mrr23

iTrader: (3)

ok got back with roger and got the VEs for you.
valve events @ .050
IO -5.0* ATDC
IC 35.0* ABDC
EO 43.0* BBDC
EC -5.0* BTDC
intake dur @ .004 272*
exhaust dur @ .004 280*
intake dur @ .050 210*
exhaust dur @ .050 218*
intake centerline 110*
exhaust centerline 114*
valve events @ .004
IO 22.0* BTDC
IC 70.0* ABDC
EO 70.0* BBDC
EC 30.0* ATDC

Sport Side

iTrader: (6)

Thanks MRR23!

Hurricane knocked out the power, thats why I haven't responded. I'll get to it when I get some time.

appreciate your responses.

marc_w

Just letting you guys know I'm lurking in this very informative thread here...

I don't have enough tech knowledge to really butt in. I'm just that dopey guy who likes his VHP cam.

Sport Side

iTrader: (6)

Ok, I'm not familiar with that logic, but I have heard of it. Where the larger exhaust durations creating more tq for a longer stretch of the rpm band. Correct?

But, isn't it more important to match the head flow characteristics to create the camshaft? For ex.
Stock 5.3 Head Flow #
.100 = 85.7%
.200 = 72.6%
.300 = 67.6%
.400 = 69%
.500 = 74.7%
.550 = 76%
.600 = 76.9%
For CID under 400, 75% exh ratio to intake dictates a single pattern cam. For every % point over you need to crutch the intake 1/2 degree of duration

?

I agree. Just a misunderstanding.
I was referring to duration (reverse split, standard, ..)
Most enthusiasts go with a set of long tube headers, exhaust work, and then leave the stock intake manifold in place. Here we have a very well flowing exhaust and a not so good intake. I was getting at, whats the point of a large regular split (HELPING THE EXHAUST) when we don't need it. We need the duration between the valves to favor the intake.

The goal is to balance out the air coming in, and air being released. Obviously they are not equal. So, you find where your lacking. Obviously we dont have much options to improve incoming air.
Ex. A man breathes thru his nose, and exhales thru his mouth. His nose is plugged. So, he breathes LONGER thru his nose, and shorter thru his mouth. This creates an equal exchange of air. (his nose was plugged)

This is where single pattern cams dont make since. Our motors aren't equal so why put a (220/220 or 224/224) exc.

If I am off anywhere, please redirect me. I'm here to learn to.

Sport Side

iTrader: (6)

I'd like to add a tid bit more.

You've posted his reasons for going with those cam designs, and I respect his methods. But, I dont quite understand them yet.
Would you mind explaining some more of this.
I'd like to grasp Vinci's way of designing if he wouldn't mind.

marc_w

My only guess would be that we really don't need the help on the intake side.

I ran that 220/220 cam, and the powerband was just too high.

Actually, I think something just clicked...

It was my understanding that more intake duration brings the entire powerband up in RPM's. I don't think the intake lobe is like the exhaust lobe, in that the exhaust lobe 'helps' the exhaust system in the truck...... I think it's more like the intake lobe is it's own entitiy, seperate from the physics of the intake system.

Not stating facts, just taking a stab at this.

Sport Side

iTrader: (6)

valve events @ .050

ASP KICKER 210/218
2002 Z06 Cam 204/218
Everyone knows that the LS6 cam idles like stock.
Valve events play a key part in this. Here you can compare intake valve closing, intake valve opening, exhaust valve opening, and exhaust valve closing.

Now heres a camshaft that most would think. HOLY ****! A 242/242 on a 105lsa. But guess what. It idles like a baby also.
VALVE EVENTS

Aussie Camshaft 242/242 105
You guys catching on to what I'm getting at?
compare the aussie cam to the vette cam.
Now you can sorta see how valve events play a key part in camshaft selection.

Let me gather some more info.

Sport Side

iTrader: (6)

Marc.

For someone just trying to pick an off the shelf cam and work it in with stock heads, you could do alot of comparing and come up with a pretty solid stick.

Ok, 220 was to high. It peaked at where? Alright back it down some. Say a 215 on the intake?
Reverse Splits have better idle qualities and generally make more power if spec'd correctly.

So maybe a 215/212. Soften up the exhaust lobe and run something like a Comp X-ER on the intake.

marc_w

How do they get 242* stuff into that small of an 'area'?

And that's a 105LSA?

*thrown for a loop on that one!*

marc_w

I really can't tell you where it peaked... it was just high. It shifted too much power from the lower part of the RPM range.

I haven't been a fan of XE-R lobes since the valvetrain noise I had with the 220/220 - which was similar to XE-R lobes.

Like you're pointing out with the VE stuff - there are way too many variables, and I'm not confident enough to work out anything myself. I looked around at off the shelf cams designed by the pros. I was leary of custom cams because I don't want to be the 'beta tester on a one-off cam.

VHP was stating that they make cams designed for torque, streetability, and that streetlight performance... something I didn't hear any other company claiming. I gave them a try... You know the rest from there...