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Old 12-30-2007, 10:30 PM   #1
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Default Which Cams to use?

Well we all know that my motor was running flat above 7,000 simply because I didn't have enough Camshaft, so which cams would you run and why?

Intake
204 degree .326" <-Stock
238 degree .408" <-Crane
270 degree .376" <-Webcam

Exhaust
210 degree .350" <-Stock
244 degree .378" <-Crane
270 degree .376" <-Webcam

I got a smoking deal on the aftermarket cams, $300 for all four! So these are what I can mix and match with. Any thoughts? Yes, my valve springs are up to it.

I was thinking the 238/.408" intake with the 270/.376" is the combo to run.

Mark
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Old 12-30-2007, 11:23 PM   #2
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your selection makes sense, larger intake for more A/F mixture, less extreme exhaust for more velocity and less overlap....Is that your thinking?

Last edited by Braineack; 12-30-2007 at 11:33 PM.
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Old 12-30-2007, 11:34 PM   #3
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Quote:
Originally Posted by Braineack View Post
your selection makes sense, larger intake for more A/F mixture, less extreme exhaust for more velocity and less overlap....Is that your thinking?
you dont think theyd be too long? I'll take the exh one you dont use.
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Old 12-30-2007, 11:52 PM   #4
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I no little to nothing about cam profiling. Never done it, never learned it. Eventually, when I build my spare parts, I'll learn up and upgrade my valvetrain and pick up some cams to keep my torque up at redline.
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Old 12-30-2007, 11:55 PM   #5
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sounds like a good choice based on my limited knowledge. question, how would one calculate overlap based on those specs? or is there not enough info?
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Old 12-30-2007, 11:57 PM   #6
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I'll know better when I have the cam cards. I don't have the opening and closing specs yet. Once I do, I will post 'em. I can actually change quite a bit with cam gears.

Mark
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Old 12-31-2007, 02:37 AM   #7
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Hey Mark just a question/comment, dont you usually want longer duration on the intake more so than lift in boosted apps?

I have zero knowledge in this field but I believe I've read something to that effect, please correct me if I'm wrong.
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Old 12-31-2007, 09:16 AM   #8
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With about as much knowledge as an aspiring cam wannabe almost novice, I think the webcam intake is going to be what you want for your high rpm motor. it doesn't have the extreme lift of the crane, but it has good lift and a ton more duration, and should flow more. I would try it with the crane exhaust cam.

And I'll buy from you whatever cams you don't want. Even the stockers

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Old 12-31-2007, 12:17 PM   #9
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Quote:
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Hey Mark just a question/comment, dont you usually want longer duration on the intake more so than lift in boosted apps?

I have zero knowledge in this field but I believe I've read something to that effect, please correct me if I'm wrong.
My thinking is that boost pressure can overcome duration, but that exhaust duration is more important to get all the gas out of the cylinder. I could be all wrong here though.

Mark
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Old 12-31-2007, 12:29 PM   #10
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Quote:
Originally Posted by Markp View Post
My thinking is that boost pressure can overcome duration, but that exhaust duration is more important to get all the gas out of the cylinder. I could be all wrong here though.

Mark
I was thinking the opposite. Let the fresh air push the exhaust out.
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Old 12-31-2007, 06:53 PM   #11
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with his original choice i would think it would idle much better than if it were the other way around
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Old 12-31-2007, 08:05 PM   #12
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If you want power up top go with the longest duration, turboed or not
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Old 01-01-2008, 02:33 PM   #13
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Since this thread is current, I'll ask here and try not to jack the thread.

96 shortblock, ported 99 head with +1mm valves, 94/95 Miata valvesprings, Fidanza cam gears. I have a set of Webcams in there now, the grind listed on their website for a 99 head. Webcams said it would still be good for a turbo setup, but I wanted to know which way to adjust the cams to reduce overlap if necessary. Advance intake/retard exhaust? Engine is currently wearing an MP62, but a 2871R kit is sitting in my closet.
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Old 01-01-2008, 03:40 PM   #14
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I don't see why all of you want to dial out overlap. The overlap in boost allows the pressurized fresh air to push out the exhaust. Look at evos, they have no vtec type mechanism. One of their biggest upgrades are cams to help extend power into the upper rpms (they have huge tq dropoff stock). They run hks 272 and up cams, you don't see them cutting back the overlap.

Overlap, on any motor, allows the motor to breathe better at higher rpms. You will loose some boost pressure, sure, but by allowing the motor to breathe better you will actually make more power at that lower boost level.
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Old 01-01-2008, 04:34 PM   #15
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