Simon
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| posted on 22/1/06 at 09:27 PM |
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Appropriate 'box ratios (R V8)
Chaps,
I have R V8/LT77 and 3.92 diff.
I pulled away (quite quickly) in 3rd gear today. Never use 1st.
Now I know that once I get a 3.14 diff things will improve, but will it be enough. Can box ratios be changed - I've looked at the R380 and the
only difference was the 3rd decimal, so insignificant.
Any suggestions for alternative - easyish fit boxes with better ratios
Thanks
ATB
Simon
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02GF74
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| posted on 22/1/06 at 09:48 PM |
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not sure if this is gonna help you, but Land Rover gearbox rations are: (formatting may be off!)
LT77 90/110 LT77 V8 Disco LT77 TDI Disco LT95
1st 3.585 3.321 3.692 4.0691
2nd 2.3008 2.132 2.132 2.448
3rd 1.5074 1.397 1.397 1.5049
4th 1 1 1 1
5th 0.8314 0.77 0.77
Rev 3.7007 3.429 3.429 3.6643
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Bob C
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| posted on 22/1/06 at 11:40 PM |
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I had rv8 & 3.14 diff in my mx5 & it worked very well with the T5 box - 2nd did ~65, 3rd in the 90s. 3krpm was 80 in 5th. Later I put the
0.63:1 5th gear in & that was too high, something like 0.75:1 would have been better, I was getting about 34mph per 1000revs, which , though
excellent on the motorway, was too high a gear to use below 40odd when pottering. OK re your question, the T5 is a bombproof box, goes on with an auto
bellhousing and a 12mm adapter plate on the gearbox end if you use a cossie 'box. The spline on the cossie box fits a rover driven plate but
you'll need to turn an annular adapter to fit the ford (neeedle roller) spigot bearing.
cheers
Bob
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Simon
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| posted on 23/1/06 at 12:37 AM |
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quote:
Originally posted by Bob C
.............but you'll need to turn an annular adapter to fit the ford (neeedle roller) spigot bearing.
cheers
Bob
Bob,
? What's that mean then
Did you cut out the adaptor plate, or is one readily available. I have an auto bellhousing lying around somewhere
FYI I'm getting 21mph/1000 - not good. KamDiffs were supposed to be doing some 3.10 diff internals - That may be the cheaper/quicker route to
go.
Anyone else interested!
Cheers
ATB
Simon
[Edited on 23/1/06 by Simon]
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froggy
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| posted on 23/1/06 at 12:50 AM |
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ive got a 3.15 7" sierra diff from classic conversions which cost just under 500quid fitted. cost wise a t5 might be cheaper but without the
taller diff you wont gain much .the yanks use an 8.8 ford diff in some cars which il bet have good ratios ,i seem to remember they went into south
african xr4i s with a big v8 in.
ive got the same problem with mine and as i cant use the 3.15 diffs im stuck with 3.62 so il keep looking for another gear at 70mph
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Messenjah
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| posted on 23/1/06 at 07:20 AM |
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there are companies in LR magazines that will change all the internals over to change ratios completely not particularly cheap but you can have pretty
much whatever you want iirc
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Bob C
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| posted on 23/1/06 at 01:09 PM |
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OK spigot bearing: the cossie 'box input shaft has to spin in a wee bearing in th middle of the flywheel (at least it does when you press the
clutch) The wee bearing (or spigot bush) in a rover flywheel doesn't wotk with the bearing part on the end of the 'box inpu shaft so you
have to adapt them to fit. I first tried a phosphor bronze bush but that wore out so I replaced it with the ford part (which is a needle roller
bearing) and that worked fine. As I said, I had to turn a 'ring' which went round the ford part and into the hole in tha flywheel
(actually the end of he crank if memory serves correctly).
The auto bellhousing (don't know which one....) had a hole enlarged in the side for the release arm - though if doing it again I'd just
use a concentric slave cylinder e.g. saab. I can post a picture later on tonight if you want.
The other possibility is to get a TVR bellhousing - they sell 'em as spare parts - to bolt a T5 to a RV8 + all the clutch release gubbins.
cheers
Bob
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Bob C
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| posted on 23/1/06 at 01:15 PM |
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PS - you need to turn down the cosworth box input bearing housing for it to fit in the TVR bellhousing (10 minute job if you have a lathe)
plus I suspect you may be rather old before you see high ratio diffs from Kammdiffs - I looked into this myself 2 years ago & it was being talked
about then.... I got lucky & found a scrap 3.14:
maybe the freelander option is worth pursuing?
Bob
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Simon
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| posted on 23/1/06 at 08:50 PM |
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Thanks very much chaps.
For the mo, I'll keep my eyes peeled for a 3.14 diff - one may well be sitting on someone I know's driveway - better ask
Cheers again.
ATB
Simon
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Simon
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| posted on 23/4/06 at 02:09 PM |
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Sorry to drag this back up, but found this, and thought it may be of use to some:
http://www.gearboxman.co.uk/psbellhousings.html
ATB
Simon
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AdamR
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| posted on 24/4/06 at 03:44 AM |
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Simon,
One thing to think about if you're considering the T5 is that its external dimensions are quite different to an LT77. From memory its wider, so
you may have to mod your tranny tunnel. I have all the dimensions (including a nice SolidWorks model) but I'm out of the country at the mo so
cant get hold of them for you.
If you do get anywhere with new internals/freelander diffs or you come across a hidden stash of 3.14 diffs, be sure to let me know as I'll be
facing the same problems eventually.
Cheers,
Adam
[Edited on 24/4/06 by AdamR]
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AdamR
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| posted on 24/4/06 at 03:50 AM |
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quote:
Originally posted by Bob C
PS - you need to turn down the cosworth box input bearing housing for it to fit in the TVR bellhousing (10 minute job if you have a lathe)
Bob
Bob, you dont happen to have the dimesions scribbled down for the spiggot bearing adapter (or whatever you'd call it) do you? Unfortunately I
don't have a lathe so I'll be relying on someone making me one.
Cheers,
Adam
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Bob C
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| posted on 24/4/06 at 11:44 AM |
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Sorry Adam, I finally got shut of all my V8 stuff a while back: I remember considering making the thing by wrapping some 1.6mm or 1.2mm steel plate
round something, so it's quite a thin ring (BTW it was shite - don't even think about it... get it turned properly!)
I'm sure you'll feel safer if you've bought the bearing and measured it and the hole in the crankshaft yourself!
cheers
Bob
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locostv8
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| posted on 30/6/06 at 01:08 AM |
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FYI I believe these to be the ratios of a v8 mustang in the US.
first transmission gear ratio =3.35
second transmission gear ratio =1.93
third transmission gear ratio =1.33
fourth transmission gear ratio =1
fifth transmission gear ratio =.68
My 93 Cobra does 2000 at 70 mps with 3.08:1
[Edited on 30/6/06 by locostv8]
http://wrangler.rutgers.edu/gallery2/v/7slotgrille/hssss/
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