Economy run - beating 3l wall with stock cars

[noxman]

Hi!

This month is in my country the 27. vol. Economy run.
I knew about this legendary run 5 years ago. But now is more important for me because i'm traveling over 20 000km per year and wanna "know how".

I'm wondering how is possible with stock cars without any modifications (including higher tire pressure, weight reductions atc.) get this amazing results.

It is a international run, so you can join

Only condition, you must have a Skoda car (member of VW group). Shame i don't have Skoda too.
I wanna to go just watching, but have not got vacation :-(

You can see results with records at the:
Economy Run - Autoklub Škoda Mladá Boleslav (use translate google)

A incredible rating for Skoda Fabia 1.2/47kW (2003) with average speed 54,10 km/h and just 2,888 l/100km and others cars listed.

I really interesting how its possible.
I think is:
1. cruising with engine off from 80-90 km to 50km/h and repeating on flat roads?
2. don't use lights ( even if in your country must be on all day)
3. cheating, but every tanks are sealed at start.

I wanna go next year like watcher or maybe competitor with Skoda car.

Can you share with yours opinions how is possible?

Thank you.

[tasdrouille]

I recently did 2.60 l/100km at 63.16 km/h in a VW Jetta 1.9/67kW (but 82kW since it's modded).

I think it's possible to get 3l or less with pretty much any stock sub 2 liters diesel manual trans passenger car.

Keep it in top gear no matter what. Go as slow as possible. Kill the engine as soon as you have an opportunity.

[Billy_BAD_Boy]

On a flat road, driving in 5th gear with 35 mph theoretically I should get 1.62/100 (according to the Aerodynamic & rolling resistance, power & MPG calculator) which shows that under 3/100 is not impossible at all.

[noxman]

I have not very good calibrated external board computer
Instant consumption show me with crazy number (its "home made" BC).
But for basic know about injection times and "0" consumption works very well.
Trace, that instant consumption is about 5l/100km. Isn't so much for my car? Factory tells 4.7 l/90 km/h.
So i'm little confused if you write here your 3l at top gear.
I know is with diesel car, but think still is too much.
My best trace i think is refueling fuel up to tank neck.
Today i did it first time. Before this i did it just for first click tank pistol.
I'm not skilled with this, but looks like better choice for best trace consumption. Tank can hold about 1l fuel more and good visible liquid level.

Next question is for you guys.
You have very good consumption, even you have diesel.
I'm interesting if you had lights on, and shut off engine power so often like its possible? If engine off. how off? When i kill the engine, my brake booster didn't work and its very hard brake. Also my key in ignition can be lock automatically, which is very danger.

I tried the key after killing put again on place no. 1 (be ready) but don't know if is good.

How can i solve this 2 big problems?

[Piwoslaw]

Originally Posted by Billy_BAD_Boy

On a flat road, driving in 5th gear with 35 mph theoretically I should get 1.62/100 (according to the Aerodynamic & rolling resistance, power & MPG calculator) which shows that under 3/100 is not impossible at all.

When I was doing coastdown and FE testing, I got an average of 3.0-3.1 l/100km @ 70 km/h (44 mph). I'll add that my car has the same Cd as a Skoda Fabia (0.33), but is at least 30-40% heavier and has much larger frontal area.

Originally Posted by noxman

I'm interesting if you had lights on, and shut off engine power so often like its possible? If engine off. how off? When i kill the engine, my brake booster didn't work and its very hard brake. Also my key in ignition can be lock automatically, which is very danger.

I tried the key after killing put again on place no. 1 (be ready) but don't know if is good.

As soon as the engine is off, turn the key to the '1' or 'start' or 'ignition' position! This turns everything back on, except the engine, and unlocks the steering wheel. You shouldn't be rolling with the car completely off! It's easier to start the car from there (either turn the key to activate the starter, or 'bump-start' by putting in a high gear and releasing the clutch, assuming you are still rolling). The brakes should be good for 1-2 presses, unless you have a leak in your vacuum system.
There are some threads here on how to make a switch to turn your engine off or on without turning the key, which is good if you do EOC often. Your car probably is better suited for EOC than the newest models, with a lot of electronics, power steering, etc.

[Billy_BAD_Boy]

@noxman
Lights are always on (safety reasons), no a/c, using the cd of the car almost permanently. Never use EOC till now because of the steering and braking loses.

@Piwoslaw
Coasting down with 70 km/h (with no or little throttle) should return a number close to zero. I don't know why you are getting 3/100.

[Piwoslaw]

Originally Posted by Billy_BAD_Boy

@Piwoslaw
Coasting down with 70 km/h (with no or little throttle) should return a number close to zero. I don't know why you are getting 3/100.

I should have rephrased that: I was doing not only coast downs, but also checking average FE at a steady speed (70 and 100 km/h) over a given distance using cruise control. See more in my modding thread.

[Billy_BAD_Boy]

I put the data for your car in the calc....here what it shows:

Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

Pretty close results to what you get. However the weight of the car and the frontal area are the two factors backing you off IMHO.

Regards,
Veselin

[Piwoslaw]

Originally Posted by Billy_BAD_Boy

I put the data for your car in the calc....here what it shows:

Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

Pretty close results to what you get. However the weight of the car and the frontal area are the two factors backing you off IMHO.

Thanks, Veselin. From the calc I can also see that 170-180km/h should be the max speed for my 80kW engine, which is also close to official figures. I've never tried to max out (and probably never will), but the only time I went faster than 130km/h was when I got to 150km/h and felt I could keep going. But I really feel no need to go faster than 110km/h.

You're right, weight and FA are the bad guys, and there isn't much I can do about it But I'll keep tweeking the Cd. My aeromods seem to have lowered Cd from 0.334 to 0.324, so I wonder if 0.30 is possible?

OK, back to the thread. I have this great urge in me to buy an old car, heavily ecomod it, maybe even swap the engine, and try my luck in some ecodriving contests. My car is too big to give me a fighting chance, though I've seen that in some contests, it's not just how much fuel you used, but how much fuel per 1000kg of car weight. Still, I'd prefer to do it in a small, light car.

[elhigh]

Hi,

You shouldn't lose all your braking boost immediately when you turn off the engine. There should be a vacuum reservoir that gives you a couple of stops after the engine turns off.

If it's not holding vacuum after turn-off, maybe you have a vacuum leak? I notice you have the 1.1 engine, which means you're driving the oldest generation Punto. Maybe you've got a worn-out hose or something. Or you need to add a check valve in the booster line?

If you're driving where you are required to have lights on during daytime, could you add LED (Light Emitting Diode) lights? Less power requirement, but satisfies the law. Change turn signal bulbs to LED, too.

Somebody else has probably already said it: add a kill switch to your ignition. It turns off the engine, but you don't have to touch the key and that way you don't risk locking the steering! And then flip the kill switch back on, bump the clutch and you're running again.