Right, there's two ways to build horsepower, either increase the torque or increase the RPM. V8's tend to do it by building torque and keeping a low RPM. 4 cylinders do it by keeping a fairly low torque at a very high RPM. Same means to a different end. The trouble is that since these high revving engines idle at low speed and they don't make much torque it's easy to bog them down and thus it takes longer to get them into their power band from a dead stop. Once you do get them in their power band though all bets are off.

That's why you can beat a 500 HP 4 cyl with a 200 HP V-8 if the race is short enough.

This is also why you can continue to make more horsepower past your torque peak. Even as torque starts to fall your RPM's are climbing fast enough to compensate and allow you to make more horsepower. At some point the RPM is climbing and compensating at the same rate torque is falling, at which point your HP curve becomes flat. If the torque curve falls at a steeper rate from this point, your horsepower will begin to fall. You can see this perfectly if you look at an L98 dyno graph vs an LT1. The LT1 continues to build power to the redline while the L98 actually has a power peak and begins to taper off. The difference is that while both are losing torque as the RPM increaes beyond the peak, the L98 loses it faster.

Now the ultimate is if you have a torque curve that continues to build as the RPM does. I saw a friend do this on his '95 supercharged mustang. He had heads, cam, blower, intercooler, etc, etc. In short this car was awesome. On the dyno as the RPM's increased so too did his boost and he made more and more torque, it simply continued to build all the way to the redline. Since torque was a linear gain and the RPM was a linear gain the HP actually saw a non linear gain, it became a power function. In short it was flat awesome to look at, it was the coolest dyno graph I've ever seen.

Contrast this with my friend's F-150 300 6-cyl. That things torque curve falls perfectly in time with the RPM in order to maintain a perfect 100 HP clear across the board. You can feel this when you're driving it. You can't put that truck in the wrong gear because really it's making the same power everywhere.

 

I need to know the thickness of each ply in order to calculate that!!

 

Interesting situation....it definately illustrates the point of putting the motor at peak horsepower in order to get maximum rear wheel torque.....

But after thinking about this a little, this engine is more like you can't put it in the right gear rather than you can't put it in the wrong gear.....

In any gear as soon as you increase speed the rwtq will go down even if the horsepower stays constant........I would think this would actually result in a very sluggish responding vehicle.......remember in a constant torque engine the horsepower will increase linearly with increasing rpm....or constant rwtq means increasing rwhp...check my previous post about needing more horsepower with increasing speed in order create the same accelerating torque....

I never did much like Fords...that truck has to start falling on its face right from the get go..

 

It doesn't feel sluggish, it just at no point is particularly responsive. The horsepower never decreases, it just never increases. So the rate at which you can get work done is exactly the same no matter where you are. IE if you nail the throttle at 2000 RPM's it feels exactly the same as if you ease it up to 5000 RPM's and punch it.

Where our cars certainly like the higher RPM's, the truck just really doesn't care. Talk about boring. I'm not a Ford fan either, but that 300 6-cyl will run forever. It's not an exciting motor but it's outlive damn near anything else on the road.

 

My reason for asking the question to begin with was my dyno sheet results. Im reaching max torque of 390 at 3300 rpm and max hsp of 310 at4600 rpm with both crossing at about 5200rpm .Im running a383 stroker,super ram(untill I get my single plane done),forced air,58mm asm t-body,dart pro 1(200 heads), 219/ 225 comp cam with 1.6 roller tips, 3 inch straight duals and a few other go fast things over the years.I guess I thought I would be getting more hsp out of the combo.Ive been told that my cam is way to mild . Tks to all you guys that responded to the post. I agree with the KISS theory and torque gets it moving and hsp finishes the job. Ive just got to find some more ponies.

 

That is a relatively small cam for a stroker motor. One of the biggest drawbacks to running a big lumpy cam in a 350 is that it gives up low end torque to build upper RPM horsepower. When you build a stroker though you have built in more torque, so you can go with a more aggressive cam and still maintain good street manners.

Also figure that the Super Ram is intended more for low - mid RPM grunt then it is for ultimate top end horsepower. If you want more horsepower you can swap intakes for a Mini Ram and put in a more agressive cam. You'll make a ton more horsepower but you'll also make a good deal less torque.

 

Sounds like it is actually a very well built "purpose" motor intended for good low end torque suitable for hauling light truck loads with good economy and long life....

 

Except for the good economy part. This engine is in a manual transmission truck. It gets 14 MPG driving around town normally. It gets 14 MPG if you drive with your foot planted through the radiator. It gets 14 MPG on the highway.

V-8 automatic trucks can easily top this.

What I'm curious about though is if the constant horsepower plays into the constant gas mileage.

 

I'd like to see that spreadsheet, if you still have it...

 

I should have the spreadsheet on my home computer. PM me after 5 P.M. sometime. If you PM me before 5 I'll get it while I'm at work and I'll promptly forget about it

 

Oh son of a bitch, I completely botched that one last night and spoke completely backwards. We had to consider the maximum stresses at the torque peak, not the horsepower peak.

Oh well, I got it right when it counted. That's what I get for trying to rely on my memory.