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5 speed + 1.22 transfer box on V8


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Searched boxes and ratios but cant match any info to what fits what :unsure:

If I want to gear up the road speed my 110 V8 which has a 5 speed Santana gearbox, would a 1.22 transfer box do the job or would I need a diesel gearbox to go with it ?

I ask because I am unsure as to the out put speeds of the different gearboxes and how the various transfer box ratios will affect road speed.

Don't want to be turning too few revolutions at motorway speeds and there again don't want to be low geared as of the moment.

Please help :(:(:D

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Guest diesel_jim

Factory spec V8 90's had the santana and a 1.2:1, with 205x16 tyres, and they were gutless in this setup. so i'd imagine that the extra weight of a 110, combined with 7.50 tyres would really make it struggle (this is assuming you're running a standard 3.5 carb 118bhp V8 like the 90's had...)

Now, if you're running something like V8freak has, then you'll be OK with the 1.2

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On my 90 (Which is a Factory V8 (1.22 TBox 3.54 diffs) the std V8 and 205x16s it came with was "Ok" but not in any way blistering.

When I then popped on 235x85x16s, its was long legged, and frankly gutless, 5th being at times a struggle...

When I fitted the engine I have now, (4.5JED Rover V8) it was far far better, but, when I then fitted 34x10.50x16 Simex, 5th was also useless other than maintaining speed, it was hugely now overgeared.

Fitting Ashcrofts Pegging ARBd 4.11 CW&Ps did the trick, after much reserach the gearing I calculated was close to Factory V8 with 205s :),

.........just with "A Bit" more BHP :rofl:

Nige

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Maybe add an efi upgrade to your list with the 1.22. The standard rover bits are easy and cheap to come by and will give you a few more horses. Alternatively, go the whole hog and hit it with Megasquirt.

FWIW, I have a 110 with 3.9 on flapper efi. I believe as it is an auto, the xfer box is 1.02 (although not sure about the auto gearing). When on song, it has more than enough grunt (almost sporty :lol: - for a LR).

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Thanks for the replies, the information will come in very useful.

Can any one post speed + rpm data,? e.g. 60mph at 3500rpm

or 40mph at 2000rpm with santana + 1.4 T/B

that sort of thing would give me an idea of what my engine would pull gearing wise.

At the moment it is 70mph at 4000rpm and I would prefer 70mph at 3000 (3500max) I feel the motor would easily pull that gearing on most of my journies.

Thanks :D

Diesel figures would be very useful as well, e.g. 200tdi engine and boxes say 2000 at 50mph? etc etc...

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Can any one post speed + rpm data,? e.g. 60mph at 3500rpm

Why don't you click the link I posted then you can do it yourself with the spreadsheet, compare your current gearing to your prospective gearing, compare gearboxes, tyre sizes, diff ratios... :rolleyes:

The factory V8 is ~100hp, by contrast the RR 3.5 EFI is 160 and the 3.9 is 180.

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Why don't you click the link I posted then you can do it yourself with the spreadsheet, compare your current gearing to your prospective gearing, compare gearboxes, tyre sizes, diff ratios... :rolleyes:

The factory V8 is ~100hp, by contrast the RR 3.5 EFI is 160 and the 3.9 is 180.

Cheers for the link but I'm not that bright and am having difficulty relating all that info to actual on the road gearing.

My out put is about 17+mph per 1000 revs and I can relate to that post-10430-1217588752.gif

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Apologies, I thought that link contained this spreadsheet which does it all for you, that might be easier! :P

Thaaaaaaats better Ta :D

Am I right in thinking that option one is my five speed box with a 1.4 transfer box

And option two is a four speed box with a 1.22 transfer box

I didn't try jiggling with the charts, should I ? :)

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I didn't try jiggling with the charts, should I ? :)

Yes, that's the point! :P

You use the "Sample data" page to cut-n-paste your ratios into the top half and your speculations into the bottom one, then you can compare.

You'll notice there's very little difference between main gearboxes, it's mostly in the transfer box gearings.

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Factory spec V8 90's had the santana and a 1.2:1, with 205x16 tyres, and they were gutless in this setup. so i'd imagine that the extra weight of a 110, combined with 7.50 tyres would really make it struggle (this is assuming you're running a standard 3.5 carb 118bhp V8 like the 90's had...)

Now, if you're running something like V8freak has, then you'll be OK with the 1.2

I have to disagree here. My factory V8 90 had 7.50 Rangemasters when I got it (1.19 t/box + LT85), not at all gutless, was seen doing 90mph between petrol stops once (wind behind etc), but not nice to drive at that speed. Changed tyres to 265s and still plenty of go. Now I have a 3.9 under there there's LOTS of go :D

Should mention that as far as I was aware, mine was a 134bhp engine (built 1986)

Rough cruising speed in 5th - 50mph = 2000rpm. Hope this helps.

Michael

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Rough cruising speed in 5th - 50mph = 2000rpm. Hope this helps.

Michael

Great stuff :D

That's about 25mph per 1000 revs which is diesel gearing I would have thought, I'm doing 35 + at 2000 which is a LOT of difference.

So looking at that a 1.4 Transfer Box would give approx 20 mph per 1000 which is perfect for me

FridgeFreezer[/i

I dont know how to do all this stuff

Yes, that's the point!

You use the "Sample data" page to cut-n-paste your ratios into the top half and your speculations into the bottom one, then you can compare.

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I dont know how to do all this stuff

Click on the "Sample data" page.

Find your chosen gearbox

Select the cell with the ratio for 1st gear

Press "Ctrl" and whilst holding they key, press "C". This will copy that value.

Select the main page

Select the cell for 1st gear

Press "Ctrl" and "V", this will paste the number into the cell.

Repeat for the rest of the gears, transfer box ratio, etc.

Stand back and admire the results :P

You can also use the menu "Edit -> Copy" and "Edit -> Paste", or select the cell and right-click on it and select "copy" or "paste".

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Click on the "Sample data" page.

Repeat for the rest of the gears, transfer box ratio, etc.

Stand back and admire the results :P

You can also use the menu "Edit -> Copy" and "Edit -> Paste", or select the cell and right-click on it and select "copy" or "paste".

Thank you mate.

Done all that and very impressed with the results.

What I need is a 1.4 transfer box which will be fantastic for cruising without stressing the motor as it is at a guess around 150bhp. It pulls from 1200 rpm in 5th at the moment so I never need to change gear :) Too low geared.

Just need to find one that will fit now, any ideas.?? :lol:

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What I need is a 1.4 transfer box which will be fantastic for cruising without stressing the motor as it is at a guess around 150bhp. It pulls from 1200 rpm in 5th at the moment so I never need to change gear :) Too low geared.

Just need to find one that will fit now, any ideas.?? :lol:

What kind of driving do you do?

1.4 tbox for your setup is the best all round, you should max out just under 90mph in 4th with 5th being a true overdrive.

If motorway mileage is low and urban is high then I would prefer 1.22 - this makes first a useable gear and you can use the engine's flexibility in 2nd and third.

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I have to disagree here. My factory V8 90 had 7.50 Rangemasters when I got it (1.19 t/box + LT85), not at all gutless, was seen doing 90mph between petrol stops once (wind behind etc), but not nice to drive at that speed. Changed tyres to 265s and still plenty of go. Now I have a 3.9 under there there's LOTS of go :D

Should mention that as far as I was aware, mine was a 134bhp engine (built 1986)

Rough cruising speed in 5th - 50mph = 2000rpm. Hope this helps.

Michael

Agree here, mine is a 1989 90, so is the 134ish HP version, and isn't too gutless (well not compared to a N/A 2.5), and I'm running on 235/85s. 70mph is approx 2500rpm.

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My speeds per rpm don't match anything on the calculator even allowing for the speedo being 10% slow.

I have an LT85 gearbox and 31inch high rear tyres. I rarely change out of 5th gear even in town so it's very low.

The 1.6 shows faster than mine and the 1.4 miles faster so I must have an odd transfer box fitted. No matter as it's knackered anyway and I will be going for a 1.4 as long as it will fit my LT85.

Very interesting and informative discussion so thank you everybody. :D

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How about just for one last idea get a petrolly rag, get underneath and rub and find the serial no on the transfer box, IF if has the correct internals for the number you may find what you have :)

From the ever helpful ashcroft transmission website (and frankly for the money I would recomend one from them :) )

List of Serial numbers and corresponding Ratios

All stock LT 230"s have a low ratio of 3.321, the following list refers to the high range ratio.

12D = 1.667 LT 230R

13D = 1.410 LT 230R

14D = 1.003 LT 230R

15D = 1.192 LT 230R

20D = 1.667 (2.5 N/A 110),

22D = 1.410 (all 4Cyl 90/110 bar above),

25D = 1.410 (V8 110 LT 85), :)

26D = 1.003 (RR Classic 3 speed auto),

27D = 1.192 (early RR Classic),

28D = 1.222 (RR and Disco I),

29D = 1.192 (V8 90 LT 85), :)

32D = 1.222

34D = 1.410 (2.0 Disco I),

36D = 1.211

38D = 1.211

40D = 1.211 (NAS/Japan 90&Disco),

41D = 1.211 (Disco II, diff lock stud),

42D = 1.211 (Disco II, diff lock stud),

43D = 1.410 (90/110 TD5),

57D = 1.410 (90/110 TD5),

61D = 1.211,

62D = 1.211,

68D = 1.211,

69D = 1.211,

70D = 1.211 (Disco II, no diff lock),

LT 230 Transfer case comparisons

1.003 > 1.222 = 17.92% Drop

1.003 > 1.410 = 28.86% Drop

1.003 > 1.667 = 39.83% Drop

1.222 > 1.003 = 21.80% Raise

1.222 > 1.410 = 13.33% Drop

1.222 > 1.667 = 26.70% Drop

1.410 > 1.003 = 40.57% Raise

1.410 > 1.222 = 15.38% Raise

1.410 > 1.667 = 15.41% Drop

1.667 > 1.003 = 66.20% Raise

1.667 > 1.222 = 36.41% Raise

1.667 > 1.410 = 18.22% Raise

More here : http://www.ashcroft-transmissions.co.uk/part_8.html#pa1

Nige

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