Have a built 416 LS3, adding forced induction? Compression Ratios (pics)
Have a built 416 LS3, adding forced induction? Compression Ratios (pics) Running a built LS3 currently, compstar crank, wiseco -3cc dome pistons, ls3 cnc ported heads (73cc).. I'm not positive on compression ratio but using a calculator and assuming standard deck height (need to have this measure when engine is out). It comes out to be a compression ratio of ~11.4:1 or ~10.7:1 depending on the piston being dome/dish and the calculator -/+ for piston dome value
I bought the shortblock already assembled with Wiseco K464X7 installed.. Summit lists this as a DOME piston with "-3.00cc piston head volume" and on the Wiseco application sheet Wiseco also lists as -3cc on their chart..
On the compression calculator summit says to list dome pistons as negative cc so that's what I entered, showing it as 11.4:1 but I think this is incorrect as Wiseco lists their high boost application pistons as -15 and -20cc, if that were the case plugging those numbers in the calculator raises compression to 14:1 ! Plugging in +15 or +20 lowers the compression.. so assuming I plug in +3cc it is 10.7:1
Wiseco Sheet:
Using -3cc for piston volume (11.4:1)
Using +3cc for piston volume (10.7:1)
I believe the 10.7:1 figure is more accurate.. please let me know if it is incorrect!
I'm planning on running 93 pump gas, and the ZL1 supercharger kit I have has 2.45 pulley on it and planning on running ~10-12psi.
If I am ~10.7:1 compression is that still too much compression for running boost on pump gas? Prefer to save a few bucks but if required I will put in the 8cc (10.1:1) or even the 15cc pistons (9.5:1)
Sorry about the rambling, a bit new to this and makes my head hurt!
This is the "kit", already have had nitrous but unsure if I'll be running it with the supercharger.. maybe down the road in a year.
http://www.wiseco.com/PDFs/ChevroletLS.pdf
I bought the shortblock already assembled with Wiseco K464X7 installed.. Summit lists this as a DOME piston with "-3.00cc piston head volume" and on the Wiseco application sheet Wiseco also lists as -3cc on their chart..
On the compression calculator summit says to list dome pistons as negative cc so that's what I entered, showing it as 11.4:1 but I think this is incorrect as Wiseco lists their high boost application pistons as -15 and -20cc, if that were the case plugging those numbers in the calculator raises compression to 14:1 ! Plugging in +15 or +20 lowers the compression.. so assuming I plug in +3cc it is 10.7:1
Wiseco Sheet:
Using -3cc for piston volume (11.4:1)
Using +3cc for piston volume (10.7:1)
I believe the 10.7:1 figure is more accurate.. please let me know if it is incorrect!
I'm planning on running 93 pump gas, and the ZL1 supercharger kit I have has 2.45 pulley on it and planning on running ~10-12psi.
If I am ~10.7:1 compression is that still too much compression for running boost on pump gas? Prefer to save a few bucks but if required I will put in the 8cc (10.1:1) or even the 15cc pistons (9.5:1)
Sorry about the rambling, a bit new to this and makes my head hurt!
This is the "kit", already have had nitrous but unsure if I'll be running it with the supercharger.. maybe down the road in a year.
http://www.wiseco.com/PDFs/ChevroletLS.pdf
Last edited by epix; Feb 18, 2018 at 09:02 AM.
My car is sbe and runs the 10.7:1 compression. When I was running 93 only without methanol it handled 740whp just fine. I would recommend a meh kit though for sure if you’re gonna stay 93 only. Leave comp alone you don’t want it too low.
