Jimmyz

iTrader: (3)

The cam I currently have is a (224/228 .567/.571 113) I believe with the 20-30 cfm increase I've got, I'm losing compression and cylinder pressure with the small duration and not effectively using the additional air flow.

the Z06 heads flow:

100 200 300 400 500 600
Int 67 147 201 246 282 305
Exh 53 104 142 189 208 214

This is a daily driver and I'm looking for more low to mid-range TORQUE then just peaky HP numbers. I also will spray a 125-150 shot once and a while.

What do you think?

Here's what I'm thinking (230/228 duration, .592"/.588", 112) but, Is there a MORE technical way to pick the correct cam than just trial and error if one has correct flow numbers?

Suggest away.

mike#9

iTrader: (3)

You can use that reverse split cam...but I would recommend doing a bigger standard split...if you want something bigger.

I am putting a 230/236 cam in my car and I am probably going to spray it with a 75-150 jettable kit. No spray in the immediate future, but give me a week or 2 and I can tell you how the cam drives...it will be installed along with my stage 2 heads soon!!!

z98

Desktop dyno maybe?

Camaroholic

iTrader: (1)

DD2K will NOT work for you unless you have very accurate data.

For example, with my head flow numbers alone (similar to what's posted above), the cam iterator said that I should run a 228/242 .48"/.65" solid roller to maximize power. heh.

But, scale back those intake port numbers (by bolting on an intake and TB), make some new measurements, and you may get something more realistic. I scaled back my intake port flow numbers (just to simulate an intake being bolted on), and wound up at a 239/236 .65/.65 cam with DD2K. So you can see, without more data - REAL flow data for the SYSTEM - the numbers are worthless. Even my reverse split numbers were based on "made up" intake flow numbers.

DD2K is a fun toy to waste away a rainy Sunday afternoon with, and learn about how valve events affect RPM performance, but I wouldn't build a LS1 around it.

-Andrew

Cstraub

iTrader: (1)

Actually this is where "most" go wrong with the bigger thing. As cylinder heads have progressed with port velocity, clean air, and good numbers down low the common thing to do is go bigger cam, this is the wrong thing to do. If you think about what the cam is, it controls the air in and out. Now take an engine with poor flowing heads. For the engine to make power the cam is going to have to over compensate for the heads based on a performance engine exceeding the RPM range of the engine. IE Super Stock. Now take the heads available today and terrific low lift numbers the heads get. Most of these heads will sustain the CID of engines into the rpm range with no problem, the head doing the work. Knowing this, the camshaft does not have to be as large because the head will achieve cylinder fill in a shorter time (less duration) and the head flows suffiecient air at lower lifts (less lift) to sustain the engine and make power.

Case in point, I was asked to provide a camshaft to a WoO engine builder a few years ago for a new cylinder head that was going on the 410CID engines. The engine was not performing with 3 supplied grinds from other cam companies. Once I was supplied the info on the engine and airflow off the heads, I ground a camshaft that was 20degree shorter in duration and .100" less lift. The cylinder head manufacturer was insulted by the cam but at the insistance of the engine builder he wanted to try it. Dyno results were 70HP more, 100#/ft of torque and a power band that was 2400 rpm broad with a 5% variance across it.

So, when selecting cams, I would go conservative especially if you have good flowing heads.

Cstraub