Month in, month out, you plunge all your hard-earned duckets into aftermarket accessories that, in theory, should make your car a bit quicker down the quarter mile.
As you are all well aware, anything from an air intake to a turbo system will cost you an arm and a leg, so it is imperative you get the best-bang-for-the-buck. But unfortunately, we often hear of stories or come across vehicles that are lit up with all sorts of power-proven products but aren't running as well as they should. More often than not, the problem lies with good, old, basic maintenance.
Think about it, you can upgrade your ignition to dish out more spark than Independence Day, but if you're still running on the same plugs that came with the car three years ago, you can hardly expect to gain anything, now can you?
The same applies to other bolt-on products such as air filters. How well can your Hi-Flow filter actually flow when it's clogged with dirt? In cases like these, which are just simple examples, you actually end up losing more power than you would have gained if everything was in tip-top shape. Not to mention, these also reduce the longevity of your engine. If you feel that top-of-the-line exhaust system really just cleaned out your bank account, you might want to go back to the basics.
Those of you who follow our "Power Page" section monthly will no doubt have noticed that for every vehicle we select as a test bed, we always establish a baseline run on the dyno before testing the "Power Page" products. Of course, this allows us to evaluate power gains or losses once the product is installed, but it also allows us to assess whether or not the vehicle is running up-to-par beforehand. This is an important procedure that is often overlooked by many entry-level enthusiasts. If you purchase your import ride brand-new, it is generally safe to assume the vehicle performs to its full potential. However, if you purchased a used vehicle, which is often the case, a basic maintenance overhaul is the first upgrade you should make.
Imagine this--if your vehicle is in desperate need of a thorough tune up, it could be as much as 20 hp down on the factory rating. A basic tune-up consisting of spark plugs, plug wires, cap and rotor, oil and filter, air filter, fuel filter, transmission fluid and checking the tire pressure will cost less than $100 and is quite possibly the best bang-for-the-buck you will ever get. Even if your newly revived powerplant doesn't exactly pin you in your seat at the touch of the throttle, at least you can feel content in knowing that it's running to its full potential and is now ready for some bolt-on modifications.
So what happens after you modify your ride? When you add high-performance products and start to drive the car harder, basic maintenance becomes preventative maintenance. Regular and thorough maintenance should be on the top of your priority list once you've built a high-performance vehicle--optimum condition is imperative if you want your additional power to last. Of course, the basics remain the same--regular oil changes, plugs, cap and rotor all need to be maintained and replaced when necessary. Aside from the visual or scheduled maintenance, another worthwhile and informative procedure is a compressions test and leak down. A compression test will tell you whether or not the cylinders are performing equally at an optimum level. The compression tester is a gauge that fits into the spark plug thread, then, when you crank the engine over, the gauge will give you a reading. You repeat this process on each cylinder with the throttle wide open. Unfortunately, there is no standard reading, as compression differs from engine to engine, but if your engine is in good shape, you should end up with a similar reading across all cylinders. If not, then something is probably amiss.
This is where the leak-down tester comes into play. If you are familiar with using a leak-down tester you can actually pinpoint where the problem lies. The leak-down tester, works in a similar way to that of the compression test, only this time you begin at the No. one cylinder with the motor at top dead center (TDC).
For the leak-down test, the motor does not need to be cranked over; instead, the leak-down tester pressurizes the cylinder to a certain pounds-per-square-inch and then measures any blow-by--the amount of cylinder pressure lost through worn piston rings, defective valvetrain or blown head gasket. This procedure is repeated across the cylinders, only this time, you test each cylinder according to the engine firing order. Also, a coolant pressure tester which attaches to the radiator will allow you to test the coolant system for leaks around any of the hoses, head gasket or radiator. If you don't have the necessary tools to perform these tests yourself, any automotive service center should be able to do it for no more than $50.
Hopefully, we provided enough information and insight to enable you to take advantage of the horsepower gains available through the aftermarket.
We dyno-test an abundance of hop-ups every month in our "Engine Tuning," "Just Tested" and "Power Page" sections to keep you, the reader, in touch with what works and how well. But remember, we always establish a solid baseline first, so use this advice to keep your ride running to its full potential.