N54 Tech Data on Camshaft Options

rac

Sergeant
Nov 14, 2016
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Data in one place some people may find useful or of interest.
If there are more available cams with known information I can add to the below, a summary of the the camshafts is in the table and relevant data sheets attached if available.

Schrick did not provide me with a data sheet for the "Low Lift" and I have not asked VAC for it, the assumptions I made should be pretty close.

Cam Summary.jpg


VANOS has 55 degrees advance available on intake cam and 45 degrees available retard on exhaust.
Depending on the source of information and reference lift some angles differ by +/- 1 degree in other documents.

For US guys used to seeing duration @ 0.050", 0.050" = 1.27mm so it's not exactly the same but similar.

If people have actual profile detail / data that would be great to share as well.
 

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Torgus

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Nov 6, 2016
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Thank you for making the thread and compiling the data in an easy to read format.

I have seen very few builds use cat cams.

Given vanos doesn't the lift make more sense than the duration?
 

rac

Sergeant
Nov 14, 2016
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Australia
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For two cams with the exact same cam timing and lift the added duration can still benefit high rpm.

I think with VANOS the trade off's normally associated with duration aren't as significant but ultimately at high rpm you are still dealing with less and less time for air to fill the cylinder and so duration still plays a role. For an all out race application with turbo not being run way out of efficiency I'd be surprised if the biggest CatCam wouldnt be making the most power. What would be really interesting is the CatCam "Hot Street - Dirt Track" versus Schrick "High Lift", at what point in the rpm range does the duration overtake the extra lift.

In an ideal world the opening and closing events are as fast as the valve train allows, Schrick's original "High Lift" design is the most aggressive in this sense. Assuming they did their homework and stock valve-train can handle the profile then it seems like a good option. You can assume the extra lift itself on a stock head is not where the benefit would be coming from (relative to the others), it would be the how quickly the valve is opening for that given duration.
 
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iminhell1

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Jun 17, 2018
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Given vanos doesn't the lift make more sense than the duration?


No.
In a boosted application I would give both an equal weighted average since you have the push of the positive pressure from the turbo working in your advantage. The goal is to have the valve open as long as possible and to try and overfill that cylinder to get the maximum bang.
As a general rule 'boost cams' have more duration and less lift (along with a slower ramp rate) because you don't need a sudden pressure differential at the seat to create a vacuum induced cylinder charge; you're not solely relying on the vacuum of the piston to suck the air in.
In the case of our cams, the lift is probably a side effect of the duration desired. All have the same ramp rate but to get to the desired duration it has to lift further. You'd have to physically degree the cam to see what I'm talking about here. I've never seen ramp rates published by MFG's.

Far as NEEDing to replace stock stuff, I guess my first question would be where coil bind could occur and second the spring pressure vs lift relationship. More spring pressure can be better for higher RPM, but it'll eat up more power to move that valve and cause faster ware.
 
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