Hey guys i do alot of kms and i have the sd33 with the four speed. At around 110 the car is revving its box off and my fuel consuption is pretty shite. On average 6.75km/litre on a long trek. I was wondering what would be the best way to lower the revs and get my fuel economy back up. I am running 32's, its a LWB with 165k.
Any help would be muchly appreciated.
Marc
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4spd to 5spd or change diff ratio's
To fit a 5 speed into a patrol with the original engine is a headache at the best of times, will take some effort.
Will have to relocate gearbox mounts, shorten rear shaft, lengthen front shaft and modify the gear shifters through the floor.
If u had a V8 it would be easy! Just move the engine mounts forward and most other things are consistant.
U dont have room to this with the big 6 in there.
U will already have the highest diff ratios that are easily available, in it.
( 4.625's ), so try bigger tyres, tune up, or less weight or foot off the throttle, Or u could get a V8
screwy
Will have to relocate gearbox mounts, shorten rear shaft, lengthen front shaft and modify the gear shifters through the floor.
If u had a V8 it would be easy! Just move the engine mounts forward and most other things are consistant.
U dont have room to this with the big 6 in there.
U will already have the highest diff ratios that are easily available, in it.
( 4.625's ), so try bigger tyres, tune up, or less weight or foot off the throttle, Or u could get a V8
screwy
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God of Magnificant Ideas!
4.3s will help
33" wont make that much of an impression
35" Will help heaps.
Fitting a 5 spd to a diesel WILL BE and I repeat WILL BE a nightmare !
For example lift ya bonnet and imagine the fan sitting 135mm closer to the radiator !!! ........ ok so its now IN the radiator !!
Alternatively you will have to shift the gearbox back and this means new transfer mounts, new driveshafts. Then you will need to make new gearshift, new HiLow shift, or make and fit a new gearbox/transfer cover for the hump in the floor which you WILL have to cut and enlarge if you dont want to make new shifters !...... I know its not impossiable but its a shyte load of work and will require engineering.
Fitting a V8 is not for those that want or care about ecconomy.
Kingy
33" wont make that much of an impression
35" Will help heaps.
Fitting a 5 spd to a diesel WILL BE and I repeat WILL BE a nightmare !
For example lift ya bonnet and imagine the fan sitting 135mm closer to the radiator !!! ........ ok so its now IN the radiator !!
Alternatively you will have to shift the gearbox back and this means new transfer mounts, new driveshafts. Then you will need to make new gearshift, new HiLow shift, or make and fit a new gearbox/transfer cover for the hump in the floor which you WILL have to cut and enlarge if you dont want to make new shifters !...... I know its not impossiable but its a shyte load of work and will require engineering.
Fitting a V8 is not for those that want or care about ecconomy.
Kingy
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
As much as i would love a v8 its really not an option. At present i am doing around 7 to 10k a month with a fishing club and economy is really important. So after reading all of that info i can pretty much say that a 5spd is out of the question. Why would 35's be benificial?? I dont really wanna go there cause an old car is a cop magnet over here at the best of times and the last thing i want to do is attract more attention. Ultimately what i am chasing is some way to drop the revs at high speeds. I know i will get better economy at 90kph but thats not an option! I am happy with the straight diesel as far as power is concerned.
MArc
MArc
Shark wrote: So after reading all of that info i can pretty much say that a 5spd is out of the question. Why would 35's be benificial?? I dont really wanna go there cause an old car is a cop magnet over here at the best of times and the last thing i want to do is attract more attention.
MArc
Why would 35"s be beneficial? 35"s are almost 10% taller than 32"s.
4ths speed to 5th speed is normally about 15% difference.
35"s = 4 3/4th speed
33"s will help but only by a smaller amount - approximately 3% so not justification for new tyres. Of course if you're up for new tyres anyway..... that's a GOOD ENOUGH REASON.
mq
Your all forgetting the std sd33 is as slow as a wet week and as for 35's they will make it all but stop in its tracks on anything greater than flat going and So will lowering the diff ratios. It won't help fuel consumption it will make it worse as the motor has to work way harder. At 110 ks the thing is nearly flat out ( they will only do about 120ks). Try driving 90 - 100 and you will use heaps less fuel and make the poor thing last a bit longer. Either that or get more power! Sorry if i sound like im preaching, but they the facts.
DR F you do make a few good points. There are alot of opinions here and i take them all in and decide the best route to take. I basically am happy with the std sd33, of course i would of loved a turbo diesel but they are out of my price range. I will try with some skinnier tyres and then go from there. I must admit the when i do cruise i tend to hammer the shite out of it and will often sit on 120 all the way. Maybe i should stop that 
Anyway thought i would tell you all there is a guy here with a MQ SWB with a 302 in it selling for 14k WTF???
Thanks
Marc
Anyway thought i would tell you all there is a guy here with a MQ SWB with a 302 in it selling for 14k WTF???
Thanks
Marc
Re: mq
\DR Frankenstine wrote:Your all forgetting the std sd33 is as slow as a wet week and as for 35's they will make it all but stop in its tracks on anything greater than flat going and So will lowering the diff ratios. It won't help fuel consumption it will make it worse as the motor has to work way harder. At 110 ks the thing is nearly flat out ( they will only do about 120ks). Try driving 90 - 100 and you will use heaps less fuel and make the poor thing last a bit longer. Either that or get more power! Sorry if i sound like im preaching, but they the facts.
i agree with some of this and disagree with other points. ( sorry Peter )
35's will make fuel consumption worse around town, but on a free way cruising at higher speeds the larger tyres will allow the motor to rev lower getting a greater top speed and slightly improved highway economy.
Dont no about u guys but my old SD33 drove down to melbourne and 3 hours on top of that on 35's with 3 tonne of trailer on the back and was sitting on 110-120 most of the way. without any load on board it was easy for me to get up and over the 140km/h mark. I remember once i got the speedo pinging off the dial on 35's in the deisel down the M5 on the way back from menai......
They are a strong motor and can handle the tyres no dramas.
You guys just dont know what an accelerator is yet:D
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God of Magnificant Ideas!
I tried the 35"s on my diesel and she took to em ok but 33"s or 34"s would be better for the long term..... mind you this is on a motor thats slightly down on performance
I was silly enuff to drop the 38.5 swampers on and I have to admit that wasnt a good look...... 1st & 2nd gear around town and it took for ever to hit 4th on the open road !
33"/34"s would work well asuming the motor is in fair condition,
35" s were good but Id only run em with a strong donk.
38" ........ forget it !
Kingy
I was silly enuff to drop the 38.5 swampers on and I have to admit that wasnt a good look...... 1st & 2nd gear around town and it took for ever to hit 4th on the open road !
33"/34"s would work well asuming the motor is in fair condition,
35" s were good but Id only run em with a strong donk.
38" ........ forget it !
Kingy
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
Okay okay a bit of thinking needs to be done here. After re-reading all your comments im pretty sure i dont want to do any of them. Changing the diff ratio's sounds okay but it might not work. A 5speed would be great but by the sounds of it isnt worth the hassle, i must admit i thought it would of been a easy job but i trust the might 8patrol. 35's on my bus?? Dont think so, would get pulled over by the cops so quick and there is the cost factor so really im up s%^t creek without a paddle eh??
MArc
MArc
God of Magnificant Ideas!
Shark wrote:Okay okay a bit of thinking needs to be done here. After re-reading all your comments im pretty sure i dont want to do any of them. Changing the diff ratio's sounds okay but it might not work. A 5speed would be great but by the sounds of it isnt worth the hassle, i must admit i thought it would of been a easy job but i trust the might 8patrol. 35's on my bus?? Dont think so, would get pulled over by the cops so quick and there is the cost factor so really im up s%^t creek without a paddle eh??
MArc
I never said fitting a 5 spd was an imposiable job, it is however a fairly large project that I would not recemend for the feint hearted or non welding skilled type people.
The cost of having someone do it for you would be in my opion be a waste of $$$$ simple because those $$$$ could drive you a long way , and you would have to do even more miles in order to pay for the outlay of the box too.
I recon a 2nd hand box will cost in the vacinity of a grand
I recon I'd charge atleast $800 to fit it for you......
Thats $1800 that if spent on fuel is a hell of a lot of miles !
A simple change in the tyres to 33s or 34s is a lotless expensive in the short term, this combined with the option of a better diff ratio wiould put you where you want to be ecconomy wise and with less engine revs..... the down side is that your abillity to accellerate or tow is reduced significantly....
pack a cut lunch to overtake granny's car...
I still belive that 33s or 34s would work enuff in your favor for the short term fix......
Like everything else it all comes down to "how much can you afford ?"
If your like me then not a great deal !, I rarely drive my chevypowered rig simply because of the costs in running it...... its phucken thirsty !, so I drive my dead stock MQ diesel around 99% of the time. The reasons for this is simple, the cost of the additional
rego,
tyres,
services,
maintainance,
is far cheaper than running the big rig !!!
Dont belive me ????? well my fuel account fell by $400 a month since I stopped using the big rig as a daily driver !
$400 a month times 12 months = $4800 dollars better off
With those sorts of figures then for me its worth fitting a 5 spd to my diesel for even more savings. A 5 spd drops the engine revs by around 20% and this will save me at a rough guess a further 15% at the pump.
Kingy
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
God of Magnificant Ideas!
Shark wrote: Would changing back to standard rims and small tyres help?? I dont want it to be too slow around town cause thats where it spends most of its life.
Marc
The std tyres for a Patrol are 750 X 16, which = 31"
Increasing it to 33" or even 35" will help the revs drop a bit ( also added ground clearance ).
To really get the revs down your looking at big bucks, ... the 5 spd and diff centre changes will cost you.
Kingy
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
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