Cam timing experiences with boost

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Mar 6, 2011 | 08:52 AM

#11

Sideways

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Joined: Oct 2000

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From: South of the pier, Huntington Beach, CA

Quote:

Originally Posted by Sideways

I added one degree to the intake and three to the exhaust. (+1,+3) This decreased the overlap by 2 cam degrees (four crank degrees) and was expected to increase torque.

The cam timing changes along with a Hytech header specifically made for supercharged applications developed an increase of 22 ft lbs of torque and 33 rwhp at 8800 rpm.

I'll have some further numbers at the next dyno session.

I can tell you that driving this thing is scary now. It has a whole lot more torque and that makes control of the car much more of an art.

I have done some reading on boosting the supercharged engine and it is quite different from a turbocharged engine. It appears that supercharged engines like some intake cam retard and that decreases overlap as does exhaust cam advance. It also appears that the amount of exhaust cam advance necessary varies with the restriction of the exhaust system. Stock exhaust would take several degrees more than open headers. Interesting stuff.

I'm at -1 degree on the intake and +3 on the exhaust for a total of 4 cam degrees less overlap. Torque is up and it pulls like crazy.
I'll be back on the dyno in a few weeks.

Mar 6, 2011 | 06:11 PM

#12

06S2k07Si

Joined: Sep 2005

Posts: 1,941

Likes: 47

From: Baraboo, WI

Watching...Thanks for doing this!

Brian

Mar 10, 2011 | 11:18 AM

#13

RAIN H8R

Joined: Dec 2007

Posts: 4,757

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From: Waukesha, WI

Yeah me too! (I have to be able to keep up with you Brian haha)

Mar 14, 2011 | 04:30 AM

#14

Sideways

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Joined: Oct 2000

Posts: 9,033

Likes: 21

From: South of the pier, Huntington Beach, CA

Pulled out a couple more degrees of overlap (6 cam degrees total) and the butt dyno says power is up, up, up....

Going to the dyno this week if possible. I need to find out where exactly I am at.

Apr 18, 2011 | 06:29 AM

#15

Sideways

Thread Starter

Joined: Oct 2000

Posts: 9,033

Likes: 21

From: South of the pier, Huntington Beach, CA

Wow, it took me forever to get to the dyno. Appointment is today starting out with a baseline.

I was going the wrong way with the intake cam and still saw major torque/power increase by decreasing the overlap just a little bit. The potential for more power is mind boggling.