http://www.defender2.net/forum/topic43410.html
MY1990 110 200TDi SW beautifully faded Portofino Red - https://www.defender2.net/forum/post743641.html#743641
MY1984 90 V8 Slate Grey - https://www.defender2.net/forum/post744557.html#744557
Instagram @suffolk_rovers

24th Jun 2019 12:53pm

LandRoverAnorak

Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

That particular ratio is high range only. These sorts of mods typically leave the low range ratio alone. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia

24th Jun 2019 12:58pm

hank

Member Since: 12 Sep 2016
Location: South Wales
Posts: 2300

2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

Similarly I am no expert but believe the ratio applies only to high range - see here https://www.ashcroft-transmissions.co.uk/lt230-ratio-changes.html

The ratios are the same principle as a gearbox. Change gear to suit engine revs, torque and road speed

The way I understand it, think about the drive coming from the gearbox, into and through the transfer box and then out the other end to the propshaft(s)

So, if the transfer box ratio was 1.0 and the gearbox is outputting 1000rpm then the propshaft(s) also spin at 1000rpm

If the ratio is 1.2 then the props spin at 1200rpm,
If the ratio is 1.4 then the props spin at 1400rpm

So the lower the ratio then the easier(faster?) acceleration in lower gears, but will top out at lower speed/require higher revs to achieve the same speed > 110 XS Double Cab

Last edited by hank on 25th Jun 2019 5:19am. Edited 1 time in total

24th Jun 2019 1:02pm

excossack

Member Since: 22 Feb 2012
Location: North West
Posts: 5843

1999 Defender 110 Td5 SW Caledonian Blue

I went from 1.2 Disco in 110 td5 back to a Ashcroft 1.4 box with sleeved upgrade and ATB option.
Times where I thought I might need difflock, I haven't - overall I am happy with it. 1999 Defender TD5 110

Regards
John M0VAZ
Econet Station 48 no clock

24th Jun 2019 6:11pm

mrd1990

Member Since: 16 Aug 2012
Location: Wales
Posts: 600

@hank

That is incorrect as I understand it.

If the output from the gearbox is 1000 rpm, the output of the transfer box would be as follows:

1.2 = 833 rpm
1.3 = 769 rpm
1.4 = 714 rpm

I find that I can actually accelerate as fast with 1.3 as I could with 1.4, I put it down to the engine spending more time in the sweet spot of the power curve due to the way a turbo diesel works.

24th Jun 2019 10:29pm

hank

Member Since: 12 Sep 2016
Location: South Wales
Posts: 2300

Ahhh thanks mrd1990, so it works the opposite way round! > 110 XS Double Cab

25th Jun 2019 5:19am

blackwolf

Member Since: 03 Nov 2009
Location: South West England
Posts: 17386

Correct, the transfer box is a reduction gearbox, not an overdrive. The output is turning slower than the the input.

25th Jun 2019 6:52am

Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

So would a Puma benefit from going from 1.2 to 1.4? --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

25th Jun 2019 6:57am

LandRoverAnorak

Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

Not unless you've put huge tyres on it. Otherwise, it'd be painfully slow and 1st would be redundant. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia

25th Jun 2019 7:07am

Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

Ah, so with the Puma, we're looking to go down, as in a 1.1 box? --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

25th Jun 2019 7:08am

LandRoverAnorak

Member Since: 17 Jul 2011
Location: Surrey
Posts: 11324

If you want to raise the gearing then yes. Darren

110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak

"You came in that thing? You're braver than I thought!" - Princess Leia

25th Jun 2019 7:12am

hank

Member Since: 12 Sep 2016
Location: South Wales
Posts: 2300

Some interesting info on the ratio options https://forums.lr4x4.com/topic/104279-new-lt230-ratios/ > 110 XS Double Cab

25th Jun 2019 8:58am

Naks

Member Since: 27 Jan 2009
Location: Stellenbosch, ZA
Posts: 2638

I take it no one has done the 1.1 mod yet then? --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport V8 Supercharged

Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

26th Jun 2019 7:31am

ashtrans
Site Sponsor

Member Since: 08 Nov 2008
Location: Harpenden
Posts: 257

Hi,

yes, many customers have, works very well with a tuned TDCi, Dave

26th Jun 2019 12:07pm

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