LQ4 compression with AFR 205 heads
#21
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#22
Guys I need some help with the dynamic compression calculations. Im plugging the numbers into the Wallace racing calculator, and the results seem awfully high.
For the intake valve closing ABDC, do I enter the .050 figure on the cam card or a .006 number? If it's the .006 number, how is it calculated?
This has me stumped as I'm coming up with dynamic numbers close to 9, which I don't believe to be accurate.
For the intake valve closing ABDC, do I enter the .050 figure on the cam card or a .006 number? If it's the .006 number, how is it calculated?
This has me stumped as I'm coming up with dynamic numbers close to 9, which I don't believe to be accurate.
#23
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for dynamic compression, use the 006 valve event
Edit - if you are wondering how to get the 006 valve event, because it is not available, just add 27 degrees to your 050 event. That's by no means absolute, but it will get you close enough (within 0.1)
Edit - if you are wondering how to get the 006 valve event, because it is not available, just add 27 degrees to your 050 event. That's by no means absolute, but it will get you close enough (within 0.1)
#27
This cam is going into a sbe lq4 with .051 gaskets. I factored in a .020 mill to put static at about 11.45:1 with 63 cc chambers.
By adding the 27 degrees to the cam cards 39 degress, i ended up with 8.25:1 using the Wallace racing dynamic calculations. Which would suit me fine. I "think" the result is correct. Not 100% sure though.
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Now, the next part. Your intake duration is 269 at 006 and 218 at 050. 269-218 is 51 degrees. 51/2 = 25.5
So, use 25.5 instead of 27 to get to 39+25.5 = 64.5. There's your IVC at 006.
#29
Shale answered it. 51-55 degrees is very typical 006 to 050 ramp rate. So, 27 is a good enough estimate to get your numbers. Now, could it actually be 26 degrees? 26.5? Yes, but that's not going to change it by more than 0.1 or so on your DCR.
Now, the next part. Your intake duration is 269 at 006 and 218 at 050. 269-218 is 51 degrees. 51/2 = 25.5
So, use 25.5 instead of 27 to get to 39+25.5 = 64.5. There's your IVC at 006.
Now, the next part. Your intake duration is 269 at 006 and 218 at 050. 269-218 is 51 degrees. 51/2 = 25.5
So, use 25.5 instead of 27 to get to 39+25.5 = 64.5. There's your IVC at 006.