a new low in fuel economy for my sd33t

[84mksd33t]

well, after whinging and bitching about fuel economy (400ks from 60l)
i did some tests - instead of shifting at 1900rpm to 2200rpm, i shifted at 2600rpm to 2900rpm...The arguement was that this is where optimal power was and that the motor was labouring less....I was barely half throttle when reaching these RPMs

Out of 65l of fuel i managed 310kms!!!

When i had the dyno done the bloke said judging by the power curve and air to fuel ratio the injectors are good, as is the pump.

Could I put this bad economy down to my fuel filter? I will get it changed and see how I go...But this is worse than a bloody carbied 308!

I honesty cant afford to be driving this thing at this rate - 3 days and $95 - almost 200 a week on fuel!!

Cheers,

Cody

[Beastmavster]

Cue long boring stories on how cheap diesels are to run here........

[pongo]

Yeah but if you get a carloan and buy a new smaller car, Then you would be paying a loan instead of fuel. I really dont know what i get out of mine but be realistic, Its a 2 ton car with an old skool diesel that has less aeroefficency than a house brick.

SO, What figures are you hoping for anyway ?


Cheers

[84mksd33t]

450ks to a tank!

[Brendan-s]

something must be up. i get 15l/100km or thereabouts with my 82 SD33 (non-turbo), which weighs in at 2.5t with winch bar, roof rack, rear wheel carrier, etc etc. and is badly out of tune...

[pongo]

450ks to a tank!

well a tank holds 80 litres, so you are about on the money before you started trying different stuff. Maybe different diff ratios or a bigger exhaust may help. Have you tried blocking off the waste gate on the turbo and letting it hit the pressure relief valve.

I am now running a 3inch mandrel bent and have notice a little power gain but have notice that my foot isnt as heavy on the load pedal as before. This should mean more economy, but i dont really do enough kays ATM as work is 5 mins up the road.

Another thopught is letting it warm up properly in the morning before you drive it. If you already do, Just ignore this.


Cheers

[84mksd33t]

afaik the tanks are 68l - normal is 60l and then 8l reserve.

I dont have the pressure release valve - i have blocked it with a bung. I am running 12.6psi boost.

Going to 3" mandrel next week.

Yeh I always warm it up before i leave. 5 mins at least - 10 usually.

I'll clean the fuel filters and let you know how I go.

Cody

[zen]

i get 28mpg on a run..25 around town(london,so loads of traffic)twice wot you are getting!)

sd33 n/a but turboed..mz pump..16psi boost.straight through exhaust.car weighs over 2 ton.

you got someone nicking your fuel at night???!!

[Patchy]

buy a scooter, you dont need a loan and they cheap on fuel just keep the 4b for fun or when you need a car... if your "too cool" for a scooter buy a motor bike.
(trust a west aussie to realise and point out the fact that bikes use little fuel and take up no room to store )

p.s: how much you spending on fuel a week

[84mksd33t]

filled up saturday
$96
that was gone by tuesday 12pm. I put another $20 in that afternoon. Its gone now.

SO $116 - Im going to need to fill up tonight - Another 90 odd dollars.

Im not even covering 700ks a week!!!

Taking it in for a major service next week - also mandrel exhaust going on.

Could a fucked motor be the cause of bad economy? (not saying the motor is fucked - but im open for ideas)

[tweak'e]

thats not to bad for an old tech deisel. even the ZD30 we have uses around 10l per 100km.

main problems that i have found with deisels (i still have my older toyata) is the EGR causes soot to build up in the intake, EGR gets stuck open and sometimes build up of soot in exaust pipes. then of course loss of compression etc as the motor wears.

looks like a few people have been swapping holden v6's into surfs cause they are cheaper to run than the deisel. mind you i would like them try and say that when they are pulling 3-4 ton of payload.

[84mksd33t]

i am gettin 20.8l per 100km. FUCKING JOKE

so something is dastardly wrong - hell even new tech diesels are around 10l/100km - so wtf is up with my car!??

[MKPatrolGuy]

It's probably the 5-10 minutes idling every morning that is using the extra fuel

[tweak'e]

if i understand your post......

you where useing 60l per 400km (15lper 100km) then you changed your driving style and it went to 65l per 310km (~22km per 100km).

so go back to the way you where driving before. you go from short shifting to shifting at high rpm of course it will chew gas, your spending more time at higher rpm's

[badger]

take it somewhere decent n get a full tune up done

i got mates with alot of work and big boost getting better fuel econamy even running 35's

[Patchy]

so your spending $90 give or take every 3 & 1/2 days? perhaps i wont buy an MQ/MK

[Beastmavster]

so your spending $90 give or take every 3 & 1/2 days? perhaps i wont buy an MQ/MK

You would find a petrol MQ would be cheaper to run if that's representative of the SD33's.


However, for my friends who have them (and I have 3 with diesels and 1 with a petrol) about 13-15l/100km is more representative of an SD33 (NA or Turbo).

[badger]

from my experiances ive found the td to be the most economical and easiest to drive

the l28 is a good motor but needs a few revs if u like to keep with traffic

[84mksd33t]

Well the arguement was this is where peak power was (2700rpm)

And that diesels hate to labour at low revs...

But it honestly shouldnt be that bad should it?

[84mksd33t]

It's probably the 5-10 minutes idling every morning that is using the extra fuel

If i drive it before its warm it is a pig (glow plugs are dying) So i prefer to drive it warm. 5 mins in the morning gets rid of the unburnt diesel smoke and its easier to drive.

Would I need anything changed to go to biodiesel? Will my pump seals be ok? I can get bio diesel for $1 a litre...for a 44 gallon drum full....

[tweak'e]

But it honestly shouldnt be that bad should it?

i don't know those particular motor, or how manys km's/engine hours its done or weight of vechile.

i know the 2.4 turbo surfs can be 10-15l/100km and yours is a larger motor and i'm guess a lot heavier vechile.

all i can suggest is do the usual economy mods, hi flow exaust, good oil, good airfilter, block off EGR (if it has one), cheak inlet manifold, check how much oil is being sucked into the intake from the breather. and most importantly monitor your driving style.

[cooter]

what is your air cleaner like?
blocked?

diesels are built to be driven hard at full revs even my tweaked disco 300tdi gets 10 to the hungy even with 33s 18psi eavy right foot shifting at 4000
what does your oil look like is it watery as your engine is probly carboned up not allowing the rings to seal properly and letting raw fuel into the sump you can buy decarbonizers that you pour down your injector hole that work ok do a search i have read a write up on this forum a while back

[Patroldude]

afaik the tanks are 68l - normal is 60l and then 8l reserve.

I dont have the pressure release valve - i have blocked it with a bung. I am running 12.6psi boost.

Going to 3" mandrel next week.

Yeh I always warm it up before i leave. 5 mins at least - 10 usually.

I'll clean the fuel filters and let you know how I go.

Cody

What do you expect? Oh and ya shift point too - you should be able to to drive shifting at under 2500RPM.... The rad line is about 3900rpm, do you sit there and drive a skyline or something and shift a 6,000rpm every time? Then you whine your not getting any economy.... change your filters, give her a service, stop thrashing it so hard, its a 20 year old diesel, drive it like one... maybe wind ya boost down, you are either after power (like I siad in earlier post - go buy a petrol v8) or your after reliability and economy.... you CANT have it both ways.

Try the service and shifting at 2,000-2,500rpm, its got the torque to pull you on road, sure - its gonna take a bit longer to get up to 60,70 or 80 kph but you don't drive these things for speed hey. I notice your also driving on mongrels with a SWB TD, so that means 4.33 ratios, maybe change to 4.625 for better street driving and a set of tires that don't create so much drag on road. This may increase your economy a bit - I could get 550 out of a tank in city use if I was careful, if your worried about $ then change ya driving style.

Mk

[tweak'e]

diesels are built to be driven hard at full revs even my tweaked disco 300tdi gets 10 to the hungy even with 33s 18psi eavy right foot shifting at 4000

no offence but compareing a later model landrover to a bigger old tech nissan is not really fair or accurate.
deisels are built to handle large torque. motors with heavy pistons and heavy cranks do not like high rpm, revving them hard simply wears them out quicker.

as far as encomy goes the more rpm the more fuel your going to use, exspecially on the older style motors which have good low down torque. if anything you should be shifting around the peak torque figure not peak power.

[Patchy]

so are these things worth the $$$ strain they put on the wallet or would a V8 conversion thats set up on gas be better on $$$ and power or even the larg petrol variant on gas???

[tweak'e]

the cost of a conversion can buy you a lot of fuel. no point spending big $$$$ to save a few cents.

if running cost is the main problem then sell it and buy something smaller and cheaper to run. having said that the prices for big engined and exspecially older deisels has gone down greatly, noone wants to buy them.

[Patroldude]

They are not a strain on the wallet but....

Would you drive a new 427 Cui comodore to the max power mark each time thru the city? Course not. You don't shift at max power or torque, you don't drive a diesel that way, they don't rev hard and are not meant to.... why else is redline on a 6 that of a petrol 8?

No offence but you guys sound like you have gone from a ricer to an SD33T SWB and expect to drive them the same way? Would you take a lowered silvia on some of the tracks you have posted pics of your truck on and expect the same perfomance? (nice looking truck by the way - they are so hot with no roof, no tail gate and no doors on hey) Course you wouldn't so don't expect to drive an SD33T the same way you drive a 4 cyclinder import/fast 4 and expect the same on road performance.... its all about horses for courses.

Like I say, wind down the boost a bit if needs be but just try driving it at low RPM - set a challange, try not to shift above 2250 RPM then tell me your economy figures (don't drive at 2250 rpm all day either.... its a 5 speed - use em) should be nicely surprised dude. You can always run a fuel cleaning product thru it if ya really worried, you would enjoy it - you got to rev the crap out of it every 15 minutes till its all gone

Seriously - try modifying driving style first before playing with truck... amazing how it changes things. What your saying is like tying to get Mitshbishi Mirage economy from Top Alcohol Drag car.... its all good - at least your asking people, best to learn from others mistakes which is why outers is such a good place to hang out...

Mk

[badger]

if the glow plugs are dieing did u happen to think that perhapse if your replaced them you may get better econamy

they were 77 bucs a set on ebay last week

still say quit the bitching n get someone decent to tune it

[tweak'e]

i got to ask...... how do you guys tune a deisel ?

[Boxhead]

chuck a fitch fuel catalyst in it and it will clean your motor up and get better fuel econ.

Boxhead.