Have older KermaTDI tune, should I go back to factory tune?

The other day I met a guy with a 2005 Passat TDI who swears his car gets in the upper 40s MPG regularly. I get about 36-37 MPG average, maybe 42 on the highway, at 60, air on. Anyway, he got me to thinking that I might actually get better MPG using the VW factory program. When the KermaTDI tune was done 7 years ago I asked for best MPG program.

Should I consider getting my car retuned to the factory tune? If so, must I go to a dealer to get it done, and how much should it cost?

Thanks much,

Grampa Pete

I don't think the little mpg tune is sucking all the fuel away , might be your shifting way late in the RPM band ?

also your cars poor mpg number makes me think its a automatic.

GrampaPete said:

The other day I met a guy with a 2005 Passat TDI who swears his car gets in the upper 40s MPG regularly. ...

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You, sir, met what we call a "liar". He should go into politics.

I can get upper 40's on the highway but it'd have to be running under 50 MPH, on a flat road, A/C turned off, probably hypermiling.

I routinely get 45 mpg calculated with my B5.5 tdi wagon A/C on on the highway - *disclaimer - I have a DUK 5 speed manual trans and Malone stage 2 tune*

My B5.5 sedan with the DUK 5 speed manual gets a little better, 46-47 depending on what state I am in (speed limit on highway, KS is 75 in interstates, while Illinois and Missouri is 70 max.)

I have seen low 40's on all highway driving with my B5.5 that still has the ZF auto, but usually 38 is about the max in summer and 36 in the winter.

Best that I have ever seen in our wagon was just a shade under 42 MPG. It was a long road trip all highway with the cruise set at 60. I was trying to break 40 MPG and it worked… once. I can generally get ~ 37-38 mixed but mostly highway, but I don't think that's bad given the size of the car. RC2+ tune and B20, BTW.

Under normal driving my 6 speed manual gets about 45 mpg. I can hypermile it up to 50, but who has time!

I use to be able to get 42mpg consistently on the highway at 65. Something changed after my last timing belt replacement and even playing with the torsion, I'm still 5-10% below that now. Or maybe I"m just driving faster

GT Beetle said:

also your cars poor mpg number makes me think its a automatic.

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Yes, that is the default for the 04/05 passats.

back in the day with my 05 I could get about 47 if I was no air, windows up and keeping it at 55 which would hardly happen. In fact I can only recall once on a long trip and it was raining etc so I had to keep my speed down due to my nervous passenger wife that I achieved this on a trip over say 300 miles. BTW, with my daughter now driving that car she averages about 33-35 but does mixed driving and probably a lead foot.

Most of the time my car does 38-42 if kept in a constant speed state. I will easily get 42 if the speed is kept around 60. However, it is not fun that way. Most of the time, on a long interstate trip it will get 40-41 max. In other words, the gent that tells you he is getting getting high 40s with his, probably is an expert at selling swamp land. If you want high 40s, probably converting to manual or getting a new proper manual shift common rail-engined passat will do that.

A manual with a BSM delete will get you pretty close to that if you watch your speed.

My 2013 Passat SEL TDI will get low 40s on the highway. My B5 tdi usually does 32-37 mpg with the same driving.

The B5 is much more fun to drive.

Also, the stock tune has a noticeable hesitation when accelerating from a stop.

Either you transit the highways in your B5 at speeds greater than 80 or so or something is not quite right with it. At normal highway speeds, even with an automatic, you should be getting 38-42. With the manual, it is even better than that.

tdireader said:

My 2013 Passat SEL TDI will get low 40s on the highway. My B5 tdi usually does 32-37 mpg with the same driving.

The B5 is much more fun to drive.

Also, the stock tune has a noticeable hesitation when accelerating from a stop.

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Only hand calculated mpg's should count, which requires filling, driving, stopping and refilling, IMO.