Worse fuel economy after timing belt change.

[buyingconstant7]

I changed the belt and all components on my mk5 BRM tdi. I’m noticing about 1-3 mpg worse than before and the weather has even gotten warmer since then. So it’s probably even worse. My torsion value prior to the belt change was -1.5. After the belt change is at +0.49. I thought this timing variation would improve economy since I thought the best was between -.5 and +.5. What should I adjust this to?

 

[Windex]

Torsion seems to be individual to each engine as far as "sweet spot". I would change it back to -1.5 and re-evaluate your MPG

 

[buyingconstant7]

Torsion seems to be individual to each engine as far as "sweet spot". I would change it back to -1.5 and re-evaluate your MPG

Should’ve figured as much. I drive lots but it takes a good week to go through a tank so I will report back with some results.

 

[Vince Waldon]

A bit of reading for ya:

PD Engines - The Problem of Setting Torsion Value

Since first working on the PD motors, we found the setting of the torsion value a bit of a mystery. The torsion value is located in VCDS/Engine Module/ block 4/ torsion value. We tended to figure that 0.0 was a good figure and originally let it go at that. However, early on, we had a Passat...

forums.tdiclub.com

 

[buyingconstant7]

Thankyou everyone for your insight, I filled up a few days after this post and then went through one more tank to be sure, and it appears that I had an unrelated issue for my fuel economy. My culprit was the ziptie is use for the wastegate actuator, which seems to plague these BRM engines, it was broken when I replaced my timing belt, and I forgot to replace it. The boost was surging and peaking during random drive events that required no boost, so I know for a fact that it was taking a hit on my mileage. I replaced it a few days after this post and have consistently gotten BETTER fuel economy before the belt change and when the ziptie wasn't broken. So that solves it! Consistent average is now about 55mpg, used to be about 51-52 in the summer, and the temps right now still haven't warmed up to what they would be in summer time and still have cold spells, so it may get even better. We will find out!

 

[Metal Man]

That mileage is with those bigger Canadian gallons, correct?

 

[buyingconstant7]

That mileage is with those bigger Canadian gallons, correct?

No that’s US gallons. Canadian/UK gallons, I’m getting over 60mpg. Best so far was 68mpg on a road trip last year. I’m a few mpg away from that number on my mainly highway work commute in wet spring time so I’m hoping for 70 on my road trips this summer.