Newbies and Vets: Tips for better fuel economy!

[Ellery]

you all can disregard my last post about break in - wrong forum for it, and I have discussed it in the other forum -

 

[40X40]

Good - I have no intention of really messing with the DRG's "manual mode" - I find it strange and awkward to use anyway - some folks on this thread recommended skipping gears at times, but I think with the automatic it would be over the top perhaps, again, most of my driving anyway is highway, so likely no big effect.

I am just wondering if my wagon will really be able to get 50mpgs too? - I mean, my computer rated me a trip avg of 49 the other day to work, but most times its more like 44 and when I do my math today after refilling (just till the pump shut off automatically) I got 41.6mpg calculated - but I think I will keep tracking it now, I think it will get better with my more careful driving and perhaps a tad more tire pressure than the manufacturer.

There is no way to skip gears if your car has a DSG.

If you figure your mileage manually but base it on the 'first click' of an automatic pump you will get weird results. In order to get good data with that technique you will have to keep records over a much longer time and average them.
I suggest instead that when you fill the tank, fill it to the brim with no foam at all. This gives repeatable, reliable data. The tank will not overflow after you park.... Reset the dash computer and you should find that the results start to agree. There are two different mileage readouts on your dash...

Bill

 

[40X40]

<SNIP>The tank has a vent tube, and filling to the vent means filling it till fuel spills out that tube onto the ground. <SNIP>

Ted

UMM.

Bullsh*t. Filling the tank until it is full does in no way mean it has to run over onto the ground. 'Venting the tank' was for the A4 cars, not the newer A5 or A6 models. You simply fill the tank completely full and stop before you make a mess.

Bill

 

[Ellery]

Question for everyone:

I have read through some of the threads about "breaking in" your engine - basically the premise being keeping the rpms up a bit higher between gears to keep the turbo engaged and to break in the engine better for better long term fuel economy and ? longer longevity of the motor.

I dont wish to debate that here, but if one is going to follow this principle, how will it affect my non-highway gas mileage? Will that drag it down significantly? I only have 10K miles at this point and I use cruise control all the time - which is preferred for better mileage, but should I use S mode more often for better long term fuel efficiency? and longevity? - in S mode I change gears more like around 2800-3000 RPM's - this would presumably eat up more gas and not follow some of the principles of this thread? Or does this thread only apply to 60K plus mileage TDI's??

 

[Ellery]

Also, I have recieved mixed signals on here - due I top off my car and how do I go about doing that? Or should I just avg what I get when the pump clicks off?

 

[ruking]

Also, I have recieved mixed signals on here - due I top off my car and how do I go about doing that? Or should I just avg what I get when the pump clicks off?

However you decide, do it consistently. I would not recommend topping, even as a lot of folks document on this web site that they in fact do it. As you read the technical manuals, and perhaps do searches on this august web site, the real reason for the extra volume (15.5 gals for a max capacity of 14.5 gals) is because oem engineering allows for EXTREMES in temp, aka, ROOM for the fuel to expand and contract and EPA regulations.

I just let it fill untill the "first click off", unless of course it clicks off way below expected fill. The only time I would consider so call "topping the tank" is to get a tad extra range when I know I will burn off app 1 gal right away. (40-50 miles)

I do keep a pen and ink log book. On my 2009 where I do have a MFD, the pen and ink calculations really do not deviate all that much from the MFD. You can of course do it "inconsistently," but don't be alarmed if your calculations appear... inconsistent.

 

[40X40]

However you decide, do it consistently. I would not recommend topping, even as a lot of folks document on this web site that they in fact do it. As you read the technical manuals, and perhaps do searches on this august web site, the real reason for the extra volume (15.5 gals for a max capacity of 14.5 gals) is because oem engineering allows for EXTREMES in temp, aka, ROOM for the fuel to expand and contract and EPA regulations.
Because our DIESEL fueled care share the same tank/filler with GASOLINE powered cars that require the expansion room. Fill it as full as you like, it is very very unlikely to expand enough to overflow.


I just let it fill untill the "first click off", unless of course it clicks off way below expected fill. The only time I would consider so call "topping the tank" is to get a tad extra range when I know I will burn off app 1 gal right away. (40-50 miles)

I do keep a pen and ink log book. On my 2009 where I do have a MFD, the pen and ink calculations really do not deviate all that much from the MFD. You can of course do it "inconsistently," but don't be alarmed if your calculations appear... inconsistent.

500 miles burning 13 gallons =38.46 mpg Example 'first click'
500 miles burning 13.5 gallons =37.03 mpg. Example 'full to the brim'

1.43 mpg discrepancy in the above example. Either method can be used, but better accuracy will result when you top off the tank in the same exact manner the second time as you did the first time.


However you choose to fill the car, do it the same way every time or you risk inducing an error into your calculations. This can be overcome by increasing the amount of tanks you average the mileage into.

For instance:
Over the first 20,000 miles of driving, my manual 06 Jetta averaged 42 mpg for the entire distance.

I top off each tank to the brim, but I also keep records of every tank I put through the car(s). This simply serves as a check for either method.

It ain't rocket science.... which means we don't get to blow things up....LOL

Bill

 

[ruking]

500 miles burning 13 gallons =38.46 mpg Example 'first click'
500 miles burning 13.5 gallons =37.03 mpg. Example 'full to the brim'

1.43 mpg discrepancy in the above example. Either method can be used, but better accuracy will result when you top off the tank in the same exact manner the second time as you did the first time.


However you choose to fill the car, do it the same way every time or you risk inducing an error into your calculations. This can be overcome by increasing the amount of tanks you average the mileage into.

For instance:
Over the first 20,000 miles of driving, my manual 06 Jetta averaged 42 mpg for the entire distance.

I top off each tank to the brim, but I also keep records of every tank I put through the car(s). This simply serves as a check for either method.

It ain't rocket science.... which means we don't get to blow things up....LOL

Bill

http://forums.tdiclub.com/showthread.php?p=2857769#post2857769

I posted this recently in another thread. The acuracy of "first click" against the MFD is .0061919% off vs (your) topping the tank of .037 to .039 %? (a tad more than 1/2 of 1 % vs 3.7 to 3.9%)

So yes, what is 5.98 to 6.3 x difference between friends !!?? Like I said "in the ball park", and what you said:

..." It ain't rocket science.... which means we don't get to blow things up....LOL"...

and yes, I sometimes wax nostalgic about those days.

 

[Ellery]

Also, please refer back to my question prior to my recent topping off question - the one where I ask about the apparent conflict of the "breaking in priciple" and lowest possible RPM's for best fuel efficiency....thanks.

 

[ruking]

Also, please refer back to my question prior to my recent topping off question - the one where I ask about the apparent conflict of the "breaking in priciple" and lowest possible RPM's for best fuel efficiency....thanks.

Have you read "Break In"? http://forums.tdiclub.com/showthread.php?t=252501

If you have questions about MSG #1, OP being Drivbiwire, fire away.

 

[40X40]

Also, please refer back to my question prior to my recent topping off question - the one where I ask about the apparent conflict of the "breaking in priciple" and lowest possible RPM's for best fuel efficiency....thanks.

Worry about break-in for the first 10,000 or so miles so that you get good mileage after that. It can take 30,000-40,000 miles to reach peak cylinder compression numbers.
The members here tend to keep their cars longer than most owners.....

Bill

 

[Ellery]

Also, given my car is a wagen...what is a realistic best case scenario gas mileage for me without any modifications (nozzles, chips, etc..)? I just in the past week started slowing down during my commute to 60mph/1900RPM and my mileage has apparently improved greatly - my first fill up was the other day after doing this and my avg was 41.67 (that is using the volume with the pump clicking off).

My commute is about 15% stop and go, the rest HWY on cruise - 100 miles round trip - I use Chevron diesel (which as I understand on here is good). Does around 42mpg seem a bit low? Or am I doing about what can be expected?

 

[ruking]

Also, given my car is a wagen...what is a realistic best case scenario gas mileage for me without any modifications (nozzles, chips, etc..)? I just in the past week started slowing down during my commute to 60mph/1900RPM and my mileage has apparently improved greatly - my first fill up was the other day after doing this and my avg was 41.67 (that is using the volume with the pump clicking off).

My commute is about 15% stop and go, the rest HWY on cruise - 100 miles round trip - I use Chevron diesel (which as I understand on here is good). Does around 42mpg seem a bit low? Or am I doing about what can be expected?

You might want to look at a couple of other places 1. on this web site and that are the monthly "competition" figures. Jan/Feb 2010 being the latest. 2. The Fed has a site also http://www.fueleconomy.gov/feg/sbs.htm

It is not as "graphic" as some Honda poll sites I have seen where one can self report and it gets captured in a sort of (bell shaped curve) ranking.

 

[Ellery]

Thanks Ruking - I will look into that! Appreciated!

 

[tmac123]

Using Neutral

I drive an 06 Jetta TDI.
I was just curious if throwing the car in neutral on straightaways with a slight decline, and hilly areas is worth the gas mileage I save.

Obviously when I need to use the gas again I put the transmission back in drive and slightly ease back on the gas.

 

[roadhard1960]

If you can go down that decline with your foot off the throttle, the engine is receiving no fuel. When in neutral it is using fuel. This assumes the engine is running faster than about 1,000 rpms when in gear.

 

[vdubJettaTDI_2010]

Worry about break-in for the first 10,000 or so miles so that you get good mileage after that. It can take 30,000-40,000 miles to reach peak cylinder compression numbers.
The members here tend to keep their cars longer than most owners.....

Bill

That the number I have read the most about 10k. My mpg's are very good now, just need to be mellow out and enjoy the ride. average is 44.

 

[FlyBones]

Winter mileage is typically worse than summer for most cars, I presume no less so for the JSW ( I just brought home a red one with DSG and the 17" Porto wheels). We have picked up several mpg in winter by grill blocking in our Prius, using pieces of split foam pipe insulation between the grill bars, idea courtesy of one of the Prius owners groups. I did a search for "grill blocking" and variations on this site with no results. Anyone try this yet? I took them out for the first summer, but last year left them in all year with no ill effects; we have a ScanGuage so I can see the actual coolant temp--the Prius only has idiot lights for coolant temp.

 

[roadhard1960]

I tried grill blocking for a few days and I could not see any faster engine warm up. But I might not have been observant. This was during one of our cold snaps. I guess I would have to try again making use of a stop watch, measure outside temp and be as scientific measuring variables as possible.

 

[JettaJake]

You are confusing marketing hype with science. According to what you just wrote we can just put air in our tires and after a time all the oxygen will leak out leaving only the nitrogen. (air is 85% N already)

This has all been hashed out many times in the past on this forum...

It pains me to read stuff such as this here and while it is practically senseless to reply with the hope of containing all the butchery of fact that goes on, let me remind you that the air you breathe has closer to 79% nitrogen but what's 6% among friends?

 

[Digital Corpus]

... but what's 6% among friends? ...

Depending on inhalant it could be panting, passing out, or hysterical laughter!

 

[40X40]

It pains me to read stuff such as this here and while it is practically senseless to reply with the hope of containing all the butchery of fact that goes on, let me remind you that the air you breathe has closer to 79% nitrogen but what's 6% among friends?

You are absolutely correct. 78 or 79% is what I find when I bother to look it up.

Bill

 

[Peppie37]

2005 VW Beetle TDI getting only 40MPG changed oil use Mobil 1 Synthetic, new fuel filter and installed new K&N air filter. What else can I do

 

[Bob_Fout]

2005 VW Beetle TDI getting only 40MPG changed oil use Mobil 1 Synthetic, new fuel filter and installed new K&N air filter. What else can I do

1. Trash the K&N. It's doing nothing.

2. Which Mobil 1 oil did you use?

3. What kind of a commute do you have? 40 MPG in the city or short trips is normal in the winter.

 

[Baumeister]

2005 VW Beetle TDI getting only 40MPG changed oil use Mobil 1 Synthetic, new fuel filter and installed new K&N air filter. What else can I do

How many miles on it? manual or auto? What tire size? New Beetles came stock with larger(heavier) wheels/tires than Golf/Jetta at the base level.

Get rid of the K&N and use an OEM filter. If it's been in there any amount of time or you have a lot of miles consider changing out the Mass Airflow Sensor. and maybe a few other sensors.

Make sure to read at least the first dozen pages of this thread..

Our 2003 5 speed gets about 42 around town..

 

[Hank101]

Drive as is you are almost out of fuel, and stop as if you don't have any brakes.

 

[London Luke]

could "stopping the engine at traffic lights etc" INVALIDATE your insurance ?

 

[bluestifford]

HI
I live in England and I have a Golf 150 pd 2002. If I drive from a cold start on my 22 mile journey to work, half of it at 60 mph and the other half stop-start I can get 51 mpg. Some people I know with the same engine can get 55+ on long journeys doing 70 mph the whole way.

 

[NarfBLAST]

HI
I live in England and I have a Golf 150 pd 2002. If I drive from a cold start on my 22 mile journey to work, half of it at 60 mph and the other half stop-start I can get 51 mpg. Some people I know with the same engine can get 55+ on long journeys doing 70 mph the whole way.

Those are UK mpg correct? UK gallons are 20% bigger than US gallons, therefore:

UK 51 mpg = US 42.5 mpg
UK 55 mpg = US 45.8 mpg

http://www.tdiclub.com/misc/conversions.html

 

[bradleyo]

Idled 2000 jetta tdi for 14 hours in minus 20's with rad covered and used less than 1/8 of a tank. 2500' elevation. There is'nt a generator out there that can match this.