Improving mpg in Vw TDI

[oldbeaver]

Originally Posted by Angmaar

The nut behind the wheel is you, the driver.

Ha, ha, ha !!!

Thank you much!

I should have discovered that myself, was not so hard.
However, I took "nut" literally, figuring that there is some kind of thing to be tighten on these cars.

Good joke.

[ConnClark]

Originally Posted by oldbeaver

Dear Mario,

I am also waiting to see the next part of the Autospeed mod of the exhaust.
My mother´s language is Spanish, but what I understood from part 3, is that freeing exhaust flow didn´t improve power, what means that it probably didn´t improve MPG also. Do you agree on that?

It didn't improve power because as he has discovered the computer keeps reducing fuel. Mileage might have gotten better though as he hasn't reported on mileage after each mod.

[MaxHedrm]

If it were a couple years older, you could turn it into this:
Smyth Performance | Facebook

[Mario_Marques]

Originally Posted by oldbeaver

Dear Mario,

I am also waiting to see the next part of the Autospeed mod of the exhaust.
My mother´s language is Spanish, but what I understood from part 3, is that freeing exhaust flow didn´t improve power, what means that it probably didn´t improve MPG also. Do you agree on that?

How would you classify Skoda Octavia TDI 2009: MK4, MK5, or ...?
Do you know where is the Intercooler located in this car?

Thank you and good tuning!

Oldbeaver

Your skoda has front mount intercooler.
your car is a relatively recent, since the released of the golf mk5, all the tdi vw group cars have fmic, only the older ones have smic.
Everything you can do to decrease exhaust gaz temperature(EGT) will help you to get better mileage(remember egt is not the same as temperature of the exhaust piping), that's why vw is using fmic on tdi's, to get lower intake temperatures.



I´ve done some mods wich improve my mileage, one of the biggest improvement at the moment was the 15" wheels (my car has 17" from factory with sport tyres), with 15" the car is a lot free in the highway(notice that i lost handling and braking power but it's quite acceptable).
I also have a low restricted exhaust system, low restricted intake manifold with thermal coating on the intake manifold, i dont recommend you to delete egr if you want good fuel consumption, deleting egr will increase your fuel consumption, i only delete mine because i dont have another choice, but i recommend you to clean your egr and intake manifold at 100k-100k, because the dirt from the egr+oil vapours from the ccv will get your inatek manifold and egr clogged.

If you want to check some mods on my tdi engine take a look at my gallery at my forum profile, i will update my galleri soon, with pictures of my new 15" wheels and some very small aero work.



Saludos

[dremd]

I'd be shocked if airflow mods will increase mpg.
With my intake 75% plugged, there was no noticeable change in MPG after cleaning..

[NachtRitter]

Originally Posted by dremd

I'd be shocked if airflow mods will increase mpg.
With my intake 75% plugged, there was no noticeable change in MPG after cleaning..

Same with mine... cleaning the intake made no difference in FE. What made a huge difference for me is getting updated nozzles / injectors. Could be because the old nozzles were not flowing as well, but putting new larger nozzles improved my freeway FE from ~28MPG to ~48MPG... huge difference!

I'm sure it wouldn't have made anywhere near as much difference if my current nozzles didn't have ~300K miles on them.

[Arragonis]

The biggest improvement for FE for the car excluding the engine is tyres and aero.

The biggest improvement for FE or power for the engine is regular maintenance and a remap in that order.

[MaxHedrm]

The advantage of freer flowing air is that when you do request more power by dumping in more fuel you can get the air to burn it rather than just dumping it out the exhaust. So, you may not see a FE improvement, but you may see improved drivability.

[oldbeaver]

Originally Posted by Mario_Marques

Your skoda has front mount intercooler.
.....
Everything you can do to decrease exhaust gaz temperature(EGT) will help you to get better mileage(remember egt is not the same as temperature of the exhaust piping), that's why vw is using fmic on tdi's, to get lower intake temperatures.

I´ve done some mods wich improve my mileage, one of the biggest improvement at the moment was the 15" wheels (my car has 17" from factory with sport tyres), with 15" the car is a lot free in the highway(notice that i lost handling and braking power but it's quite acceptable).
.....
Saludos

Dear Mario,

Ok to all, however, I don´t see why yr 15" tires have better fuel yield than the 17" ones. I would have thought the opposite!

I also have a set of 4 17" sport tires, however, I have never used them. What you say is a surprise to me, as I was thinking sport larger tires may yield more.

By the way, I visited once Lisbon, took the tarin to Sintra and the coast train to the end (where there is a F1 circuit too). Very nice sight over there.

Ok to the EGR valve. Taking it out is no good, but there is a way to optimize it.

Cumprimentos,

Oldbeaver

[MaxHedrm]

There is no reason going from 17" to 15" wheels alone would improve your FE. The key is the weight of the wheels & what tires you put on them. If you get lighter wheels (so don't go with those cheap steel wheels, or even cheap alloys for that matter) you will see an improvement in ride, handling (including braking) AND fuel efficiency (particularly in stop & go situations, less so on the highway). Low rolling resistance tires will see a decrease in ride quality and handling (including braking) but an increase in fuel efficiency.

Mario probably replaced the all season performance tires with a more economy minded LRR tire to get that improvement.