does the CPU sense premium gas

=WD=big-X · Jan 30th, 2006, 06:38 PM

i hear the CPU in my frontier will sense premium fuel, adjust itself
accordingly and make more power.(06 4.0L)

anyone else heard this?

Misery-Tom · Jan 30th, 2006, 06:40 PM

if its setup anything like the titan, the ECM will actually retard timing when higher octane fuel is used

=WD=big-X · Jan 30th, 2006, 06:42 PM

your Titan looks VERY nice.

Misery-Tom · Jan 30th, 2006, 06:59 PM

thanks....

canuuu · Jan 30th, 2006, 07:51 PM

interesting. I like to 'splurge' and use premium in my 95 hardbody 2.4, but am I screwing up?.... I have a CEL on most of the time......havent run codes but it runs fine.....LOL.....I think. Any thoughts on this subject? thanks

Misery-Tom · Jan 30th, 2006, 08:07 PM

probly not messin anything up, the CEL is probly just a sensor

GTIMANiac · Jan 30th, 2006, 08:18 PM

Quote:

Originally Posted by Misery-Tom

if its setup anything like the titan, the ECM will actually retard timing when higher octane fuel is used

Retard or Advance?
I thought as you increased octane you would advance timing.

Misery-Tom · Jan 30th, 2006, 08:21 PM

no, the ECM's retard it, ( at least on the titan ) i can only assume the fronty would be similar

mainerunr · Jan 30th, 2006, 08:22 PM

The Fronty has been dyno'd on premuim. No gain.

http://www.reverendbiker.com/frontier/frontier.htm

GTIMANiac · Jan 30th, 2006, 08:24 PM

Quote:

Originally Posted by Misery-Tom

no, the ECM's retard it, ( at least on the titan ) i can only assume the fronty would be similar

Why on earth would it retard timing with higher octane? Performance is gained by advanced timing.

Misery-Tom · Jan 30th, 2006, 08:24 PM

thats because of the retard by the ECM, thats why most cars/trucks now a days recommend 87 oct fuel

GTIMANiac · Jan 30th, 2006, 08:26 PM

Quote:

Originally Posted by Misery-Tom

thats because of the retard by the ECM, thats why most cars/trucks now a days recommend 87 oct fuel

Well it the Frontier I have only owned German autos, Porsche, VW and Audi. I guess that is where my mind set comes from the German ECU tuning advances timing and always reccomends at least 91 octane.

jeffro · Jan 30th, 2006, 08:51 PM

I am pretty sure that it retards it also, it is supposed to be about the same no matter what fuel you use (within reason). Unlike my old hardbody that had to have mid-grade in order not to ping all the way down the road.

Jeff

Reverendbiker · Jan 30th, 2006, 11:18 PM

Quote:

Originally Posted by =WD=big-X

i hear the CPU in my frontier will sense premium fuel, adjust itself
accordingly and make more power.(06 4.0L)

anyone else heard this?

The VQ40 Frontier's owners manual states that 87 octane can be used but higher octane can be used for increased performance. That would mean that the ecm is capable of ADVANCING the ignition timing to create more power. Some--but very few--vehicles have ecm's that are capable of this, so I ran dyno tests and fuel economy tests, as carefully as I could, to determine if the VQ40 engine did the same. Dyno tests showed no significant horsepower or torque increase when using 93 octane instead of 87 octane. I got a very small increase in fuel economy when using 93-octane, but it was so small that it didn't justify the additional cost. See the tests here:
Dyno tests--93 vs 87 octane
Fuel Economy--93 vs 87 octane
My truck runs great on 87-octane fuel and delivers nice gas mileage; I see absolutely no reason to spend my hard-earned cash on the expensive stuff.

GTIMANiac · Jan 30th, 2006, 11:41 PM

I have a tank of 87 in right now. I will log data on my way to and from work and post the xls files tomorrow. Then in a week or so I will run 91 through it and post that data as well. My equipment will only log at about 3hz but it is better than nothing.