MPG

[StefanUK]

Just wondering what your MPG is and what mods you have on.

Currently to a 10a im getting 50Miles out of the hdi with stage 1 remap being a tad heavy footed.

[sweeney1987]

cant work out mpg using such a small figure. neeed to do tankfulls to be semi accurate....

Bought a hdi last night, lad reckons standard it got 49, well see when i get it on road..

[C.A.R.]

In the cold weather we had just before xmas mine dropped to 52.

Generally averages about 55-56 with a heavy right foot. Stage 1 map, otherwise standard. Have just added a decat so will see if that makes any difference at all!

[Toms306]

Well, I've driven 2 HDi estates (bear in mind a little heavier than the hatch) and I get 50-52mpg everywhere, no matter how hard or soft I drive! Stage 1 map on both, was no different before the map though.

Both had done over 100k though, that may make a difference....

[Poodle]

Getting about 46-47. Mine is old and knackered and desperately needs a service, so...

[C.A.R.]

Well, I've driven 2 HDi estates (bear in mind a little heavier than the hatch) and I get 50-52mpg everywhere, no matter how hard or soft I drive! Stage 1 map on both, was no different before the map though.

Both had done over 100k though, that may make a difference....

You've owned 2 but over such a short period of time that it doesn't really count, Tom. Both estates have been run when the weather conditions were colder than usual, which means the 50-52 you managed was actually quite good.

Even a Volkswagen product gets affected by 'little' things like the climate.

[THE_Liam]

Pure town driving I'm getting 38mpg which is epic considering on my drive to work a 1.8T does 18mpg...

DT stage 1 Lucas

[cully]

stop driving the car like pansies!

38mpg here ragging it or 52mpg on a good long eco drive
normaly tank-tank i get 43-45mpg normal driving

stage 1 hdi Estate
pro-steve map
de EGR
decat
mid to rearbox conversion

[Pete]

Van: 2.0 hdi, straight through exhaust, egr blank and tuning box (yes I know) 52 mpg mixed driving. Car: 3.0 V6, boggo bar induction kit 25 mpg..does get driven quite hard though.

[Toms306]

Well, I've driven 2 HDi estates (bear in mind a little heavier than the hatch) and I get 50-52mpg everywhere, no matter how hard or soft I drive! Stage 1 map on both, was no different before the map though.

Both had done over 100k though, that may make a difference....

You've owned 2 but over such a short period of time that it doesn't really count, Tom. Both estates have been run when the weather conditions were colder than usual, which means the 50-52 you managed was actually quite good.

Even a Volkswagen product gets affected by 'little' things like the climate.

If you're reffering to the Golfs.....I owned them in the shit snowy weather this time last year lol. 60mpg easy, even in snow, as I say, my tank average never really changes, regardless of temperature or extra load or anything, over a tankful it ends up the same. But the difference was they PD actually heated up, within a few miles was bang on 90c and didn't move. The HDi wont be economical as 1, it never warms up and 2, even when it does, it sits at 75c which isn't warm enough to be decently efficient IMO.

Plus, it wouldn't use so much fuel in traffic if it could keep a steady idle!

[procta]

i thought this was a toms306 thread at 1st, anyone else think that?
i have found it can be what the dervs like where you fill up has a lot to do with it too.

[sweeney1987]

Well, I've driven 2 HDi estates (bear in mind a little heavier than the hatch) and I get 50-52mpg everywhere, no matter how hard or soft I drive! Stage 1 map on both, was no different before the map though.

Both had done over 100k though, that may make a difference....

You've owned 2 but over such a short period of time that it doesn't really count, Tom. Both estates have been run when the weather conditions were colder than usual, which means the 50-52 you managed was actually quite good.

Even a Volkswagen product gets affected by 'little' things like the climate.

If you're reffering to the Golfs.....I owned them in the shit snowy weather this time last year lol. 60mpg easy, even in snow, as I say, my tank average never really changes, regardless of temperature or extra load or anything, over a tankful it ends up the same. But the difference was they PD actually heated up, within a few miles was bang on 90c and didn't move. The HDi wont be economical as 1, it never warms up and 2, even when it does, it sits at 75c which isn't warm enough to be decently efficient IMO.

Plus, it wouldn't use so much fuel in traffic if it could keep a steady idle!

you do realise all vag group cars indicate 90 as normal operating temperature, only read different if sensors think theres something wrong....

[THE_Liam]

You've owned 2 but over such a short period of time that it doesn't really count, Tom. Both estates have been run when the weather conditions were colder than usual, which means the 50-52 you managed was actually quite good.

Even a Volkswagen product gets affected by 'little' things like the climate.

If you're reffering to the Golfs.....I owned them in the shit snowy weather this time last year lol. 60mpg easy, even in snow, as I say, my tank average never really changes, regardless of temperature or extra load or anything, over a tankful it ends up the same. But the difference was they PD actually heated up, within a few miles was bang on 90c and didn't move. The HDi wont be economical as 1, it never warms up and 2, even when it does, it sits at 75c which isn't warm enough to be decently efficient IMO.

Plus, it wouldn't use so much fuel in traffic if it could keep a steady idle!

you do realise all vag group cars indicate 90 as normal operating temperature, only read different if sensors think theres something wrong....

As said, you don't think that's the real temp do you? My Octavia would say that when all the hoses were cold...

[Toms306]

The sensors fail regularly on them lol... But you can check them with VAGCOM to see if the gauge is accurate......mine was bang on at 90.

[Jonny81191]

I get 42 average, that's with a LOT of hooning to and from work etc...

And 55 or so I guess on a long drive.

[Toms306]

you do realise all vag group cars indicate 90 as normal operating temperature, only read different if sensors think theres something wrong....

Well, I've just had to do some research to check and it appears youre right.

What a ridiculous system lol. Must've just been coincidence that mine read right at the time (idling in a car park at a dubmeet). I think knowing that isnt accurate is more worrying than knowing the exact temp!

Edit - But that brings up another question.........if its not the temp that ruins the hdi mpg, why is it so poor comparatively?

[sweeney1987]

Well, I've just had to do some research to check and it appears youre right.

What a ridiculous system lol. Must've just been coincidence that mine read right at the time (idling in a car park at a dubmeet). I think knowing that isnt accurate is more worrying than knowing the exact temp!

Edit - But that brings up another question.........if its not the temp that ruins the hdi mpg, why is it so poor comparatively?

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

[C.A.R.]

HDi is much, much simpler Tom, and much, much cheaper.

It's like comparing apples and oranges.

If you can afford to buy and properly service the PD engine then fair play to you - I don't doubt they are good to own. But should they go wrong then you're problems could cost 10x as much as a similar problem on a HDi would cost to rectify.

A similar spec / condition Golf costs 2x as much as a HDi...

[Toms306]

Well, I've just had to do some research to check and it appears youre right.

What a ridiculous system lol. Must've just been coincidence that mine read right at the time (idling in a car park at a dubmeet). I think knowing that isnt accurate is more worrying than knowing the exact temp!

Edit - But that brings up another question.........if its not the temp that ruins the hdi mpg, why is it so poor comparatively?

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

Well, I wouldn't say always right.

The block/bottom ends are almost identical weirdly, the piston 'hole' is even the same shape and everything, so it can only be the top end that makes the difference, and even then the older PD is still only 8 valve, so that just leaves the injectors. But I can't really see how the unit injectors are much better for mpg, the only real difference is the top mechanical 'pump' type part, the nozzle end and solenoid opening operation is near enough the same isn't it?

Granted the VNT turbo will help mpg, as it's nearly always slightly on blow. And the 6 speed 'box helps on a run, but when you're averaging like 30mph (just going off the trip computer, I can't work out avg speed in my head lol) then even the 'box can't make much difference either.

I was really surprised when I stripped the Golf how there wasn't loads of extra sensors and clever things, infact, it only has the same sensors as a HDi (one extra but thats MAP for the VNT), I was expecting loads of amazing new tech, that just wasn't there lol. I'm just struggling to get my head around how you can have two engines that seem extremely similar, but one has twice the power, tonnes more torque and still gets over 60mpg with ease while the other left the factory with 90bhp and will struggle to even hit 50mpg unless you drive it carefully.


As for apples and oranges Chris, I'd say more like Granny Smiths and Pink ladys...they're not totally different. And PDs mainly cost more because they're in VAGs....1.4 petrol Golfs cost over twice as much as 306 1.4s, but they're no better.

I'll stop talking about VAGs now though.........but it's ridiculous I can have a better VAG discuassion and learn more about them over here than I can on the Dub forum.

[C.A.R.]

Tom, when you say there isn't "much" different about them...

Then go on to say "apart from the entire injection system"

It makes you sound either a bit dim (which we know you're not) or a bit of a fanboy...

[Mr Whippy]

I think the main benefit of the VAG for power/mpg is the gearbox.

As standard the gears with 90bhp feel right.

With 125bhp it feels like you have a fairly racey gearbox for the power (ie, short ratios)

With 155hp it feels like you have something with ratios for a super special rally stage hehe.


There is no doubt that with 20% longer gearing, or a 6th gear, you'd be adding a LOT more economy on a 60-70mph cruise!

Dave

[THE_Liam]

Can I just point out, to settle the 15th HDI vs PD argument between CAR and Toms306, the common rail, electronic pumped PD is overcomplicated and problematic compared to a HDI, but the common rail, electronic pumped HDI is overcomplicated and problematic compared to the rotary injection pump, ECU-less, indirect injection XUD, which gets nearly as much to a gallon (and practically the same with a HDI box) as the HDI but it far cheaper to tune, run (veg oil) and maintain than either!

Basically, your both wrong.

[sweeney1987]

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

Well, I've just had to do some research to check and it appears youre right.

What a ridiculous system lol. Must've just been coincidence that mine read right at the time (idling in a car park at a dubmeet). I think knowing that isnt accurate is more worrying than knowing the exact temp!

Edit - But that brings up another question.........if its not the temp that ruins the hdi mpg, why is it so poor comparatively?

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

Well, I wouldn't say always right.

The block/bottom ends are almost identical weirdly, the piston 'hole' is even the same shape and everything, so it can only be the top end that makes the difference, and even then the older PD is still only 8 valve, so that just leaves the injectors. But I can't really see how the unit injectors are much better for mpg, the only real difference is the top mechanical 'pump' type part, the nozzle end and solenoid opening operation is near enough the same isn't it?

Granted the VNT turbo will help mpg, as it's nearly always slightly on blow. And the 6 speed 'box helps on a run, but when you're averaging like 30mph (just going off the trip computer, I can't work out avg speed in my head lol) then even the 'box can't make much difference either.

I was really surprised when I stripped the Golf how there wasn't loads of extra sensors and clever things, infact, it only has the same sensors as a HDi (one extra but thats MAP for the VNT), I was expecting loads of amazing new tech, that just wasn't there lol. I'm just struggling to get my head around how you can have two engines that seem extremely similar, but one has twice the power, tonnes more torque and still gets over 60mpg with ease while the other left the factory with 90bhp and will struggle to even hit 50mpg unless you drive it carefully.


As for apples and oranges Chris, I'd say more like Granny Smiths and Pink ladys...they're not totally different. And PDs mainly cost more because they're in VAGs....1.4 petrol Golfs cost over twice as much as 306 1.4s, but they're no better.

I'll stop talking about VAGs now though.........but it's ridiculous I can have a better VAG discuassion and learn more about them over here than I can on the Dub forum.

Did you not read that line?
better atomisation of fuel in cylinder means using less fuel for same energy and less emissions which means more mpg.
and as dave said, the gearing is a considerable help too, the ratios on 306s is terrible in general and not as well calculated or engineered, hate to admit it but its true

[Toms306]

Can I just point out, to settle the 15th HDI vs PD argument between CAR and Toms306, the common rail, electronic pumped PD is overcomplicated and problematic compared to a HDI, but the common rail, electronic pumped HDI is overcomplicated and problematic compared to the rotary injection pump, ECU-less, indirect injection XUD, which gets nearly as much to a gallon (and practically the same with a HDI box) as the HDI but it far cheaper to tune, run (veg oil) and maintain than either!

Basically, your both wrong.

There's no common rail in a pd though. It's also no more complicated than a HDi, literally the only difference with fuelling is the HDi uses a mechanical pump to pressurise the fuel and the pd uses what's effectively a mechanical pump for each injector. Both solenoids operate in exactly the same way at the nozzle end. Which Chris seems to have failed to understand, yes its a different delivery system, but it does exactly the sane thing, even using the same sensors and actuators! It even uses an edc15 ECU the same as the HDi iirc....

And hdis aren't more complicated than xuds either.....give some computer geek a mechanical pump he'll have no idea what to do....give him an ECU he can write a map. Just because new tech is different doesn't make it MUCH more complicated, its how you personally percieve it, different people find different things easier.

What's interesting though, is I'm looking at a car atm with with a 6 speed box and gt1749 vnt turbo (same as the golf)....BUT with common rail instead of pd.....if I go for it, will be interesting to see what the mpg difference is... Obviously there's a few more variables, but still...

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

Im always right...

regards to other question, most likely completely different engine design using unit injectors, HDI on 306s is the first version of commonrail, since then theres been different revisions and improvements, higher rail pressures, piezo-electric injectors and vnt turbos, all attribute to better atomisation of fuel in cylinder leading to better mpg

Well, I wouldn't say always right.

The block/bottom ends are almost identical weirdly, the piston 'hole' is even the same shape and everything, so it can only be the top end that makes the difference, and even then the older PD is still only 8 valve, so that just leaves the injectors. But I can't really see how the unit injectors are much better for mpg, the only real difference is the top mechanical 'pump' type part, the nozzle end and solenoid opening operation is near enough the same isn't it?

Granted the VNT turbo will help mpg, as it's nearly always slightly on blow. And the 6 speed 'box helps on a run, but when you're averaging like 30mph (just going off the trip computer, I can't work out avg speed in my head lol) then even the 'box can't make much difference either.

I was really surprised when I stripped the Golf how there wasn't loads of extra sensors and clever things, infact, it only has the same sensors as a HDi (one extra but thats MAP for the VNT), I was expecting loads of amazing new tech, that just wasn't there lol. I'm just struggling to get my head around how you can have two engines that seem extremely similar, but one has twice the power, tonnes more torque and still gets over 60mpg with ease while the other left the factory with 90bhp and will struggle to even hit 50mpg unless you drive it carefully.


As for apples and oranges Chris, I'd say more like Granny Smiths and Pink ladys...they're not totally different. And PDs mainly cost more because they're in VAGs....1.4 petrol Golfs cost over twice as much as 306 1.4s, but they're no better.

I'll stop talking about VAGs now though.........but it's ridiculous I can have a better VAG discuassion and learn more about them over here than I can on the Dub forum.

Did you not read that line?
better atomisation of fuel in cylinder means using less fuel for same energy and less emissions which means more mpg.
and as dave said, the gearing is a considerable help too, the ratios on 306s is terrible in general and not as well calculated or engineered, hate to admit it but its true

Yes I read it, but its gotta be well atomised to run well with a DI engine in the first place, I just can't see how slightly better atomisation would make such a major difference, I'll take your word for it though. I agree the higher ratios are better (sit in 6th at ~40 just above idle and watch the mpgs mount up), but the low ones (1,2,3) are still awful as with any diesel....there's really no point in 1st as it doesn't get you anywhere, I know its meant for tugging a caravan or whatever though lol.

Anyway....I'll stop now.

[aircool]

I would love to know how I only managed 45.8mpg on the last tank when driving like a saint when the previous tank got 51 driving spiritedly and idling for ages to defrost. Same route everyday. Low rpm is worse?

[sweeney1987]

There's no common rail in a pd though. It's also no more complicated than a HDi, literally the only difference with fuelling is the HDi uses a mechanical pump to pressurise the fuel and the pd uses what's effectively a mechanical pump for each injector. Both solenoids operate in exactly the same way at the nozzle end. Which Chris seems to have failed to understand, yes its a different delivery system, but it does exactly the sane thing, even using the same sensors and actuators! It even uses an edc15 ECU the same as the HDi iirc....

And hdis aren't more complicated than xuds either.....give some computer geek a mechanical pump he'll have no idea what to do....give him an ECU he can write a map. Just because new tech is different doesn't make it MUCH more complicated, its how you personally percieve it, different people find different things easier.

What's interesting though, is I'm looking at a car atm with with a 6 speed box and gt1749 vnt turbo (same as the golf)....BUT with common rail instead of pd.....if I go for it, will be interesting to see what the mpg difference is... Obviously there's a few more variables, but still...

[quote='sweeney1987' pid='193358' dateline='1357939779']
Yes I read it, but its gotta be well atomised to run well with a DI engine in the first place, I just can't see how slightly better atomisation would make such a major difference, I'll take your word for it though. I agree the higher ratios are better (sit in 6th at ~40 just above idle and watch the mpgs mount up), but the low ones (1,2,3) are still awful as with any diesel....there's really no point in 1st as it doesn't get you anywhere, I know its meant for tugging a caravan or whatever though lol.

Anyway....I'll stop now.

VAG opted for the PD engines so as not to pay fiat/GM(forget off top of head but fiat started research) royalties for using common-rail.
the unit injector system has higher pressures than hdis see, thus improving atomisation of fuel, as said the better the atomisation the cleaner the burn and less waste(heat/unburnt fuel) in cylinder thus improving mpg.
There are much technological improvements just you may not be bright enough to notice them
Older design injectors that didnt use piezo crystals for instance dont meter fuel as accurately, causing more fuel than desired entering cylinder, as piezo ones open and close far quicker.
tolerences etc have also got finer in development of the engines.
yes the PD and hdi are of a similar year but comparing two different systems and wondering why one gets better mpg is very dim...

I would love to know how I only managed 45.8mpg on the last tank when driving like a saint when the previous tank got 51 driving spiritedly and idling for ages to defrost. Same route everyday. Low rpm is worse?

very possible, if youre labouring engine instead of using it in torque band you will more than likely use more fuel.

[aircool]

Thats what im thinking with the low rpm running.

The ELM327 OBD reader is lying then

It doesn't appear to be calculating fuel consumption correctly even with some calibration - I get infinite MPG with the clutch in when moving in traffic

Will add some mild hooning and lower gears.

May also check brakes.

[Poodle]

Ah, now i get it Sweeney, thanks, and i suppose anyone attributing the total mpg difference between two completely different cars to be down to just injector type is remarkably intelligent?

[Toms306]

They're hardly completely different, they weigh the same for a start. And Infact everythings heavier in the golf drive line (dmf, massive thick shafts, big heavy wheels)....and let's face it both cars are boxy and not particularly aerodynamic.

Anyway, fair enough if it is mainly down to the injectors, obviously the inside of those isn't visible lol.


Aircool, I've noticed this too, the HDi actually prefers revs! . The other diesels I've owned would sit just above idle (not labouring) and get good mpg. BUT. I think the difference is the crap HDi turbo isn't blowing extra air in at idle, so you have to drive a bit faster to get the benefit of the non vnt. That's my excuse when I'm caught speeding anyway haha.

[DeeTurbo]

Would anyone be interested in how to fit a 406 trip computer to their 306?



Please excuse the shoddy cutting on the panel.