Fairey Overdrive V8

[Boxoftricks]

Hi,

Pondering options to increase the mpg on the motorway.  I have a 1965 88 with a Rover 3.5 classic range rover V8 conversion running a standard 4 speed series 2 gearbox. Love it to bits but it sure does drain the tank fast. 

Would adding a Fairey Overdrive help?  What I know about overdrives can be written on the back of a small stamp with plenty of space to spare. Or is there a better gearbox option?

Thanks

[nathanglasgow]

What Mpg do you get with the V8? I get 17-21mpg with standard 2.23. Could have sworn I once got 24mpg on a long gently driven 200mile trip but never repeated.

[Adam1958]

What diffs have you got bud? The 3.54 rrc diffs make it much less frantic. Still more than enough torque to pull away without looking like a thrash-fest-chav.

[cswagon]

I'm a complete anorak when it comes to fuel consumption because I believe it's one of the best ways of telling if you have a start of a problem
with the engine if the consumption starts being affected.
Every time I fill up I brim it and press the trip so that I can keep a record, and when I was without the overdrive for a few weeks recently I
can honestly say it didn't make a jot of difference to the figures.
Mine is behind a 2.25 diesel and I definitely missed it for the difference it made to the noise levels though.

[Boxoftricks]

What Mpg do you get with the V8? I get 17-21mpg with standard 2.23. Could have sworn I once got 24mpg on a long gently driven 200mile trip but never repeated.

Doing a 120 mile trip I used 6.59g = c.18mpg. However this was a straight run down the A1M doing 50-60 mph with only a 5 min leg either end on B roads. For about half of this I tucked in behind large lorries to get sucked along.

[Adam1958]

I'm a complete anorak when it comes to fuel consumption because I believe it's one of the best ways of telling if you have a start of a problem
with the engine if the consumption starts being affected.
Every time I fill up I brim it and press the trip so that I can keep a record, and when I was without the overdrive for a few weeks recently I
can honestly say it didn't make a jot of difference to the figures.
Mine is behind a 2.25 diesel and I definitely missed it for the difference it made to the noise levels though.

Nice. I'm a sucker for data. Knowledge is power and all that.
I did check my MPG properly once... I was so horrified that I just stopped thinking about it, now I just treat the petrol station visit as an excuse to have another pasty.

[Boxoftricks]

What diffs have you got bud? The 3.54 rrc diffs make it much less frantic. Still more than enough torque to pull away without looking like a thrash-fest-chav.

It has the 3.54 high ratio Range Rover diffs.  LWB steel wheels with 7.50x16 tyres. 

Agreed not frantic and a lovely drive with plenty of torque and no issues going up any hills. 

[cswagon]

That's the other reason not to bother with a Fairey, they were pretty fragile even
when new so wouldn't live for long with a big lump up front.

[Boxoftricks]

That's the other reason not to bother with a Fairey, they were pretty fragile even
when new so wouldn't live for long with a big lump up front.
[/quote

That's the other reason not to bother with a Fairey, they were pretty fragile even
when new so wouldn't live for long with a big lump up front.

So is a Santana Overdrive more robust than Fairey? I understand they were designed for military vehicles but there does not seem to be a  lot of comparison data out there.

[Serious Series]

A roamerdrive should be able to take the power but expensive to buy direct from Canada

[NoBeardNoTopKnot]

Agreed, if for different reasons. If you stop for a minute - if mpg is hte reason - there's no way fitment of an Overdrive can make sense. Not back in the day, not now. How could it? But then thinking about such things never stopped a purchase decision before. It won't now.

I own a Roverdrive - in the other thread you'll read it's coming out. Only hang on mo' before we consider why, I paid £8-900ish back-when.... these days, or when I last looked, they're £1600+

A decent Fairey is near £900-1000 when I looked.

In 20 odd years I have never ever checked to see if my Roverdrive gives more mpg. Er... why would I? If I ever do, you'd be right to take me outside and shoot me. My fate well deserved. You see, £800-900 for an overdrive then, or whatever it'll cost today, can never be recouped. How can it?

And this on a vehicle in daily use? Even if it gives 5% improvement - which is doubtful - it's in use for 5% of the time. If we're kind, and say 10% and 10% of the time (unlikely) things still won't add up.

Unless you can get a new Roamer or my old Roverdrive for £50. And you can't.

Hence one of the main advantages of an overdrive is to lose money. I knew this BEFORE fitting. Which is why no one has shot me. Yet.

The reason you fit an overdrive is to give your LR longer legs and cut noise. The driving a 'sjgnal-box' thing appeals to me, or did back then. The novelty has long since worn off. A Fairey is fragile, in bad order they're noisy.

So why remove a Roverdrive? I'm removing mine to put a 5-cog box. However take aim, in some quarters  this misdeed alone has me best to decide on my last menu.

Without the option of a 5-cog would I fit an overdrive now? Of course, I like them, and no - a  5-cog won't save me money either.

[Richard]

Would an Ashcroft high ratio transfer box work?
Richard

[Alan Drover]

Should be ok with a V8; because there's more power unlike the2.25.

[Boxoftricks]

Would an Ashcroft high ratio transfer box work?
Richard

Great shout and cheaper option. I'll give them a call.  Has anyone fitted one?

[Old Hywel]

Should be ok with a V8; because there's more power unlike the2.25.

As well as 7.50s and RR diffs?