Saturday Night Racer

Saturday Night Racer
http://www.latemodelracer.com/cgi-bin/yabb2/YaBB.pl
Saturday Night Racer >> RACE TECH >> Octane Calculator
http://www.latemodelracer.com/cgi-bin/yabb2/YaBB.pl?num=1325730546

Message started by dirtmopar44 on 01/04/12 at 6:29pm

Title: Octane Calculator
Post by dirtmopar44 on 01/04/12 at 6:29pm

Thought I would share this with everybody.I keep in my race log book. http://www.motorsportsracingfuels.com/OctaneCalculator.html

Title: Re: Octane Calculator
Post by triplexl46 on 01/08/12 at 6:23am

This may be a really dumb question but how do you determine what octane you should be using???

Title: Re: Octane Calculator
Post by dirtmopar44 on 01/08/12 at 12:32pm

This is just a general rule of thumb that was on the net
Compression ratio = Octane
5:1 =72
6:1 =81
7:1=87
8:1=92
9:1=96
10:1=100
11:1=104
12:1=108
The best way to tell if you need a higher octane (or less timming) is when you rebuild your engine, when you remove your rods and the upper bearing falls out of the rod,you had to much timming in it or you were getting pre ingition. That will always bend the upper rod bearings to were they just fall out. That is why it is so important to check the factory timmimg marks.

Title: Re: Octane Calculator
Post by triplexl46 on 01/08/12 at 1:11pm

Thanks for the help Mike.

Title: Re: Octane Calculator
Post by dirtmopar44 on 01/08/12 at 1:27pm

One other thing. If you are using aluminum heads you dont need as much octane as the above chart. That chart is for cast iron heads.

Title: Re: Octane Calculator
Post by triplexl46 on 01/08/12 at 7:28pm

No no. No aluminum heads here. Street stocking it this year. LOL

Title: Re: Octane Calculator
Post by dirtmopar44 on 01/09/12 at 10:09am

Great, we sure need more cars. Good luck

Title: Re: Octane Calculator
Post by ezcruisn71 on 01/11/12 at 4:50am

Good info, Thanks

Title: Re: Octane Calculator
Post by ezcruisn71 on 01/11/12 at 4:53am

He is right with aluminum heads you dont need as much octane as the above chart.