818camaro95

My buddy has a Comp Cams 227-227 112 lobe cam .525 intake and .525 exhaust. It's for his 95 Z. My question is what type of cam is it, with the Intake,Exhaust #'s the same I don't know if it will work on his setup. He's only doing a cam and heads no blower or NX.

Dave Feerst

it will be a good strong mid-range cam that will probibly peak around 5800-6000 made to be NA and streetable.

Cams with bigger exhaust than intake sacrifice a little HP for a few extra torque they also run N20 alot better.

I can elaborate if you wish...

818camaro95

ttt

ishz28

I'm interested, please do.

Mindgame

Tough to make general comments knowing what little we do. First impression is, this cam would work better with a free flowing exhaust. Headers, catback, a free flowing muffler and you'd never know you were down 4-6º of exhaust duration in comparison to the typical dual-pattern cam.
I don't agree with the comments made in regards to a HP sacrafice with more exhaust duration. Just doesn't go along with what I've seen first hand. If you dyno an engine sometime, start the baseline with 1.5:1 rockers, then switch to 1.6:1 rockers. Everytime I've done this I saw more peak tq but a drop in low rpm tq. Swapping the exhaust rockers back to 1.5:1 always shows a gain in the lower revs (tq). You can make your own conclusions but most of this is probably due to a longer exhaust duration's EVC (closure) event. Later closure traps more exhaust residual in the chamber and hurts low speed torque numbers.

-Mindgame

Eff

Heres a bit of the theory, make what you want out of it...

If you have a came like my XE 230 /236 it opens the exhaust valve 42 degrees BBDC. That allows the still hot expanding gas to expel itself from the combustion chamber before the piston comes up. By opening it early you loose the small amount of combustion that was still accuring as soon as the exhaust valve opens because there is nothing to push against. On the other hand you GREATLY reduce pumping losses. When the piston goes up on the exhaust stroke much of the exhaust has already left under its own expanding pressure and the piston coming up encounters less resistance. This translates for less of a power draw on the next cylinder which is now in its power stroke.

All 4 valve events are important, there is really a science to this stuff, bigger is not always better

Intake valve closing for example will usually occur a few degrees into the compression stroke.. If you have high air velocity in your intake and heads an effect called the inertial ram effect can not only fill the combusstion to atmospheric pressure but it can go well beyond it! I believe there have been N/A motors in the 130%s for volumetric efficiency. That means the incoming air actually compresses the air in the combustion chamber while the piston is idle at the bottom of the cylinder.

If you can get the actual cam spencs (the timing of all 4 valve event) off of the cam card you can play around with desktop dyno and find some really cool stuff. Especally if you have all of your flow #s in there for determining Flow.