MARKUS_P

I think this is an interesting poll:
You have to use only the graph to make up your mind and I bet some of you will be surprised about the cam type and their results.

PRNDL

They are so close I probably couldnt tell the difference, but just on principle I would take #1 because it produces more hp and torque in the useful range, up to 4500 rpm. :) MJ

Clink69

:iagree:

Chris :flag

gdh

:iagree:

dually4wd

Something seems a little fishy about the graphs. It seems like number 2 is being held back by the intake/heads or exhaust. Just when the cam is coming in, it can't breath. I would love to see the complete combination used for the test.

adam

The two curves remind me of:

1. cam advanced 4 degrees vs. not.
2. H268 vs. energizer 272

I too would pick more torque... get's you faster through the rpms, no?

9SecVette

:iagree:

81vette

I'll take stroker 2 just because no one else did. :D


mark

WA 2 FST

Getting down the 1/4 mile or any other form of acceleration is about "area under the curve", and no, not TQ, but HP. HP is just a function of torque (and how efficient it is in the rev-range you're using anyway). If you disagree with me, that's cool, but if TQ wins races then we'd all put monster turbo-diesels that make 1000ft/lbs of TQ at 1500rpm in our Vettes. :D

That being said, the winner of a theoretical race b/w these two engines in vehicles of equal weight and aerodynamics would be the one who had the better overall gearing (taking into account trans and rear gearing).

In a drag race with low enough gearing to get your car out of the hole in 1st gear, I go with #2 b/c the average HP is greater. It makes a little bit less HP/TQ down low, but from 4500+ it is = or higher. If you were to upshift these engines at 7500rpm, it would be no contest. #2 would win easily.

Now I'm assuming the vehicle would be equipped with a close-ratio gearbox. But take the M21 gearing, for example. 2nd gear has a TQ multiplication of 75% of 1st gear. So if you shift at 7500rpm, you will drop to 5625rpm on the upshift. Plot this on the curve posted, and you'll see #2 is barely ahead, but pulls away hard at this point. 3rd gear has a TQ mult. that is 78% of 2nd, so on the upshift rpms only drop from 7500 to 5850.

In all likelihood to achieve maximum ET for engine #2, you would shift at 7000+rpm...not 7500. I was just using that to show a point, as I had not actually tried to calculate optimum shift points for each engine. And engine #1 should probably be shifted ~6500-6700rpm for best results (meaning it does not require as much rear gear as engine #2).

But engine #2 has a broader HP curve, even if it does indeed pick up later in the rev-range. All it would take is proper rear gearing and this engine would win...although I agree with one of the above posters that said these are very, very close combinations. Some are going to say #2 is more "peaky", but if you really look at it, that's not the case. If you are limiting BOTH motors to an artificially low shift point, then #1 is better.

MARKUS_P

Maybe a little...
Here´s the same graph with large tube headers and open exhaust (for both applications)

MARKUS_P

Good suggestion, here´s the spec card of the stoker:


stroker 2 uses XS282S-10 cam:
282 intake, 290 exhaust, 110 lobe sep. 106 intake center line
244 intake at 0.05, 252 exhaust at 0.05




[Modified by MARKUS_P, 1:25 AM 1/24/2003]

dually4wd

Just for kicks, can you try #2 with 210cc heads, 2.05 or .08 intake valves and at least 10.5 compression?

63Banshee

Is this a trick question?