More horsepower comes with a cost

I must say that I am as guilty as the next when it comes to dreaming about a little more power. 

In fact, for every vehicle I have owned — minivan to 68 VW Beetle — I have had a performance improvement plan. Lately most of my plans lie fallow (responsible parent that I am). A guy can dream. 

Early in my career, some of my plans came to fruition. From each of these plans came the realization that serious performance improvements require time, money (maybe that is what is keeping my current plans on the back burner) and compromise.

There are plenty of companies out there willing to sell you the latest performance-enhancing device.

Don’t believe for a minute that they will fulfill your desires without some sort of compromise and a lighter wallet.

As I mentioned in my last column, the modern automobile is well engineered as a whole. A simple 10 per cent bump in horsepower and fuel economy at the same time is not likely for the sum of $199.95.

Until quite recently 0 -100 km/h times have factored very prominently in almost any vehicle advertisement and if not that, a horsepower figure or two are usually bandied         about. 

Four-hundred horsepower pony cars are de rigueur again. If the Camaro engineer could get another 40 horsepower and two miles per gallon for $200, his boss would be setting him up for one serious bonus.

One of the most common performance upgrade components is the so-called cold air intake. As described, one of these units seems like free horsepower. Make it easier to get fresh cold air into your engine and voilà, more horsepower and better fuel economy. How can you go wrong?

When you are taking off your vehicle’s many plastic, funny-shaped air intake pieces and replacing them with a very large simple tube with a cone-shaped filter on the end, does it make you wonder, ‘Why such a complex unit? Keep it simple, stupid. What were the engineers thinking?’

I can assure you that they were thinking about a lot more design criteria than the guy who came up with the big tube and a cone filter.

When you fire up your vehicle for the first time and hear that new deep throaty sound of air easily finding its way into your engine, you know those newfound ponies are ready to be unleashed. You can hear them.

In fact, two hours of highway driving under your belt later and           you recognize that you are hearing that air rushing in a little too much above your Brahms, Beethoven or Beatles. 

Yes, sound level and quality was one of the engineers’ design criteria.

It may be likely that when the under hood air is cool (the vehicle has not been running very long), and your gas pedal foot is on the floor, and the engine is near red-line (maximum revolutions per minute), your vehicle is making a couple more horsepower than it had with all the plastic bits installed. 

You have in fact suffered some serious compromise. All that extra plastic tubing was fashioned in a way that from idle to red-line, your vehicle’s engine produced an optimized amount of torque, horsepower and pleasing sound. 

The actual size and shape of the tubes likely took advantage of intake air pulses to help fill the engine beyond 100 per cent capacity at lower engine speeds and loads.

The air was likely picked up from in the fender where it would never be saturated in water and be less effected by high underhood temperatures when the vehicle has been driven for some time in hot weather.

So, yes, you gained a little extra top-end horsepower on a cold day but likely lost some overall performance. For some of us, that new sound of horsepower is getting annoying.


 Trail’s Ron Nutini is a licensed automotive technician and graduate of mechanical engineering from UBC. He will write every other Thursday. E-mail: