13' Eco Towing Performanec

joshuajim wrote:

BenK wrote:
Add that the compression ratio of the gasser isn't high enough to attain the
temps needed to ignite without a spark

Plus the rate of burn (not explosion on regular gasoline compression
ratios...but on one high enough for self ignition...it *WILL* become
an explosion) for gasoline is too fast for compression ignition. A
gasoline engine with compression ratios high enough to self ignite
'can' do it...but not for long

..and I thought the PRE-IGNITION was ignition before the spark occured! Hmmm... guess I was wrong.

Guess you haven't read the OP's opening statement of higher octane
and the responses yes/no of using higher octane because of direct injection. So the why of your confusion...it is out of context

One poster thinking no longer need a spark plug because direct injection
is just like a diesel cycle...

My answer/comment is to those thoughts

Repeat and with more context of the topic at hand:

Direct Injection Ford F150 ICE does NOT have the compression ratio
needed for compression ignition. So it NEEDS a spark plug

Higher octane is to manage pre-ignition, or ping, or knock. There is
no more energy and only seems so because the computer will NOT back
off timing. Why some folks 'think' higher octane has more power...kinda
sorta yes, but no...just more advance allowed...therefore the engine
does produce more power with the same BTU content fuel

Even with direct injection, there is an air/fuel mixture after the
direct injection, which is before the planned/needed spark

During that period, there is a chance of pre-ignition/knock/ping/etc

The hotter the conditions (towing is one of the hardest on any ICE)
the higher the predisposition to pre-ignite, generally. There are many
other factors involved, but won't mention them here for now

Hope that clears your confusion on this matter