winter tread affects MPG?

[karl_karl]

I've just put on winter rubbers for my 94 and it seems my fuel efficiency has taken a dump. I used to get like 750 kms before a fill-up and now it's down to 650 kms. I just bought a BG44k emissions cleaning kit to clear up the engine but was wondering if winter tires really affect my fuel economy? Any thoughts?

[xtremeskier97]

I always forget which way it is...but either cold or hot air decreases MPGs. If it's cold that decreases it, maybe you're experiencing that + the tread...and it's making it that bad?

Just a shot in the dark here. Dont really know about the air temp thing..but the tread could possibly cause worse mpg...but it shouldnt be that significant.

Nothing else has changed on the car? Anything else replaced or different fuel used?

[Curry]

Are you sure you have them inflated to spec? Too low or high can screw up your mpg.

[gladis]

Originally Posted by xtremeskier97

I always forget which way it is...but either cold or hot air decreases MPGs. If it's cold that decreases it, maybe you're experiencing that + the tread...and it's making it that bad?

Just a shot in the dark here. Dont really know about the air temp thing..but the tread could possibly cause worse mpg...but it shouldnt be that significant.

Nothing else has changed on the car? Anything else replaced or different fuel used?

I'm thinking cold. I'm a complete noob at this, but it seems like the cold air (denser) would produce more oxygen for the fuel to combust with, and thus a more complete combustion, which should improve the power to fuel economy ratio.

It's possible that the treads, which in the snow encounter more resistance is forcing the engine to work harder to go the same distance.

[EvoFire]

That, and maybe they switched to winter blend gas. It is November already, and I remember reading that winter blend gas you get lower MPG.

[Blackhawk3D]

Any change in tire changes fuel mileage to some extent. Crr (Coefficient of rolling resistance) is different for every tread and sidewall etc so no two tires will give exactly the same mileage. This is different that Cf (coefficient of friction) which is what we want to maximize for grip. Friction is what makes our cars move forward. Rolling Resistance is caused by the flex of the sidewall etc and the wasted energy turned to heat by this deflection of the tire and other factors that I don't know much about so I'll stop rambling now.

[deezeejoey]

Cold air really fucks up ur MPG. Especially when you first start your car.

Then add snow... ice... tires slipping... engine revving, going nowhere... yeah, it sucks.

[vuspec]

IMO i think its just the cold...ur car takes time to warm up. usually when i start my car it starts at 800rpm but since the cold it start at 1500rpm. plus when ur driving in the cold ur car revs higher than normal to warm up the engine.

[deezeejoey]

Originally Posted by vuspec

IMO i think its just the cold...ur car takes time to warm up. usually when i start my car it starts at 800rpm but since the cold it start at 1500rpm. plus when ur driving in the cold ur car revs higher than normal to warm up the engine.

exact same with mine.
and the car is a lot louder.

[karl_karl]

I'll check the tire pressure, since I just got the tires put on I assumed the shp inflated them to spec.

As for gas, I always use the same brand. The temperature is not that low as of yet so we'll see what happens.

Can anyone tell me if you're supposed to change your oil BEFORE or AFTER using BG44k fuel injector products?

Thanks.

[Black95Cam]

Originally Posted by deezeejoey

Cold air really fucks up ur MPG. Especially when you first start your car.

Then add snow... ice... tires slipping... engine revving, going nowhere... yeah, it sucks.

everything else make sense, but shouldnt cold air provide better MPG?

when you first start, it idle so higher then normal is for the engine to warm up.

[Hajoca]

Cold air does give you denser air, but remember your going to have to check the cold tire pressure (eg first thing in the morning) and be sure that it is about 35 psi.
Cold rubber, grease and cold fluids are contributing to drag as well until it is warm. The engine loses efficiency at temperatures below 80 degrees C.

[EvoFire]

Originally Posted by Hajoca

Cold air does give you denser air, but remember your going to have to check the cold tire pressure (eg first thing in the morning) and be sure that it is about 35 psi.
Cold rubber, grease and cold fluids are contributing to drag as well until it is warm. The engine loses efficiency at temperatures below 80 degrees C.

I thought cold rubber has less resistance.

[TMetalMan]

It does (lower coefficient of friction), but when tires are cold, that means the air inside them is cold. Air expands as it heats up, so it shrinks when it cools down. A tire with "shrunken" air will have less pressure, allowing for more tread to contact the road. So from this perspective, colder temps can increase drag from the tires.

[Hajoca]

The tire will also flex more as it rolls, and the energy return from un-flexing is much less than what was put in, so there is another loss.