. This is also from a 394 and yes the RPM is correct.
That is indeed a flat curve. Here is another you might enjoy. . This is also from a 394 and yes the RPM is correct.
. This is also from a 394 and yes the RPM is correct.
HP and torque curves always cross at 5250 rpm...are you sure these curves are correct?
Jack
Jack
Jack
Look at the scaling along the left hand & right hand borders of the graph. The scaling for horsepower & torque are different, if the scaling was the same they would cross as expected.
-G
Look at the scaling along the left hand & right hand borders of the graph. The scaling for horsepower & torque are different, if the scaling was the same they would cross as expected.
-G
The owner of the motor in question has commented that after some development work and more dyno time his motor ultimately made 549 foot pounds torque and 627 horsepower at 6700 rpm. The torque was 500 foot pounds or more between 3500 rpm and 6500 rpm. The owner also commented a TFC manifold (single plane) found 10 extra foot pounds through the mid-range, but did not make 1 more horsepower on top.
Scott mentioned the motor ran on 98 octane Australian gasoline, which would be equivalent to 93 octane in the US and Canada. Scott also commented it used one of his dual plane manifolds, modified, nothing fancy just lots of R&D to get it right.
I know everyone is into the big numbers, chest thumping and bragging rights. That's cool. The owner is happy with the motor, and Scott is rightfully proud. Those of you who know me understand that's just not where my head is at any longer. If peak horsepower were only 400 bhp I'd still be as amazed at the width and flatness of the torque curve.
If somebody shares the final dyno curve with me I'll post it up for you guys.
-G
Scott mentioned the motor ran on 98 octane Australian gasoline, which would be equivalent to 93 octane in the US and Canada. Scott also commented it used one of his dual plane manifolds, modified, nothing fancy just lots of R&D to get it right.
I know everyone is into the big numbers, chest thumping and bragging rights. That's cool. The owner is happy with the motor, and Scott is rightfully proud. Those of you who know me understand that's just not where my head is at any longer. If peak horsepower were only 400 bhp I'd still be as amazed at the width and flatness of the torque curve.
If somebody shares the final dyno curve with me I'll post it up for you guys.
-G
28 degrees total timing is consistent with controlling the combustion chamber pressure to avoid detonation of US 93 octane pump gas.
If you were detonating the fuel at somewhere in the 30 to 36 degree range and you lowered the advance to a point where it no longer detonated, you would show an increase in both hp and tq.
That is an indication that the engine was detonating and there were no other obvious indications.
A big engine might not show it except in the dyno numbers, particularly if the combustion chambers had been modified.
The controlling factor to the entire experiment is the octane of the fuel used. You must determine at what pressure the 93 will detonate and then arrive at solutions on how not to exceed that.
Static compression ratio, total timing and camshaft timing are all major contributing factors to that.
If you can control detonation with chamber design alone, without a computer control of the ignition and tailoring those factors to comply to the fuel requirements, then you had better patent this chamber design because you have change the laws of physics and you may have also discovered Warp Drive for the Enterprise?
Changing to a single plenum intake manifold would change the characteristics of the engine and is just a tuning choice.
It is entirely possible that this dual plane will out perform the single plane entirely. Especially since this engine seems to be limited to 6700rpm. Particularly if it has been modified and flowed itself to compliment the air flow characteristics of the heads and induction it is mated to? I'll bet this one was seriously flowed before the dyno test?
The main advantage to the single plane would be above that.
The Yates and Nascar "Ford" single plane manifolds were created to yield hp gains up to 9200 rpm. That right there should be an indication of which is the "better" intake to use for this application.
Anyway you look at this, this is really a hell of an engine.
It out preforms the race 427 Fords at every level at a lower cid number.
The 427 Ford is now quite expensive to build. I don't know if this Australian Cleveland is going to have any price advantage. Looks like a dollar monster to me?
I mention them simply because I use those as the standard by which I measure BB performance and this 393 like it or not is a "BB" in that sense.
BUT there are other issues to consider with it. First of all, it may not necessarily been built for a Pantera.
As such to run it hard in one, you have to consider the longevity of the ZF with it.
I suppose the term "running it hard" now has to be defined as well. Looking at those torque numbers, it is running hard just idling, sitting there doing nothing?
Second as has been mentioned here, does it have the same small block "rev-ability"?
It would appear from the numbers posted that it is just a big bully that is going to break traction consistently just off of idle?
To me, that isn't what I like in an engine.
This really is just a bench racing post with debates over what taste in an engine should be and whose manhood is bigger then the other guys?
If you were detonating the fuel at somewhere in the 30 to 36 degree range and you lowered the advance to a point where it no longer detonated, you would show an increase in both hp and tq.
That is an indication that the engine was detonating and there were no other obvious indications.
A big engine might not show it except in the dyno numbers, particularly if the combustion chambers had been modified.
The controlling factor to the entire experiment is the octane of the fuel used. You must determine at what pressure the 93 will detonate and then arrive at solutions on how not to exceed that.
Static compression ratio, total timing and camshaft timing are all major contributing factors to that.
If you can control detonation with chamber design alone, without a computer control of the ignition and tailoring those factors to comply to the fuel requirements, then you had better patent this chamber design because you have change the laws of physics and you may have also discovered Warp Drive for the Enterprise?
Changing to a single plenum intake manifold would change the characteristics of the engine and is just a tuning choice.
It is entirely possible that this dual plane will out perform the single plane entirely. Especially since this engine seems to be limited to 6700rpm. Particularly if it has been modified and flowed itself to compliment the air flow characteristics of the heads and induction it is mated to? I'll bet this one was seriously flowed before the dyno test?
The main advantage to the single plane would be above that.
The Yates and Nascar "Ford" single plane manifolds were created to yield hp gains up to 9200 rpm. That right there should be an indication of which is the "better" intake to use for this application.
Anyway you look at this, this is really a hell of an engine.
It out preforms the race 427 Fords at every level at a lower cid number.
The 427 Ford is now quite expensive to build. I don't know if this Australian Cleveland is going to have any price advantage. Looks like a dollar monster to me?
I mention them simply because I use those as the standard by which I measure BB performance and this 393 like it or not is a "BB" in that sense.
BUT there are other issues to consider with it. First of all, it may not necessarily been built for a Pantera.
As such to run it hard in one, you have to consider the longevity of the ZF with it.
I suppose the term "running it hard" now has to be defined as well. Looking at those torque numbers, it is running hard just idling, sitting there doing nothing?
Second as has been mentioned here, does it have the same small block "rev-ability"?
It would appear from the numbers posted that it is just a big bully that is going to break traction consistently just off of idle?
To me, that isn't what I like in an engine.
This really is just a bench racing post with debates over what taste in an engine should be and whose manhood is bigger then the other guys?
it could be worse, we could be debating which crate motor to buy from walmart.
quote:it could be worse, we could be debating which crate motor to buy from walmart.
I am not even going to try and understand what that means...
George, thanks for pointing out the difference in torque and HP scaling that I obviously did not notice.
Jack
Jack
is it cowboy from hell or granpa from hell just a joke. but interesting about the the scale of the hp vrs torque what would it look like scaled properly?
Grampa from hell 
The formula for horsepower is (torque x rpm) ÷ 5252
so horsepower = torque at 5252 rpm.
When the scaling for horsepower & torque are the same, then the torque curve & horsepower curve will always cross at 5252 rpm.
The formula for horsepower is (torque x rpm) ÷ 5252
so horsepower = torque at 5252 rpm.
When the scaling for horsepower & torque are the same, then the torque curve & horsepower curve will always cross at 5252 rpm.