Are Overdrives worth it?

[crankin]

I am thinking about dropping some money on an overdrive (a Fairey one to be exact)...but have not really found a huge amount of details on them.

I know about the makes and models and the pros and cons of each, but what I really want to know is if they are worth it!

I have read that on tried old engiens that you really will not see any improvement. Roverdrive states that thier product helps mpg and reduces noise...but said that this will not increase speed. Fairey Overdrives seem to increase speed and power. But I have not heard anyone talk about the before and after.

Whats the truth to all this? Can someone chim in with if it is worth it or not?

[bkreutz]

One way you can replicate the experience of an overdrive is to drive around for a while without using high gear, then do the same thing only this time use high gear. Big difference. The confusion about gaining top speed comes from people expecting to go faster because of higher gears when the engine doesn't have enough power to do it. It can occur where you can go faster without overdrive, but that's normally because there isn't enough power in a higher gear (overdrive) but a numerically lower gear is a better power match. I like them because of the lessening of noise and engine speed, plus it gives me more options, sometimes there are hills where one gear is too high but the next lower is too low, the overdrive gives me an option between the two. In the end it's personal preference.

[Lalo88DK]

First of all if it's speed you want you have bought the wrong car .
But I think if you can find a Fairey overdrive in good working condition and one that doesn't whine, it's worth the money. I have a Fairey overdrive in my Series III 88" 2,25 Diesel, and I am very pleased with it so far. I used to have a Ashcroft high ratio transfer box in my last 2,25 petrol, and that was not a good combination (lack of power).
You do get better MPG with a Fairey overdrive and Higher cruising speed, and it does reduce the engine noise, quite a bit (if the Fairey is not whining).
I never go above 55 mph with overdrive (without 48 mph) they are not really built for speeds above 55 mph, (Series trucks are perfect for small British country lanes) of course they can go faster, but try and listen to the engine if you want your engine to last, don't push it too hard and too long, trying to reach highway speeds to keep up with traffic, especially not if it's a diesel.

But if you really want to go faster, and save fuel, you can fit Range Rover diffs (does destroy offroad ability some what when crawling), Fairey overdrive, taller road tires 235/85-16 and freewheeling hubs, fit a Kenlowe fan, instead of the belt driven original.
But I'd say that a Fairey overdrive is a good investment.

[73series88]

i got a fairey last fall and it made all the difference.
i lucked out and got a pretty quiet on. i couldnt do the highway very well
with out making the motor scream. 6 hour highway ride to winter romp this year i couldnt have done it without the overdrive. it is nice for spliting gears up hill when the one your in isnt quite enough. i would recomend one. on back roads its not that im going faster just not making the motor rev so high. IMO
aaron
2.25 doesnt have enough power for range rover diffs.
ive left my overdrive on by mistake and thought something was wrong with the truck
its was basically the same as having fulltime rrc diffs
no power wouldnt barley make it up hills. lucky it was only for a few minutes.

[stomper]

I will agree with everything that has been said above about the fairey overdrive. Drive your truck around town at 55mph. listen to the engine. now slow down to 45mph. the engine will quiet down considerably. This is what it will sound like at 55mph with the overdrive engaged.

I honestly cannot imagine traveling long distances without one. With a good unit, and a good synthetic oil, the whine is minimal on mine. Usually only when you back off the throttle and coast some will you hear a bit of a whine.

My engine is not tired, so I don't know how that will affect things, but mine will accellerate up a slow gradient in overdrive from 45-55mph. and I will engage the overdrive in 4th at a speed as low as 35mph. I use it around town when I have the room to cruise without stopping and starting for traffic or lights. Not just on the highway.

Buy one, you won't regret it.

[I Leak Oil]

Think of an OD as nothing more than 5th gear on your tranny. At a given RPM it will allow the wheels to turn faster, allowing the vehicle to go faster. Or, at a given MPH it will allow the motor to turn slower, increasing MPG and decreasing wear and tear on the driver.
A 2.25 isn't always able to push an OD fast enough on hills and such though. An OD is NOT a power adder, which is what some people confuse it with.
I bought my superwinch OD brand new 17 years ago. It's well worth it to me and what I do with my truck. It's getting tired and screams like a banchie so I'm looking at a Roverdrive next.

[siii8873]

<P>I have a santana OD.&nbsp; where would parts be found for it?&nbsp; I do not need any but could some time.</P>
<P>&nbsp;</P>

[TeriAnn]

<P>I have a santana OD.&nbsp; where would parts be found for it?&nbsp; I do not need any but could some time.</P>
<P>&nbsp;</P>

Heystee automotive in the Netherlands is reproducing Santana overdrives and selling parts to maintain the older Santana overdrives.

http://www.heystee-automotive.com

Paul also sells a very high quality disc brake conversion for Series trucks.

[TeriAnn]

Whats the truth to all this? Can someone chim in with if it is worth it or not?

If I still had a 2.25L engine I would consider an overdrive to be an essential enabler for driving my truck in the hills.

When you are driving highways on hills without an overdrive you often find your engine bogging down, the temperature needle creeping and your truck loosing speed in one gear and revving too high in the next lower gear. So you are either floored going through a ton of gas or going too slow but with your engine in a sweet RPM range. Where the overdrive really shines is being able to split gears to get that RPM that puts your engine in its happy sweet spot and getting the best speed and best fuel economy.

Third over was my best friend on mountain highways, second over on some really steep mountain secondary roads.

If you find yourself driving into a stiff headwind on the slightest grade, third over can put a lot less stress on the engine and give you better fuel economy.

The 2.25L petrol prefers to highway cruise at around 3200 RPM, which depending on your tyre size is around 50 to 55 MPH. Fourth over will allow you to cruise 60-65, depending upon tyre diameter and still be in the engine sweet RPM range. However you have to be careful here. If there is any head wind or uphill or your tyres are too tall you may loose in fuel economy. The harder your engine has to work the more fuel you burn. If you have to press down on the accelerator to maintain 4 over you will be seeing filling station a lot sooner.

If I still had a 2.25L engine I'd buy one just for the third over gear option and consider the other gears to be just added benefits.

If you get one, stay on top of the oil. Makes all the difference in the workd for OD longevity.

[73series88]

YEP