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eduardocastrejon
Samba Member
Joined: September 29, 2007
Posts: 43
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 Posted: Sun Dec 04, 2016 11:01 pm Post subject: Inlet Valve Closes ABDC calculator |
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Please help me with this:
I want to know the inlet valve closes of the scat c45 cam
SCAT C45 Type 1 Camshaft, 1.1 or 1.25 Rockers, 20006 is designed for 1.1-1.25 rockers, and it's specs are .390" Cam Lift, .430"/1.1s, .490"/1.25s, and a whopping .546"/1.4s! It has 298 degrees of advertised duration, and 254 degrees of duration at .050", on a 108 Lobe Center.
I want to calculate the dynamic compression ratio using
http://wallaceracing.com/dynamic-cr.php
I found this:
http://www.csp-shop.de/technik/pdf/de/18209.pdf
thanks in advance |
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Dougy Dee
Samba Member
Joined: August 21, 2004
Posts: 1669
Location: Niagara Region, CANADA
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| Posted: Mon Dec 05, 2016 6:18 am Post subject: Re: Inlet Valve Closes ABDC calculator |
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| IC is 51 @.050. |
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eduardocastrejon
Samba Member
Joined: September 29, 2007
Posts: 43
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| Posted: Mon Dec 05, 2016 9:07 am Post subject: Re: Inlet Valve Closes ABDC calculator |
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| Dougy Dee wrote: |
| IC is 51 @.050. |
thanks, and this calculator need this value at .050 ?
2110cc 82 x 90.5
cb wedge ports 44x37 56cc
5.4 rod
c45 cam
1.25 rockers
cb ultra competition fuel injection 48mm , big beef ported manifolds
9.5 static cr
0 deck height, 040 deck height with copper gasket
with this values this calculator gave me a dynamic cr of 8.3 at sea level
at this moment I living at 7381.89 feet of altitude, then I want to raise the static cr to work at this altitude
I supose that I need at least 8 of dynamic cr then If this calculator is correct i need to raise the static cr to 10.9
I red that combustion chamber shape, manifold lenght, weather temp affects dynamic cr ?
Please help me with this |
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mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Mon Dec 05, 2016 11:34 am Post subject: Re: Inlet Valve Closes ABDC calculator |
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| the IC might be at 51, it might be 54 it might be 49.....CHECK IT!!!! as for the lmnopdcrthingy......that thing remineds me of those rubbery slipper shoe's with the big lizzard on them....crock |
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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Mon Dec 05, 2016 6:36 pm Post subject: Re: Inlet Valve Closes ABDC calculator |
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Half the duration+"centerline angle"=you get "closing point in degrees after tdc".
To change that to after bottom dead center, subtract 180
You can use seat duration, .050 duration, or .050 duration+15
Different people do it different ways, and there is no right way to do this.
The right way is what predicts the cranking compression, as that is what you are actually calculating.
I feel it the idea is flawed, because "dynamic compression" should be dynamic, and cranking compression is static. |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
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| Posted: Tue Dec 06, 2016 2:19 am Post subject: Re: Inlet Valve Closes ABDC calculator |
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+ 15 is just an approximation, no? For actual closing time?
277° adv.-234°@0.050" = 43°
43°/2= 21.5°
this cam has slow ramps,
so add 21.5° if you're looking for the seat times. None of these calculators will give you that much to go by, but it's a start.
21.5° + 51° = 71.5° ABDC for calculators that want seat °.
Hope this helps |
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