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| milo 302 |
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GeZza200 wrote: gday, i have a 3.08 EL single spinner diff that has been shimmed up so both wheels spin. Im wanting to get the diff rebuilt with 3.9 gears and a proper LSD center. I have been looking around and there are 25 and 28 spline diffs? Which one is mine and with a rebuild can i change that or will the diff have to be replaced? Cheers What shims and where on a single spinner centre do you add them to make an lsd? Only way i thought possible was to run an lsd centre, feel free to take me to school. When you say shimmed up do you mean a cig locker(welded centre) |
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| milo 302 |
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Also thought id add there are hypoid and amboid type differentials, refers to the pinion gear and whether it sits above or below the crownwheel centreline.
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| GeZza200 |
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im not to sure what he actualy did, but at first it was like a locker. I would turn a corner and you could here the tires skipping and it would leave big a** marks on concrete when turning. I got it backed off but its not tight enough now so i want a proper LSD centre.
_________________ EL Futura: CVE head, Wolf V500, ICE Ignition and Coil, 36lb injectors, Walbro 255lb, Paci comps, 3" exhaust, T5, Harrop Truetrac with 3.9s. Now with 198.9rwkw, (~185rwkw and 13.80 @99.1mph) with more power to come |
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| TimmyA |
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Apparently LSD's will still spin one wheel...
I've been told if you jack up one wheel off the ground and try and drive it will still just spin the wheel with least resistance (as they are limited slip, not no slip)... As such I've gone with a Lokka which I still haven't installed yet but have been told they are the go... These work that when you accelerate they lock up, when you coast around corners they work opposite to single spinner where they drive the inside wheel and allow the outside wheel to overspeed... Make by Lokka, distributed by 4wd systems Australia (they have a website)... You have remove the insides of the hemisphere out of your single spinner and put these in the guts, but they wont fit in an LSD centre, is apparently a different shape... So with these, as long as you bolt everything exactly back where it came from then you don't need to re-shim anything as nothing will move meaning you can install in your back yard if you wanted to... Just want to get my hands on some spare shims for inside the hemisphere before I pull it out in case the the Lokka doesn't measure up properly, trouble with small town, no one carries any and I can't afford to be without my car... Something different to think about... Supposedly the best of both worlds...
_________________ 93 Red ED 5spd Manual Build Thread |
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| EDXR6-Poly |
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so can anyone clarify what RPM im going to be doing at 100KPH in top gear in an auto ed falcon with 4.11 diff gears? and top speed?
_________________ AU2 engine with Hoppers head/cam performance package & spool rods / CP pistons ,Snort 1200 plenum, T56 Manual & Billet short shifter, Front & Rear Slotted rotors, Pedders lowered suspension, LSD and tuned with EMS stinger 4424 347rwkw THE ED XR6 IS BOOSTED |
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| TimmyA |
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you'll also need the size of wheels and tyres too... You need to consult your owners manual and dinf the box ratios...
Then google search for a calculator... there are heaps on the net to calculate this for you... Yeah wheels, tyre profile, tyre width, final ratio and box ratios and speed and it'll work back through the measurements to find flywheel revs... Just hunt around the net for it... Cheers...
_________________ 93 Red ED 5spd Manual Build Thread |
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| FordFairmont |
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Posts: 6113 Joined: 8th May 2007 |
mine is 2350rpm
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| FordFairmont |
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Posts: 6113 Joined: 8th May 2007 |
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| TimmyA |
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This one might be better... Shows a whole line up in go
http://pw1.netcom.com/~sgalaba/mph.htm
_________________ 93 Red ED 5spd Manual Build Thread |
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| TimmyA |
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Ok...
Discovery... None of these take into account tire buldge (IE because it has weight on it)... So I have 235 45 17 so to calc radius (I'll work in metric so it ends in km/hr) 45% of 235 = 105.75mm profile 17" = 431.8mm So calc radius of my wheels are half of mag + profile = 431.8/2 + 105.75 = 321.65mm Upon measuring (for whatever factors cause the difference) I measure 298mm So that is 1 inch in radius and 2 in diameter that these equations are out... If you use this formula to get km/hr (where * is times, / is divide, r is measured loaded radius from ground to wheel centre, R1 is transmission ratio, R2 final (diff) ratio, and RPM is your desired RPM, and remember order of operations (do whats in the brackets first)) (0.00037698 * RPM * r) / (R1 * R2) = km/hr or to calc RPM when you know speed this way (km/hr * R1 * R2) / (0.00037698 * r) = RPM Example: So in theory (still doesn't measure quite right though) I think 5th is .63:1? and my diff is 3.27:1 at 100km/hr with 298mm radius (100 * .63 * 3.27) / (0.00037698 * 298) 206.01 / .11234004 = 1833.81 RPM Compare with the 322 calc'd measurement of the wheel is 1697.13, so 136rpm of difference. Not much but it makes it more accurate this way... Hope it helps 
_________________ 93 Red ED 5spd Manual Build Thread |
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| peetys here |
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hi guys i have 2 questions to ask here !
i own an 1999 au forte 4 speed auto stock ! with the stock diff i imagine 3.08 sd or 3.23! crap! and here goes i wont some extra punch off the line and this is what i need to know from an expert or someone who has done this. would a 3.71 lsd centre fit straight into my original single spinner diff housing! without changing anything ! drive in drive away ! if i do need a lsd diff housing : eg from rotor to rotor ! does your nearest diff centre have brand new ones and then they just fit them on. is this how it works. i am not mechanicaly minded and solely rely on mechanics to do my work. just the way it is. let the pro's do it i reckon. i dont want the usual 3.45 lsd centre ! i never go the norm. please help. 
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| TimmyA |
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Take it to a diff joint..
They will be able to tell you what ratios are made to suit the diff... I get the feeling there is a 3.7, but there is definitely a 4.11... They get your diff and unbolt the centre, remove the crown wheel from the centre, and remove the pinion... They install the new pinion and crown wheel and then proceed to reset the preload, blacklash, toe/heel and face/flank between the two gears... While you're getting all these settings reset you may as well get new bearings put in otherwise if they go in 20,000km you up to get it pulled to bits and everything set again for new bearings (tolerances vary slightly between bearings)... Best to take it to someone like that to get it right if you're not confident (which I'm not)... Just be aware that odd sized ratios are worth a fortune too... esp for a brand new ones off a store... I'd either be trying to find someone selling a good second hand set or a new set they didn't use... You could be looking at over 1 grand to get a new set installed from a diff place... and you still don't have LSD, its still an open centre... The better option is to wait for a 9" or something like that to come up... Or a diff that someone has already used... That way its been set... You have to weigh up over 1k for a new 3.7 install in a single spinner or 300 bucks for a half decent 3.45 LSD out of an XR6... Ratios like this, due to cost are rarely used in road cars and a left to professionals who fit them for a reason... Cheers and good luck with your search...
_________________ 93 Red ED 5spd Manual Build Thread |
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| peetys here |
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thanks so much tim tim ! i went to my local pick n pay less wreckers this morning and had
a look around !unfortunately there was nothing around for the au !there was 1 au xr6 but someone has already taken the guts out of it ! (wich would be ideal really ) i know nothing about cars but i did notice that the diff was different to mine. i think it was inderpendent rear suspension! does that open up a new can of worms as the rear would have to be modified to fit that would it not. the rear of this diff housing had a different look to it.there was two bars running from the back of the diff going over to near the rear wheels. please excuse my mechanical ignorance. 
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| TimmyA |
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hey thats cool...
AUI models were live axle (same as EA/EB/ED/EF/EL) and these are all the same diff right through... AUII and AUIII are independent rear suspension... So you have live axle like this: Attachment: Diff.jpg [ 176.52 KiB | Viewed 471 times ] Or IRS like this: Attachment: IMGP1351.jpg [ 227.21 KiB | Viewed 452 times ] Photos curtosy of other peoples for sale threads off here... as you can see there is a lot more to IRS and I imagine different mounting points yes... (I own an ED so never had to worry about IRS... Here is an example of 3.89:1 gears: post1068011.html?hilit=el%20diff#p1068011 I imagine to suit EA to AUI differentials.... Cheers...
_________________ 93 Red ED 5spd Manual Build Thread |
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| 67RCE |
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timmytimtim wrote: hey thats cool... AUI models were live axle (same as EA/EB/ED/EF/EL) and these are all the same diff right through... AUII and AUIII are independent rear suspension... So you have live axle like this: Attachment: Diff.jpg Or IRS like this: Attachment: IMGP1351.jpg Photos curtosy of other peoples for sale threads off here... as you can see there is a lot more to IRS and I imagine different mounting points yes... (I own an ED so never had to worry about IRS... Here is an example of 3.89:1 gears: post1068011.html?hilit=el%20diff#p1068011 I imagine to suit EA to AUI differentials.... Cheers... Not quite right Tim, All AU low spec (Forte, Futura, Fairmont and XR6HP) got live axle as standard, with IRS optional. XR6 VCT, XR8, Fairmont Ghia and Fairlanes got IRS Standard. IRS gears are the same as live axle. Also, AU got a wider diff to change the offset.
_________________ ILL60 - EF XR8, Sunroof, Ticky Kit, 19x8.5/19x11 TE37's, 347, AFr185's, TFS BoxRcustom converter, Hurst Quarterstick, huge billet cam. |
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