The 3L Challenge: 79.9 MPG US over 615 miles in a Jetta TDI

[tasdrouille]

This isn't a success story just yet, but I hope it'll become one in the next two weeks.

Let's just say I have 900 miles in front of me, and I'm taking back roads.

I want to do it with one tank, and beat a 3L/100km average (78 USMPG) for the trip.

I've had a 65 MPG tank which was 50% city and 50% highway at 53 MPH. This tank will be secondary roads only and I'll be driving 47 MPH, so I'm confident I can do it.

I did a lot of things since my last tank in preparation for this challenge:

Deleted passenger side mirror
Reworked my air dam
Added side skirts
Added full disk hubcaps
Deleted the radio antenna
Deleted DRL
Blocked the lower grills
Sealed front end gaps
Replaced dragging brakes and rear wheel bearings, packed with synth grease
Changed my MT fluid (200k miles on it) to Redline MTL
Logged a lot of data with vag-com to find best boost levels, timing and acceleration rates for my car (results were least amount of boost during cruise, max timing advance within specs during cruise, and the bsfc map was right about acceleration)

This will probably be as much, if not more, of a mental challenge than a FE one. It'll be 20 or so hours of driving at 47 MPH in four segments over two weekends.

[Daox]

Looking forward to updates on this. Thats a good jump in FE, but you've also done a lot.

[tasdrouille]

On the highway part of my previous tank, I was pulling around 70 mpg at 53 mph.

So basically what I'm hoping for is a 12% increase in FE from a reduction of 6 MPH + all the mods I made.

The passenger mirror removed + driver mirror folded should give me 2.5%
The side skirts and hubcaps, let's say another 2.5%
The 2 small lower grill blocks + antenna + drl maybe 1.5%
Who knows what the brakes were costing me, maybe 1%

The 6 MPH slower speed should give me the other 4.5% I need.

I should add a diffuser before I leave to seal the deal.

[MetroMPG]

Sounds like quite the challenge, and within reach. Here's hoping for calm or following winds! When are you leaving?

[tasdrouille]

I'm leaving Saturday morning for Montreal and back in Quebec Sunday in the afternoon. The first weekend won't be too bad, only 300 miles.

Next week I'll leave Friday morning for Mont-Laurier, my home town, 2.5 hours north of Ottawa, and 300 miles from Quebec City. I'll be back Sunday in the afternoon.

It's funny you talked about the wind, that rang a bell. The road I'll be taking between Quebec City and Montreal is following right along the north shore of the St-Lawrence river. When I cycled around the Ile d'Orleans a couple years back I remember they recommended going around in a specific direction in order to take advantage of the wind which was going in one direction in the morning and the other in the afternoon. I wonder if that have anything to do with the tides. I'll have to check to see if I can take advantage of that.

[MetroMPG]

I'll be stopping in Quebec City on Thursday or Friday on the schooner. Not sure if we're staying over night or not, but I'll let you know what I learn.

I'd be surprised if the wind changes direction - SW is pretty much prevailing. But I wouldn't be surprised if they generally recommended the route based on avoiding riding against the prevailing direction in the middle of the day when winds are typically strongest.

Did they suggest going counter-clockwise? That way you'd get a tailwind on the exposed south shore and some shelter on the north side as you headed back into the prevailing wind.

[tasdrouille]

If possible I would recommend staying overnight, especially if you stay at the bassin louise as you'll have the chance to experience the image mill. Every night at 9:30, for the 400th aniversary of Quebec City there is a megaprojection on the history of the city. It is on the grain silos in the port. 600 metres long by 30 metres high, pretty impressive. Here's a pic



Yup, they did suggest going counter clockwise. Your explanation makes much sense.

[MetroMPG]

Yes! I've heard about the mill show, and talked to someone who's seen it. It's likely we'll be staying in the bassin - at least that's what we've done the past few times I've gone to the east coast on the boat.

We'd have a great seat: usually we tie up to the wall at the right side of that pic.

I wish we had a bit more time to spend in the city, but we're on a somewhat tight schedule.

[tasdrouille]

Back to the car, I finally took some pics of the "finished" product this morning. I have the hubcaps off atm as my commute is in the city and they are 17 inches, 3 inches wider than the rims, so they sit flush with the most outward part of the tire, but cover the valves, so I'll just install them for my trip.



The skirts hold with 3 screws in each wheel well and black silicone adhesive.





I basjooed the front end using clear silicone and clear tape on the bigger gaps.

Nice ubolt dragging down eh? The pipe broke just after the cat yesterday, I'll have to fix that during the weekend, but will just hang it up in the meantime so it's not right in the middle of the flow for the first part of the trip.

[MetroMPG]

Looks good... can't wait to hear the numbers.