This question came up not too long ago and I believe someone made a calculated guesstimation that it would only be about a 1 mpg hit. Wish I could find the topic and link you to it. Maybe you'll have better luck searching for it. I'm not too good at digging up old topics on this site.
No, the mud flaps will not have a noticable effect on MPG. Most of the old threads are gone but even Evan found that the benifit far outweighed any possible loss.
Thanks, I guess I will add the flpas to my prius. Another question, can someone tell me what the cars that pile up on the graph of the consumption screen symbolize? And an unrelated question is while going though a car wash can you just put the prius in neutral as you would any other car?
50 Watts of electricity per full 'leaf car' put into the big battery - from regen or coasting generation only, does not include excess ICE alternator output. Yes. Push the shifter to the left and hold it a second or two. Also, remove (unscrew) the antenna as it could be damaged by some 'touch' car wash places with the big cloth strips or the like.
There's so much turbulence around the wheels that the mud flaps do not contribute *any* noticeable hit to MPG.. The real hit, is small and fractional so even 1 MPG is a gross *over*estimation IMO.. I certainly do not see any difference in mileage before and after on my car, but I do see a big increase in vehicle cleanliness as the flaps really do help keep stuff from being flung up onto the fenders and the doors..
I agree with C4... get 'em on your car! They are worth it and do not make any MPG difference. Also, NEVER drive a Prius thru a "touch" car wash! Ack! It'll scratch your paint. Shame on you, bruceha_2000!
It isn't a frequent occurance I wash it maybe 3 times a year and generally that is in the winter after a big salt spread so I can get the under carriage cleaned off. I don't think we have any touchless car washes locally though there are some do-it-yourselfs. Not sure I want to lay on the ground to get everything underneath clean
I second the above, never, never, run any vehicle through a carwash. You'll put fine scratches in the clear coat, the car will look less nice each time, collect dirt more quickly. Put a good sealant on your car, hand wash it every few weeks. It will clean very easily.
I noticed no measurable difference when I added mine and they do keep the care looking better longer.
Re: mud guards I installed four mud guards in December 2005 and have noticed no appreciable (measureable) loss of mileage. 48-55 on warmer days in city driving. (35-45 Farenheit) 45-50 on colder days. (15-35 Farenheit) The vertical surface area that projects out beyond the tires is negligible. Furthermore, the extra surface area may be offset by the rib creating a bernouli effect (an airflow disturbance) that may actually reduce drag. They seem to reduce pebble and mud splash on the side and protect the front doors from excessive salt exposure of Northeast Ohio. I think that the dirt on my Prius reduces mileage much more than the mud guards. Good drivin' B)
If the effect of mudflaps is negligable, then why do Toyota bother fitting the assorted spats around the wheels? Surely they'd have even less effect.
The lower spoilers are in *front* of the wheel and help deflect the air *before* it gets to the turbulent zone immediately around the rotating tire.. The mud flaps are behind the tire and located right in the turbulent zone, thus they make no measurable hit to MPG..
