Hey tuners... question about my fan.

lancruza · Aug 19, 2023

I have an 09 CityX running a Buell race exhaust and a matching race tune on my ECM. Bike is running GREAT! I think it's running the best since I've had it.

I have a question about my cooling fan. My fan is running a lot LESS with this tune than it did before. I'm not complaining, just curious. Is the fan controlled be a heat sensor?
I'm guessing my bike was running too lean before, therefor it ran hotter and the fan took longer to run to cool the bike down. With the proper tune the lean condition has been corrected.

Would this be the reason my fan is running less?

Barrett · Aug 19, 2023

Levan: YES to all of the above. And that Cherry Bomb SX is a beauty.

Cooter · Aug 19, 2023

These lots of reasons why the fan is running less and all pretty easy to find a better definite answer! Fun diagnostic times for us dorks

#1 I would suspect ambient temp is lower and key off fan settings the change with the Race Tune.

I dis-agree with the commonly repeated old wives tale that running stock vs. race tune would change the engine running temp at all for many reasons. I know it is an overly common thing to read, but facts say it's wrong. 'Running too lean can make your engine hot' is true, BUT it hasn't applied since the 90's.

Fact: The EPA wants the least amount of emissions. Running even slightly lean = terrible emissions. Running lean enough to make the engine temp go up is drastically too lean.

Fact: Fuel injection is adjusting constantly in Closed Loop, searching for the perfect mixture (best emissions are there too, so the EPA wants that). That perfect mixture can NOT be lean. Again, the EPA hates lean because you get terrible emissions when lean (High HC, High CO, High NoX) and yes, higher engine temp too.

Fact: The Closed Loop targets OE and 'Race Tune' are the same, meaning your bike is running identically to the OE tune while in CL. Which is anytime you are not at WOT or making aggressive throttle changes. So 98% of the time (including idling) it is running identically to OE. Same tune, same temp.

I also wouldn't assume the fan running less anything to do with engine temp, because I would assume the fan settings were changed with the tune. I don't know which race tune you have as the market is so diluted with them and mis-labelled now, but I find that 98% of the time (including the IDS "Buell Race Tune") settings are different than OE. And sadly the ones from unknown sources have them dramatically different or even reversed(!!) compared to a stock tune. Very easy to look up though using ECMDroid, ECMSpy, or TunerPro. I forget if you have that ability or not? But its worth a look to be sure, and I'm willing to step you through it if you want to know!

There are fan temp ON and OFF settings for both ignition ON and OFF, as well as a "speed-based" fan setting that simply runs the fan continuously above +/-25mph for extra noise, wear, and no additional cooling:down:

TL;DR
Fan settings changed with the tune:eagerness:

lancruza · Aug 19, 2023

Barrett said:
Levan: YES to all of the above. And that Cherry Bomb SX is a beauty.

Thanks John

lancruza · Aug 19, 2023

Cooter said:
These lots of reasons why the fan is running less and all pretty easy to find a better definite answer! Fun diagnostic times for us dorks #1 I would suspect ambient temp is lower and key off fan settings the change with the Race Tune.

I dis-agree with the commonly repeated old wives tale that running stock vs. race tune would change the engine running temp at all for many reasons. I know it is an overly common thing to read, but facts say it's wrong. 'Running too lean can make your engine hot' is true, BUT it hasn't applied since the 90's.

Fact: The EPA wants the least amount of emissions. Running even slightly lean = terrible emissions. Running lean enough to make the engine temp go up is drastically too lean.

Fact: Fuel injection is adjusting constantly in Closed Loop, searching for the perfect mixture (best emissions are there too, so the EPA wants that). That perfect mixture can NOT be lean. Again, the EPA hates lean because you get terrible emissions when lean (High HC, High CO, High NoX) and yes, higher engine temp too.

Fact: The Closed Loop targets OE and 'Race Tune' are the same, meaning your bike is running identically to the OE tune while in CL. Which is anytime you are not at WOT or making aggressive throttle changes. So 98% of the time (including idling) it is running identically to OE. Same tune, same temp.

I also wouldn't assume the fan running less anything to do with engine temp, because I would assume the fan settings were changed with the tune. I don't know which race tune you have as the market is so diluted with them and mis-labelled now, but I find that 98% of the time (including the IDS "Buell Race Tune") settings are different than OE. And sadly the ones from unknown sources have them dramatically different or even reversed(!!) compared to a stock tune. Very easy to look up though using ECMDroid, ECMSpy, or TunerPro. I forget if you have that ability or not? But its worth a look to be sure, and I'm willing to step you through it if you want to know!

There are fan temp ON and OFF settings for both ignition ON and OFF, as well as a "speed-based" fan setting that simply runs the fan continuously above +/-25mph for extra noise, wear, and no additional cooling:down:

TL;DR
Fan settings changed with the tune:eagerness:

The tune I have is from Rev-Mo. I've noticed a completely different fan "personality" with this tune. I took a short ride a couple of days ago to a local cantina and ate lunch. It's about five miles away. When I got off the bike, the fan started as normal. As I got to the front door, the fan cut off. That NEVER happened before. Such a short fan run time. I eat lunch, ride back home, shut the bike off and the fan didn't even come on. On longer rides, the fan will run after the bike is turned off, but not as long as before. I was, "assuming", lol, and I know what that usually gets me, that by the fan not even coming on, when it normally would have, that there was less need to cool. I have a LOT to learn.

How do I determine the correct fan settings?

Thanks Cooter for the input.

Cooter · Aug 20, 2023

Happy to help

Rev-Mo changes those fan settings for sure. OK to leave them alone, but easy to change back to OE temps if you wish? I wouldn't worry either way.

If you wanna mess with them, it's literally under "fan settings" in the ECM parameters on ECMDroid. I wouldn't change them more than 20* or so from stock, but it's a long way between the 170*-ish where it turns on to the 290* where it's actually overheating and safeties intervene.

It turns on when you shut the bike off because the 'key off' settings are usually 10* or so lower than the 'key on' settings. Pretty normal settings.

You can see what your old settings were by loading that program back into ECMDroid (no need to flash the ECM), write them down, load the Race tune, change the settings, hit the 'Apply' button, flash the tune on to the ECM. Done.

Hey tuners... question about my fan.

Help Support Buellxb Forum:

lancruza

Well-known member

Barrett

Well-known member

Cooter

Well-known member

lancruza

Well-known member

lancruza

Well-known member

Cooter

Well-known member

Similar threads

Latest posts