Cam selection

[Don W.]

It's been discussed many time I know. Lotsa folks running Comp 412, 415, 422 cams. I believe that is, in large part, due to Camp calling these cams as good for computer controlled motors. But why? Well I talked to a cam lobe designer and he said it's because of vacuum. "Hotter" cams don't produce enough vac.

All that being said I'm gona have to buy a cam rather soon. (Motor should finally be back from the machinist this week.) Thinking something sightly different might work.

Here's the 412. 415, 422 compared to what I think might work. FYI It's a Comp 430, Reasoning? Intake Timing mostly, then, of course, exhaust. Intake center line moves a bit. All, I think, to advantage.

Shoot holes in this if you want. :rotf: That's why I'm posting. I want opinions.

Sorry if the list is hard to decipher.

RPM range 412=1200-4500 415=1800-5000 422=2000-5500 430=2000-5500

In order specs are:
Lobe Seperation 112 112 114 110
Intake Centerline 108 108 110 106

Duration @ .050:
Intake 206 210 215 224
Exhaust 210 215 220 224
Lift 0.5 0.5 0.5 0.525
Intake opens BTDC -5 -3 -2 6
Intake closes ABDC 31 33 37 38

Exhaust opens BBDC 41 43 48 46
Exhaust closes ATDC -11 -8 -8 -2

"Overlap" 6 5 6 4

 

[qbnkiller]

Re: Cam selection

Don..call me sometime to discuss. Its more than I care to write after the amount of alcohol consumed today.

What I will say publicly is that cam design is still a black art. We have been fortunate to have been designing them long enough to know what works and what doesnt. Some guys look at our cam numbers and say 'thats a shit cam..it wont make power', yet we still build more >2000hp engines every week than most do in a year.

 

[Quickstop [UK]]

Re: Cam selection

Just saw your avatar, Alex - nice

Need any Gummi Bears? :tup:

 

[jamnut]

Re: Cam selection

Qbnkiller should know a lot more than I do working for Steve Morris, but the lobe separation of should all be in the 114 range or even 115 range for a good boosted cam. Bad thing about 4.3's is the lack of available cams. You get into LSx motors and there seem to be 100's of cams.

 

[bigmileage]

Re: Cam selection

I'd call and just have comp grind you something custom.

That said, most of the cams you posted are mildly larger than a stock CPI cam and appear to be setup for NA not boost. Most good turbo cams will favor the intake over the exhaust...

 

[Don W.]

Re: Cam selection

If, big if, I have it correct lobe separation determines "overlap" all else being equal. But AS CALCULATED BY ME overlap is less with this cam. Steeper ramps I assume.

Anyway, Thanks Alex. I'll give you a call.

 

[It's just a six]

Re: Cam selection

I personally like a wide lobe center 115 & higher. Smoother idle, better mileage, great power.:2cents: Talking turbo cams here.

 

[qbnkiller]

Re: Cam selection

Just saw your avatar, Alex - nice

Need any Gummi Bears? :tup:

Jelly Babies please...black if I had a choice!

Custom cams from us are NOT from Comp ams. We take a lot of details from your build anddesign something custom from that. Having tried my hand at talking to the Comp Cams guys over the phone before, I can tell you they are not 'specialists' - they either look at whay cams were recently ordered for your engine combo or whatever Bobby the shift manager says. A custom cam from us (not a billet core) takes 3 weeks to arrive. It will come with the cam card, along with our suggestion on where to install it at for your combo.

Like I said, you cant really say 'do this for turbo engines' because chances are you're incorrect. We can make changes to the cam to compensate for excessive exhaust backpressure or inefficient com ustion chamber or fuel type or altitude or..............get the picture?

 

[bigmileage]

Re: Cam selection

I've typically had similar experiences with comp in the past as well, I usually go into it with enough knowledge of what I'm looking for and what has been proven, to help steer it towards what I want. My point was - and not to steal business from you - was too many people rely on shelf cams when in reality there are far better alternatives available. There is no point in spending money and time on something that will make marginal improvements or mediocre gains.