I have the mods listed below. Sometimes my Mini seems very quick and powerful, sometimes much less so. It seems to be a day-to-day thing. That is, if it's strong in the morning it stays that way all day and vice versa. I always use the same brand of gas.

I'm at a loss to explain it. Anybody have any ideas?

Thanks

V3

 

Without a boost or intake temp gauge you can't know for sure, but it's probably boost related.

 

Check your bypass valve. It can be stuck slighlty open and cause a huge drop in boost.

 

What intake temp gauge are you using? Is the probe after the intercooler?
I agree that the more info you have at hand the easier it is to understand conditions affecting performance/trouble shooting the car.
Air temp and humidity play a large part.

 

I read the IAT sensor data.

 

Thanks, I'll take a look.

 

Well, the outside temp. is another small factor.

 

Try Big...

 

But he says day to day, not morning to night.

And I see Zak's back online.

 

If your tank is full of gas, the car will weigh a lot more, i.e., gas probably weighs maybe 8 lbs per gallon or so. Carrying passengers adds even more weight. Your A/C robs power too. Also as others just said, air temperature makes a huge difference, as cool air is more dense -- I think it has more oxygen in it. More oxygen (in the same air mass) equals more power. :smile:

 

Also, some days the butt dyno is crankier than others.

 

It's definately more than subtle. Some days the Mini feels super strong, somedays just stock. It doesn't seem to have anything to do with gas tank fullness (I doubt I could guess how full the tank is based or performance alone). I almost never have passengers. Two subsequent hot days can still mean wildly different amounts of power. It's almost as if there were 2 ecu programs: mild and wild.