[Stan Weiss]

Originally Posted by Tim Corcoran

Based on the simulations that Stan provided the Voodoo 703 outperforms all other cams discussed.

JMO but with an automatic and stock converter and 3.08:1 or higher rear the 702 might be a better cam.

Stan

[Jay S]

Originally Posted by Stan Weiss

JMO but with an automatic and stock converter and 3.08:1 or higher rear the 702 might be a better cam.

Stan

X2

And the 702 will have decent street manors, between a XE256 and a XE262, even with very low compression. But it will hold on to power like a bigger XE 274, and does it without beating the snot out of the cam and valve terrain. Like Cliff, I am really not a fan of the XE’s cams either, but sometimes (like right now) that may the best of what’s available.

[Shiny]

Originally Posted by Stan Weiss

JMO but with an automatic and stock converter and 3.08:1 or higher rear the 702 might be a better cam.

Stan

Originally Posted by Jay S

X2

And the 702 will have decent street manors, between a XE256 and a XE262, even with very low compression. But it will hold on to power like a bigger XE 274, and does it without beating the snot out of the cam and valve terrain. Like Cliff, I am really not a fan of the XE’s cams either, but sometimes (like right now) that may the best of what’s available.

These threads often end up focusing on peak HP and/or peak torque, which makes sense to me for a race car.

But as these two comments suggest, not everyone wants to drive a race car.

What chart and/or metric is the best predictor of "street manners"?

Would the answer be a comparison of the torque curves or is it more about "area under a curve"? I'm pretty sure it isn't peak HP nor peak torque... but more about what happens at low rpm up to peak and where the peaks happen.

A long long long time ago, I had a 2-stroke 100cc Hodaka Super Rat. My room-mate had a 4-stroke Kawasaki 175. The Hodaka was useless at low rpm and was basically either "on or off". The Kawasaki had low end grunt and what I would call better "street manners".

I also owned a couple VW Jettas that were fun to drive. Granted there was no power, but the torque curves were so flat you often couldn't tell what gear you were in. To me, this is "street manners".

Maybe my definition is wrong... but I'm curious what others think "street manners" means and whether a simulation like Stan's can predict it?

[Steve C.]

Stan, Run a simulation for two hydraulic flat tappet cams that have the same .050" intake duration. Not in a 350 combo but a 455 combo.
I'm aware they are not rated at the same tappet lift but just for interest.
Lets look at a comparison of the torque curves or "area under a curve".

The ever popular Crower 60919 cam:

304 /316 ( or what ever seat duration they use these days )
231 / 240 @ .050
.470 / .470 lift
112 LSA / 106 ICL

A very popular UltraDyne Pontiac cam years ago:

288 / 296
231 / 239 .@ . 050
.485 / .507 lift
110 LSA / 104 ICL


.

[Stan Weiss]

Originally Posted by Steve C.

Stan, Run a simulation for two hydraulic flat tappet cams that have the same .050" intake duration. Not in a 350 combo but a 455 combo.
I'm aware they are not rated at the same tappet lift but just for interest.
Lets look at a comparison of the torque curves or "area under a curve".

The ever popular Crower 60919 cam:

304 /316 ( or what ever seat duration they use these days )
231 / 240 @ .050
.470 / .470 lift
112 LSA / 106 ICL

A very popular UltraDyne Pontiac cam years ago:

288 / 296
231 / 239 .@ . 050
.485 / .507 lift
110 LSA / 104 ICL


.

Steve,
What CR, head flow, exhaust manifolds or headers, intake dual plane or single plane?

Stan

[Steve C.]

Stan,
If possible create something typical that might be suitable for each cam, yet one that doesn't obviously favor one over the other.

I'm curious on the 'dyno' numbers presented and I no longer have any computer programs to run the two.
It's just a fwiw exercise since as already eluded to here it won't demonstrate a smoother idle, better off-idle response, superior low speed drivability and a broader power curve.




.

[Steve C.]

I should of edited the above post and removed "and a broader power curve."

That should not of been included as the 'dyno' numbers might indicate it.


.

[Stan Weiss]

Originally Posted by Steve C.

Stan, Run a simulation for two hydraulic flat tappet cams that have the same .050" intake duration. Not in a 350 combo but a 455 combo.
I'm aware they are not rated at the same tappet lift but just for interest.
Lets look at a comparison of the torque curves or "area under a curve".

The ever popular Crower 60919 cam:

304 /316 ( or what ever seat duration they use these days )
231 / 240 @ .050
.470 / .470 lift
112 LSA / 106 ICL

A very popular UltraDyne Pontiac cam years ago:

288 / 296
231 / 239 .@ . 050
.485 / .507 lift
110 LSA / 104 ICL


.

Steve,
I have file for the Crower 60919 which when I calculate duration from events is
290/300
231/240
.470/.470
112 LSA/ 108 ICL

It is from a few years ago and I don't remember where those number came from. Does anyone have a cam card for the Crower 60919 that they can post

Stan

[Steve C.]

Cam card in post #12, but noted it is old.

https://forums.maxperformanceinc.com...60919+cam+card

As discussed in that thread, and others related, Crowers numbers for the 60919 cam have varied over the years.

A few more here:

https://forums.maxperformanceinc.com...60919+cam+card

.

[Jay S]

With 1.5 rocker arms, we have never used anything more than stock valve springs with that 204/214 cam.

[Jay S]

Without knowing what the rest of the combination is, I don’t know that you could gauge street manors very easy by looking at dyno chart. The gears and the weight of the car make a difference too.

Decent street manors to me can have some roughness to the idle, engine can have some lope sitting at a stop light, but clears up immediately off idle, with enough torque that on a manual transmission your not slipping the clutch to get the car rolling, and you don’t need to change gears to a lower gear to pull the load at part throttle. Or in a nut shell…can my wife drive it

I was mostly gauging the street manors in my comments by the cams overlap. The 702 is between the XE256 and XE262 for overlap. With 8:1 of less compression in a 350, much over 50* of overlap with those voodoo and XE cams the idle will start to get snotty, and loose quite a bit of bottom end power in trade for HP. If you were after stock type manors, those cams are probably one step big.

[PunchT37]

Looks like he`s got enough advise now to pick his cam for his combo. He has to decide what kind of street manners he can put up with.


Course, he ain`t ran any of these cams to find out.