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Jun 10, 2007 | 05:48 PM

#16

thesoundandthefury

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Joined: Aug 2005

Posts: 862

From: Columbus, IN

Quote:

Originally Posted by crazydavez28

doesn't changing the ratio of the rockers increase the duration a little bit?

i mean duration measured at .050" with 1.6/1.7's would actually be greater than that of 1.5's

That is correct.

Jun 11, 2007 | 10:26 AM

#17

JAKEJR

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Joined: Apr 2007

Posts: 549

From: Lancaster, Texas

Quote:

Originally Posted by crazydavez28

doesn't changing the ratio of the rockers increase the duration a little bit?

i mean duration measured at .050" with 1.6/1.7's would actually be greater than that of 1.5's

Yep. The number I see most often is a 2/3 degree increase in effective duration. That increase is always associated with a one ratio change though.

So if you happen to move TWO ratios - like moving from 1.5s to 1.7s - would the effective duration double? If so, we'd be talking 4/6 degrees. Ponder, ponder, . . .

Jake

Jun 11, 2007 | 11:13 PM

#18

crazydavez28

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Joined: Aug 2005

Posts: 178

From: Hutchinson,KS

i guess it would really depend on the grind of the cam and the contour of the lobe.

the higher ratio would defintely increase the rate at which the valve opens and that may have some benefits ... however it would also increase the stress on all your valvetrain components.