cams and the bp4w exhintake
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cams and the bp4w exhintake
I am working on a mild head build and due to acquiring this particular head from a junkyard, the intake cam was pitted from rust. Long story short I ended up with 2 serviceable exhaust cams and no intake => Exhintake. I will shortly have an adjustable timing gear to set the cam timing correctly. I know the "magic number" is 197.5 deg CW from the exhaust cam mark, but my google-fu is bad and I am not totally sure how it was calculated. Closest I could find was this:
https://www.miataturbo.net/engine-pe...answers-27294/
Using the solomiata numbers I get 8+49+180=237 duration @??? lift intake and 180+9+53=242 duration @??? lift for exhaust.
Assuming a symmetric cam profile, that gives intake peak lift at (237/2)-8=110.5 deg ATDC, or 180-110.5=69.5 deg BBDC and exhaust at(242/2)-53=68 deg ABDC. therefore the LSA is 68+69.5=137.5 <=That sounds wrong!
Does anyone here have actual numbers on the stock 99-00 cams? in Duration @(lift) preferably @.050 lift
The more important question, Doing an exhintake the overlap will increase as the exhintake cam has more duration, Does it make more sense(power) to advance the intake cam to reduce the overlap, increasing the LSA, or not?
How would this effect my upgraded rods only 10:1 comp motor with a t25 (OE s13)?
Please correct my (possibly wrong) math
https://www.miataturbo.net/engine-pe...answers-27294/
Using the solomiata numbers I get 8+49+180=237 duration @??? lift intake and 180+9+53=242 duration @??? lift for exhaust.
Assuming a symmetric cam profile, that gives intake peak lift at (237/2)-8=110.5 deg ATDC, or 180-110.5=69.5 deg BBDC and exhaust at(242/2)-53=68 deg ABDC. therefore the LSA is 68+69.5=137.5 <=That sounds wrong!
Does anyone here have actual numbers on the stock 99-00 cams? in Duration @(lift) preferably @.050 lift
The more important question, Doing an exhintake the overlap will increase as the exhintake cam has more duration, Does it make more sense(power) to advance the intake cam to reduce the overlap, increasing the LSA, or not?
How would this effect my upgraded rods only 10:1 comp motor with a t25 (OE s13)?
Please correct my (possibly wrong) math
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BAHKACK
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05-28-2018 09:43 PM