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Discussion Starter #1
i'm at 4100 elevation and it looks like i can get 100 LL from the airport i can only get 91 out the pump locally, and the car is only for the strip right now ,is it worth running the 100 octane or should i just go with the sonoco 110 or something along that nature

motor is a 11:1 557 solid roller motor with aluminum BT heads and a victor intake and a dominator


thanks
rick
 

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My engine builder Guru informs me that with that comp. ratio you should be running a minimum or 105 octane. Of course I'm running iron heads and have quite a bit of quench area ( 11.2:1 and I'm basically @ sea level), you might need a little less with your aluminum heads???......Somebody help us out here....
Rob
 

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i'm at 4100 elevation and it looks like i can get 100 LL from the airport i can only get 91 out the pump locally, and the car is only for the strip right now ,is it worth running the 100 octane or should i just go with the sonoco 110 or something along that nature

motor is a 11:1 557 solid roller motor with aluminum BT heads and a victor intake and a dominator


thanks
rick
100LL has a 100 Motor (M) octane rating, not 100 Research (R) Octane Rating, and not 100 (R+M)/2 (<---like most pump gas) octane rating.

It has 2 grams per gallon lead in it and can help substantially with detonation control. It's physical properties are different than race gas and pump gas. At 11:1 with aluminum heads (and assuming good quench), I think you should run 91 octane pump gas with some 100LL blended in, perhaps 50% or possibly less than that....and then time/jet your engine accordingly.

Paul
 

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^^^

Great link Paul,

Next time on the dyno with my re-build (13:1) I hope that after I tune it on C-12 I plan on running my Av gas 91 mix (4:1) and seeing what I get. In 2000 with 11:1 on a 4:1 mix Av gas 91 with no tuning changes the Av gas made 850 hp at 6,800 vs 855 at 6,800 on Trick 104. We didn't re-jet or change the timing.

G-

Jon
 

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AV gas mix

I mix AV gas with 87 pump gas. 50/50. I have been running it that way for yrs on numerous BBF strokers. my current motor is 557", flat top pistons, zero deck with Ford Racing SCJ Aluminum heads. my guess is 13:1. smallish roler cam. dyno showed 843 hp at 6200 with 28 degrees timing and 803 torque at 5100 with 26 degrees. of course its in a boat so I can keep it pretty cool. cool enough to hold my hand on the head when running. boat runs good! also has a 200 shot NOS on it just in case.
 

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I mix AV gas with 87 pump gas. 50/50. I have been running it that way for yrs on numerous BBF strokers. my current motor is 557", flat top pistons, zero deck with Ford Racing SCJ Aluminum heads. my guess is 13:1. smallish roler cam. dyno showed 843 hp at 6200 with 28 degrees timing and 803 torque at 5100 with 26 degrees. of course its in a boat so I can keep it pretty cool. cool enough to hold my hand on the head when running. boat runs good! also has a 200 shot NOS on it just in case.
What the hell stoke do you have in that thing and what intake manifold?

Your combo has made me scratch my head more than once ????

My 565 is (4.60 x 4.25) made 765 lbs ft at 6,000 (874 hp) and 935 hp at 7,000. I wanted power to 7,000. The restrictive 1050 dommi is holding it back, but we'll see this year after the re-build and it runs with the 1,200 and 1050 on the same dyno.

This time I'll spin it a bit past 7,000 on the dyno to see what's up stairs and give us some ideals on the cam.

G-
 

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Discussion Starter #8
thanks guys, i think i might give it a go and see how it turns out, finally back from afghanistan again and ready to play with the car

rick
 

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thanks guys, i think i might give it a go and see how it turns out, finally back from afghanistan again and ready to play with the car

rick
Military or contractor ?

G-
 

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One thing that I really like about 100 LL is that it is very stable. I just opened the fuel cap on my boat that has been setting a long time and the gas still smells good. If that were 93 octane it would have turned into shellac a long time ago !

Gary :)
 

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Discussion Starter #13
thanks

on the side note i was thinking of 50% 100 LL and 50% 91 octane would this take care of the "dry" that people talk about and give me the lubrication properties that are desirable and also let me read the plugs for tuning?


rick
 

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For a little lube in when I ran it in the engine with 11:1 ( 10.8:1) actual I ran it at 2:1 ( 10 gal av gas 5 gal 91) most of the time some times at 3:1.

A little bit of 91 helps. Some people don't like running it or are afraid of it when Bruce Crower told me it was fine to run I stopped listening to those who said it was bad.

I hope to be able to do some C-12/Av gas comparison testing in a month or two when I'm done with my other testing.

G-

Jon
 

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Discussion Starter #15
think i'll try the 3:1 and try tuning and going from there, i assume i would need to lean it out for the higher octane level and drop some timing ?


rick
 

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Don't quote me on this but I think that you have to actually go richer on the jetting with 100 LL. It was a long time ago so my memory may not be right. Check on it to be sure.

Gary :)
 

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Don't quote me on this but I think that you have to actually go richer on the jetting with 100 LL. It was a long time ago so my memory may not be right. Check on it to be sure.

Gary :)
I guess is depends on what the baseline was. If he knows and his mixture.

Example: VP C-12 has a specific gravity of .717 = 5.99 lbs per gal

100LL is 6.02 lbs per gallon

For many engines the tuning might be a single jet size.

G-
 
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