G Atsma

Well, it would seem YT has their act together pretty well, and hopefully aluminum rocker fears as they applied to YT have been somewhat alleviated.

wph351

iTrader: (3)

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.

Darth_V8r

iTrader: (4)

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)

wph351

iTrader: (3)

A Lot of people have been having success with this type of rocker. The net would be blowing up with failure stories otherwise.
However is strikes me as counter intuitive using aluminum in this manner. But that's just my stubborn opinion.

wph351

iTrader: (3)

Where does the 27 originate from? Is there any way to calculate the actual degree?

by adding 27 it puts me at 8.25 dynamic. I feel better about that!

A.R. Shale Targa

iTrader: (2)

27 is half of 54......guesstimating that your @ .006" number from the cam card is 54 degrees more than your @ .050" number

wph351

iTrader: (3)

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.

Darth_V8r

iTrader: (4)

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.

wph351

iTrader: (3)

ah ok. Gotcha. Thanks for breaking it down for me. NOW I finally get this!