• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Driving slower saves gas?

F

freakyj92

Member
A coworker made a comment saying she doesnt drive past 70 anymore to save gas. Does driving slower really use less gas even if the you're on the freeway and speed is generally constant?
 
Depends on the car, but most reach there peak mileage around 55-60mph. That said, I drive closer to 80 on the freeway.
 
It most certainly does. What your coworker is doing is become quite common too. It also helps to let go of the gas earlier when approaching red lights.
 
Of course driving slower saves gas. But there is always a sweet spot. For me it appears to be ~65 mph where I can get around reasonably fast and still get 28-30 mpg in my 2001 A4.
70 and my mileage drops to 24-25.
 
yes, because the higher the speed even if you are in the highest gear is causing you to have a higher rpm which means you are burning more gas.
 
It's not necessarily how fast you're going. It's more the RPM's, vs. speed. The optimal speed would be where RPM's aren't high, but you're still travelling fast, as in 65MPH. As you go faster, your RPM's will be higher and you will use more gas - your engine is working harder to maintain the higher speed.

So going 90MPH @ 3K RPM may get you there quicker, but you will use less gas when travelling at 70MPH @ 2K RPM or whatever.

There's other factors such as tire pressure, wind resistance, etc. But that's a simplistic look at it.
 
Really.... the freeways i take to and from work are always open to where i can drive as fast as i want. I always drive with the cruise control because of it... its really that big of a difference on gas if i lower the cruise control?
 
It's not a gas-rate issue, Summit - it's the fact that wind resistance geometrically increases as speed linearly increases.

The efficiency of an engine is nearly the same at 40mph or 80mph. The force of the wind resistance is incredibly different.
 
Originally posted by: Summit
yes, because the higher the speed even if you are in the highest gear is causing you to have a higher rpm which means you are burning more gas.
Click to expand...

I dont think its that. I think its that there is alot more wind so your car has to work harder. At 5th gear going 60-70ish my rpm is around 3000. While 50 they are alot higher.
 
Depends on the car and gearing. In a TL I get better gas mileage at 85-90 than I do at 70. 31/32 at 85 vs. 27-28 at 70.
 
I normally got about 26-27 mpg on trips w/ my Mazda6. The last one I took a little slower (~65-70) and got 31 mpg for the trip. Definitely makes a difference. My car could use a tall 6th gear. 70 mph in 5th has the motor turning a little over 3k RPM.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top