BP Ultimate means engine quicker warm-up? - Toyota Yaris Forums

jkuchta · 12-16-2008, 12:06 AM

The Octane rating of the fuel has nothing to do with flame front speeds....in other words regular and premium fuels take the same amount of time to burn.

As far as our car's ability to "sense" the type of fuel in order to advance timing...that's not how it works. The ECU runs the most advanced timing it can, and retards when detonation is detected. The manual says the car can run on regular, not that it was designed to run on regular. Barring any information as to the specifics from Toyota about how aggressive the timing was programmed to get, and taking into account the fact that the 1NZ runs a pretty high compression ratio of 10.5:1, I would posit that the ECU has the capability to retard timing to run on regular, rather than no ability to take advantage of premium.
I would also through out the idea that running regular gas in hot/dry climates may be running the ECU pretty close to it's limit of compensation. I say this because LtNoogie basically couldn't run his new supercharger in pretty cool/wet conditions under any kind of load without getting detonation on regular gas. The Blitz kit is only putting out around a half a bar of pressure, which, if the ECU was programmed specifically for regular gas, should not max out the ECU's ability to adjust the timing to that extent. If he was able to run O.K. on regular (detonation only under extreme load/high ambient temps.), then I would be a little more receptive to the idea that the car was designed to run specifically on regular.

The bottom line for me is this:

Will the car run fine on regular? Yes it will.

Will the engine be producing its maximum performance on regular? No. Detonation will cause the ECU to retard timing, thus keeping the engine from seeing the most advanced timing that it can.

If anyone has any hard data from Toyota concerning the ignition and anti-knock programming for the ECU I would really appreciate it.

Also, if anyone with a scangauge running regular could post some data about their ignition timing vs. load and intake temp that would be really cool. I’ve posted my data here: http://www.yarisworld.com/forums/sho...2&postcount=14

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12-16-2008, 12:06 AM	#26
jkuchta View User's Garage Drives: 2007 Yaris hatch (red) Join Date: Sep 2007 Location: L.A. Posts: 557	The Octane rating of the fuel has nothing to do with flame front speeds....in other words regular and premium fuels take the same amount of time to burn. As far as our car's ability to "sense" the type of fuel in order to advance timing...that's not how it works. The ECU runs the most advanced timing it can, and retards when detonation is detected. The manual says the car can run on regular, not that it was designed to run on regular. Barring any information as to the specifics from Toyota about how aggressive the timing was programmed to get, and taking into account the fact that the 1NZ runs a pretty high compression ratio of 10.5:1, I would posit that the ECU has the capability to retard timing to run on regular, rather than no ability to take advantage of premium. I would also through out the idea that running regular gas in hot/dry climates may be running the ECU pretty close to it's limit of compensation. I say this because LtNoogie basically couldn't run his new supercharger in pretty cool/wet conditions under any kind of load without getting detonation on regular gas. The Blitz kit is only putting out around a half a bar of pressure, which, if the ECU was programmed specifically for regular gas, should not max out the ECU's ability to adjust the timing to that extent. If he was able to run O.K. on regular (detonation only under extreme load/high ambient temps.), then I would be a little more receptive to the idea that the car was designed to run specifically on regular. The bottom line for me is this: Will the car run fine on regular? Yes it will. Will the engine be producing its maximum performance on regular? No. Detonation will cause the ECU to retard timing, thus keeping the engine from seeing the most advanced timing that it can. If anyone has any hard data from Toyota concerning the ignition and anti-knock programming for the ECU I would really appreciate it. Also, if anyone with a scangauge running regular could post some data about their ignition timing vs. load and intake temp that would be really cool. I’ve posted my data here: http://www.yarisworld.com/forums/sho...2&postcount=14