some dumb questions

S

scottsmp5

Member
:
2003 mazda protege5
first
does everybody's car tach at like 2500 rpm going 60 mph....or is it just mine

second
what is the proper tire psi for stock size tires....i got mine set at about 35 pounds

third

how big is the gas tank in a 2003 mazda protege5? i think its around 12?
i got to know if my recent mpg calculation is right, if it is, these things are amazing on fuel
 
Dunno about 60, but at 75 I'm around 3500rpm's, IIRC.

PSI is dependent on the tire, not the car. Look at your tire sidewall, and see what the maximum is; fill it to 10psi less than the max, cold. Pressure will increase by 4-5 psi after driving a while.

Lolzors on the 'good on gas' comment. It's 14.5gal, IIRC, so yes, your mileage sucks. It's not that bad, I get 21-22 in mostly city driving, 25-27 highway. But when you consider a GTI, MS3, Civic SI all have 200hp (more like 230), 280, and 200hp respectively, and all get better mileage overall, it kind of blows. Whatever.
 
I believe the PSI printed on the door is 32psi all around.

I get 28-30 MPG around town and have gotten as high as 36 MPG on one tank when doing about 70 MPH on the Interstate. I'm completely stock...except the tire size is 205/50/16 instead of the stock size of 195/50/16.
 
ok sounds good, im at 35 psi right now, i will go lower it a couple pounds later tonight to make sure they are cold, as far as how many gallons

if it is 14.5

i got just over 200 miles to 1/2 tank

so thats 200 miles to 7.25 gallons

turns out thats 27.58 mpg
round down to 27

thats not bad, i just came from a jeep cherokee getting consistant 16... i will take it


and the rpm is the same as mentioned above...these cars must have lower gears or something
 
dont just calculate what you have gotten as of 1/2 a tank... after 1/2 a tank the needle drops a lot faster IMO
 
Yes. Don't go by half tank calculations. It's not accurate that way. 1st half lasts longer than the 2nd half :)
 
ya that second half a tank disappears quick but then sits at the bottom for a while before going all the way down.

I like 34PSI for the better highway fuel efficiency.

Also for me going 100km/h (bout 60mph) im at ~3200rpm
 
As Hank said 32psi is on the door sticker but I run 35psi as do quite a few others....you will be just fine if you leave it there.

And listen to the others...don't calculate your mpgs by a 1/2 tank...the needle starts to drop faster after a 1/2 tank and at a quarter tank it drops like a lead balloon. Click the fuelly link in my sig and sign up.... I keep a pad and pencil in my glove box and while the tank is filling I fill out the info and log it later that day.
 
Question 3.

I've run mine to absolutely dry; rolled into gas station.
Filled absolutely to the very top of the fill tube, mine takes 15.8 gallons.
Edmunds owner specs show 14.5.

When calculating mpg, I fill & refill to the top, as different pumps will shut off inconsistantly. From pump shut off, I can usually get almost 1.4 gallons more to top of fill tube.
 
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ok i wont judge the first half tank...either way i know its a great improvement over a jeep

as far as tires go, i will just leave them at 35 lbs when cold

sounds like everybody is at the same rpm's as i am......im just use to having lower rpms at 60 mph

but sounds like thats normal
thanks
 
Guys, you can't go by the psi written on your car door, that's crazy talk. Every tire is different; a summer tire will require a different pressure from an all season, and two differentt summer or all season tires may require different pressure. Your door panel, and places like jiffy lube, think 32psi is some magical default number, but it ignores tire construction as well as tire type and size. If you think going from 32 to 34 psi is going to help gas mileage, you're wrong. Going from. 32 to 40 (or whatever is around 10psi from the max stated on the tire, cold) will.

The falken 452's on my wife's passat give a max psi as 51. I've played around with anythhing from 38-44psi, and settled on 40psi as the best combination of performance and comfort. The passat door panel says 33psi; at 33psi these tires are like marshmallows, wear is poor, gas mileage sucks, and performance is terrible. As an aside, I attended toni scotti's defensive driving school, and they advocate very high tire pressures.
 
Mine's sportauto and it rolls at 3000rpm at 70mph with 205/40/17s with 37 psi all around and gets 25mpg on avg with 70/30 mix of frwy/city driving.
 
ok thanks again

i will leave them at 35 for now, maybe go up a little

good to know that my rpm's are the same as everyone else

thanks again for the info!

scott
 
dunlop direzza or something.....really nice winter tires.....i just bought the car and im not up on car tires since this is my first "car" i always drove jeeps or trucks

but i know they are dunlops for sure
 
Stickman said:
Question 3.

I've run mine to absolutely dry; rolled into gas station.
Filled absolutely to the very top of the fill tube, mine takes 15.8 gallons.
Edmunds owner specs show 14.5.

When calculating mpg, I fill & refill to the top, as different pumps will shut off inconsistantly. From pump shut off, I can usually get almost 1.4 gallons more to top of fill tube.
Click to expand...

uhh...your not gonna want to keep doing this, the gas pump shuts off for a reason
gas needs space to expand, plus u might be getting liquid gas in your evap system...which pretty much renders it useless
 
Facinating. Always learning from you guys on this site.

I'm a "numbers" analytical person, so always calculating.
At top of fill tube, I always knew I was calculating same amount.
Gotta keep this in mind from now on, only top fill when calculating.

Thanks for the info.
 
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