Shell V-Power test

[Rick Rae]

Originally Posted by n0rt0npr0

Old timing belts get hard, brittle or begin fraying and all that increases friction. Water pumps and tensioners have bearings, and as they age that bearing loses its ability to freely rotate.

So with you getting those replaced, your engine is definately spinning more freely due to less friction inside the belt system and inside the timing system!

The other benefit to getting the timing belt replaced is now your timing is more exact than with the old stretched belt. That will also give you some increased efficiency.

Makes sense. Thanks!

And yes you will see increased RPMs after all that work simply because the Tech's unplugged your battery to work on the car...

Ah crud, I completely forgot about that. Ironic; I was careful not to disconnect the battery when pulling/replacing my instrument cluster so as not to disturb the ECU, and as soon as I get the cluster re-installed I take it to the shop so they can do it. D'OH!

Seems odd, though: I'd have thought losing the mappings would cause FE to go down.

I'll bet your LOD was 3, and now its going to be 2.

I had to take a short drive this morning -- idle load was at 3. Also, idle RPMs were back in the mid- to upper-800s again.

Rick

[Rick Rae]

First Shell mid-grade segment complete; 33.92MPG over 308 miles. There are entirely too many variables to make any assumptions at this point, so I'll wait for trends to emerge.

Rick

P.S. The odometer ran lower than the GPSr by about 2%. This is a relatively small error, equaling only 1/2 MPG or so.

[n0rt0npr0]

Rick,

I had to take a short drive this morning -- idle load was at 3. Also, idle RPMs were back in the mid- to upper-800s again.

I'm not sure if the fuel map was reset, but I do know that the route the ecu takes and under which conditions getting to "target idle" was reset.

And when I spoke of the idle load, I should have noted that 2 will be when fully warmed. I think that has to do with the warmth of the serpentine belt and ring seals...after running for so long, belt becomes more plyable and the rings seal the energy better then the lod decreases.

And if you made more than 4 turns in your short commute, I would trust the odometer over GPSr. And I agree on waiting for trends to emerge for your FE.

[Rick Rae]

Second Shell mid-grade segment complete; 33.75MPG over 349 miles. This is very consistent with the first mid-grade tank. I refilled with mid-grade again to see if continues to be repeatable.

I rechecked the odometer/GPSr calibration, and again saw approximately a 2% error (about 1/2 MPG over a tank).

My impression of getting better FE post-service was apparently due to the ScanGauge losing its tank-fill adjustment factor. Gallons were low on the first post-service fill and adjusted; on this fill the reading was once again low and about a 4% offset was required. On this tank I'll probably see MPG numbers more in line with what I was used to seeing. (Note that these misleading numbers had no bearing on the VW's gaslog or the numbers reported here -- those come directly from odo mileage and gallons pumped.)

Rick

[Rick Rae]

Third Shell mid-grade segment complete; 35.54MPG over 378 miles. I pretty much screwed up the test series with this tank. First, I had to make a fairly long trip on a road that was absolutely perfect for high-FE driving, and I took full advantage of it.

Then, since I knew the numbers would be off anyway, I installed an upper grille block and front air dam about halfway through the tank.

I'll continue forward with the test then go back and re-baseline everything. I'm hopeful that, by then, my driving style will have settled in pretty well and any variances in Shell V-Power versus other Shell gas grades versus random gas will be more visible.

Also, if there's a strong discontinuity from this tank forward, it might still be possible to subtract out that offset and see other trends.

Rick

[Rick Rae]

Fourth Shell mid-grade segment complete; 35.46MPG over 331 miles.

Rick

[Rick Rae]

Fifth and final Shell mid-grade tank complete; 33.49MPG over 298 miles. I refilled with Shell regular this time.

Capsule summary to date, using five fills for each section:

Random Regular: 1439 miles and 44.13 gallons at 32.61 MPG.
Shell V-Power: 1577 miles and 45.301 gallons at 34.81 MPG.
Shell Mid-Grade: 1664 miles and 48.255 gallons at 34.48 MPG.

Rick

[Rick Rae]

First Shell regular segment complete; 34.30MPG over 330 miles.

Rick