Derating a 2.0 TDI for better fuel effiency.

[neil]

Been reading about the new Audi A3 and the newish 1.8 litre diesel.
Supposed to be the old Golf/polo 1.9 derated to 77 kw and with a few other
changes in the box they have the fuel consumption down to 4.5L/100km.

Question is would it be possible to derate a 2.0tdi and get better efficiency.
Been a few threads in the past about chipping and getting better economy so what about derating.
So far VWAus have been hopeless at answering my question.

[gldgti]

if you ran less fuel in the maps and less boost, you would get better economy (providing you werent trying to make up for the power loss by driving harder).

smaller capacity will usually allow lower fuel consumption for any given scenario... 2.0l down to 1.8 is a 10% reduction, and so that accounts for a fair chunk of the improvement.... maybe

[brad]

Been reading about the new Audi A3 and the newish 1.8 litre diesel.
Supposed to be the old Golf/polo 1.9 derated to 77 kw and with a few other
changes in the box they have the fuel consumption down to 4.5L/100km.

Question is would it be possible to derate a 2.0tdi and get better efficiency.
Been a few threads in the past about chipping and getting better economy so what about derating.
So far VWAus have been hopeless at answering my question.

Have you tried driving more economically? It would be easier than faffing about derating the engine.

I won a fuel economy competition in a showroom stock (even had 32psi in the tyres) Golf 1.6 petrol automatic - we achieved 4.56L/100km driving a 160km course from Sydney up to the Blue Mountains & back.

[Greg Roles]

I'm sure if you disabled the turbo, it'd be far more economical, but take you most of the night to get home from work....

[neil]

Have you tried driving more economically? It would be easier than faffing about derating the engine.

I won a fuel economy competition in a showroom stock (even had 32psi in the tyres) Golf 1.6 petrol automatic - we achieved 4.56L/100km driving a 160km course from Sydney up to the Blue Mountains & back.

After 10000 k's I have an average of 4.8L/100km and this is mostly Hwy.

Was just curious if I could improve on this when the official usage for a jetta is 5.8L/100 ,
So if the new Audi is 4.5L/100km than maybe it would be possible to get 3.5L/100 from My Hwy driving.

Had an update from my dealer today saying the new VW MY09 TDI's will not be fitted with the new 7 speed DSG,
only the TSI engines at this stage.

[Mischa]

After 10000 k's I have an average of 4.8L/100km and this is mostly Hwy.

Was just curious if I could improve on this when the official usage for a jetta is 5.8L/100 ,
So if the new Audi is 4.5L/100km than maybe it would be possible to get 3.5L/100 from My Hwy driving.

Had an update from my dealer today saying the new VW MY09 TDI's will not be fitted with the new 7 speed DSG,
only the TSI engines at this stage.

lol how fast (slow) do you drive on the highway!?

[VW Convert]

lol how fast (slow) do you drive on the highway!?

Probably not as quick as you Misch! :biggrin:

Cheers

George

[brad]

After 10000 k's I have an average of 4.8L/100km and this is mostly Hwy.

That's pretty good.

Getting 4.56L/100km out of the petrol motor was painful to say the least but I had an enjoyable few hours sharing the driving with a guy who was a famous motorsports nutter. Won $5k too:)

Do you run high(ish) tyre pressures or the low rolling resistance tyres?

I reckon my 6th gear is too low - I'd like it to be revving about 500rpm less @ 110kph

[neil]

lol how fast (slow) do you drive on the highway!?

Mischa.

I always give myself plenty of time to get to my destination, If I get the chance to slow down due to light traffic I do.
I do not hold up the traffic on the Newcastle/Sydney Fwy as anybody knowing this Fwy it would be a death sentence.
If I get the chance to slow down its usually at 90km/h.
If late at night it takes just over 10 mins extra if driving at 90km/h.

[neil]

That's pretty good.

Getting 4.56L/100km out of the petrol motor was painful to say the least but I had an enjoyable few hours sharing the driving with a guy who was a famous motorsports nutter. Won $5k too:)

Do you run high(ish) tyre pressures or the low rolling resistance tyres?

I reckon my 6th gear is too low - I'd like it to be revving about 500rpm less @ 110kph

Brad.
Running tyres at 40psi.
Not game to ask what the cost of roll resistance tyres are.
Neil.

[neil]

if you ran less fuel in the maps and less boost, you would get better economy (providing you werent trying to make up for the power loss by driving harder).

smaller capacity will usually allow lower fuel consumption for any given scenario... 2.0l down to 1.8 is a 10% reduction, and so that accounts for a fair chunk of the improvement.... maybe

Dealer says derating would cost more than the savings.

[Mischa]

Mischa.

I always give myself plenty of time to get to my destination, If I get the chance to slow down due to light traffic I do.
I do not hold up the traffic on the Newcastle/Sydney Fwy as anybody knowing this Fwy it would be a death sentence.
If I get the chance to slow down its usually at 90km/h.
If late at night it takes just over 10 mins extra if driving at 90km/h.

yep thats fine not having a go at you just seems like ultra low consumption :)

[neil]

yep thats fine not having a go at you just seems like ultra low consumption :)
Mischa
My dealer mentioned today my fuel economy fairly normal for a Jetta as the drivers are more economical with the right foot than Golf owners, especially the GT owners. :biggrin:

90% of my driving is on the Fwy. also try not to stop at the lights, just cruise up to them and go and this has also shown a big saving around town.

Just read your Audi S2 thread nice one.
Neil.

[brad]

Brad.
Running tyres at 40psi.
Not game to ask what the cost of roll resistance tyres are.
Neil.

Michelin do 2 or 3 versions. I think they universally label them ENERGY. eg MXV ENERGY...... /searches. These ones (http://www.michelin.com.au/tyres/passengerCar.asp)

My simple mind tells me that less resistance=less grip but we had the XM1 Energy as OEM on a Toyota Avensis Verso (people mover) and you had to drive like a ****head to make them lose grip.

In these days of speed cameras, wowsers & high fuel prices it's almost more fun trying to achieve ridiculously low fuel economy than going fast. (did I say that!:duh::eek:)

[bluey]

Cheapest way to use less fuel is to put a bigger return spring on the accelerator.

Cruise control seems good at accelerating efficiently. Perhaps it could be modded to accelerate from rest.

Cheap fun is going round corners without slowing down (much).