I have a set of ported stock heads and a stock cam...
My Desktop Dyno says my car should rev to 6000, but it gets all weird around 5000.

What is the limit of an actual stock cam?
On some spots of my compressor flow map, I should be making 100+ hp more than the map says it can support. Would that limit rpm?

 

N/A stock cam is done in between 48 and 5200.That might be why if gets weird around 5000.You can of course rev it to 6250
but all its doing is making noise.I would think stock timing events
and low liftwould limit airflow under boost.Valvesprings will also
come into play.

 

8500 with boost!

 

5000-5500rpm anything above the power is falling off and the torque is more than likely long gone.

Tony R

 

I think it depends on your entire combination, not just the cam.

Take a completely stock system (H/C/I), it won't peak very high at all.

Then change to some AFR 185's and a Holley/RPM manifold, and I wouldn't be surprised that it pulls ALOT more useable rpm up top.

 

That's what I'm wondering...
My computer program says it should be pulling till 6000..

 

Exactly what I was going to say

 

try advancing your cam to move the powerband.

 

Retard the cam for top end.

 

Hi, I'm stupid.
that's what I meant. Retard.

Sorry, working too much lately.

 

I ran a stock cam installed straight up in my old motor with the same turbos. Pulled hard to the 6000rpm shift point.

Rob

 

Try both, retarding and advancing.

You may be surprised with what you find depending on the combo.

 

I'm not exactly running a Danny B belt drive. I can't just tweek the advance and retard of the cam with a quick loosening of a nut and bolt. That whole option is just out of the question.

I am curious about what happens when you push a compressor too far outside it's limit.

 

I used a stock cam in my old car retarded 4 degrees with 1.7 rockers. It "seemed" like it pulled all the way to and past 6000 when you drove it but with it on the dyno it was done by 5200. So even though it pulled to 6000 the car would go faster shifting it lower, kind of like a stock stang does. If you needed a few hundred rpm in fourth to get through the lights it would work for that.

 

Dang,
That sounds what like I said in the 2nd post!

 

Keep it straight up and just keep pouring on the boost.

I noticed very little difference on my motor messing with the cam timing.

 

OK I gotta ask, how do you RS guys do that with the stock cam.

 

I will be honest, is the stock cam the best for what we do? No and the cam does have a peak efficiency range and it is the RPM range as previously posted by the other guys.

Although, as the efficiency of the cam starts to fall off at higher rpms, pouring in more boost will help counteract that. The HP curve on my car is pretty flat and you will see it start to drop off some at higher RPMS, but it is still making usable power up there.

All of this information is based on the fact that you have the propper valvetrain setup to support the higher RPM's.