More power from any engine?

[raygreenwood]

There are a lot more variables in there that affect how HP andtorque may be affecting the vehicles increasing rate of speed as well. For instance, a given shape be it aerodynamic or not will have a variable drag coefficient as air is compressed around different surface features. So as speed in creases...that can change the load imparted to the engine. Some positive...some negative. Also the friction of various other parts of a car on a drag strip change a speed increases. Like the tires. Yes they are heating up...but they are also changing cross section andcontact patch as their rpm of the axle increases...due to centrifugal force from the air within.....lots of little variables. Ray

[yilon]

If I can get off track a little, (the article refered to thinking outside of the box so this does relate...)

Power to weight ratios are relied upon to predict rate of accelaration and things like 1/4 mile ETs. Fact is down the track the car is not acc at a linear rate. As rpm increases Hp increases and the rate of acc is also increasing. It does this repeatedly in each gear. How is it that peak hp and vehicle weight converts to Meters/Sec/Sec when the car is spending only a fraction of its time making peak power?

O.K maybe I think too much, but If I am actually on the right track with this, how would you design an engine with this in mind? Would you want a broad power band with the maximum area under the lines on the dyno chart? Would you sacrifice peak power to accomplish that maximum area below the curve?

Thanks
Ron

You ask such a simple question with such a very complicated answer.

In general, a drag race engine works best if the area under the horsepower curve is maximized for the RPM ranges actually used. HOWEVER, each shift point is a zero horsepower under the curve incident. Also, the above more or less tacitly assumes a gearbox with equal spacing between gears; not always the case.

Also, the above assumes that maximum traction is being obtained at all points. The last is VERY complicated as automotive tires have maximum traction under acceleration at SLOW slip speeds. (Yes Virginia, a tire that is smoking JUST a little bit is getting better bite than a tire that is not slipping. This last point is what allows a dragster to accelerate faster than one G.)

Oh yes, you also have to factor in weight transfer to get the maximum available force.