After much head scratching it is finally time to swap out the stock cam on your Harley Davidson and go for the right cam for your style of riding. Do you go for horsepower or do you go for torque?
Essentially a torque cam will enable more combustion efficiency to deliver a greater piston power stroke at a given RPM which will usually peak in the lower to mid range.
A horsepower cam will enable more combustion efficiency to keep the force maintained to drive the piston in the power stroke at higher RPMs.
Torque is the ‘piston power’ to turn the crankshaft, whereas horsepower is a factor of torque multiplied by RPM. Therefore they are linked with each other but usually you will sacrifice some torque at higher RPMs to maintain the power.
In an ideal world you would want a high torque and high horsepower in a high performance engine. However you can achieve the higher torque through gearing too. Therefore compare a race car vs a tractor. (A poor comparison I grant you) Both may have 200hp but the torque exerted at much lower rpms in the tractor e.g. 2500rpm could be a lot greater work than the car given the same engine. However the car may also have different gearing so that the torque to drive the car at slower speeds isn’t much but the gearing will allow the car to accelerate and keep delivering torque over a longer period to drive the higher gears thus yielding greater horsepower.
So what does this mean for Harley Davidson riders and which would be the best choice of cam. Well, there isn’t a correct answer here as it purely depends on the kind of riding you want to achieve. If you want to ride in the higher rpms and ride faster but be more aggressive with acceleration and gear changes, then the power cam is the best choice. Think race car here!
If you are looking for the bike to have ample power in the low rpm and low to mid speeds or when loaded, then a torque cam is the way to go. Think tractor here!
Most people just want the extra torque and horsepower for everyday riding. That is some improved acceleration, better power delivery for overtaking etc and to operate in the 2500-4500 rpm range. For this the torque cam will be the best option as it delivers the extra torque and power where it is really wanted. The horsepower and torque will still be greater at higher rpms than a stock cam but nowhere nearly as agressive.
Many people choosing power cams soon realise that a torque cam would be a better choice for their kind of everyday riding. In some cases they swap out the power cam once again for a torque cam. Of course many choosing the power cam are totally satisfied with the net result too.
So you’ve decided which direction you want to go, whether torque or horsepower. Now comes the tricky part…which manufacturer and what specs to go for. You would need to look at the data for each and compare with each other but ultimately a horsepower cam will open the intake valves sooner and close the exhaust valves later than the torque cam and even more so than a stock cam.
Each manufacturer should be able to provide specifications of these values but fundamentally there will be varying degrees of capability between cams whether torque or power. The difference will be how much capability you would want and really need and how reliable and durable this new cam will be for your kind of riding.
Whichever cam you choose from whichever manufacturer, also keep in mind that the overall net result in performance will also be affected by the exhaust, air filter and tuner on the bike and any other work to the engine such as lifters, pistons, valves, clutch springs etc.
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