Newbies and Vets: Tips for better fuel economy!

MikeMars · Aug 9, 2013

come on guys, get an Ultra-gage(i have) or a scan-gage(don't have), and get an accurate mile per gallon as u drive ...

The gauges are not necessarily accurate when used in this way. You can only calibrate them at a tank level. For example, my scangauge underestimates the effect of RPM and coolant temperature.

roadhard1960 · Aug 10, 2013

I have not been keeping up with what tires give the best fuel mileage. There can be huge differences. A friend had a Prius and he lost something significant like 5 mpg. He got it back when he swapped those tires after a few tanks. I use some Michelin Primacy MXV4s. Michelins have worn well and delivered good fuel mileage for me.

For me I tend to drive 65 indicated which is really about 63. Usually far right lane is safe at that speed. I do open windows if it is not too hot or humid. Car is up in the air right now as I discover bad cvjoints. Driving my Cummins only getting 20-22 mpg is killing me. My TDI which is of the better fuel mileage years tends to get 47-50 mpg.

deejaaa · Aug 10, 2013

MikeMars said:
The gauges are not necessarily accurate when used in this way. You can only calibrate them at a tank level. For example, my scangauge underestimates the effect of RPM and coolant temperature.

using the instant mpg while driving informs the driver what is affecting the overall mpg. ie: cruising 70 behind a semi, road conditions (concrete, asphalt), head/tail winds, diff speeds. it doesn't have to be accurate (because mileage should be figured with pen and paper) but allows better use of fuel when you pay attention to it and adjust to the conditions. that's how i got 58.8 on my last fill up.

gary9696 · Sep 7, 2013

rotarykid said:
The grill opening is closed for several reasons, a closed grill vent gives Longer filter life, gives some Engine noise reduction and lowers Emissions output ( less cold fresh air gives lower NOx ).

This engine was detuned for the US market to pass emissions so really doesn't require the vent be opened to give stated output rated power.

First, a closed vent helps in keeping the air filter clean longer increasing the rated filter life time and mileage rating range. Diesel engines suck in large volumes of air compared to their gasoline counterparts, many times that of their gasoline counterparts. So it can clog up quickly in adverse conditions. A closed front air ram vent can keep this from happening sooner in the filter life. Americans are notorious for ignoring maintenance so a long filter life was a must for the US market.

Second, a closed vent lowers overall engine noise from in front of the car, cars have a maximum allowed noise limit. VWofA has been using this trick here in the US/Canada for decades on diesel powered models to lower engine noise. VWofA figured diesels were a hard sell outside of the VW diesel die-hard market. So to increase sales numbers here to include other than the diehard diesel market the vent was closed. For VWofA to consider bringing a diesel powered model to the US market it must have wider sales appeal which the closing of this vent gave.

Third and likely the main reason the duct was closed was that fresh cold air increases from a open air duct is denser. Denser air gives more power from more complete combustion which leads to higher N0x levels. This car was really close to N0x limit and a open grill more than likely caused the car to fail emissions. Closing the vent lowered power( the engine was already detuned for the US market to pass emisions ) and it lowered N0x emissions to help pass our stupid emissions rules.

You will see better throttle response at speed with the duct open and you will see higher mpgs. But N0x emissions will be significantly higher and air filter life will be shorter if you are exposed to dirty or wet conditions.

I made this modification to a friends 04 Passat TDI a while back and he clocked a 3-5 mpg increase also, biggest increase in mpgs was on the highway at higher speeds. The car is however now louder if you are standing right in front of the opening while running.

A precaution that must be taken into consideration is that you must keep closer tabs on the air filter cleanliness. A look-see air filter and air box inspection ever so often will be a must once this mod is made. Once this change is made if you drive through dusty conditions or in very wet conditions you must inspect the filter for damage or clogging issues regularly.

Are there any other VW TDI vehicles with this ram air vent closed?

Baumeister · Sep 7, 2013

gary9696 said:
Are there any other VW TDI vehicles with this ram air vent closed?

my 2004 Passat 1.8t gasser has it closed...haven't compared it to the TDI version to see if it's any different.

thomamon · Sep 8, 2013

So i have a 2013 Jetta TDI, automatic.

I got my best mpg this last fill up at 45.8 but I do use cruise control as I have a 40 Mile straight run on highway from home to my job. I set it to 65 and usually never have to hit the break.

I am doing some reading in this thread and I am a bit confused. The trip is quite hilly as I head down 78 from NJ to PA. Some hills are steep and I notice that the average MPG for the trip go down quite a bit as I go up and as I head downhill the MPG for the trip go back up. By the time I get to work the trip estimator for MPG is usually 49-50. (the estimator is always wrong tho as when I fill up the tank its usually just over 3 miles off from the actual mpg for the fill up).

I have done the trip several times without using CC and I can still get the mpg to estimate at 49. But I notice when I go up the hill it shows the current estimated mpg goes down way more then when I use CC. My speed also seems to slow down going up the hill and the mpg stays low as I try to get back to 65.

Any pointers on how I can improve or is CC the best option for me?

Jagerbecher · Sep 9, 2013

thomamon said:
I have done the trip several times without using CC and I can still get the mpg to estimate at 49. But I notice when I go up the hill it shows the current estimated mpg goes down way more then when I use CC. My speed also seems to slow down going up the hill and the mpg stays low as I try to get back to 65.

Any pointers on how I can improve or is CC the best option for me?

Sounds like when yo do not use CC you do not work with your accelerator pedal good enough to keep the speed at 65 when the road starts going up and your car loose momentum. Then you try to get back to 65 already going up hill and that requires more fuel then if the CC just maintains the speed at 65. If it's a long incline i would say CC it's better to use CC. Also, you can have the CC set at 65 all the time and just accelerate with the pedal on downhill or level sections to gain more momentum "for cheap" before next hill.

thomamon · Sep 9, 2013

Jagerbecher said:
Sounds like when yo do not use CC you do not work with your accelerator pedal good enough to keep the speed at 65 when the road starts going up and your car loose momentum. Then you try to get back to 65 already going up hill and that requires more fuel then if the CC just maintains the speed at 65. If it's a long incline i would say CC it's better to use CC. Also, you can have the CC set at 65 all the time and just accelerate with the pedal on downhill or level sections to gain more momentum "for cheap" before next hill.

So as I am about to approach downhill, even when using CC I should increase my speed? How much?

I would say its safe to assume going up hill I am not the best, yet...

gary9696 · Sep 9, 2013

thomamon said:
So i have a 2013 Jetta TDI, automatic.

I got my best mpg this last fill up at 45.8 but I do use cruise control as I have a 40 Mile straight run on highway from home to my job. I set it to 65 and usually never have to hit the break.

I am doing some reading in this thread and I am a bit confused. The trip is quite hilly as I head down 78 from NJ to PA. Some hills are steep and I notice that the average MPG for the trip go down quite a bit as I go up and as I head downhill the MPG for the trip go back up. By the time I get to work the trip estimator for MPG is usually 49-50. (the estimator is always wrong tho as when I fill up the tank its usually just over 3 miles off from the actual mpg for the fill up).

I have done the trip several times without using CC and I can still get the mpg to estimate at 49. But I notice when I go up the hill it shows the current estimated mpg goes down way more then when I use CC. My speed also seems to slow down going up the hill and the mpg stays low as I try to get back to 65.

Any pointers on how I can improve or is CC the best option for me?

If you have the DSG have you tried pushing the gearshift to the right from D to keep it in 6th gear. I have noticed on the highway that when going uphill with it in 6th gear not in D that it doesn't increase speed, and lets the car drop speed a little, then on the way down the hill the mpg increases with it in that 6th gear. Of course though this depends on how steep your hill is on the downside as to how much the mpg will increase.

thomamon · Sep 9, 2013

gary9696 said:
If you have the DSG have you tried pushing the gearshift to the right from D to keep it in 6th gear. I have noticed on the highway that when going uphill with it in 6th gear not in D that it doesn't increase speed, and lets the car drop speed a little, then on the way down the hill the mpg increases with it in that 6th gear. Of course though this depends on how steep your hill is on the downside as to how much the mpg will increase.

I have not tried that...

When I go up the hill it seems to decrease speed, not increase. Is that what you meant? If not what exactly should I try?

gary9696 · Sep 9, 2013

WestyConvert said:
I'm getting REALLY poor fuel econonmy on my 2006, Jetta Wagon TDI (8 L/100 km or about 29 US MPG - all city driving). Just wanted to see if anyone out there had any suggestions as to why this might be and how I can get improve my economy.

Help!

What is the curb weight of your vehicle considering you added a cast iron diesel engine to a VW Vanagon? What was the mpg with the gasoline engine before you or someone did the TDI conversion?

gary9696 · Sep 9, 2013

Is my mpg good, or at least above average for my 2013 JSW DSG TDI 38 city, 45 - 54 (depending on hills) highway? My factory air intake near the front of the hood has a fresh air opening in the front, and engine compartment air opening on the back. Has anyone tried blocking the rear intake to find out if getting more fresh air, and closer to a ram effect helps increase the mpg?

Jagerbecher · Sep 9, 2013

thomamon said:
So as I am about to approach downhill, even when using CC I should increase my speed? How much?

I would say its safe to assume going up hill I am not the best, yet...

I meant increase the speed on flat sections or downhill sections before the next hill regardless of whether you are using CC or not, but for long grades I think it makes more sense to use CC since it keeps the car in constat speed and it does not loose momentum.

Look at the post #147 and #148 in this thread http://forums.tdiclub.com/showthread.php?t=335035&page=10
http://forums.tdiclub.com/showpost.php?p=4272041&postcount=147

skipdrag · Sep 10, 2013

Lots of great info on this site. I am a Newbie to this Site I just picked up my 1st TDi a month ago. (2002 beetle 90,000 really good shape) I have been reading through post for tha last couple week. My goal right now is to get to 50 MPG. my 1st 2 tanks - 44 and 46.5. I just ordered a Ultra-Gauge. I drive almost 45 miles a day. thanks for all of the helpful information.

gary9696 · Sep 13, 2013

WestyConvert said:
I'm getting REALLY poor fuel econonmy on my 2006, Jetta Wagon TDI (8 L/100 km or about 29 US MPG - all city driving). Just wanted to see if anyone out there had any suggestions as to why this might be and how I can get improve my economy.

Help!

Sorry somehow I thought you were talking about your mpg on the converted Vanagon.

gary9696 · Sep 13, 2013

thomamon said:
I have not tried that...

When I go up the hill it seems to decrease speed, not increase. Is that what you meant? If not what exactly should I try?

Try this next time. When you engage the cruise control push, or slap the gear shift from the "D" to the right. It will be in 6th gear. Try to leave it there. If you have to slow down step on the brake lightly because someone caused you to slow down, or something happens. You can also downshift to slow down, then upshift as soon as you can to 6th gear again. Just doing this alone, and watching the traffic to see if you will need to slow down ahead, or possibly pass so you can do it without having to do it suddenly. With it in 6th gear it will slow down some on the hills, then going down the hill it will not be using any fuel until it gets to the bottom.

gary9696 · Sep 13, 2013

I have a 2013 Jetta TDI SportWagen. Has anyone tried to block the back (engine side) of the air intake to try to increase ram air effect to increase fuel economy/performance? Would this help fuel economy?

steve05ram360 · Sep 13, 2013

havent tried it but would expect it would not help. for the best fuel economy, warm air & warm fuel. As temps drop and the average temps are below 70's block the lower grille and monitor IATs & engine temps. get the iats up into the upper 70's with the motor warmed up & you'll see via the MFD you're mpg will go up.

thomamon · Sep 15, 2013

gary9696 said:
Try this next time. When you engage the cruise control push, or slap the gear shift from the "D" to the right. It will be in 6th gear. Try to leave it there. If you have to slow down step on the brake lightly because someone caused you to slow down, or something happens. You can also downshift to slow down, then upshift as soon as you can to 6th gear again. Just doing this alone, and watching the traffic to see if you will need to slow down ahead, or possibly pass so you can do it without having to do it suddenly. With it in 6th gear it will slow down some on the hills, then going down the hill it will not be using any fuel until it gets to the bottom.

So leave the CC on and put it in 6th gear? I can do that. Sounds neet that going down hill it won't use any gas. I look forward to trying this on Tuesday when I head to work next.

The other day my trip home I wound up doing 55 MPG for the trip, which is about 5 MPG better. What I did different that time was put the car in N when going down hill. I had not been able to repeat that since the other day, but I think maybe I was putting it into N on hills that were not steep enough and was slowing down when I tried to do it myself!

titleist1 · Sep 16, 2013

thomamon said:
The other day my trip home I wound up doing 55 MPG for the trip, which is about 5 MPG better. What I did different that time was put the car in N when going down hill. I had not been able to repeat that since the other day, but I think maybe I was putting it into N on hills that were not steep enough and was slowing down when I tried to do it myself!

I thought in the OM is says to not put in N while going downhill on DSG's. Keeps transmission fluid from cooling properly i believe and says it could cause damage. Maybe its different for Jetta than Passat?

thomamon · Sep 16, 2013

titleist1 said:
I thought in the OM is says to not put in N while going downhill on DSG's. Keeps transmission fluid from cooling properly i believe and says it could cause damage. Maybe its different for Jetta than Passat?

Maybe I should not do that anymore? I thought I read on here that people do that?

titleist1 · Sep 16, 2013

I don't know for sure as i am new to my passat tdi and only going by the owners manual, but it does say on page 209 not to coast in N.

I was wrong about the cooling though because it says the transmission will not be lubricated and could be damaged.

The more experienced can let us know for sure. I did search here and it seemed posts that mention using N downhills seem to be manuals.

thomamon · Sep 16, 2013

titleist1 said:
I don't know for sure as i am new to my passat tdi and only going by the owners manual, but it does say on page 209 not to coast in N.

I was wrong about the cooling though because it says the transmission will not be lubricated and could be damaged.

The more experienced can let us know for sure. I did search here and it seemed posts that mention using N downhills seem to be manuals.

Thanks! Hopefully someone else can chime in with more experience

rotarykid · Sep 16, 2013

titleist1 said:
I don't know for sure as i am new to my passat tdi and only going by the owners manual, but it does say on page 209 not to coast in N.

I was wrong about the cooling though because it says the transmission will not be lubricated and could be damaged.

The more experienced can let us know for sure. I did search here and it seemed posts that mention using N downhills seem to be manuals.

In europe the DSG is programmed to automatically go into & out of N in over run & at idle conditions. I have not seen one piece of data that shows any issues with using N in over run. The only issue there could possibly be with using N in over run is if you increase throttle too soon before the trans is fully engaged, something the ECU prevents in the pre-programmed to do this automatically cars. If you are careful to rev match but not throttle up above rev match leading to increased slip while engaging there should be no issue.

gary9696 · Sep 18, 2013

thomamon said:
Thanks! Hopefully someone else can chime in with more experience

In my Owner's Manual for my 2013 JSW DSG TDI on page 188 there is a NOTICE: Never let the vehicle coast or roll down a hill in Neutral (N), especially when the engine is not running. The transmission will not be lubricated and will be damaged.

I do, and will continue to shift to N at times in city traffic to coast to a traffic light, or where the traffic has stopped ahead of me. I will also continue to coast down a hill on the highway if I think it is steep enough to either maintain my speed, or let it get slightly faster, but if I think there is a possibility that it will exceed the speed limit enough to receive a speeding ticket I will shift to the Tiptronic mode by shifting to D, then moving the gear shift to the right which will have it in 6th gear, and re-engaging the cruise control. If I don't think the hill is steep enough I just leave it in the Tiptronic 6th gear, and have the cruise control on.

Just some caution to the newer TDI owners I do not have long term experience with a TDI since I trade in every 3 years, or 32,000 miles.

Considering the Notice, and Caution above I do think that rotarykid has some very good advice on fuel economy with a VW TDI

Max Period · Sep 19, 2013

On the mk6 Canadian Jetta, there is one owner's manual for all Jettas including 2.slow, 2.5, and TDI(not Golf Wagon). The "Automatic transmission" section are shared between the 6-speed slushbox (for gassers) and the DSG (for TDI), and a few DSG-specific paragraphs will be indicated as such. The same "Manual transmission" section applies to both 5M (gassers) and 6M (TDI).

gary9696 · Sep 27, 2013

thomamon said:
So leave the CC on and put it in 6th gear? I can do that. Sounds neet that going down hill it won't use any gas. I look forward to trying this on Tuesday when I head to work next.

The other day my trip home I wound up doing 55 MPG for the trip, which is about 5 MPG better. What I did different that time was put the car in N when going down hill. I had not been able to repeat that since the other day, but I think maybe I was putting it into N on hills that were not steep enough and was slowing down when I tried to do it myself!

I would never recommend turning off the engine with the DSG in Neutral unless you are not moving the vehicle. When going down a hill using the cruise control you can shift to Neutral without turning off the Cruise Control since it will turn off the Cruise Control as soon as it is shifted to Neutral.

rotarykid · Sep 27, 2013

gary9696 said:
I would never recommend turning off the engine with the DSG in Neutral unless you are not moving the vehicle. When going down a hill using the cruise control you can shift to Neutral without turning off the Cruise Control since it will turn off the Cruise Control as soon as it is shifted to Neutral.

In the DSG with the dual wet clutch systems turning the engine off while coasting for any length of time could possibly lead to extra wear. There is naturally some lubrication & cooling for at least a little while after the engine is turned off. But I am not sure how much tolerance there is in the system for this so you could run into trouble quickly or it might be able to handle this for while. I just don't know.......

I would say there would be less heat generating friction so less wear if you can successfully rev match when re-engaging. Avoid doing this if it is really hot weather when the fluid is really hot. What you would not want to do is have a long coast with the engine turned off in high heat then a hard re-engage of the trans where there is a lot of strain to re-rev the engine.

Also I would say if you do this very much just to be safe you will likely need to change the fluid sooner than without. I would say if these techniques are used correctly at least a 5 mpg gain might be seen.

In other offerings I have seen numbers go from 28-29 to mid 30s, 34-37 mpg range. I always try to see how far I can push things this time of year. In the fall we still have good higher BTU diesel & gasoline( no winter fuel yet ). Also there is little if any ac use needed, still light out for a while so less headlights required and it is cooler outside so you can generate a little extra friction in the trans without getting into trouble as soon......

I had a 35 mpg tank in my 05 Accord last week with a lot of effort. Once we get the change in the fuel and the days start to get really short headlights are required more so I have less opportunity use these techniques so mpgs go down.

donlon152 · Oct 1, 2013

Explanation - Newbie

NOTE: Per VW memo's, it's not recommended to run an additive in a 2009+ vehicle. If something higher than 42 is listed then the retailer adds their own additive package in addition to the standard refinery additive package. Generally speaking as long as 49 or higher is listed you do not need to worry about adding any additives yourself.

BP (Amoco branded), 51;
Countrymark fuels Diesel-R, 50
Chevron, 49; or 51 with Techron D labels in select markets
ConocoPhillips through the 76 stations (California) 47-53
PetroCanada, 47-51
BP (Powerblend 47, otherwise 40-42)
Shell, 46;
Sinclair, 46;
Sunoco Gold, 45 (often +1-5) Sunoco regular is usually 40.
Exxon/Mobile, 43-46
Holiday Stations, 40-43
HESS, 40-42, can be up to 45.
Husky, 40 + diesel Max additives raise another 1-3 from there (41-45 max)
Love's: 40
Pilot: 40
Valero: 40
Sheetz: 40
Flying J, 40
Wawa, 40[/QUOTE]

_____________

I have a 2012 Jetta TDI - So what you are saying is to not run and additive and stick to the highlighted brands at the top of the list?

CrossWood · Oct 1, 2013

These cetane numbers seem to be the same that began surfacing on the web in 2009 I believe. I would really be surprised if they are still accurate. I haven't come across a recent list (this one has been referenced all over the place) and it is my understanding that actual cetane levels of particular brands of fuel vary constantly and it is a real tough task to actually get a reliable number from anyone involved. I have yet to see a number posted at any of the stations I've been to in Western, PA.

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