compression?
09-05-2006, 10:50 PM
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compression? i was just wondering at what compression do you have to run what gas? i live in a small town and to get any gas higher that 89 octane i have a 8 mile drive. this is for a future engine build
09-05-2006, 11:26 PM
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DCR not SCR is what your after.....Compression, Fuel Octane, Altitude, RH, Air temp, Engine Temp, Engine Cooling, Engine VE. and type of engine, gearing. Is the car manual or auto. If auto what stall!
As an example: 89 Octane may not be a problem in high altitude with high DCR. But, once the car comes down (off the hill) you would need 92.
What type of engine? then if you only run 89 at sea level. I would not run more then 8.5 DCR. With ok flowing engine (VE). If really kick *** heads and in warm weather I would look for a max 8.3 DCR. These reccomendations are for an LT1 based engine only....I'm making an assumption here....
As an example I run a DCR of 8.77 here at sea level in OK weather with no problems...on 92 octane.....
My SCR is 12.48 to 1. If you don't know this already your Intake lobe ABDC (closing point) + SCR, dictates your DCR...Within reason....Do a search for "Pat Kelly" DCR calculator....This is why I can run a high SCR and have no problems what so ever with KNOCK....
As an example: 89 Octane may not be a problem in high altitude with high DCR. But, once the car comes down (off the hill) you would need 92.
What type of engine? then if you only run 89 at sea level. I would not run more then 8.5 DCR. With ok flowing engine (VE). If really kick *** heads and in warm weather I would look for a max 8.3 DCR. These reccomendations are for an LT1 based engine only....I'm making an assumption here....
As an example I run a DCR of 8.77 here at sea level in OK weather with no problems...on 92 octane.....
My SCR is 12.48 to 1. If you don't know this already your Intake lobe ABDC (closing point) + SCR, dictates your DCR...Within reason....Do a search for "Pat Kelly" DCR calculator....This is why I can run a high SCR and have no problems what so ever with KNOCK....
Last edited by jimbob; 09-05-2006 at 11:43 PM.
