Compression ratio on 460 question
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Brian, i was wondering if i could pick your brain really quick one more time 
The cam that i'm going to be getting is CompCam's 34-255-5, grind FF XE256 H. It's their cam for fuel-injected engines, TONS of low-end and good mileage.
When calculateing the effective compression (useing that KB calculator), this cam gives Intake opening at 18, closeing at 58 @ 0.006 lift. Should i add 15 to that, or do i only need to add 15 for the mesurement at 0.050 lift? Adding 15 gives me 73, and even with 10.2:1 pistons gives an effective compression of 7.570, which i think sounds pretty safe all things considered. But if i don't add 15, useing 9.2:1 pistons gives an effective of 7.709.
So do i add 15? If so, i think i'll get 10.2:1 pistons. Sound good to you?
The cam that i'm going to be getting is CompCam's 34-255-5, grind FF XE256 H. It's their cam for fuel-injected engines, TONS of low-end and good mileage.
When calculateing the effective compression (useing that KB calculator), this cam gives Intake opening at 18, closeing at 58 @ 0.006 lift. Should i add 15 to that, or do i only need to add 15 for the mesurement at 0.050 lift? Adding 15 gives me 73, and even with 10.2:1 pistons gives an effective compression of 7.570, which i think sounds pretty safe all things considered. But if i don't add 15, useing 9.2:1 pistons gives an effective of 7.709.
So do i add 15? If so, i think i'll get 10.2:1 pistons. Sound good to you?
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That is what I did. I would not think there is much difference in the the duration at .005 and .006. I am not sure why comp does not use an .005 figure, so I just added the 15 degrees to the .006 figure
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I'm gonna call Comp Cams tomorrow and ask if i can get the .050 number. For the time being though, i'm just makeing a wild guess and adding 2 to the closeing time at 0.006. In that case, with a 10.2:1 i would have an effective of 8.5:1; Race gas time. I think i might need to bump that back down to 9.2:1.
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Just for the sake of information, i called Comp and got the .050 number. That cam, the fulie one (34-255-5) has the inake close at 36. Adding 15 gets you 51, but plugging all that into the caluclator with even 9.2:1 pistons gives an effective compression of 8.04:1; Far too high for this engine. It looks like i'll have to stick with the stock 8.5:1 pistons, even they yeild an actual compression of 7.4:1.
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[QUOTE=Tsaven Nava]As long as hard shifts won't damage anything, i don't think i would mind much at all. While the car will be daily driven, 95% of the time i drive like an old person anyway. So while i wouldn't like it to be like dropping the clutch in a manual, harder shifts then stock would be cool.
Just re-read this I know you aren't doing the tranny right now, but seeing your reference to drop the clutch reminded me. My friends Lightning tranny shifts like a manual would feel if you did a 1-2 without letting off the gas and you side-stepped the clutch 2-3 and OD are the same way. It is pretty cool
Just re-read this I know you aren't doing the tranny right now, but seeing your reference to drop the clutch reminded me. My friends Lightning tranny shifts like a manual would feel if you did a 1-2 without letting off the gas and you side-stepped the clutch 2-3 and OD are the same way. It is pretty cool
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Heehee! Bet that lights the tires pretty well
When i eventually do start looking at transmission work, would it be better to rebiuld a fried transmission, or have them rebiuld one that's still operational? How much would it run with the required parts?
I won't want SUPER hard shifts, but fimer then stock would be cool.
When i eventually do start looking at transmission work, would it be better to rebiuld a fried transmission, or have them rebiuld one that's still operational? How much would it run with the required parts?
I won't want SUPER hard shifts, but fimer then stock would be cool.
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