Getting the most mileage out of your gas.

[skeeters_keeper]

155/80/13 should be about the best mileage tires... you want skinny and tall. but buying a new set of wheels/tires will offset the savings for the next few years!

most of your mileage comes from the way you drive + having a properly tuned car... festivas get the best milege around 50-55mph (i did a full tank at 55mph and got around 52mpg, when i'm going 65-70 i only get 45 or so)

of course if you have a 4spd carb'd then a 5spd FI will get you quite a bit of mpg too...

[Pu241]

correct size for festy is 185/60/14 or equivelent... proven w/ radar and rolling road. this will result in lower mpg figures though, but they will now be accurate mpg figures.

So the P145/80/12's that are OEM are not the correct size tires?
Please let us know how you determined this!
Because with 185/60/14's your speedo and Odo. are going to be off!

Pu241

[kuntry_boi06]

they say from 0-10mph is what takes the most gas, but my question is if i am going 0-45 does it save more gas getting there really fast and just cruising, or going really slow?

[FestYboy]

pu241: i found the correct size by doing a little math with known values (circumferance of tire, final gear ratio, speedo gear ratio, etc.) and then found the absolutley closest tire/wheel combo possible and tested it. while on a dyno i matched indicated speed with actual (dyno) speed and was within .5 mph, this is how i know this....

so it's still 185/60/14 or equivalent.

[Pu241]

pu241: i found the correct size by doing a little math with known values (circumferance of tire, final gear ratio, speedo gear ratio, etc.) and then found the absolutley closest tire/wheel combo possible and tested it. while on a dyno i matched indicated speed with actual (dyno) speed and was within .5 mph, this is how i know this....

so it's still 185/60/14 or equivalent.

So what your saying is that everyone not running a 185/60/14 tire is getting incorrect speed and Odo. readings?
And that the KIA/Mazda engineers really screwed-up because there is a substantial difference between the OEM 145/80/13 and your "proven" 185/60/14!
Oh, and where did "radar and rolling roads" come in to play with your calculations?

Pu241

[25Horseplay]

Try this tire size calculator, it will tell you speedo differences. http://www.net-comber.com/tirecalc.html

[darkdan]

Things that worked best for me:

1.) www.auto-rx.com

2.) :

[img][http://home.mchsi.com/~etornnad/ramair.jpg[/img]

3.) FP60 by www.lubecontrol.com

4.) Synthetic engine oil/atf


That's in order of how well it worked. I've been tracking my gas mileage on every tank for 3+ years now.


Actually, I suppose #1 should be "fixed head gasket when I bought it". That took it from 18 mpg to 30!

[roycehof]

Skeeter Keeper is right on with I have experienced. Typically I'll get around mid 40's MPG going 70 to 75 and I have gotten 50 on a trip by staying around 60. These cars are about as aerodynamic as a cinderblock, so that extra 10 to 15 MPH's really affect the gas mileage. I'm afraid to hold the speed at 50 to 55, for fear of somebody flipping out with road rage. I find in the Mid-Atlantic area if you are in the right hand lane and stay around 60 to 05 that is adequate speed to keep the raging lunatics in check and still deliver gas mileage in the mid 40's. Just thought I would pass on what I know about gas mileage with a stock 5-speed EFI Festiva. Oh yeah, my Winter mileage is typically 2 to 3 mpg's less (number above were Summer numbers). (Must be the engine running a little rich until it warms up and of course, sitting there idling while you clear your windows)

[roycehof]

Hey I have a typo 4th line down - that should say- stay around 60 to 65. Sorry

[Dwane]

I rebuilt the stock engine and swapped to the 5 speed trans and put 14 " rims with 155 55 14's with 1/2" wheel spacers and I'm getting 63 mpg hwyIMG_20170317_104428128.jpgIMG_20170317_104439082.jpgIMG_20170317_104446846_HDR.jpg

[ryanprins13]

This is super old but a good thread anyway.

I use a block heater. Winter gas milage is always worse than summer.

I do as well. If your just after saving money keep in mind that block heaters add a decent amount to your electric bill and you should at least use a timer.

Here is a link that suggests that adding acetone will improve gas mileage by 20-30% http://www.diylive.net/index.php/200...r-gas-mileage/

What do you think?

I tried it years ago. Made no difference on my festiva. Sold the rest of the acetone to my parents
All fuel milage gas tank additives i tried didnt work, some actually worsened it a lot. Canadian tire motomaster fuel injector cleaner cost me 6mpg!

they say from 0-10mph is what takes the most gas, but my question is if i am going 0-45 does it save more gas getting there really fast and just cruising, or going really slow?

Its half way in between. Acellerating super slow is bad and super fast is bad for milage. Around 5 inhg on a vaccum gauge is what you want.
Guys who do long distance racing get into that a bit more. Its been quite a while but i learned a bunch from their forums.



Best fuel milage tool i have is a vaccum gauge. Watch it. Keep the reading steady on the flat. Most people drive accellerating and then decellerating all the time, which isnt that great.
If your doing 100km/hr and you go up a hill be doing 90 at the top, speed up to 110 or 120 going down the other side and when it flattens out use your vaccum gauge to slowly wear off that speed back down to 100 over the next mile or 2.

Going up the hill you dont want to slow down to 90 right at the bottom or half way up and then hold 90 the rest of the way. You want to continue decellerating linearly the entire length of the hill and have just slowed down to 90 or whatever by the crest. That takes practise.
Same with going down the other side. You dont want to be doing 110 or 120 as soon as you start the decent and then have to brake. Your goal is only to be doing that speed by the bottom.
Sent from my SM-G920W8 using Tapatalk

[FestYboy]

I rebuilt the stock engine and swapped to the 5 speed trans and put 14 " rims with 155 55 14's with 1/2" wheel spacers and I'm getting 63 mpg hwy[ATTACH=CONFIG]20709[/ATTACH][ATTACH=CONFIG]20710[/ATTACH][ATTACH=CONFIG]20711[/ATTACH]

Your tire size will cause your odometer to lie to you. By 5.8% to the positive...

[TominMO]

Your tire size will cause your odometer to lie to you. By 5.8% to the positive...

Yeah, those tires are about 1" less diameter than the 155/80-12s, and 2" less diameter than 155/80-13s. With such short tires, his mileage would more approximate what you get with a 3-speed Festy auto trans, due to higher rpm.

Plus he has not told us what his testing protocol is, or how many trips he took to check consistency, or what speed he was going, or how he filled the tank. Getting a true 63 mpg is highly unlikely at hwy speeds, unless he had a great tailwind.

Give us more info on what you did, Dwayne.

[william]

Or he's pulse and glideing!
Can't forget about them hypermilers tom.

[WmWatt]

Ray writes re block heater: "I do as well. If your just after saving money keep in mind that block heaters add a decent amount to your electric bill and you should at least use a timer" I just go out an hour or two before going anywhere and plug in the heater. Yes there is a trade off between gas saved and electricity consumed and I wish some government environmental agency would do some tests and give us an idea of what it is. Here in Ottawa you can borrow an electric power meter and plug the electrical cord into it which I've done for the block heater and some household appliances as well. At the time it cost 1.5 cents per hour to use the block heater.

Ray also gives some speeds but Amercians need to keep in mind those are kilometers per hour. My Festiva doesn't get up to 100 in mph.

I'd also like to add I think snow tires increase milage in winter because ordinary tires slip more on ice and snow. But take them off when snow season is over because the rough tread creates drag on bare pavement. You can actually feel the drag riding a bicycle with knobbly off road tires on pavement.