Any benefits to high octane
Are there any benefit to running octane gas when towing? I had heard when towing use high octane gas.
Forum Discussion
eichacsj wrote:
No. Just keep running what you normally do. With today's ECM's they "learn" and it takes 2 - 3 tanks for it to balance back out, if you switch for a couple of tanks you will not get the results you are thinking about.
Also as said above, follow the MFG recommendations but as a note also stated above octane requirements go up depending on the compression ratio. You'll notice manuals with ratios around 10:1 or above generally requires premium.
Not true on my car with "today's ecm and not likely true on any.
Octane requirement aside, the "learning" involved, is instantaneous. A knock sensor or multiple knock sensors detect pre-ignition (detonation) as a certain frequency of vibration in the engine block. When that vibration is present, the knock sensor signals the ecm to adjust ignition timing to compensate. On newer engines, both 2 stoke and 4 stroke it happens instantaneously and silently.
My snowmobile actually has a light on the gauge that blinks when detonation occurs and it starts pulling timing. Great feature on 2 smokes. Saves a lot of burned up pistons.
Wifes SRT8 runs fine on low octane, but fuel mileage is down, low end power is down and it's generally rougher sounding/feeling if you floor it with cheap gas. Under the right circumstances can actually make it ping just a little. Put the octane back and it runs smoother and faster.
The 6.4 truck Hemi is designed to run on 87 or 89, from what I've read and will hand out a few more ponies on higher octane. Not sure if theres and advantage to running premium though.
