Posts: 3065
Joined: 1/18/2007 From: Las Cruces, NM Status: offline
I ran both of these tools, they came out about almost a point higher than my calculations for my sons engine, so I ran my figures again, same result. Has anyone else checked these links against their own figures? Seeing that BOTH of these came out higher than my figures, it seems that it is probably my math that is suspect, but I would like to know for sure!!
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66 Coupe I-6 Conversion, 408 Windsor, Tremec TKO 600 Wilwood fronts, SSBC Rears 9" Track Loc.
"This sticker is dangerous and inconvenient, but I do love Fig Newtons."
Posts: 3065
Joined: 1/18/2007 From: Las Cruces, NM Status: offline
Yea,,,, I did have a "math issue" I was failing to add the total cumbustion chamber volume to the cylinder displacement prior to dividing. OOPS.
So, I guess I will be running 11 to 1 instead of 10 to 1, hopefully my cam selection and the altitude I am at will help a little.
There are some cool calculators in this section.
Are you running at 13 to 1 CR? If so what are your octane requirements? To be honest I am a little concerned at running 11 to 1, even with my alum heads, my camshaft selection, and my home elevation of about 4,000 feet.
(I would like to hear that you have no problems running pump gas, but .... tell me the truth anyway, I can take it!!!)
< Message edited by JMD -- 3/7/2007 12:14:42 PM >
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66 Coupe I-6 Conversion, 408 Windsor, Tremec TKO 600 Wilwood fronts, SSBC Rears 9" Track Loc.
"This sticker is dangerous and inconvenient, but I do love Fig Newtons."
Yes, that is my 390HP. I run 91 octane pump gas and have taken out about 6 degrees of timing. It would definitely like more octane, but at 8 mpg, she isn't going to have a diet of racing gas. Only treats.
My 12.5:1 302 runs on 91 octane with about 4 degrees taken out.
I'm around 5k feet.
EDIT:
Forgot to mention a little known tidbit about your local octane rating. 91 octane gas in Denver isn't the same octane as 91 octane in LA. The octane rating uses the elevation of the target area in determining what the octane rating will be. This is part of the reason why your owner's manual says to use 87 octane no matter what elevation you are at (at least my '03 GT says that). I'm pretty sure racing fuels aren't rated this way.
< Message edited by Colorado_Mustang -- 3/7/2007 7:57:13 PM >
my set up says about a 10.5 comp, the calculater says 10.3//// not enuff to makae a diff and make me mad ..lol i cam get a smaller gasket thickness nexttime..
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quit lookin at the pic to the left,and listen to what were all sayin!!!
Posts: 3065
Joined: 1/18/2007 From: Las Cruces, NM Status: offline
Hmm...
So, then gas bought at a higher elevation should be cheaper to produce than gas sold at sea level,,, I don't imagine that the high elevation consumer ever sees this benifit...
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66 Coupe I-6 Conversion, 408 Windsor, Tremec TKO 600 Wilwood fronts, SSBC Rears 9" Track Loc.
"This sticker is dangerous and inconvenient, but I do love Fig Newtons."
I found this while researching my own compresssion issue. Thanks for this alternative.
Good luck
thanks man .. dam i got 2500 hits , yes i was c/note at one time. its fairly close the link i had . like some one else said has anybody checked to a real blueprinted eng? i havent .all i got to be is close. with 262 / 274 at .050 lift.and .701 lift, it dont matter if i got 12to1 or 11.5 to1 on the spray baby 408w.
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compression calutator - 
