Mileage Increase

Will I see a mileage increase when switching over to biodiesel?

I may be shot down here but mine went down 5% when swapping to B100.

To compensate for this I fooled the fuel temp sensor into thinking it is cooler (thicker) www.pdtuning.co.uk this improved fuel economy by 15% so in the end I get 10% increase.

This is just my personal experience.

Diesel has about 10% more energy per gallon, so your answer is no, you will see a decrease, by about 9 or 10%. If you have a warranty, you will see a 100% decrease in that , as in gone, no more.

See the links in my signature.

Bio has less energy per weight than Dino. Some people claim that because of its higher cetane rating and other 'properties' of Bio, it acts as a catalyst to more completely burn the Dino, so the net effect is zero.

YMMV. 8)

I don't have VAG-COM to check this but does the timing retard slightly when the fuel temperature is lower?
My tuning chip has made a massive difference in fuel economy and it only tells the ECU that the fuel temperature is lower than orginal. The only thing I can think is that the timing has been retarded to get as much energy out of the bio.

I see a slight rise in fuel consumption when I use biodiesel blended in with Audi-juice, perhaps 3-4% higher consumption if using near B100 in the tank. I'm working to correlate my fuel data, but admit it's quirky, as my trips tend to be long while my wife's tend to be short. The car gets as much City driving as it does highway.

I have not adjusted timing with VAG-COM for the simple reason that I don't run a consistent blend of fuel, it varies according to where I am when I need to fill up. Still, any loss of economy due to biodiesel in the fuel is so slight I don't worry about it, the car routinely returns 40 MPG in City driving, so no complaints at all.

First off ignore Audi5000TDI. He is just a bitter, hatefilled, anti-BD ranter who is getting frustrated that he is no longer taken seriously by anyone and is set to be ignored by so many people.

The key here for mileage on the TDI is whether it is a VE or PD engine. The PD engine appeared in 2003 on some of the cars. The VE engine was the 90 Horsepower engine, the PD is either the 19.L 100 HP for the Jetta/Golf or the 2.0L 130 HP engine starting in the 2004 Passat.

With the VE engine you will see no change in MPG. With the PD, especially the Passat you will see a decrease of about 10%.

The reality is that the TDI is a heat engine. That means the amount of energy in (total BTU's) equals the amount of work out. The 2.0 PD engine extracts every bit of that energy to achieve the 130 HP from 2.0 liters using the energy content of Dino. This means that a slight drop (10%) in energy content in the BD will relate to a direct drop in MPG.

This is based on my actual experience and testing. I have had two Jettas with the VE engine running B100 and now the 2005 Passat with the PD engine running B100 and Dino diesel.

TomB said:

First off ignore Audi5000TDI. He is just a bitter, hatefilled, anti-BD ranter who is getting frustrated that he is no longer taken seriously by anyone and is set to be ignored by so many people.

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Actually he's usually correct, just not politically correct.


Many biodiesel lovers won't admit any fault with the fuel. There are pros and cons with all fuels, but point out a cons of biodiesel here and you get called names.


I find those loosing the arguement resort to name calling.

After 16k miles running B100, I have seen a 5% reduction in mpg.

According to AudiTroll, a warranty will be 100% gone if you use BioD. That is total bullsh*t. It flat out is UNTRUE. His posts are not correct and he does a huge disservice to this forum.

B5 is VWOA's standard. We hear that in every AudiTroll post. Who cares? Not me. Run quality BioD (B20, B100, whatever) and there will a very small chance of problems.

b4black said:

...Many biodiesel lovers won't admit any fault with the fuel. ...

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And many bio detractors instantly pounce on any Bio blend as the source of problems.

b4black,

He has yet to prove himself right on anything. Quality BD is available, so don't trash BD because some homebrew went bad and safeguards ignored and then use that as the poster child for your campaign.

As I said many times, once the verdict is in with an Injector Pump failure as a result of BD, I will be the first to admit it. Till then he has just hot air that he keeps blowing in every post. I will be the test case and I will have the analysis done to see what happens either after failure or 100K miles. Then we will have FACTS, not supposition.

Again, based on you BD detractors a radio problem warantee fix would be denied because of BD usage, huh?

Stop scaring people into believing what you believe. Give them facts and let them make decisions as the adults they are, not the child you treat them like.

I met Audi5k in person at a meet-up and he told me my injection pump will fail. Of course it will. It's a mechanical device. My cell phone will break someday and my house will fall over from dryrot eventually. My injection pump hasn't failed yet and when it does it will be fixed and then I'll pump some more B100 into the tank.

You will loose a slight bit of mileage and power. Especially notable in a highly modded car. No way around it. Period.

I run between B5 winter and B90 some of the time in the summer. All depends on availability and time to do it.

ReportedIncrease

Please note that the author admits to a driving style change as well. There are many factors that affect your fuel economy, and B100 BTU's vs. B0 BTU's is just one variable (and perhaps not the most important one).

My best tank ever was on B100, but it also happened to be the only roadtrip that consisted of mainly of state highways (65mph) and very little interstate (80+mph).

TomB said:

...With the VE engine you will see no change in MPG...

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I have not heard this before (in fact I've heard the contrary). Certainly not in my experience. With both my pre-PD's I see a noticable decrease in fuel economy when using B20 and up.

For the record, I'm not a bd "hater". I use it for the other benefits it provides.

What transmission.

TdiTom,

Auto or Manual transmission on the VE engines?

both are manual

I can only speak from what I have seen. I drive the same milage week in, week out getting the same milage +/- 2 mpg. I swapped to B100 and dropped by 5%. Added the fuel temp chip (resistor instead of sensor) and it has put it up by 10% from dinodiesel (measured over 2 weeks). My computer is about right but I do vent just to make sure.

The risistor mod does retard the timing for the bio, someone else can try it an either prove me right or wrong!