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Dissect this CR calculation sheet..please

Posted: February 1st, 2015, 9:14 pm
by nicpaige
Scan.jpg
I plugged in a comp cams 231 profile(really planning on a custom late model profile cam for retaining plate so these numbers might change), and dished BullTear pistons @26cc, also plan on the Edelbrock head which I believe is 55cc chamber.

Re: Dissect this CR calculation sheet..please

Posted: February 1st, 2015, 9:45 pm
by Cheromaniac
Looks correct to me but try adding 0 feet as the altitude and see what SCR and DCR you get.

Re: Dissect this CR calculation sheet..please

Posted: February 2nd, 2015, 3:22 am
by nicpaige
Why would I want zero altitude, I'm not at sea level?

Re: Dissect this CR calculation sheet..please

Posted: February 2nd, 2015, 4:40 am
by nicpaige
At zero altitude it goes to SCR 9.5:1 and 8.30 DCR. Will this live on 89-91 octane with .045" quench.

Re: Dissect this CR calculation sheet..please

Posted: February 2nd, 2015, 5:09 am
by Cheromaniac
nicpaige wrote:At zero altitude it goes to SCR 9.5:1 and 8.30 DCR. Will this live on 89-91 octane with .045" quench.
Should run on 91 octane no sweat.
nicpaige wrote:Why would I want zero altitude, I'm not at sea level?
I know but you need to enter 0 feet altitude to get the correct SCR.

Re: Dissect this CR calculation sheet..please

Posted: February 2nd, 2015, 6:15 am
by nicpaige
How do the numbers look for a street driven XJ that I tow a 10x12' trailer with on occasion? I hope Bulltear can do the 26cc dish with their blanks.

Re: Dissect this CR calculation sheet..please

Posted: February 13th, 2015, 9:34 am
by Muad'Dib
Cheromaniac wrote:
nicpaige wrote:At zero altitude it goes to SCR 9.5:1 and 8.30 DCR. Will this live on 89-91 octane with .045" quench.
Should run on 91 octane no sweat.
nicpaige wrote:Why would I want zero altitude, I'm not at sea level?
I know but you need to enter 0 feet altitude to get the correct SCR.
Keep in mind that altitude does effect SCR, so entering 0 or nothing in the altitude fields will give you the results based on your engine running at sea level both DCR and SCR. If your at a higher or lower altitude and you want to build specifically for those conditions, then make sure you enter the altitude you are running the engine at.

Re: Dissect this CR calculation sheet..please

Posted: February 13th, 2015, 10:48 am
by jeepxj3
Use a different cam choice closer to what you will be using with the cam retainer plate cam.