Performance differences - Hot vs Cool weather???

[enels57]

It actually cooled down to about 60 this morning and my bike seemed so much more perky than during the 85 - 100 degrees summer temps I am used to .
 
 
Should outdoor temperature make a big difference in how much power our bikes put out given that they are fuel injected?
 
 
Also, recently just had my ECU reflashed so I am trying to quantify the performance increase - I wish our dragstrip was open but they changed hands and are closed until January.  I could easily compare the two times I was there before the reflash to what it could do now but no such luck.
 
Anyway, can someone enlighten me on the effects of temperature with regard to max torque and horsepower on our bikes?
 
Thanks much

[fz07fanboy]

Colder air is more dense. Like the principle of turbo chargers with intercoolers. The purpose of the intercooler is to cool the compressed air the turbo creates before it enters the combustion chamber.

[Beemer]

 

[sorkyah]

Cooler air being more dense means it has more oxygen.. o2 sensor reads this as lean burn and richens the mixture to allow for proper combustion
hence the feeling of a more powerful/peppy bike
 
 

[enels57]

So should my fz07 seem like two completely different bikes all in one day...a perky young stallion at 60 F and a less excited old mare at 95 F? This time of year those temps are normal in AZ (along with low humidity)
 
That didn't surprise me with old fashioned carbs, but I thought electronic fuel injection would minimize that effect.
 
These same temperatures don't seem to affect my cars the same way.
 
Is just more noticeable with the reflash?

[norcal616]

Engines run better with nice cool/cold air... the best power I ever seen is just after a nice cool rain runs thru...something about that clean cool air...it's down to the mid-low 40s here at night  P-)... we even put our dirt bike gas on ice when we race or go ride...

[stefano225]

In hot summer days I usually put couple of ice cubes in my gas tank,what a difference   .

[fooschnickens]

Some states also switch to "cold weather blends" of gas. It has a higher rate of combustion that helps with cold starts and also makes it feel like your engine is running "better". The downside is that's it's a bit less efficient so your fuel economy will go down. Think of it like making a fire using pinestraw, burns super easily but doesn't last long.

[yamahappy74]

I noticed yesterday when it was in the 50s how much more easily the front would come up. Got some decent clutch ups in 2nd. Still learning though, and I don't get too crazy. I was grinning ear to ear the whole time.

[sorkyah]

 
 

Some states also switch to "cold weather blends" of gas. It has a higher rate of combustion that helps with cold starts and also makes it feel like your engine is running "better". The downside is that's it's a bit less efficient so your fuel economy will go down. Think of it like making a fire using pinestraw, burns super easily but doesn't last long.

 
Winter blends are usually more "light" hydro-carbons(propane/butane/heptane... etc) worse fuel economy, better cold starts
summer blends are usually higher in ethanol but contain much heavier hydro-cabon chains(kerosene/diesel/gasoline...etc)
So better fuel economy, more power, but due to higher temps you dont notice the excess power