Desktop Dyno: Seat to Seat or @ .050
02-04-2007, 04:45 PM
#1
Melting Slicks
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Desktop Dyno: Seat to Seat or @ .050
Why does Desktop Dyno show significantly different numbers for the same cam at .050 vs seat to seat in a given combination? I understand its two different methods but its still the same cam. AND which are more accurate? 
02-04-2007, 05:09 PM
#2
Drifting
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You use the different points of measurement depending on what brand cam you are using. For example, the Crane and Summit cams give their measurements at .050. However, for a Comp cam, Comp gives their numbers at .006. Therefore, for the Comp cam, you use the seat-to-seat.
It gives you the choice of using either because cam companies don't feel like giving measurements at the same point.
It gives you the choice of using either because cam companies don't feel like giving measurements at the same point.
02-04-2007, 10:09 PM
#3
Le Mans Master
Seat to seat is more accurate with that program. It even says that in the documentation. If you input .050" numbers it will back out to some assumed seat to seat numbers when it does the calculations.
-Mark.
-Mark.
02-04-2007, 11:11 PM
#4
Melting Slicks
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I think I understand where you are coming from but if you put in the timing at .050 for THAT cam and then you put in the timing seat to seat for THAT cam shouldn't it be virtually the same? Some cam manufacturers give timing at .050 AND seat and it still shows different #'s. I know they say seat is more accurate but it would seem .050 is the same point for every cam and some measure their seat timing at different points. So I don't understand why seat timing would be more accurate.
02-05-2007, 08:12 AM
#5
Le Mans Master
The program makes some assumptions based on seat to seat timing and an assumed ramp rate. If your lobe profile is different from what it assumed and you use .050 numbers in the program, you have introduced a discrepancy. Garbage in - Garbage out.
Solid lifter cams require special care when inputting the data as your cam card info does not reflect net lift due to lash. The cam card spec numbers are for cam checking and assume zero lash.
Play with it until you get the biggest horsepower
-JK
-Mark.
Solid lifter cams require special care when inputting the data as your cam card info does not reflect net lift due to lash. The cam card spec numbers are for cam checking and assume zero lash.
Play with it until you get the biggest horsepower
-JK-Mark.
02-05-2007, 05:02 PM
#6
Drifting
Seat to seat timing gives you the exact ramp intensity. Using .050 numbers forces the software to estimate ramp intensity. This is the reason for the differences in output.
BigBlockk
Later.....
BigBlockk
Later.....
