X2 vs X4 dyno graph

[wobble]

Does anyone have a link to a comparison between an X2 and X4? Preferably stock bore, stock stroke, but anything would be helpful. I'd like to compare the curve between the two before I choose my cam for my next build.

Thanks in advance.

[NaturalRaptor]

Good idea. This I would like to see too! 

[Kenny]

Here is a test that Kam at KBR did some time ago. You will notice the Hotcam 3 is up there as well.


There are e few points to be made about the  Hotcam vs the more aggressive lift cams. The Hotcam is very reliant on long duration which really stands out with stock or mildly ported heads that don't flow so well. As heads start to move more air, the X-series cams start to come into their own. There is always a tradeoff when using longer duration cams, and that is usually in throttle response and low-mid torque

[wobble]

Thanks Kenny! Damn that graph is hard to read.

Let me see if I understand this correctly. The longer the duration, the more low-mid torque it gives, but the less throttle response it will have?

[PDX Raptor]

No the longer the duration the less low end TQ and less throttle response.

[wobble]

Thanks for the clarification. So, to keep it simple for my little brain.....I want a cam that provides more low-mid torque with a ported head. It sounds like the X2 cam will serve my needs.

[VelociRaptor]

Usually thats the case on duration but DL700 had a test of the HCIII vs the X4 on a cnc head that had simular results. I still feel the X series cams from Megacycle are better than the HCIII on all out raw power production.

[Kenny]

Usually thats the case on duration but DL700 had a test of the HCIII vs the X4 on a cnc head that had simular results. I still feel the X series cams from Megacycle are better than the HCIII on all out raw power production.

This is correct...... I should have done a better job of completing a thought. The Hotcam 3 will usually make more overall power on a very mild or stock head that will make better use of the added duration than it will with added lift. The opposite will be true with a big head. The HC3 and X series are very close in power, but the throttle response and low end torque suffers a little on the HC3. To give an example the HC3 has lift/ duration numbers of .405" int lift and 268°@.040" duration. If you can control the valvetrain, a cam with 236° duration and .550" lift would make similar power with FAR superior torque and efficiency through the RPM range. It would be a far more rewarding quad to ride with the shorter duration cam.

For those that are new to this game, lobe shape makes a huge difference. I am working on a lobe design that has the same .050" duration as the RJ cam (248° @.050"), but by .200" lift it has 20° more, and by .500" it has almost 60° more duration. To relate those numbers you'll see the big torque curve of the RJ cam, with a top end pull that will rev well past 9,000 RPM. This is a pretty big project so it is taking some time. I am at the mercy of a NASCAR cam grinder to get the lobe masters built... going from concept to reality is a bitch sometimes A couple of in house builds are using very aggressive cams at the moment. Once we got past some initial pitfalls, they are working extremely well with no signs of valve float or wear problems.

I am using a build philosophy that is kind of strange as traditional 4-valve builds go. We have spent a lot of time in the past couple of weeks manipulating valve bowl shapes combined with some real trick seat angles and top cuts that make the +2 valve head work very well with stock bore sizes. I actually have several tricks to help flow on small bores. What we have ended up with is a head that nudges the 400 cfm mark with +2 valves. I like to use this huge flowing head with the shortest duration cam possible for a really broad powerband.

A really good example of how well this works is on Jade67's 869 build that is using the RJ cam that would be totally inappropriate with a lesser flowing head, exhaust, and TB. Of course we will be going bigger, but we have serious questions about if going for bigger dyno #'s will translate to being faster on the dunes, and the effect this has on the overall manners.

Of course credit has to be given to the crew at Joker's Vault for turning the thing into a genuine bruiser!

[07lightning]

how are the ramp rates on the x2 in comparison to the stage 3 hotcam? just wondering how abusive on the valvetrain it is.

[Krandall]

Kenny, whats the progress like w/ the new cam?

[Kenny]

Kenny, whats the progress like w/ the new cam?

We have been working on two different cams today (and the next couple of weeks) We have one that is 10° less duration than the RJ but has .540" lift instead of .519. Even though this cam has less(238° @.050") seat timing than the RJ, it has about 15° MORE duration over the nose, which will give it even more bottom end torque than the RJ with a small gain up top. The beehive springs should handle this cam just fine. We have one with the same duration as the RJ (248@.050") with the same .540" lift as the other cam to work with stock length valves, and has about 30° more duration over the nose, which will keep the insane torque of the RJ while being worth 3 hp or so better up top with a bit more overrev......... Preliminary testing is showing this cam to be considerably faster than the current standard.

Now here is where it gets more interesting....... I have a very reliable grind that again has the same 248° duration @ .050 but has .580 lift. This one will be the smallest to come in my "kit" heads that will come standard with springs capable of .650" lift. This cam is gonna be worth a BUNCH of power over the biggest cams out right now, with a torque peak around 5,000 RPM. This cam is gonna be worth massive torque and top-end power. I am looking at springs to handle .800" for the big "pro racer" style cams....... The Raptor world is about to change dramatically if this works out, but it is a "system" that requires geometry changes and will come in kit form only. I have been as far as .925" lift with my test fixture using the new geometry without tipping the adjusters  up on the edge

[Kenny]

how are the ramp rates on the x2 in comparison to the stage 3 hotcam? just wondering how abusive on the valvetrain it is.

It really isn't abusive.....I only know of one cam that could be considered abusive with lobe shape, not lift, but it is only available through one company for in-house builds. We currently have no cams that even match street cams in automotive engines that run tens of thousands of miles

[Krandall]

It amazes me the testing that goes into all of this. Because it shows me how little I really know!!!

Great info kenny keep up the great work!