Cam/head design logic.

[Kenny]

Okay a picture is worth a thousand words. Here is a picture of the difference in lift between a HC3 and the "RJ" cam at the valve. Doesn't look like much, right? Here is where having a "package" designed to work together helps.



Even though this difference looks small, there is a 30+ cfm difference in head flow at this lift on my new CNC head.

Now if you were to change to a RJ cam from a Hotcam 3 in a stock head, the difference in flow would be only 2-4 cfm with the extra lift in the stock head. If you were to replace a stock head with a HC3 with my new CNC head and RJ cam, there would be more than a 120 cfm gain @ peak lifts.

This is why I am able to knock so much duration off these cams and match or surpass the top-end power of other designs, but the reduction in seat timing dramatically improves rideability..... There is WAY more power left in the Raptor motor..... Of course I could be full of crap...... I may be the only guy that believes in this build philosophy

I can also go the opposite way and use the same duration as everyone else, matching the low-end performace and absolutely killing them on top. Remember the theory is the average airflow gain in percent when measured at 28" is roughly equivalent to power gained. Lot's of room for deviance there, not really a hard fast rule. Tune in next time for.....AS THE WHEEL TURNS......

[preddy08]

I was expecting my head to hurt alot more than it is, judging by the topic of the thread. Good stuff kenny!

[Krandall]

Any idea what the difference in flow would be w/ your CNC port and a HC3 vs the RJ?


Great info Kenny, Keep up the great work.

[Kenny]

I was expecting my head to hurt alot more than it is, judging by the topic of the thread. Good stuff kenny!

I left out about 99.73658% of the math and physics involved 

Any idea what the difference in flow would be w/ your CNC port and a HC3 vs the RJ?


Great info Kenny, Keep up the great work.

Thanks Krandall, A tick over 30 CFM

Make sure you guys take notice of the chamfered bolt holes that help "broaden" the clamping load on the head gasket.

[Krandall]

Who knew crack heads could be good @ math and physics....

[Kenny]

Who knew crack heads could be good @ math and physics....

Well now you know :grin_nod:

[rutcutter]

Get a build done and put it to the dirt, lets see something more than theory.

[Kenny]

Get a build done and put it to the dirt, lets see something more than theory.

Hmmm.... You say that like I don't already have some out there. The prototype head is already out on a 760cc build with a smaller lift cam. I just got the heads in my hand the end of last week, so there will be 2 more motors built next week. The RJ cam is already proving it's worth, and I have some dyno comparisons.......... The theory has by all means turned into empirical evidence. As a matter of fact the 760 was built about the same time as yours, at the same place

[rutcutter]

Cool, so hows it running? I am sure it's an awesome ride.  What kind of numbers did the 760 put down?  I am a firm believer in these CNC heads.

[Pldbryan]

Kenny, can you PM me the price of the head if it is released yet???  I have not been able to find pricing yet on any of the posts!  Thanks!

[Kenny]

Cool, so hows it running? I am sure it's an awesome rise.  What kind of numbers did the 760 put down?  I am a firm believer in these CNC heads.

81.6 was the number quoted on reasonable compression. A little disappointing, but the cam was not a design that would take advantage of this head. It will be interesting to see what happens when the big TB goes on. The Racers Edge head is probably the better performing head at .500" lift or less. I gave up a bit of flow under .200" lift for bigger flow up top.  There is one more change I will be doing to the valve job....... The final seat cut should bring my up mid lift flow quite a bit, then I will be done.

The RJ cam is the least aggressive lobe design I would run with this head. When I say aggressive I am referring to lobe ramp speeds (or valve velocity), not duration or lift.

[preddy08]

Kenny, what would you expect the RJ cam to do in one of Bos updated head ports vs a X-2?

[1badazz_700r]

how would a X-4 work with one of these heads?

[NaturalRaptor]

Kenny, you always post good and interesting info. Thanks.   

[cowtownup]

Kenny, you always post good and interesting info. Thanks.  

+1   I don't always understand exactly what you are saying, but usually I can bounce it off a couple people I know and figure out whats being said....   Thanks...