What kind of gas mileage are people getting?

shotsiekid · 04-23-2008, 08:57 AM

I dont understad im only getting like 23 at most..

kev_xb · 04-24-2008, 03:08 PM

4 psi is alot to over inflate your tires by... it will cause them to wear prematurely in the center, and it will also give you less tread on the ground... resulting in decreased handling...

Flea · 04-24-2008, 03:16 PM

to accuratly compare milage, also need to know the wheel / tire setup on the car ... and to some extent the mods to motor ... driving style / type of gas that is bought ... and driving conditions ...

jahfakin · 04-24-2008, 03:24 PM

Quote:

Originally Posted by kev_xb

4 psi is alot to over inflate your tires by... it will cause them to wear prematurely in the center, and it will also give you less tread on the ground... resulting in decreased handling...

Thanks for your opinion...but I've been doing this for many years, and never had an issue with pre-mature wear and safety is not compromised. I do 30K+ miles a year, btw.

handling is only affected if you over inflate past the peak, you begin to balloon out the center of the tread. it takes more then 4psi for that to happen, considering most of the load are on the front wheels. Over inflating your tires when Autocrossing has always been a trick to combat body roll and improve the handling to your liking (more/less over/under steering, depending on the +/- PSI front/rear).

Flea · 04-24-2008, 03:30 PM

most of the time 'premature' wear doesn't happen till you inflate past the reccomended max for that tire ...

and on most all cars the reccomended is lower then that max .. so going up a bit is still within specs for the tire ...but decreasing the rolling resistance which can increase the milage.

jahfakin · 04-24-2008, 03:46 PM

Quote:

Originally Posted by Flea

...but decreasing the rolling resistance which can increase the milage.

decreasing the rolling resistance......That's what I'm trying to achieve with the xB. I took me a couple of days to find the PSI levels (front/back) that I'm happy with (level of comfort).

My VW Beetle has adjustable compression/dampening and that's a nightmare. any suspension adjustment would result in a day long process to find the ideal PSI for my driving style (aggressive).

kev_xb · 04-27-2008, 11:52 PM

yeah by decreasing the rolling resistance your having less tread on the ground +4 psi cold=alot more hot... so your going to have alot smaller foot print, which means the center of the tire is getting more wear than the outsides, ive been through extensive training on this... and i work with it everyday... you might get a lil better gas milage but your tires and performance will suffer

jahfakin · 04-28-2008, 07:30 AM

Quote:

Originally Posted by kev_xb

yeah by decreasing the rolling resistance your having less tread on the ground +4 psi cold=alot more hot... so your going to have alot smaller foot print, which means the center of the tire is getting more wear than the outsides, ive been through extensive training on this... and i work with it everyday... you might get a lil better gas milage but your tires and performance will suffer

who said I increased it by 4 psi COLD? Like I said, been doing this for years, with no issues.

Quote:

Originally Posted by jahfakin

Getting 23.5 MPG......car is two weeks old and 900miles on the ODO.

I now have about 3000 on the ODO and I'm getting 27.1 mpg.....with no mods to the car. with the car no broken in, it's doing a lot better . yippie!

Flea · 04-28-2008, 03:37 PM

my average mpg is now up to the 30.5 range (close to 3k miles on it) ... haven't reset it in 4 tanks ... about 60% highway the rest is city stop n go...

TrevorS · 04-28-2008, 04:19 PM

I'm at 1090 miles and just switched to Mobil One. My average is about 27mpg with town and vicinity driving (plenty of stops and low speeds.)

Invertalon · 04-28-2008, 11:02 PM

My MPG for this past month (seven fillups) was 29.19MPG (done manually).

At my last fillup, my range was 370mi.

Grasschopper · 04-29-2008, 12:06 PM

Ok so my last tank was nearly 29 mpg not adjusted for the tires and 29.6 mpg when adjusted.

kev_xb · 04-29-2008, 04:46 PM

... everyone refers to psi cold... why would you even try to compare it hot... thats pointless...

Flea · 04-29-2008, 04:49 PM

Quote:

Originally Posted by kev_xb

... everyone refers to psi cold... why would you even try to compare it hot... thats pointless...

not everybody ...

i check mine when it is cold and when it is hot ... esp depending on what kind of driving i am doing and the weather ...

if you are doing a lot of driving, the hot PSI is a lot more important then the cold reading ...

kev_xb · 04-30-2008, 10:36 PM

but the hot reading isn't accurate... it'll change depending on ur speed and how long you've been driving... nobody really compares hot psi in tires...

Flea · 04-30-2008, 10:43 PM

Quote:

Originally Posted by kev_xb

but the hot reading isn't accurate... it'll change depending on ur speed and how long you've been driving... nobody really compares hot psi in tires...

depending on the average speed you are driving, and the temp that day ... the air in your tires will reach a max temp ...

and the PSI while you are driving effects your handling / mpg and other things a lot more then the PSI from when it is just sitting all night ...

why else do you think that people at 1/4 mile tracks and other tracks will adjust their psi throughout the day to compensate for changing conditions ...

but to do it properly you also need to take a temp reading of the tire tread .. and use that to tweak it more ... till you get an even temp reading across the entire tire (you can also use this to see if you need camber adjustments esp on some good twisties)

jahfakin · 04-30-2008, 10:59 PM

Quote:

Originally Posted by kev_xb

... everyone refers to psi cold... why would you even try to compare it hot... thats pointless...

I adjust my PSI based on my typical commute. I drive 45 miles one way to work. So I'll take a reading before I leave, and another reading after I reach work/home. off course this is done constantly, at least once a week, since the outside temp varies, and to make sure I don't have a slow leak or anything. As long as it doesn't exceed 38PSI (front) and 36 PSI (rear) when hot, I'm happy.

kev_xb · 05-01-2008, 03:19 PM

racing applications are totally different... in racing mpgs and tire longevity is not a concern. tires also get alot hotter in a race than they would in normal driving conditions. if your happy with what your doing than more power to you, but for everyone else you should follow what the manufacture recommends, and I'm not just saying this based on personal preference or what i "think" works... i have had extensive training on tires and i work with them everyday, and the people who engineer the tires recommend your tires be at a certain psi... so its a pretty good idea to keep em there...