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Topic: Diffs (Read 1808 times) |
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Highlander
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Anyone know if these diff ratios are definitely correct on this page?
http://www.fordscorpio.co.uk/manual/rearaxle/RAxleSpecs.pdf
reason being is ive just removed what looks like an original diff from a 97 2.3 estate and its a 3.9 instead of the 4.27 it says on here.
Past experience with Escorts/Capri's etc tells me usually the lower capacity engines have the highest ratio diffs so a 3.9 in a 2.3 would "seem" to be correct
Also the 4.09 in the 8v's seems not to fit the pattern either..
Anyone shed some light? 
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on Oct 17th, 2011, 12:35pm, Simmo wrote:I give up !  Too much for an old boy!  |
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martin_rowe
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Re: Diffs
« Reply #1 on: Oct 20th, 2006, 8:53am » |
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4.27 is higher ratio than 3.9.
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martin_rowe
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Re: Diffs
« Reply #2 on: Oct 20th, 2006, 8:56am » |
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oops get brain in gear, wrong way round, 3.9 is higher than 4.27, the 'lower' diff gives lower top speed for same rpm, smaller engines dont have the power to pull the higher diff ratio. the 4.09 in the 8v is probably to suit the engines charicteristics, & provide higher cruising gear, for economy.
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Highlander
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Re: Diffs
« Reply #3 on: Oct 20th, 2006, 9:06am » |
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Yep, i understand the principles of it but why have i got a 3.9 when it says 4.27? 
When the car is running the speedo seems to read correctly when tested alongside another car
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on Oct 17th, 2011, 12:35pm, Simmo wrote:| I give up ! Too much for an old boy! |
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howiedintheplace
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Based near Evesham
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Re: Diffs
« Reply #4 on: Oct 20th, 2006, 11:02am » |
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I had a diff from a 2.0L 16v that was a 4.27:1.
People can help you out here.
If you select either 4th (manual) or 3rd (auto) & post what RPM exactly you have at say 50 mph + your tyre size then I can tell you what diff you have.
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Dave
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TiberiuS
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Ex. 1996 2.3 Ultima - RIP P789 KHJ
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Re: Diffs
« Reply #5 on: Oct 20th, 2006, 12:01pm » |
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Slightly off topic but this may help .
On the Racer Scorpio model, the 2.0 and 2.3 16v have a 4.27 axle ratio giving 3050rpm@70mph in 5th, 24v has the 3.64 as does the automatic on all 16/24valves I believe giving 2650rpm@70mph. 16v auto has same diff ratio as the 24v which puzzles me as the manual one is shorter, gear ratios are similar in both auto and manual.
If it's of any use, I think these are the correct gear ratios for the A4LDE automatic, 1st:2.08 2nd:1.56 3rd:1.00 4th:0.76 Rev:-2.08, Final drive:3.64.
Worked these out from quoted top speeds@rpm, they seem to work ok in the sim, 60mph in 1st seems a bit tall though. Pitted two 2.3's against each other, one with each diff ratio and with all the weights/torque/drag coeff setup there wasn't a big difference in performance.
Regards, Bruce.
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Bruce - '07 Jaguar XKR coupe, '95 Jaguar XJ Sport 4.0, '82 Ford Capri 2.0 Ghia, '15 Honda Civic (sloooooww..)
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Highlander
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Re: Diffs
« Reply #6 on: Oct 20th, 2006, 1:50pm » |
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Ok, just took another diff off a facelift 2.3 auto saloon, same thing, I can read the tag on this one though and it says 3.91 which confirms my method of turning the prop end of the diff just short of four complete turns to get one complete turn on the driveshafts..
Was there a change in spec for these diffs on later cars??
I did take a diff off one of the very first 94 2.0 16v estates once and it was definitely a 4.27
all the later ones seem to have the double mount at the rear of the diff, the early one had a single mount.
any more ideas?
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on Oct 17th, 2011, 12:35pm, Simmo wrote:| I give up ! Too much for an old boy! |
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TiberiuS
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Ex. 1996 2.3 Ultima - RIP P789 KHJ
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Re: Diffs
« Reply #7 on: Oct 20th, 2006, 1:55pm » |
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Manual had the 4.27 and auto the 3.91, overdrive on both auto and manual is the same ratio
2650rpm@70mph in o/d for the 3.91
3060rpm (or thereabouts )@70mph in o/d for the 4.27
I'm curious myself...
Bruce.
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Bruce - '07 Jaguar XKR coupe, '95 Jaguar XJ Sport 4.0, '82 Ford Capri 2.0 Ghia, '15 Honda Civic (sloooooww..)
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Highlander
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Re: Diffs
« Reply #8 on: Oct 20th, 2006, 2:31pm » |
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So this page has the wrong data??
http://www.fordscorpio.co.uk/manual/rearaxle/RAxleSpecs.pdf
Thats a manual 2.3 Estate and an Auto 2.3 saloon I've seen both with a 3.9 diff
The estate had huge miles on it so possibly might have had a "wrong" diff from an auto at one time if they are indeed 3.9
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on Oct 17th, 2011, 12:35pm, Simmo wrote:| I give up ! Too much for an old boy! |
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mazzy_j
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Re: Diffs
« Reply #9 on: Oct 20th, 2006, 2:32pm » |
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Just noticed 3rd box from the bottom it says 2,9 V6 Cosworth (TCI Diesel), bit of a typo but i wouldn't mind a Cosworth v6 td lump in my car
Maybe your diff was from one of Ford's infamous friday afternoon built cars?
Matt
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TiberiuS
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Ex. 1996 2.3 Ultima - RIP P789 KHJ
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Re: Diffs
« Reply #10 on: Oct 20th, 2006, 5:16pm » |
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Quite sure the 3.91 is correct, seems odd to me that Ford dropped a 4.27 into the manual, wouldn't it be the other way around with the auto having less gears i.e more load on the engine?
Thats the figures I got from this site and I looked elsewhere and got the same, did a lot of drivetrain research for that bleedin' model...
The physics of the drivetrain should be good, the chap who makes Racer also does a commercial version for a company, plonked the auto/final drive ratios I had for the 3.91 24v above and speeds/engine revs are the same as my 2.3...
3.91 diff on a 4.27 speedo setup would surely reduce the mileage, engine doing less revs etc.
Just off to put my anorak back on
Bruce.
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Bruce - '07 Jaguar XKR coupe, '95 Jaguar XJ Sport 4.0, '82 Ford Capri 2.0 Ghia, '15 Honda Civic (sloooooww..)
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Highlander
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13 Scorpios, XR4x4, Suzuki SJ413 for off road :)
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Re: Diffs
« Reply #11 on: Oct 20th, 2006, 6:29pm » |
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Did you find the info on this site Bruce? can you remember where?
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on Oct 17th, 2011, 12:35pm, Simmo wrote:| I give up ! Too much for an old boy! |
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TiberiuS
Senior Member
Ex. 1996 2.3 Ultima - RIP P789 KHJ
Posts: 2257
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Re: Diffs
« Reply #12 on: Oct 20th, 2006, 6:49pm » |
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Took me ages to find the page on this site, it's here. Scroll down and there's a final drive/tyre profile reference, no mention of the 3.91 on the 16v manual.
I found the same info on another site, can't remember what one, I'll have a search around.
Bruce.
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Bruce - '07 Jaguar XKR coupe, '95 Jaguar XJ Sport 4.0, '82 Ford Capri 2.0 Ghia, '15 Honda Civic (sloooooww..)
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Octavian_P
Senior Member
 
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Re: Diffs
« Reply #13 on: Oct 22nd, 2006, 1:16am » |
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There was a TSB (thenical service bulletin) from ford regarding clutch uder-rating for the new diff fited cars....i belive it was stated that in '97 the 2.3 got the 3.9 diff instead of the 4.27. I'll search and try to find the info again....
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2.0 16V Ultima|2.3 16V Ghia|2.9 24V Cosworth Ghia
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howiedintheplace
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Based near Evesham
Posts: 1194
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Re: Diffs
« Reply #14 on: Oct 22nd, 2006, 10:01am » |
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I think Octavian may be right, I seem to remember something about when the manual box got the higher top gear the diff was changed also on all 2.3 cars.
What build dates are these 2.3 cars highlander?
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Dave
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Highlander
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13 Scorpios, XR4x4, Suzuki SJ413 for off road :)
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Re: Diffs
« Reply #15 on: Oct 22nd, 2006, 10:12am » |
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Magic Thats what i was thinking Octavian, some change in spec for later models..
Dave, would have to check but both were R Reg so 97 likely, one was a facelift.
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on Oct 17th, 2011, 12:35pm, Simmo wrote:| I give up ! Too much for an old boy! |
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howiedintheplace
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Based near Evesham
Posts: 1194
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Re: Diffs
« Reply #16 on: Oct 22nd, 2006, 10:39am » |
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I don't think it was a TSB thou but a revised mpg figure/performance sheet.
Also you should be able to tell what diff it has from the plate.
There is a axle code which relates to the different ratio's.
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Dave
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howiedintheplace
Senior Member
Based near Evesham
Posts: 1194
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Re: Diffs
« Reply #19 on: Oct 24th, 2006, 12:35pm » |
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Hmm but it don't actually say the ratio
I know what your thinking it hints at a higher gear fitted.
I seem to remember they issued new performance figures & on there it say for cars fitted with the higher top gear & diff. But was a while ago I saw it.
Maybe in a revised owner manual for the car
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Dave
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