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Economy Drive!

Discussion in 'Series Land Rovers' started by kent ranger, Jan 29, 2010.

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  1. kent ranger

    kent ranger New Member

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    Hi all, Having owned and worked on quite a few Land Rovers during the 1980,s and after a 20 year gap ive now bought an 88 S2a. Now,im out of touch with the current modifications and whats available so perhaps someone can advise. Im intending keeping to the standard 2.25 petrol but would like to improve on economy. Basically whats available and what differnce mpg wise will it make. Im thinking of overdrive,FWH,kenlowe fan and if poss a diff exchange. Im told the Range Rover diffs fit the series axle,is this correct and are they a straight swop? If so what are the ratios available? Any suggestions welcome.
     
  2. 90truckcab

    90truckcab Well-Known Member

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    welcome to LZ mate,

    yeah , yer wont increase the mpg by much, BUT the rangerover Diffs do help, along with bigger tyres, dont recomend FWH's , mine are locked on all the time. only save yer 5p a year :D
    the fixed fan will use 10-12% of yer engine power on a 2.25 petrol so that can come off,
    no doubt someone will be on in a min to tell yer what ratios are available on the RR diffs
     
  3. kent ranger

    kent ranger New Member

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    If someone could tell me the ratios available that would help,also what the standard 2a ratio is??
     
  4. iannotts

    iannotts New Member

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    3.54:1 for range rover /disco diffs
    4.11:1 ? for std diffs
     
  5. GRATCH

    GRATCH HUGE MEMBER

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    you want economy get a prius:eek:
    you want fun motoring do what you want to the 2a, won't really make that much difference unless you're doing lots of mileage
     
  6. Davec

    Davec New Member

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    4.7:1 for a Series, 4.11's are from a Rover Saloon (60?) quite a nice ratio for a 2 1/4 if you can find two.
     
  7. The Don

    The Don Active Member

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  8. Leon.

    Leon. Active Member

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    i just changed my front diff for a rr one to match the one in the back that someone put in before i got hur. chuffed that i can use 4wd and i did 52 mph apparently (sat-nav). speedo way out with rr diffs as you can guess. considering there is a problem with my throttle linkage and i can only open my webber carb %75 thats not to bad i guess. easy job to.
     
  9. Teflon

    Teflon New Member

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    Kenlows wont save 10-12% on your MPG! If they could, it suggests that the standard fixed fan is sapping between 3 & 6 BHP off the motor.... thats a moped or two or a decent lawn mower!

    They save a couple of hundred watts, the sort of power a Kenlow draws when running.....

    EXCEPT on warm up, where the lack of constant cooling means faster warm up and less time on choke.

    Can give savings, and worth having, but not at the silly money Pacet or Kenlow kits go for!

    FWH's likewise..... still useful, they do make the steering on tarmac a bit lighter and less notchy.

    Overdrive, more useful, but anything that lifts the gearing will do little for ecconomy, as you'll be putting the motor under more load.

    Power = Force x Speed

    Do some sums and petrol used is directly proportional to power used, and thats almost directly proportional to how far you open the throttle.

    Use a higher gear, motor revs lower but more throttle needed.

    3.5 diffs are a tad too tall for a series motor, on thier own, they raise gearing by 25%, about as much as an OD, but non selectable, so pulling away its like using 1st and a half.

    You'll have less noise at about 50-60, and maybe encourage the old bus to 65-70 instead of 60-65, but you'll actually use more fuel!

    Its basic physics I'm afraid & the mechanics of the old SIII are such that it defies ecconomy by virtue of being too big and too heavy and having an engine only barely adequete to haul it all!

    Biggest ecconomy gains to be found are the old, tried, tested and simple expedients of making sure that everything is properly fettled.

    Tyres are pumped up and as concervative a tread pattern as you ca get away with. Brakes dont drag or bind; bearings are greased, box oil is frsh and as low as you dare; engine is serviced regularly and set up as close to perfect as possible, THEN you dump any excess weight like un-needed tools.....

    Hmmmmm well, IF the things fettled properly you shouldn't need them..... AA cards a LOT lighter though!

    Where was I? Oh yeah, tidy up the inside and only carry what you need for a journey.

    theres no 'magic' solution, and going diesel these days isn't much of an advantage, though sure people will suggest you stuff an old Disco TDi engine in (Solution I dont like, motor doesn't suit the car!).

    But, ONE thing I would nudge you towards looking at is LPG....... ("Gas-Guzzler?" - LPG - the 'Wonder'-Fuel? )..... dont improve your MPG, but at 60p/l ish who cares!
     
  10. fenby1976

    fenby1976 New Member

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    I make it more like 33%: If the diff pinion is rotating at y RPM, then the wheels with a 4.7:1 axle will be spinning at y/4.7 RPM, and the wheels with a 3.54:1 axle will be spinning at y/3.54 RPM. The percentage increase in speed will then be 100*(y/3.54 - y/4.7)/(y/4.7) = 100*((4.7-3.54)y/(3.54*4.7))*(4.7/y) = 100*(4.7 - 3.54)/3.54 = 32.8 (approx).

    Gearboxes sap a significant proportion of engine power. A Land-Rover comes with two gearboxes as standard, so adding yet another gearbox (which is what an overdrive is) will sap yet more power. A high ratio transfer gearbox conversion will not sap any more power (as an overdrive will) and will not affect trailer towing or off roading ability (as a diff swap will).

    The best savings will be made by keeping your speed down and not accelerating hard.
     
    Last edited: Feb 1, 2010
  11. kent ranger

    kent ranger New Member

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    Thanks for everyones views. Ive been put of diesels lately,i own Two tractors and both have had pump problems etc,not cheap to fix. Additionally diesel fuel is no longer cheaper than petrol.

    That said, as a 15 year old back in the seventies i had a part time job in a Land Rover garage. One of the mechanics converted his S2 109 from a petrol to diesel using a Perkins 4203. It was a brilliant vehicle,first time starter and pulled like a train. Nowadays they are probably thought of as being slow but from memory that one went exceptionally well and was regulary used on long trips. A lot of people say the 4203 was a tractor engine of which they are correct,however they were also fitted in Commer Vans of which this donor engine came from,in fact a Commer Walkthrough mobile shop. I dont know if a conversion kit is still available for this engine?

    As far as LPG is concerned that would suit me as i have a local garage selling it. However from personal experience im yet to hear of someone who hasnt had problems with them. Perhaps someone could tell me otherwise and what kit?
     
  12. dr pepper

    dr pepper New Member

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    The 4203 I believe is sold under the mazda guise, dunno what number they call it, someone will be along soon who does no doubt, the rangie is often converted with it, theres probably a kit or at least a bellend adaptor available for it.
    I come accross the 4106 in boats now and again, and it is very much a good motor.
    You see loads of lpg stuff on ebay, there are 3 basic types, vacuum vaporiser gas fed, continuous liquid injection and sequential liquid injection, all in expense and performance order, the liquid injected versions usually come with an ecu, some of them are based on fork lift truck fuel systems as fork trucks have been gas powered for a long time, and use modded petrol engines.
     
  13. Teflon

    Teflon New Member

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    Sorry fenby, cant be bothered to check the sums proffered, we are probably both right, one third original is the same as one quarter of original plus a third........


    Efficiency losses through the gearbox are very small, those through an OD negligible. When dissengaged the OD is 'locked' and simply rotating as the gearbox output shaft.

    Series gearbox has 'lock-out' 4th, the input and output shafts locked, bypassing reduction gears, which are merely idling, minimising efficiency losses.

    Running Tall diffs or HR X-fer, you WILL worth the lower gears harder. So, it depends entirely on your driving style and mechanical sympathy whether you get more or less acceleration; taller diff ratio may detur it, but that is as likely to encourage reving out longer in lower gear......

    It REALLY makes so little difference its not worth arguing about; but the advantage of the OD unit is that you dont HAVE to use, while having the facility to select it, IF you want, from the drivers seat.


    Oh, the old Commer Walkthru'! What memories that brings back! Made a Land Rover seem 'Fast'!

    Yeah, the 4203 was acommon fit, and the commer variant was the better one to use. My Grandad was a factory field service engineer at Commer / Dodge in the 70's/80's, and I remember going through all the old service bullatins he had in his attic a few years ago!

    These days, though, you wont find many ex commer variant motors. they are still made by Perkins Japan, I believe, with MANY revisions including a Turbo Charger, and used in Mazda vehicles, and I think another 'eastern' maker... possibly Isuzu?

    Had a number of 4204 converted Landies on my Grandads drive when I was a kid, for him to 'sort out'. They were HORENDOUSELY heavy on the gearboxes, and they were even more horendousely under-geared, though Rangie Diffs helped, get speeds back to close to original with the reduced rev cieling.

    Doing a conversion these days, reputation / experience of the 'old' 4203 would put me off, before I started looking for adaptor kits, or worrying about finding a commer variant, or converting a plant engine to commer spec. I seem to recall 'Pops' ranting at length about how "it ISN'T 'just' the bloody rev-limiter!" and going on about the injector crack-off pressures, combustion chambering and cam-profiles, before diving under bonnets muttering curses about 'ignorant idiots, messing with things they dont know'........ (he was a miserable old bastard, Pops!)


    Looking at Mazda / Perkins Japan, 'stuff', for an SIII, I KNOW it has been done, a chap on another forum I met a couple of times did a Mazda conversion on a 109, but it was a hell of a job, and I think he used an old perkie 4203 adaptor ring he got from Old sod or off another Landy with a 'dead' gearbox and clapped out commer, I cant remember.

    I know he went through two gear-boxes getting the thing to work, and there was about a year of met-fab in making all the bits and pieces he needed to make stuff fit and not shake to bits, and FINALLY when he got it working, it did about 45mph flat out, becouse the motor apparently has an even lowe rev limit than the commer-plant spec engines!

    Took an Ashcroft HR X-fer box AND Rangie diffs to get it to 'drive' something like, but pulled really well, and did about 70 reletively comfortably.

    Continuing with the ideas of LPG, I dont know whether the people you have spoken to that have told you the stuff has been nothing but trouble have had thier kits on Landies or not, or when / where / how they were fitted.

    Personally I've had two LPG converted Rangies and they work well, and have given me little or no trouble by virtue of having gas on them. Second one, HAD given last chap grief, and when I collected teh car, gas didn't work, and I suspect that in ignorance they bludgered it up. Using the kit off my old rangie to de-bug the system, I fixed it and got it running sweet, with little hassle.

    And on the whole, people I know using the stuff have had little problem with it. Main niggles are that a lot of mechanics are ignorant of the systems, every one is almost a custom system, so they dont always know what they are looking at, dont always see them very often, and dont always know how they work or how to set them up or fault find.

    On a series motor, you have a single down draft carburettor, and its a pretty straight forward conversion, with a single mixer.

    There are often SIII Kits offered on the small-ads boards, but there are a lot more kits for rangies.

    Personally, I'd do a DIY conversion. For the bits needed on a carb motor, I'd look hard at a complet kit, vs piece parts. I'd then be tempted to keep costs down by buying the piece parts or a part kit, and looking on e-blag and the boards for things like the tank and vapouriser.

    If not, a pro-conversion can be expensive, in which case, I'd try and find a car pre-converted, and hassle the sel;ler to explain it and show me how it worksed and what to tweek to keep the mixture happy etc.

    Stuff doesn't 'wreck' engines, certainly not old low-tech landy ones, unless you are completely stupid, and get the mixture & timing totally wrong AND keep driving it, with the motor knocking like a diesel!

    On a Landy, you dont have the complexity of an injection system or even electronic ignition, so the control electrics isn't too daunting, its basically solenoids. Only 'thing' about the system is change-overs and filling / draining the carb float bowl of petrol between running on gas.

    Just read up on it..... its worth it!
     
  14. dr pepper

    dr pepper New Member

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    There you go, the whole thing in one.
    Gas conversion, nice and simple, dont forget to tell your insurance.
     
  15. fenby1976

    fenby1976 New Member

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    So you say 3.54:1 diffs increase gearing by 25% and I say they increase the gearing by 33%, but you say we are both probably right....I see....;)

    So in algebraic terms what you're saying is:

    x/3=(x/4)+1/3

    Mmm... that's interesting. So what if we make x=3?

    Does that mean that 1=13/12?

    What do you base that on? i suppose an experiment would have to be done to tell for sure what losses there are in an overdrive when engaged, but I came accross this webpage: Gears- Gear Efficiency
    which gives a figure of 94% efficiency for a particular epicyclic gear. Surely a 6% loss of efficiency could be considered significant?
     
  16. Teflon

    Teflon New Member

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    Fenby,

    I studied Mechanical engineering at university for four years before going on to be a rocket scientist....... I'll try and keep thing simple.

    25% is one quarter, 33.3% is one third.

    If a 1l bottle of vodka is marked up at £10, which is better value:-

    A 1.33l bottle of vodka marked up at £10, and 33% 'Free'

    or a 1l bottle of Vodka marked up at £7.50, '25% off'

    Depending which way your reference, 25% and 33% can be the same thing! And I REALLY dont want to argue about it!

    As for gear efficiencies, 6% for an epicyclic sounds a bit high, but epi's do tend to have higher losses than straight gear-pairs, but there's far more to it.

    All transmission systems have an efficiency loss, how 'significant' it is is entirely subjective.

    A typical automotive gear-pair, depending on reduction ratio, will normally have a transmission loss less then 1%; through a conventional double-shaft automotive gear-box, like the Landies, overall efficiency from one end to the other will normally be around 3-4%, most of it the drag on the shafts from the oil in the box.

    Landiues double-box, is not a horendousely efficient system, but its ACTUALLY no worse than many, and the effect of teh X-fer is nimimal, its a simple drop set, and with big gears, losses in it dont make THAT much difference, from memory, real world losses through the old MOWOG 'Mini' gear-box with the three gear drop set from the clutch to the sump cogs, was around 4% where losses on the 'inline' 'box used in the Morris Minor & Co, was more usually around 3%. For the Landy, looses with the x-fer were about 5%.

    THOUGH I suspect that those were top gear figures, and the 'lock-out' 4th flattered them, given that the reduction gears would have simply been 'idling' without load on them, but the box would still have offered pretty much the same viscouse drag, churning the oil.

    As far as adding an OD unit goes, its not going to add ANOTHER 5% loss, as said, on OVERALL efficiency, it will be minimal, and the OD is NOT churning the volume of oil or wearing as many or as large bearings as the main box, AND when not engaged it WILL simply be locked out, addig a little extra drag as it turns in its own oil-bath, but not a lot.

    5%...... how 'significant' is that?

    From figures offered here, you can get anything from sub 10mpg up to a good 20mpg for a series, depending on how well fettled it is and how its driven......

    Give your 'box a 'perfect' efficiency, get rid of ALL efficiency losses, and on a nominal 15mpg vehicle, it wont effect the MPG results by a single MPG!

    To ME sorry, but that is not all THAT significant....... and THAT is with an 'ideal' 100% efficient transmission, ie an IMPOSSIBLY large 'improvement' to strive for.

    Lets go 'worst case' and imagine that the Series transmission is only 90% efficient, you are getting 10% losses through it. That would mean that the gear-box was absorbing and dumping as heat, between 3 & 6 bhp, roughly two or three three bar electric fires...... (Unfeasibly high, tbh; you'd have a transmission tunnel you could fry an egg on if it dumped THAT much energy, but still!)

    At 15mpg, eliminating transmission losses, you might expect to gain 1.5 MPG..... significant, possibly.....

    Except we have a +/- 30% margin or 'variability' on MPG before we even begin.

    Practically, the transmission losses, or more precicely the DIFFERENCE in transmission losses that might be won or lost from using less or lighter oil, having or not having an OD unit, or FWH etc, may indvidually seem 'significant', overall, however thier significance diminishes, while EVERYTHING becomes insignificant in relation to the 'natural variation' there is from driving style.

    As YOU said, biggest savings will be from keeping your speed and acceleration down.
     
  17. fenby1976

    fenby1976 New Member

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    Teflon,

    However many years you've spent studying mechanical engineering and playing with rockets it does not change the fact that what you said was incorrect. It is very simple: You said that fitting 3.54:1 diffs will raise the gearing by 25% from the standard 4.7:1 diffs. Given that you have studied Mechanical engineering for 4 years you should be able to see, especially since I've pointed it out to you, that you are wrong. I've even proven to you using simple GCSE level mathematics, that the correct figure is approximately 33% and you still won't accept it. If you already had 3.54:1 diffs and you fitted 4.7:1 diffs then the gearing would be lowered by about 25%, but that is not what you said. You seem to understand more about the pricing of alcohol than you do about the effect of changing differential ratios, but given your educational background I think you must know you are wrong - you just can't bear to admit it;)
     
  18. dr pepper

    dr pepper New Member

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    I think your both wrong, you cant run landys fom alchohol, anyways the correct fuel air ratio is 14.7:1 nowhere near 3.54 or 4.7:1, allthough that would be about right for methanol.
     
  19. fenby1976

    fenby1976 New Member

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    Perhaps Teflon will be able to see reason once he has sobered up!
     
  20. dr pepper

    dr pepper New Member

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    Yep, you been getting them bottles of vodka with 30% extra teffers.
    I'm still at work so theres no booze for me just yet.
     
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