No. 4 – OK, discuss to me like I am silly. I assumed I ethanol burned extra slowly, which is why you see dramatically elevated BTDC° on E85 tunes.
IIRC accurately from having E85 tunes and datalogging on the my first gen BRZ, the E85 tune would have as a lot as 50° BTDC ignition advance on throttle tip-in.
In reply to z31maniac :
E85 is bizarre, it is more durable to get the fireplace began however when it does, it burns extra rapidly. That quick burning might be the place a goodly portion of its detonation resistance comes from, gasoline that burns rapidly would not have as a lot time to detonate.
Pondering additional, the smaller chemical chains possibly react with oxygen extra readily than longer ones? However earlier than that time, it absorbs warmth quicker so the burn is more durable to get going?
That stated, I had alternative to check and distinction an E85 tune to a C16 tune on a excessive powered, pretty low revving pushrod engine, each tunes finished by the identical (effectively regarded) tuner, and the timing maps have been virtually an identical, at the least within the enhance areas. That shocked me sufficient to make an impression. (The engine made one thing like 12% extra energy on E85) The tuner did inform me that you’d by no means get C16 to detonate, so the C16 tune at the least would have been at MBT timing.
I can see needing extra timing underneath mild load, that is the worst so far as ignition goes as a result of there’s simply not that a lot in there to ignite.
In reply to z31maniac :
Ethanol is a small hydrocarbon, particularly when in comparison with common gasoline, and small molecules are typically far more secure at excessive temps and pressures, so that they have a a lot increased knock rating- it is not about flame pace that decides what the octane is.
In reply to Pete :
Methanol bringing it is personal O helps so much by way of finest power- it might run significantly richer and nonetheless burn rather well. So you’re appropriate. It actual downfall for nominal automobiles is that the power density provides you worse gasoline financial system than gasoline.
Thanks gents, I went in search of extra solutions whereas I used to be ready for responses right here. And the “it is onerous to get the fireplace going then it GOES” is what I additionally discovered relating to E85 kind stuff.
You do not want intercooling with alcohol both.
Years in the past Butler Efficiency constructed a boosted Pontiac 455 operating alcohol. There’s frost on the manifold within the dyno photos.
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