Can You Modify A Car To Save Fuel? - Fifth Gear

Tim tries to save fuel by modding a car but the results are surprising.

[creigmacc]

Anyone who has ever ridden a bicycle on wet roads knows it takes more energy to ride on wet road than dry. The pumping action to push the water aside isn't free.

[ronaldderooij]

The Fifth Gear technicians were wrong. Rain dramatically increases your fuel use. The density of water is like 1000 times higher than air. You are constantly pushing against dense stuff in the rain. Let alone the tyres pushing the dense stuff away from your grippy parts and splashing it meters high into the air. Lastly the windscreen wipers take a tiny bit of extra energy.

[markashd]

"We're giving away free money today."
"Oh great!"
"Here's 50p"
"-_-"

[realmichaeltian]

“Fuel prices have risen by record levels this year”
*2022: 😏*

[Kcducttaper]

Couple things:

1) Pumping the tank and putting in exactly 1 gallon does not take into consideration the amount of fuel you missed siphoning or the fuel left in the lines.

2) Lapping a track to negate the effects of wind does not work because drag increases exponentially with speed instead of linearly.

3) Rain increases drag on the car both in terms of modifying the aerodynamic shape of the car as well as the momentum transfer when the car hits each of those rain drops.

4) A wet surface reduces static friction, which you are not taking into consideration at all with MPG runs. You're interested in rolling resistance with MPG runs.

5) Added electrical usage (running the wipers and headlights) increases the resistance on the alternator. Similarly, if you happened to have the defog on, that would run the A/C compressor.

6) Advancing the timing only really helps in high throttle applications when you have a really big, long explosion. When you have just a little explosion just to maintain speed, you want it where the crankshaft is at the most efficient spot, which is at 90 degrees from TDC. You also increase the risk of pinging and blowing a hole in the motor.

That was not scientific at all and, frankly, a very poor test.

[bosede-nage]

If this were scientific the mods would have been done one at a time. It is likely that the new chip's profile was not optimised for driving steadily at 60 and so masked any benefit of other mods

[gnncnng]

They didn't take the fuel left in the fuel lines into account in the first run. They only vacuumed the fuel left in the fuel tank but ignored the rest of it before setting the base figures. Then they drove the car until it cuts out after using all the fuel left in the tank (1 gal), plus the amount left in the fuel lines; which was not present when they made the refill before the second run. That amount of fuel could easily help them make more miles which could affect the final score.

[micky]

Test was wrong. the engine had not run out of fuel on the first test, this means you have extra fuel in the pipe.s injector rail ect.
had you of refilled the car started it then drained it, and put 1 gallon in you may have seen an increase in mpg on 2nd test.

[DigitalicaEG]

Skip to 2:30 where the video actually starts

[ankbrq]

The problem is the brand new tyres. Fuel efficient ones or not, you should allow the tyres to settle.

[SuperWorkid]

After you ran out of petrol the first time, it would of drained you fuel line so really you got further because of the fuel in your lines that you did take out firstly

[PlAsKusJGaRn]

Best fuel saving tip: don't drive.

[sailordave]

Don't mess with the chips! A proper test would be to reduce the weight and test on the track. Change the tires and test on the track, and so on. Keep up vehicle maintenance, maintain proper tire pressure, accelerate smoothly, use cruise control on dry level roads, release the gas pedal when you see a stop light or stop sign coming ahead to coast part of the way before braking (also conserved brake pads), plan your route with one that has the least amount of stops and traffic, if running multiple errands go to the stop furthest away first and work your way back home.

[hajjdawood]

Hold on what a load of nonsense. Driving in the rain is LESS efficient as your tires have to pump water AWAY to prevent hydroplaning.

[tobiasljosnes]

I believe the difference comes from the fact that on the first run, the car only had it's fuel tank drained, but on the second run the car had it's complete system drained before the fuel was poured in

[hugopnabais]

Fuel is cheaper than bottled water?!
Today in 2018:
-In UK the averate price is 65 pence for 1 litre of bottled water.
-In UK average fuel price of fuel is 140 pence per litre.
In 2017 fuel was really cheaper than 65p per litre?

[vnicolescu]

the video looks like 480p even tough i set it to 1080p

[dparv]

Love how people are so interested in the fuel price, this episode was from 2009!

[Mrcloc]

The cheapest and easiest fuel saver I know of is to simply place a tennis ball behind the accelerator pedal.

I've found that it's not so much the car that uses a lot of fuel, but rather my driving style. At the moment I'm using about 10 liters per 100km, but if I concentrate on saving fuel, I bring this down to 8 liters per 100km. I drive very short distances, and mostly start stop and hills.

[jethrovitorioscultor]

Do this with a V8 Muscle Car and change just the Gear Ratio for each test.

The results would be astonishing.