Mud-club
Vehicle & Technical => Defender => Topic started by: Big Jon on November 08, 2008, 14:24:40
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hi my defender is needing a new transfer box and i was wondering if i put a disco transfer box on it would it improve my performance. or would it decrease my performance any advice welcome look forward to hearing from you BIG JON
07870535139 [-o<
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Won't make any difference to power but it will improve normal road driving, especially motorways and the like. Due to the difference in gearing between the 90 (1.4ratio) and the Disco (1.2ratio) it won't rev so high at the same speed compared to the normal 90 box.
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so would you say i should do it.
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I would definitely consider it if I was in that position. Plus Disco transfer boxes are aplenty compared to 90 one's I would imagine.
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I think the poll depends on what you call power, a 1:2 ratio box will give you more speed, but off road I would think it would give you less torque due to gear ratio. I have been thinking about the same but I use mione off road more that on so don't want to loose the all the grunt from that 2.5 8-[
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Low ratio gears are unchanged Mark ;)
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Cheers Chris that is very nice to know, will save alot of searching.
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I did this conversion to an old military 110 that i had fitted with a 200tdi, it made no noticable differance to driving it off road but when on road it dramatically improved the drive, as it reduced engine rev's when at higher speed. I can definatly recommend do this conversion. :grin:
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Are all the linkages the same?
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i have done this conversion to other peoples 90s but not my own
i thought that 90 transfer boxes are better and stronger if you have big 33 or bigger wheels am i right ????
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Fits like a glove ! If i was you i would put a cross drilled input shaft in it at the same time. I did a 200tdi coversion 6 weeks ago but i didn't know about the input shaft at the time. For your info the oil can't get to the shaft from the gearbox and it wears out the spline on the end.
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Fits like a glove ! If i was you i would put a cross drilled input shaft in it at the same time. I did a 200tdi coversion 6 weeks ago but i didn't know about the input shaft at the time. For your info the oil can't get to the shaft from the gearbox and it wears out the spline on the end.
were do you get the cross drilled shalf from cheers kev
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They do gearbox's and transfers for land rovers
http://www.ashcroft-transmissions.co.uk/part_28.html
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Having put 235/85s on my RRC I'd say think twice before changing the transfer box ratio. It's not as bad on the TDi with a lower 1st gear but on the V8 it's definitely like setting off in 2nd and very easy to overheat the clutch. If I had the time I'd be fitting a Defender T-Box or swapping the diff ratios (my lockers need rebuilding).
Also I find it hard to stay in 5th even with a 3.9, if I'm towing then forget it, 4 speeds is all you can use.
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This RATIO COMPARISON (http://www.ashcroft-transmissions.co.uk/category_11.html) may help you decide.
Putting a disco t/box in will not effect the low range but will gear up the high ratio. If you have large tyres you may struggle to turn the wheels in the higher gears. ;)
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I have just done the swap to a disco one in my 200tdi 90.
I would say it was well worth it. It's no faster when flat out but is not revving so much so less noisy.The only downside I have found is on big hills. With the defender one it would go up in 5th, I now need to drop to 4th.
I don't tow much so I am well pleased with the new gearing but if you do tow heavy loads i would stay with the Defender one.
The handbrake will need to be swapped over and some of the linkage and speedo drive gear.
Matt
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Fitted mine nearly 2 yrs ago, however running on 235/85/16 I found it to be a bit lethargic on hills without the bigger intercooler. With the intercooler it will happily cruise at 80-85mph all day on the motorway as opposed to 70/75mph before
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I've just swapped my 110 V8 from a 1.4 to a 1.2 but have yet to get it on the road and try it.
I'm hoping to improve fuel consumption at 50/60 mph.
Regarding power the thing to consider is, which is better, high geared t/b and run in lower gear or low geared t/b and run in higher gear.
I used to have an old truck with a two speed axle and it made no difference which diff ratio was being used when climbing hills when the revs/road speed was similar.
So which uses more fuel, 70mph in fifth at 4000rpm or 70mph in 3rd at 4000rpm?
Which accelerates better, 2nd with a low diff or 1st with a high diff?
My 'new' 1.2 t/box will give me the approximately following speeds when taken to 3000rpm in each gear
1st 19
2nd 31
3rd 48
4th 68
5th 85 (was about 53)
so running in third at 3000ish is about what it was round about doing in 5th before so I recon that if I want power for towing then run in 4th on the motorway, I'll be higher than before but not too high and should be more economical.
I'll let you know :lol:
(Figures not meant to be strictly accurate, just a guide)