I only run premium. The guy that was helping me said it's fine as long as it's not detonating under load. Or hard to start he said with me running good gas time the hell out of it that's were Ur gas milage comes in
The longest I've ever driven mine at once was about 200miles at 75-80mph if that matters.

 

It has to have a trigger and sensor other wise the computer wouldn't know when to fire. This is obd-ll no mechanical timing all electronic. also my timing is around 20-23 degreese

 

Like I said before...it's not obd 2. Still has the old school ecc plug. Still has an adjustable dist and it's definately a 97.

 

"It is not for us...to question the Ford....For the Ford sometimes work's in strange & mysterious way's!...Rejoice in it's OBD1ness,...and take refuge in the fact that,...at least it's not a "Chevy"!
Amen.

 

Your compression ratio is?

At 16 BTDC & plugs side gapped at .052, my engine won't even fire on 91 octane.. Even w/ it's 60K volt coil.

 

You mean what the ECU adds to base time when timing advance is all in?

 

you sure about that?

 

Too be honest I don't have a clue what the ratio is but if I had to guess I'd say stock HO compression and it's gaped at .060 and timing is roughly 18-19degrees it starts spark knocking at about 22
I see u don't run premium. Should I step down a fuel grade? Or is there a reason for this. I always thought premium let u time higher and get better milage

 

My stock gap calls for .044, so .52 in addition to being side gapped is a stretch for me.

What octane are you running?

Octane choice...that's a question & a half. Gimme a few minutes, I'll be back...

 

dr bowtie:

I will try to make this as easy as possible....

1st of all let me explain Octane...the lower the number IE: 87 the QUICKER the fuel will ignite and the hotter it burns...on the other hand the Higher the Octane number the Slow the fuel is to ignite and the colder it burns...

the Octane rating of Gasoline or other fuels can quickly be derived from 2 parts...Compression and heat...The Octane rating of the fuel dictates how much Compression it can handle with Heat of the compression DIRECTLY related to it...

This means that 87 Octane can handle 8:1 compression with a higher cylinder heat rating than 89 Octane...

Now as you give the engine more RPM and it starts making power the cylinder temp elevates...the hottest point MUST be within the spec of the fuel or you get...? Detonation thats right...

87 octane will give you the best performance off the line but even 86 or even 85 will do even better...but the trade off is the heat rating...they simply cannot handle the same heat load....

As the Octane rating increases so does the heat range and compression the octane can support...this is why when you run higher compression you need higher octane fuel...simply to stay within the heat rating of the fuel at the engines maximum cylinder temps...

Now you ask can a lower octane support Higher Compression....simple terms yes...but to do so we MUST stay within the heat range...but we all know higher compression equals more power...actually it equals heat which in turn decides the power...Heat = Power...more heat more power usually...

Now since we decide we want to run higher compression on lower octane the simple thing to do is regulate the cylinder temp...but how do we do that? many ways...either dont run the engine into the RPM range where the heat will exceed the fuel....lessen the amount of ignition timing...but that makes less power all around and defeats using lower octane fuel...

The most common practice is to run the engine colder...IE lower Thermostat...lower engine temps mean lower cylinder temps normally...this is not taking into account racing or forced induction...this is stock normally aspirated engines...

So it is possible to happily run 87 Octane in an engine with 11:1 compression as long as you can control cylinder temps...there are much more factors that come into play as well like the "Squish" or "Quench" of the combustion chamber....

Basically like a camshafts Duration sets the Usable RPM range of the cam the Octane rating sets the Usable heat range of an engine...


But as I basically said the lower the Octane rating the Quicker and hotter the fuel burns but less pressure and heat it can handle....where as the Higher the Octane the more pressure and heat it can handle but slower it burns...

the difference would be like lighting 87 octane and watch it flash and then lighting Kerosene....but on a much bigger scale...

then there are fuels like Diesel with a very high rating that will not burn under its own....throw a match in diesel and it will go out...but atomize it and fireball...

Alcohol is a whole different breed...mostly because it is an Oxygenated fuel....

Here's a link to the thread, "Internal Combustion & You!":
https://www.f150forum.com/f11/intern...ion-you-36727/