Hangin' my head in shame (lost an Eco-Run)

[niky]

Of course... not for the reasons you might think:

Sweaty lessons we learned during the 2014 Volkswagen Eco Fun Run | TopGear.com.ph

The rules prohibit shaking the car during the fuel-up. Shaking before the fuel-up? Completely legal, apparently.

So I lost overall, but claimed the best economy on the return leg, where the shaking trick wouldn't work. I got 27.5 km/l in 50:50 city/highway driving, with a Jetta 2.0 TDI, best of the leg. Well... best economy in class. Two teams driving the VW Tiguan got 47 and 49 km/l respectively.

Comes down to the tricky push-button starter. We had to park the cars at the gas station and push them up to the pumps when it was time to refill. The problem is, once you turn off a push-button car, it goes all the way dead, not into accessory mode. So you have to turn it on again without getting the engine to start. This means pushing the button without stepping on the brakes. The ladies driving didn't know this, so they fiddled a long time with the cars, and I surmise the fuel temperature sensor in the rail, at one, or two, or three points, decided to purge the rail of hot fuel. Hence, over a 90 kilometer run, they only "Used" one and a half liters of fuel, because the tank was miraculously three liters fuller than it was at the start!

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Still, had fun. Did a lot of EOC on the return leg... but I could have gotten higher numbers if I'd driven slower. My pulses were up to 100 km/h because I was pissed... and because I couldn't legally go under 60 km/h on the highway... (TIP: EOC'ing uphill? Pain in the arse) and I could have done better without a passenger... as I had to turn on the AC from time to time to keep them from melting into their seat. Mine was drenched in sweat at the end of the day... it was so HOT.

The other Jettas did 24.4 (AC on, driving to target speed... but those guys had a media unit with twice the mileage on the odometer, and tires worn down from hard driving... we drove exactly the same in the morning and they got 3 km/l better than me) and 25 (AC off, 70 km/h target, I expect).

Moral of the story: Next time, I'm lobbying for the media unit, and if other teams do the Harlem Shake...

[gone-ot]

Find where the Belgian Blocks are on the road course and let the driving do the shaking for you.

[MetroMPG]

For shame!

Some conversions...

Originally Posted by niky

I got 27.5 km/l = 65 mpg US = 3.6 L/100 km in 50:50 city/highway driving, with a Jetta 2.0 TDI, best of the leg. Well... best economy in class. Two teams driving the VW Tiguan got 47 = and 49 = 115 mpg US = 2 L/100 km km/l respectively.

The other Jettas did 24.4

49 km/L really??

[niky]

Yup!

Having previously owned a car with a cammed motor that ran very hot and lean in traffic, the fuel rail temperature sensor was a big bug-bear for me. My tank could vary by two to three liters on every fill, depending on how hot the rail was.

On some newer cars, if you flick the key to the "ON" position and back to "OFF" just once before your second refill, you can just throw those damn results out the window. Which is what the organizers should have done.

But hey... I wasn't running the show. And it's a shame to give a team no score for something that wasn't their fault.

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The fairest thing to do would have been to have the cars filled and parked at the station the night before... then refilled in the morning (after the gas has settled) and sealed. Give the teams no access to the cars before the run. Any adjustments to the tire pressures or anything else should be done after the initial start of the contest.

After the contest, the contestants should be instructed to turn off the cars with the gear selector (on push-button autos) in the Neutral position, so the steering doesn't lock-up. So you don't have to fiddle with the starter while filling.

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And, of course... the route needs to be much longer. Measuring accurate economy on a mere half-gallon to one gallon fill-up is not impossible, but it's very sketchy if you only do it once!

[Cobb]

I use to put a lot into eco runs, but I saw early one how easy and many avenues you can cheat at it. Granted increasing the range can help, but averaging 12 mph isnt real world either.

Your best gauge of your eco run is what the gas pump tells you vs the miles you traveled from your previous fill up.

[niky]

Unfortunately... having been doing this for years... I have very little faith in the gas pump.

We once ran a comparison using a van for a tire manufacturer. Filled that sucker with gas. Let it settle. Filled it again. Shook it. Filled it again. Let it settle overnight. Filled it in the morning...

The best you can do with limited fills, I've found, is simply to do your first fill with the car in hot and running condition... do your run... and do your second fill in the exact same conditions. Ergo... do a run that you won't record. Fill the car. Do the run you will record. Fill it again. Still not 100% accurate, but more consistent.

[user removed]

I used this trick on my VX for remakably consistent fills and found that it also works in my Sentra. Drop the 2x4 in front of the rear wheel, drive the wheel on top of the 2x4, then fill. Back up and pick up the 2x4 after you fill and keep it under the front seat between fills. If you don't want to waste fuel backing up, put it in neutral and push the car back with your foot.

When I first got the Sentra, it would not even fill to the full mark on the gauge. Last tank I got 60 miles on the tank before the gauge dropped below the full mark. I let the pump run on low speed until it cuts off, lift the rear wheel well and let it "burp" then one more top off until it cuts off again.

regards
mech

[niky]

I suppose a jack would do, as well? Hmmm...

[Xist]

Why would you use a jack when a 2x4 is that simple?

[niky]

I already have a jack. I don't have a 2x4.