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You think your TDI fuel Economy is bad?

19828 Views 13 Replies 7 Participants Last post by  MAXRPM, 
A
Even on your worst TDI fuel economy day, you've made the right choice! Here is a sampling of what I'm leaving for my TDI... (This is a copy/paste that I wrote from one of my Audi forums)

Just for ****s and grins I did some quick math after I filled up the tank in the S-pig yesterday. The trip odometer read 355.4 miles and I filled up with 18.307 gallons @ $3.05 per gal. I am not happy! Thats 19.413339 MILES PER GALLON! 19!?! Jeez! And I was driving very easy this week. I wasn't getting into the boost ever (much), I was driving nice with traffic and I just had to do this, I just had to run the numbers.... I bet my wife's 2.8 liter A6 gets better mileage. My total was $56.00 this tank and @ 355.4 miles yesterday against a 650 mile weekly average (just to and from work) thats at least $112.00 per week of fuel that I have been doing for almost two years. (give or take fuel costs/per gal) At $112 per week for 52 weeks is...drum roll please.....$5824 per year in fuel cost with this S-car. And these totals are typical for this car since I started driving it every day coming up on two years. [slaps forehead!] Just yesterday I was saying to myself.."self, your going to miss this car" and I'm still sick to my stomach thinking about it all the money I've wasted at the gas stations. For all of you guys out there that can offered to drive a "modified, high horse power" car out there as a Daily Driver, in any flavor, good for you. I make half way decent salary, but I'm done with this game. I can't believe it has taken me so long to jump onto the fuel economy wagon. 19 MPG isn't even half of what the TDI gets, so my annual fuel saving will be even higher than originally estimated. I guess this is the price you pay when you want to a drive 400 HP Quattro as a daily driver.....I'm an idiot! It's just not worth it!

There are guys out there getting 700 miles per tank with their TDI's. That's a once a week fill-up for me. Diesel at $3.21 per gallon was the lowest I found while driving my normal route to work. The Golf has around a 16/17 gal tank, so if I even took it to fill up with 16 gallons, that would yield 800 miles at a 50 MPG rate. Now thats not real world driving, so factor in the slower traffic, stop and go and idling and that 700 MPG figure starts to look very good! So at $3.21 per gallon for 16 gallons (and I'm sure that's stretching it between fill-ups) is $51.36. That a fuel saving at the gas station of about $5.00 right from the start. Not having to buy fuel until the next week, I've saved another $56.00 that week buy not driving the S-pig, so my yearly annual fuel cost (assuming I drive every week for a year) would be $2670.72....you get the idea... With my original yearly estimate of $5824 per yr of fuel, I've saved $3153.28 by switching to a TDI. I've just re-cooped the funds I paid for my paint job for the UrQuattro with that money savings. That's a good way to look at it!

So even if diesel is more expensive than 93 octane..I still saved money. LOL!
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chittychittybangbang
Diesel is normally more expensive in the winter too. Probably due to higher demand for home heating oil, etc.

You've seen the list of common issues here: http://www.myturbodiesel.com/1000q_how_to/a4/newowner.htm
that the TDI can have, some preventative checks are a good idea. I also saw that you wrote the timing belt had been changed by the dealer, some dealers do screw up the timing belt job and very few change the motor mount bolts - they are stretch bolts and if they fail the engine falls down. It's happened a few times to people. If it's lasted this long it should be fine but something to be aware of.

Do you know how to vent yet? This can add a few gallons to your fuel capacity. I can get 1000 miles/tank on the wagon because it holds 26 gallons when vented all the way. Unvented, the fuel handle clicks off at 20 gallons. You have to press on a button with the fuel nozzle to release the trapped gas.

Gewilli on tdiclub made a good writeup with pics on removing the vent on your car, it's hosted here: http://www.inmud.co.uk/page26.htm it should let you hold a few extra gallons of fuel. In theory it should decrease fuel economy slightly when you're topped off because you're holding additional weight, maybe 30 lbs, but obviously this is not statistically signifigant or noticeable at all.
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3
Extend Your Fuel Dollar

I have a 2005 Passat TDI with 16.5 gallon tank. So far this winter I've been getting 600 miles (40 MPG /15 gal) highway at 70MPH and 500 miles basic stop and go, in the city. I attribute the good mileage to a fuel enhancer called BPI (BioPerformince). If you want to know about it you can go to the website: www.getbettermileage2008.com

This stuff works for me.
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T
26 gallons seems optimistic, my passat doesn't seem to get too far past the full mark at 18 gallons. I think the tank is full at about 21 gallons.
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6
I first learned about diesel from a news article talking about someone powering their car on used vegetable oil. I searched and got the car but I found out that this is not the best way to run a TDI. Regardless of wether or not you think it's death for the car, I don't think it's the best way to fuel the car and may shorten it's lifespan. I don't know for sure but it's not worth the risk to me.

Plus, I'm getting at least 500 each tank even with the AC on. Veggie oil reduces fuel mileage and can increase NOX.
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chittychittybangbang
Tomspassat said:
26 gallons seems optimistic, my passat doesn't seem to get too far past the full mark at 18 gallons. I think the tank is full at about 21 gallons.
Click to expand...
It's because mine is a passat variant (station wagon). There's a few more gallons of fuel that you can fit in than the sedan, so any weight/aero disadvantage that the wagon has is offset by the extra fuel capacity,probably about 6-7 gallons.
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T
Ah, got it. I doubt it's possible to put a station wagon tank into the sedan either!
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M
If you really want to even make more mpg to the TDI, there are several other things you could, like applying 38-40 PSI pressure to the tires, getting a bigger nozzle, adding a lift pump, chipping it, drive it in the hwy more than the city, and you must also baby the car (drive it like a granny) especially when you go on a roll from a stop light, need to shift at lower RPM, you could easly hit from 900-1000 Miles to the tank and I am talking about a Golf, Jetta, or NB TDI vented.

If you do not belive me, I did it, and I averaged 57 MPG, when I finally filled it up my speedo read 905 miles, prior to that my car was only getting around 44-46 mpg, this is the only time I did it, I did most of what I listed above, and I got a whopping 57 MPG, I could have gone probably 1000 miles, but I went up 2 different big grades, the Grape vine, and pacheco pass,

You must remember that if you baby the car, then at least once or twice a week you have to drive it like you stole it, so you can clean the soot in the turbo, that is what I usually do.

Anybody could even go further, one of the problems is that whoever is on the wheel, needs to have patience to drive it from 55- 65 mph, I run out of patience now, so of course, I am back to 44-46 mpg, good luck with your new addition to the TDI, and I can predict to you now, you that you will never go back to a gasser.
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B
Wow! 57 mpg! The best I ever got was 51 mpg. I average about 46 mpg. Maybe if I was on a long trip that was all highway, I think I could try that but you're right, it takes patience to drive slow.
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G
MAXRPM said:
If you really want to even make more mpg to the TDI, there are several other things you could, like applying 38-40 PSI pressure to the tires, getting a bigger nozzle, adding a lift pump, chipping it, drive it in the hwy more than the city, and you must also baby the car (drive it like a granny) especially when you go on a roll from a stop light, need to shift at lower RPM, you could easly hit from 900-1000 Miles to the tank and I am talking about a Golf, Jetta, or NB TDI vented.

If you do not belive me, I did it, and I averaged 57 MPG, when I finally filled it up my speedo read 905 miles, prior to that my car was only getting around 44-46 mpg, this is the only time I did it, I did most of what I listed above, and I got a whopping 57 MPG, I could have gone probably 1000 miles, but I went up 2 different big grades, the Grape vine, and pacheco pass,

You must remember that if you baby the car, then at least once or twice a week you have to drive it like you stole it, so you can clean the soot in the turbo, that is what I usually do.

Anybody could even go further, one of the problems is that whoever is on the wheel, needs to have patience to drive it from 55- 65 mph, I run out of patience now, so of course, I am back to 44-46 mpg, good luck with your new addition to the TDI, and I can predict to you now, you that you will never go back to a gasser.
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I agree with everything except the chip. A chip turns up the boost and can extend the injection. Both of these can use more fuel. As long as you drive with a light foot the difference is small between a chipped and unchipped car but it adds up. The biggest difference is that you have to be more patient. The unchipped car will be slower to accelerate and you can't push the go pedal more to compensate. Either way, hypermiling does require a change in driving style.
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diesel guy 123 said:
I agree with everything except the chip. A chip turns up the boost and can extend the injection. Both of these can use more fuel. As long as you drive with a light foot the difference is small between a chipped and unchipped car but it adds up. The biggest difference is that you have to be more patient. The unchipped car will be slower to accelerate and you can't push the go pedal more to compensate. Either way, hypermiling does require a change in driving style.
Click to expand...


How did I come about doing the experiment in mpg in my TDI. It was because I had been reading in other forums that some tdi owners were averaging between 55-65 mpg with their cars, they were even saying with chip and nozzles. I just flat out said to myself they got to be kidding, I wrote down some of the things that they were doing to average this mpg, and put it to a test, so I had to trip to L.A from SF. filled up in Gilroy, Ca, drove to L.A, stayed behind the big rigs on Hwy5, drove back to the Bay area the following day, I went to my sister house in Pittsburg ,CA, then I drove to San Jose,CA that is when I filled the tank up, and saw 905 miles on the marker, and it came out to 56.98 mpg.

I was astonished to see that mpg, but let me tell you, you must have a lot of patience to do it, now a days driving a car at 60-62mph, is not fun anymore, specially when is modded,,so that is why it would be hard for me to do it again, anyone can do it, and I bet you that if I had driven most of the time on the HWY, I would have averaged over 1000 miles on the speedo.


Believe it or not, chipping it, and having nozzles have increased the mpg overall in my TDI, you have to remember by having both upgrades in a TDi it really becomes a beast and just with a subtle change by pushing the pedal down your fuel consuption would be down imensly, so when I was going for experiment mpg, I was really really gentle stepping on the pedal and shifting at really really low rpm,,

I have seen 2-3 mpg gains with chip and nozzles since installing them, I advanced the timing too, and I am happy where they are right now, I hope someone else goes for an experiment in their TDI because I am not about to do it anymore, 44-46 mpg is good enough for me.
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diesel guy 123 said:
I agree with everything except the chip. A chip turns up the boost and can extend the injection. Both of these can use more fuel. As long as you drive with a light foot the difference is small between a chipped and unchipped car but it adds up. The biggest difference is that you have to be more patient. The unchipped car will be slower to accelerate and you can't push the go pedal more to compensate. Either way, hypermiling does require a change in driving style.
Click to expand...


How did I come about doing the experiment in mpg in my TDI. It was because I had been reading in other forums that some tdi owners were averaging between 55-65 mpg with their cars, they were even saying with chip and nozzles. I just flat out said to myself they got to be kidding, I wrote down some of the things that they were doing to average this mpg, and put it to a test, so I had to trip to L.A from SF. filled up in Gilroy, Ca, drove to L.A, stayed behind the big rigs on Hwy5, drove back to the Bay area the following day, I went to my sister house in Pittsburg ,CA, then I drove to San Jose,CA that is when I filled the tank up, and saw 905 miles on the marker, and it came out to 56.98 mpg.

I was astonished to see that mpg, but let me tell you, you must have a lot of patience to do it, now a days driving a car at 60-62mph, is not fun anymore, specially when is modded,,so that is why it would be hard for me to do it again, anyone can do it, and I bet you that if I had driven most of the time on the HWY, I would have averaged over 1000 miles on the speedo.


Believe it or not, chipping it, and having nozzles have increased the mpg overall in my TDI, you have to remember by having both upgrades in a TDi it really becomes a beast and just with a subtle change by pushing the pedal down your fuel consuption would be down imensly, so when I was going for experiment mpg, I was really really gentle stepping on the pedal and shifting at really really low rpm,,

I have seen 2-3 mpg gains with chip and nozzles since installing them, I advanced the timing too, and I am happy where they are right now, I hope someone else goes for an experiment in their TDI because I am not about to do it anymore, 44-46 mpg is good enough for me.
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chittychittybangbang
Well, your user name is MAXRPM, so you're probably learning towards performance. I believe that nozzles can increase your mpg but I don't think chipping will change your fuel economy unless you also change your driving style. The reason why is because a chip raises the boost and fuel.

I can also see how a chip might increase your fuel economy to better match your driving style for max economy but I slowing down and driving like a granny is the main component in gains there.

I don't drive slow either :) Maybe if I'm on a long highway trip I'll top off, drive, then top off again just for fun. Around town I'm going zoom zoom.
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chittychittybangbang said:
Well, your user name is MAXRPM, so you're probably learning towards performance. I believe that nozzles can increase your mpg but I don't think chipping will change your fuel economy unless you also change your driving style. The reason why is because a chip raises the boost and fuel.

I can also see how a chip might increase your fuel economy to better match your driving style for max economy but I slowing down and driving like a granny is the main component in gains there.

I don't drive slow either :) Maybe if I'm on a long highway trip I'll top off, drive, then top off again just for fun. Around town I'm going zoom zoom.
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Chittychitty, but by installing a new performance nozzles in these TDI, you would defenitly have a better atomization in the cylinder than the old OEM nozzles, then you would save on fuel, am I wrong on this?

and I totally agree with you that if you really want fuel economy,,your right foot has to be tamed and you need to drive it like a granny,, all being said here, even in a worst case scenerio, when your TDI did a poor job in MPG ,you should be able to beat most of the gasser ($) at the pump.
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