Why am I not getting my suggested MPG???
- Thread starter Blue636
- Start date
- Status
Kestas
Staff member
The reformulated gas you have to use really sucks. This does have a significant effect on gas mileage.
What I can't understand and find somewhat ironic is that RFG forces the driver to burn more gas per mile, yet is supposed to result in fewer emissions. How can you get fewer emissions AND burn more gas?
What I can't understand and find somewhat ironic is that RFG forces the driver to burn more gas per mile, yet is supposed to result in fewer emissions. How can you get fewer emissions AND burn more gas?
Are you kidding?quote:
Originally posted by Bobert:
Except for Volvo's--they need all the help they can get.
I get 30 mpg at 65 mph in my 1987 740 Turbo.
With a CD of .39 It's rated at 25 mpg highway.
Even at 70 mph I get 28 mpg plus.
I would say that those EPA mileage numbers were on the base model. Add a few hundred pounds in accesories and 87 winter gas and I could see 2 to 3 loss in mpg. How fast are you running this car on the Highway?
But that little car should be getting close to or better than 33 mpg highway. One of my friends has a 2001 Grand Am with a V6 and an Auto and she is getting 35 on the highway.
[ March 21, 2004, 01:47 PM: Message edited by: ALS ]
XS650, thanks for noting that problem. I am used to carb'd V-8's AND drving a whole lot farther than recommended above. ("Okay", as the truck drivers say to a four-wheeler piloted by an off-duty driver, "I see that you're just driving around burning fuel". Yeah, I do tend to burn fuel to no end other than to drive around.)
I hope the owner will take the example as a guideline to establish a norm for the current best hwy mpg with your note of clarification in mind.
As to weight, etc, it is my belief that once a driver is "conversant" with his/her vehicle that the EPA-rating is a minimum for a healthy vehicle.
My best mileage on our 2001 Cherokee was at 72-mph, 105F, with two occupants and a near-400# load on a non-Interstate highway.
One can retrain oneself to drive for best mileage as it is also the exact same as driving for longest engine life.
[ March 22, 2004, 12:57 AM: Message edited by: TheTanSedan ]
I hope the owner will take the example as a guideline to establish a norm for the current best hwy mpg with your note of clarification in mind.
As to weight, etc, it is my belief that once a driver is "conversant" with his/her vehicle that the EPA-rating is a minimum for a healthy vehicle.
My best mileage on our 2001 Cherokee was at 72-mph, 105F, with two occupants and a near-400# load on a non-Interstate highway.
One can retrain oneself to drive for best mileage as it is also the exact same as driving for longest engine life.
[ March 22, 2004, 12:57 AM: Message edited by: TheTanSedan ]
Another item to check is the EPA engine/emissions sticker in the engine compartment and see which emissions package it has, then cross check it on the EPA website. Some come with quite a few different packages, and the gas mileage estimates do not cover all of the different emissions setups. You may be getting close to the designed mileage. I bought a used (2 yr old) Honda a couple of years ago that had the California emissions package, and never got close the EPA advertised mileage.
Well, I've drastically changed my driving habits since the beginning of this thread. While I don't appreciate driving like an old lady, I'm guessing I'm getting over 29mph now! Usually, when my fuel guage hits the half-way mark I'm at 125-140 miles. Now, it's at the half-way mark at 170 miles! This is awesome!
I wonder how much radial tires will make a difference when I need new tires. Will I see a 1-3mpg increase?
I wonder how much radial tires will make a difference when I need new tires. Will I see a 1-3mpg increase?
You haven't said what kind of vehicle you have, but:
1) You probably already have radial tires on it.
2) You will probably get worse fuel economy after the changeover.
a) Most vehicle manufacturers specify low rolling resistance tires in order to meet CAFE requirements. Some are more agressive than others. Aftermarket tires do not have these restrictions and since wear is a HUGE selling point, their rolling resistance will be worse.
b) Increased tire mass = increased rolling resistance. So a wornout tire gets better fuel economy than a new one.
Hope this helps.
1) You probably already have radial tires on it.
2) You will probably get worse fuel economy after the changeover.
a) Most vehicle manufacturers specify low rolling resistance tires in order to meet CAFE requirements. Some are more agressive than others. Aftermarket tires do not have these restrictions and since wear is a HUGE selling point, their rolling resistance will be worse.
b) Increased tire mass = increased rolling resistance. So a wornout tire gets better fuel economy than a new one.
Hope this helps.
Here's another reminder about getting better mileage. You get better mileage if you carry less weight. You get better mileage on the last half of the fuel tank than you do on the first half just because you're carrying around less fuel weight. I keep track of every tank of gas on my trucks, sometimes I have filled up when I was only 1/4 tank down before an extended drive. I really tell a diff on those small fillups vs the regular full tank refills.
No that is not true. As the tire wears down the diameter of the tire decreases. Thus the tire must make more rotations per mile. Thus the engine must increase the rpms to maintain the same mph.
Also noted in. Cummins artical in earlier post
I've known many people who have gotten well above the rated MPG, and many well below. It all depends on how you drive. Remember the EPA test procedure is not an accurate representation of any real life driving situation. It's very hard to estimate mileage exactly.
BTW, if I'm not mistaken, If the sticker says 33mpg, doesn't the stick say something like "you may get between 28 and 38mpg"?
-T
BTW, if I'm not mistaken, If the sticker says 33mpg, doesn't the stick say something like "you may get between 28 and 38mpg"?
-T
"No that is not true. As the tire wears down the diameter of the tire decreases. Thus the tire must make more rotations per mile. Thus the engine must increase the rpms to maintain the same mph.
Also noted in. Cummins artical in earlier post"
Read the Cummins article again:
Page 19 - A fully worn tire has 7% better MPG than a typical new rib.
It also says "7/32 treadwear represents ~10% reduction in rolling resistance (5% better MPG)"
[ March 30, 2004, 06:50 PM: Message edited by: CapriRacer ]
Also noted in. Cummins artical in earlier post"
Read the Cummins article again:
Page 19 - A fully worn tire has 7% better MPG than a typical new rib.
It also says "7/32 treadwear represents ~10% reduction in rolling resistance (5% better MPG)"
[ March 30, 2004, 06:50 PM: Message edited by: CapriRacer ]
Thanks for the replies all. BTW, my car is a Toyota 2003 Matrix (base model). I believe the Continental tires on there are bias-ply. At any rate, I'm not sure they'll make a huge difference but I do keep them inflated to proper psi and I check it every Saturday morning.
Cummins article has two versions. Page 3
Tire tread depth effect: MPG Improves by Approx 6%
from 100% tread depth (New) over a 50% tread depth tire.
The other version Page 19 talks about how New Truck tires that can have large as well as deep gaps between the treads on the tire. They made reference to different tread patterns rib and lug affecting fuel mileage. Those deeper gaps increase rolling resistance is the reason for the mileage decrease. Once the tire wears down those gaps become less of a factor in road friction or drag. I had to re-read it to figure out why the difference between the contradiction in New tires helping page 3 and hurting page 19 MPG due to road friction/drag.
[ March 30, 2004, 07:53 PM: Message edited by: ALS ]
Tire tread depth effect: MPG Improves by Approx 6%
from 100% tread depth (New) over a 50% tread depth tire.
The other version Page 19 talks about how New Truck tires that can have large as well as deep gaps between the treads on the tire. They made reference to different tread patterns rib and lug affecting fuel mileage. Those deeper gaps increase rolling resistance is the reason for the mileage decrease. Once the tire wears down those gaps become less of a factor in road friction or drag. I had to re-read it to figure out why the difference between the contradiction in New tires helping page 3 and hurting page 19 MPG due to road friction/drag.
[ March 30, 2004, 07:53 PM: Message edited by: ALS ]
Blue don't worry your car came with radials.
It did? Right on, this whole time I've never bothered reading all the writing on the sidewalls besides recommended pressure. Thanks for the info.
I think most of the time it is the speed you drive. I get 3mph better than the EPA rating for highway and I do this with combo city/highway milage. Our city is very small so very little wait time at lights etc. My trip to work is 20 miles and the speed limit is 55. I drive with the speedometer on 60 and it is 4mph fast so I actually am going 56mph. I do this because the highway patrol gives lots of tickets on this stretch of road and I do it because I'm CHEAP!
[ March 31, 2004, 08:52 PM: Message edited by: TR3-2001SE ]
[ March 31, 2004, 08:52 PM: Message edited by: TR3-2001SE ]
From Cummins document:
"Up to 30% difference between a good mpg driver
and a poor mpg driver (in each fleet).
Recommend using LBSC."
I think they are right.
I get only 27/30 city/hwy in my 2003 Corolla rated at 32/38.
As far as I remember, every car I drove had worse MPG than advertised. The only exception was 1984 Renault Encore getting 36 MPG on long streatches of hwy.
"Up to 30% difference between a good mpg driver
and a poor mpg driver (in each fleet).
Recommend using LBSC."
I think they are right.
I get only 27/30 city/hwy in my 2003 Corolla rated at 32/38.
As far as I remember, every car I drove had worse MPG than advertised. The only exception was 1984 Renault Encore getting 36 MPG on long streatches of hwy.
- Status
Similar threads
