Big Three road tests

Huntindog wrote:

FishOnOne wrote:

Huntindog wrote:
Ever wonder how GM arrived at 397 HP?

And how Ford always has nice round even numbers?

Simple, and has been proven before.

GM tested the Dmax for reliability and power, then dynoed it to SAE standards to see just how much power it makes.

Ford wanted a nice round number that would exceed the Dmax. So they tuned for a number on the dyno, but not to SAE standards.

Think about the difference between peak HP, and continuous HP.

The Ford can indeed make the advertised HP/TQ for a short time. Then the computer dials back the power to keep it from hurting itself.

The GM can make their lower HP/TQ much longer. Long enough to meet the SAE standards, and likely continuously.

So in effect the GM wins on the road,,, time after time.

I disagree... The last Ford power curves I've seen on the 6.7 PSD looked pretty darn flat to me.

Fish, I expected that you would disagree.

But it is a FACT that the GM is the only one doing dyno testing to SAE standards.

The documentation has been posted here before. I know you have seen it.
Power curves are not what I am talking about.

And you cannot deny that the Ford numbers are ALWAYS nice round numbers, that just happen to be higher than GMs.

I remember a GM engineer being asked about why they came up with 397 HP, when a nice round 400 could have been achieved. His response was to the effect of:: We have done a lot of testing with the Dmax. 397 is what the number came in at, and we are comfortable and confident with that number.

There are really only two choices anyways. Since GM has consistently spanked the Ford in many tests, either the Ford is over rated, or the GM is under rated.
It would make little sense to under rate a truck, as that will cost sales.
But if you get a higher rating by any means possible, including loose testing standards, then you can advertise that rating, and many will believe it.

I have not seen the articles you are speaking of. But there is far more to timed tests than just HP. Trans gear ratios and efficiency, wheel and tire weight, aerodynamics, total vehicle weight, torque limiting off the line just to name a few. I am not saying you are wrong but if hp was the end all of these tests than every vehicle with the same hp car, truck, moped would have exactly the same elapsed time.