Hi all just about to put upgraded rr classic diffs in my series 3 one has been completely rebuild and the other is a good used unit, which one would you put in the front and which one in the back. my theory is because I have freewheeling hubs I'd put the used one in the front. what do you all think? And why?
Thanks Cris
 
That's what I would do as you don't use the front axle much and put the re-cond one in the back, I've done this on my 2a rebuild :)
 
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Long as you trust the re-built one...put it in the rear.

Your speedo will be out by quite a bit...I just took the glass off mine and put white dots of panit in the correct gps checked spot.

Have you sorted how your going to fill the axle with oil.
 
Hi I have one from a rr classic with the filler in the housing. Im not to worried about the speedo as I live in a very small village and it is used around there mostly and across the fields with the odd trip into town saying that how far out will the speedo read
 
Around 25%....as will the mile odd meter...worth remembering for oil changes act...easy to forget.

I welded in new oil fillers...in fact I welded on new diff pans...my old ones leaked so it had to be done.
 
Yes give the same gearing as went I ran an overdrive but none of the overdrives possible probs....saying that mine was ok apart from leaking oil into the T/Box...and it was a bit noisy...heard worse though.

Would not like to run on h/r diffs on a 2.25 though...maybe you could get away with in with a petrol.

Just so much better with the h/r diffs...wish I still had the o/d to see how it would have went...high o/d and the h/r diffs....maybe it would be over geared for my 200di.

But on the flat with no wind???
 
Mines got a 200 di fitted as well and has the overdrive but im taking it out for the same reasons as you also im hoping it lets me use first gear more rather than pulling of in second, what size tyres you running ?
 
I'm on 205 16s...its a SWB soft top so quite light...so are you going to leave your od in for a bit see how the di handles it...be very interesting.
I do find I'm using second gear for starting...if on the flat...but any incline I will use 1st.

I do think I'm being lazy not using 1st...prob not doing the clutch any favours...not that it struggles.

How long have you been using the 200di and what MPG do you return...back and to to work I'm getting around 35mpg....not tried it on a run but I suspect nearer 40mpg if I kept the same 50mph I keep at going to work.

I'm not up to full temp this time of year till I have done 4 or 5 miles...they do perform better when upto temp dont you find?
 
ImI getting about 35 mpg but as I say thats around the village it doesn't take long to warm up though about mile and a half i had to put a extra vdo gauge though with sender as no matter what I did couldn't get a true temp read.yes I'll leave the overdrive in for a while and I'll report back with the info. I'm going to do a disc brake conversion in the summer it gets a bit scary coming down the steep hill into the village sometimes. I am also on 205 tyres would like 235 85 16 but I mi
ght be pushing the gearing with that extra, if anyone has done the diff and wheel upgrade together I'd be interested to here the outcome
 
I feel I could go slightly higher in the gearing...but not much...would not want to spoil is performance....the overdrive would be the answer in my opinion.
But then I wanted to get away from them....for my low miles the H/R diffs are prob perfect thinking about it.
But still be very interesting the hear of your findings.

P.S. only just calmed down after watching that sacrilege TV prog a few hours ago...Goblin Works and what they did to that lovely S11a with it galv chassis.

Nick.
 
The Ashcroft ration calculator is great for this, I put my numbers in - S2A box, 3.54 diffs, O/D and 32" (235/85/16) wheels and it comes out at around 2000 rpm at 60 mph which makes it (relatively for series) relaxed on a long run. Becuase the diffs make the 3rd/4th gap wide I have to hold 3rd for longer and on a hill I use the O/D in 3rd to split it. I'm getting good a doing the 3rd OD to 4th change. The only problems are the very high reverse and 30 mph being right on a gear change, its much better at 25 or 35 so I often use 3rd OD in the 30 zone but this could be becuase my Perkins has a very narrow rev range, a different engine may not have this issue.
 

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