|Yesterday 10:47 PM|
Coasting down hills means two things.
1) You are out of control of your vehicle
2) You are requiring fuel to me pumped into the engine to keep it idling in neutral, where as if you keep it in gear, the weight of the car is keeping the engine rotating, therefore requiring LESS fuel, than idling.
Bottomline, don't coast downhills.
Elizabeth: weigh the front and rear of your car, then tell us about tire pressures, as you are making an assumption about weight distribution.
Personally, the best thing I can do to improve fuel economy would be to avoid rush hour. Leaving earlier (or later) to avoid stop/start on the highway is a major contributor to fuel economy.
|Yesterday 02:36 PM|
I'm about to get an mk3 5spd hatch. What kind of rpm's are manual mk3 owners getting on the highway, say around 65,70, and 75mph?
Also, what do you guys think about putting it in neutral and coasting down big hills?
|05-23-2015 04:13 PM|
I've had a tank of 50mpg and 608 miles. I've made no modifications but this tank was while at Yellowstone NP where the max speed limit is 45mph. Speed is the most significant factor.
|05-23-2015 08:49 AM|
|redbuzz||39 mpg is the best I've achieved with my stock '12 focus 5-speed base model. That's approx. %75 highway Illinois 55 . Lately 36 mpg, maybe the "blend "has changed. The best mpg was with Sam's club gas, the lower mpg was the cheapest gas I found at Thorntons. The mileage did increase as the car was used more ,I think at 25k miles the motor has broken in.|
|03-23-2014 07:29 PM|
|03-22-2014 02:53 PM|
|03-22-2014 02:32 PM|
|CunFFS13||I got a gas cap lock, and it worked! I'm getting better MPG|
|03-22-2014 08:40 AM|
|bshin352||Has anyone considered vortex generators? Or has anyone done their own underside mid plate and rear diffuser?|
|03-21-2014 04:06 PM|
|03-21-2014 03:50 PM|
I want some stainless steel moons like those in the pic above for my 17" wheels.
I would liketo have small holes drilled so the moons would bolt to the alloy wheel.
Only small machine screws would be needed.
Also a comment on the higher inflated front tires: if you do a test to find the 'perfect' patch (the shape of the contact patch on the ground) You will find nearly always the right patch is only when the front tires are about 5 to 8 PSI over the rear.
The right size tire/ground contact patch is TOTALLY dependent on psi in the tire and on the weight each tire is carrying.(so in a front engine car, no way can an equal front and rear PSI be 'correct' from a performance/tire wear point of view, the equal tire pressure is for stupid people. Pretty much exclusively.)(feel free to quote me on that)
The front in a front engine car obviously carries a lot more weight than the rear tires.
So for a four banger the difference is usually 4/6PSI more in the front tires than the rear, and a six cylinder would need about 6/8 PSI more than the rear tires for a perfect contact patch.
The perfect part means the tire wears perfectly evenly.
Fo most folks the front tires edges wear out faster anyway.
I realized higher PSI did not mean bad front wear. It actually means BETTER, more even front tire wear.
So I am always at 44/43 PSI front 39 PSI rear. (39 seems to be the rear limit for good ride. 40PSI starts to cause too much harshness in the ride.
Plus typically the PSI manufacturers suggest/use is ALWAYS for 'good ride' which means the smoothest ride. With near zero concern for 'best handling' or best tire wear.
(look at the Ford Firestone/Explorer fiasco. where Ford said use a below safe air pressure for a nice ride. And to compensate for a poor suspension design)
and sorry to highjack the thread about MPG to blather about tire air pressure..
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