m always running off of the cheap stuff when i fill up. But a bud of mine runs the highest stuff in his 66 with pretty much exact same setup as me.. is there any advantages/disadvantages for running the good stuff in ani old engine like ours?
octane
- Thread starter Cobain03
- Start date
thehueypilot
Active Member
It depends on your compression ratio and/or how much your timing is advanced. Higher octane resists detonation (spark knock) better then lower octane fuels.
65fastback2+2
New Member
taylor4g63
Founding Member
thehueypilot said:
Yep thats pretty much it. If you have high compression (i'd say higher than 9.5:1 with iron heads), you're gonna have to run 93 or whatever the highest available is. With higher octane you can also advance the timing a bit thus producing more power. If your motor runs fine on the cheap stuff then i'd stick with that unless u mess with the timing.
67coupe351w
New Member
65fastback2+2
New Member
67coupe351w said:WHERE do I find some of that?
look at the bottom of the gas list it'll say $2.50, now look up at the top, it'll say $2.20, $2.20 is cheaper than $2.50 thus making that the cheap stuff
65fastback2+2
New Member
Yo.
heHeh heh Well not really.
Roy.
=============
Hey whats up?
Have you guys screwed up our avatars trying to restore stuff?
I mean - heres mine. View attachment 518052 It'sa a graphic crash helmet desighn done by Dutch.
This is a post crash change.
Roy.
Carefully refraining from comment.65fastback2+2 said:
heHeh heh Well not really.
Roy.
=============
Hey whats up?
Have you guys screwed up our avatars trying to restore stuff?
I mean - heres mine. View attachment 518052 It'sa a graphic crash helmet desighn done by Dutch.
This is a post crash change.
Roy.
65ShelbyClone
Founding Member
65fastback2+2 said:$2.20 is cheaper than $2.50 thus making that the cheap stuff
No, $2.20 is less expensive than $2.50. None of it is cheap.
Anyway, if you're not pinging on 87 the be happy it works for you. I had a 289 with factory heads and flat top pistons and I ran 87. Higher octane in and of iteself does not make more power. Heck, if you dont need it you might even lose a small amount.
Another consideration of the modern fuels in a vintage engine is the lack of lead and your valves. If you have factory heads you are going to need hardened seat-inserts and modernized guides. You either need them now or you will when your heads are being rebuilt becuase you waited.
I filled up for $2.03/gallon in my 21mpg 2005 GT this morning
I filled up for $2.03/gallon in my 21mpg 2005 GT this morning
65fastback2+2
New Member
limey66 said:
and this is where i kindly say, sucks to be you.
edbert said:
wow, so what was 87 octane??? like $1.90??? cuz i know you didnt put 87 in that car since it requires premium 93
krash kendall
Active Member
I'm running 89 in mine. The 87 makes it run like crap and burn more fuel, so what I save at the pump I lose in mpg. Running 91 gives me the same result as the 89 so I save my money and go with the less expensive of the two.
I live 5 minutes north of Washington state and gas is the equivalent of $4.93 / gallon here.
I live 5 minutes north of Washington state and gas is the equivalent of $4.93 / gallon here.
brianj5600
Active Member
At the same heat and pressure. The resistance to pre-ignition allows more heat and pressure w/o pinging, and more cylinder pressure, and more power.Max Power said:
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