Improving 300tdi mpg (the obvious and less obvious stuff!)

quattro6999 said:

Good findings. Wouldn't it have been cheaper to buy new injectors though? Last time I looked they were about 45/50 quid each for standard ones.

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from what i've read, not experienced, but the new injectors for that price are meant to be crap quality and it is probably better to recondition the old ones.

it would be interesting if someone who's tried both could chime in

It is also worth noting that 2 stroke oil in the diesel has extremely positive effects on mpg, maybe even BHP too (I doubt it is even a measurable difference but who knows?!)

Cleans the entire fuel system, lubricates the HP pump, lubricates the injector needles, helps draw water through the system and emulsify's the diesel will apparently aids combustion, especially on older injectors.

Seems common practice with good results on older HP pump/mech injectors.

Mudron said:

It is also worth noting that 2 stroke oil in the diesel has extremely positive effects on mpg, maybe even BHP too (I doubt it is even a measurable difference but who knows?!)

Cleans the entire fuel system, lubricates the HP pump, lubricates the injector needles, helps draw water through the system and emulsify's the diesel will apparently aids combustion, especially on older injectors.

Seems common practice with good results on older HP pump/mech injectors.

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Mines running with some 2 stroke in the diesel and it's definitely helped reduce smoke among other things. Just had the MOT done this morning with tweaked fuel pump and on the smoke test it scored 0.14 1/m out of a possible 1.50 1/m. I wish I had the sheet from last year to compare.

I would love to do a proper dyno test, sometimes you pour something in and ***HOPE*** it makes a difference, but because you are convinced its going to work, your brain sort of tells you its made a feel-able difference when in reality it hasn't!:hysterically_laughi

But im sure it has made a difference, I know for a fact that the engine idles slightly quieter.

Mudron said:

I would love to do a proper dyno test, sometimes you pour something in and ***HOPE*** it makes a difference, but because you are convinced its going to work, your brain sort of tells you its made a feel-able difference when in reality it hasn't!:hysterically_laughi

But im sure it has made a difference, I know for a fact that the engine idles slightly quieter.

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yep!

I don't know about the 2 stroke improving power either way but it's definitely quieter. Though mine seemed a bit more willing after I gave it an Italian tune up (good thrashing) on the way to the MOT station this morning lol!!!

That cleared the cobwebs out!!

In theory, the 2 stroke will absorb the diesel and thicken it up very slightly. Plus 2 stroke (decent 2 stroke) has the apitc/jasofb additives which create low ash burn conditions.

All helps I guess!

You do need to do a few fuel filter changes though to start with!

Mudron said:

In theory, the 2 stroke will absorb the diesel and thicken it up very slightly. Plus 2 stroke (decent 2 stroke) has the apitc/jasofb additives which create low ash burn conditions.

All helps I guess!

You do need to do a few fuel filter changes though to start with!

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I didn't know about the fuel filter changes. This is the second tank I've added it to. New fuel filter was May this year - when do you reckon I should do it again?

Sheffield said:

I have found on ordinary roads a manual is more economical, but if you can get an EDC auto on the motorway and hold a steady 55-60mph it will produce a very good mpg. It is the torque converter that saps the mpg in ordinary use. I guess an EDC 300 with a manual box would be best of all.

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At 55-60 on my EDC Auto with semi synth oil, cheap diesel, done the EGR, Down Pipe, Snokel, well serviced (every 6k I dod the diff, trandfer box, all UJ's, engine, fuel filters. every 12k full auto gearbox oil change) does 33mpg on a 500 mile run. With fully synth oil and good diesel I get another 3 mpg so 36.

On a recent mixed trip 560 miles upto to leeds and back via the m25/m1 in crap traffic I got 31mpg on cheap fuel and semi synth.

I think a Disco 1 and 300tdi are really good.

The biggest change in MPG from the 25mpg I used to get was the snorkel and the decat, that made a massive difference.

Next service fully synth will go back in and I'll try the 2 stroke oil, I have a litre in the garage I need to use.

Oh and its running GY AT2 tyres.

The EDC on a manual gearbox would be better in every way to the std bosch pump. More power, better mpg and better throttle response.

Its a shame the ecu's are a pita to work on due to the lack of sensors for a decent 3d map.

If someone could produce a tapped bell housing to take a crank sensor, and a manual flywheel with the correct reference points made for the sensor, that would make converting a auto edc to manual a whole lot easier.

Its not impossible, just not plug and play as such.

The EVRY mod makes the edc system effectively tunable for more power and slightly better mpg from a dash mounted switch. Its by no means perfect or anywhere near a re-chip/remap for reliability and the best balance of power and eco but its not a bad substitute!

jbenekeorr said:

I didn't know about the fuel filter changes. This is the second tank I've added it to. New fuel filter was May this year - when do you reckon I should do it again?

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The 2 stroke (like running svo or wvo etc) tends to pick up all the rubbish in the fuel tank, pickup sock, fuel lines etc, behind the fuel filter and move it all forward to the filter.

So its best to change the fuel filter a couple of times and always carry a spare just in case. Everything in front of the filter to the injectors tends to get mushed up by the pump and spat out through the injectors (cleaning the injectors and lubing up the pintles and pump as it goes)

It depends how clean your tank is TBH. If its a farm work horse or you spend a lot of time off-roading where its dusty, wading or near the sea I would inspect your filter by cutting the old one open. You will be surprised!

jbenekeorr said:

I didn't know about the fuel filter changes. This is the second tank I've added it to. New fuel filter was May this year - when do you reckon I should do it again?

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Also, the little filter on the chassis near the tank (if you still have one fitted) will be full of rubbish too. Very important to clean that too.

Just a note on aftermarket panel filters etc, and how, sometimes, the std airbox and filter is best!

BTW, the below is not advertising, its just me proving a point when it comes to cost comparison!



I work in the trade selling car parts. A panel filter from some of the big brands costs about £21.00 inc vat at staff price and needs cleaning every other month with a bit of green laneing etc. It also needs re oiling with a kit that costs £11.99 and lasts for 5 cleans. Otherwise I loose a fair bit of mpg and a bit of bottom end grunt.

A STD paper replacement panel filter costs me £2.90 inc vat. Needs changing every 6 months at worst as it doesnt hold large debris like the aftermarket one does. I can by 7 of these for the price of the aftermarket filter alone!

Even if you don't have that level of discount off retail, it still works out cheaper!

A test by a tuning company on a seat ibiza with a 1.9 pd tdi engine with 150bhp std found the following:

Std filter in std air box - Std makers bhp/torque quote.

No filter in std air box - No gain

Aftermarket filter in std air box - No gain

Aftermarket cone filter - Bhp/torque loss

No air box or filter - Bhp/torque loss

Std airbox/std filter with modified/improved ram effect cold air feed to box - Bhp/torque gain. Customer commented afterwards on slight mpg improvment.

The car was then mapped and went through the same tests, again the std air box and filter with better cold feed came out on top as the best option!

A few years ago I converted a LWB LDV Convoy with the 2.5 non turbo Ford Transit " banana" engine... it was woefully sluggish and uneconomical... so I tweaked the pump and blanked the EGR which improved matters , but the transformation came about when I added acetone to the fuel at a ratio of 5000:1

this antiquated brick became smoother, livelier through the gears and quicker top speed and the torque improved dramatically which allowed earlier gear changes rather than having to thrash it through the gears to try to keep up with traffic.
This resulted in a constant 35mpg at 55-60 mph on a run and about 30 mpg around town... not too bad for this high top vehicle which weighed in at 3 tons+ after the conversion... a deliberate heavy build to try to soften the very hard ride.

The Bosch pump on that engine tolerated the six years of acetone, but I believe the Lucas pumps on other models was intolerant of acetone due to lubrication problems caused by the drying effect it can have.... not sure if we can use acetone in the 200/300 TDI ... the improvement in torque and MPG is due to the acetone improving atomisation at the injectors I believe.

Alan.

Good condition Bosch pumps would probably stand it, but a high mileage one may struggle to keep its seals in shape.
Acetone also turns extremely acid like when in contact with heat and water. If the diesel filter has a bit of water in the bottom along with the heat of the engine, it could cause issues.

But yes it does atomize diesel.

I know it's went off the boil this topic but just to add my tupence worth, I get 16mpg towing. And about 30mpg at best solo. It's a 300tdi with standard airbox, almost straight through pipe apart from back box, decat, egr blank, fuel pump tweeks and good servicing, it gets a dolop of 2 stroke every half tank full. But I think my lack of mpg if not power comes from the original injectors needing replaced as now at 169000.

Back in the day when these were new we had a customer complaining about a driveline vibration (300 tdi manual) and he wouldn't accept that it was normal, anyway in the end Land Rover paid us to strip his engine and get it balanced. Afterwards I can honestly say it was the fastest and smoothest TDI I have ever driven barring tuned ones. It must have improved MPG also, not saying you should get yours balanced, just saying as it was very impressive, one of them things you don't forget.
We did get quite a few owners in who said they got 40+ mpg so it should still be possible.

It stands to reason. These engines were rushed into production. There are so many improvements that can be made, both costly and cheap to do.
I'm just about to buy another disco, one in much better condition and more suitable as an all rounder. So I will be a blank canvas to start again with.
I am going to document the above with pictures this time.
I am tempted to get a quote on balancing the crank/rods/Pistons and flywheel just to see how it reacts afterwards. Anyone know the going rate? It's been years since I have blueprinted an engine.