On Driven Daily, Jesse O'Brien writes about efficiently using your time behind the wheel, including his own BMW with 200,000 miles. Here's his recommendations for the top ten performance and safety upgrades for the serious driver's daily driver.
A good modification adds to one aspect of a car enough to offset any downside it carries with it. There are a few upgrades that can be made with virtually no downside to them, and offer a huge performance or mileage boost without too much work.
Tires are the best upgrade you can possibly make. Tires have seen the most technological progress out of any automotive part in the past decade, and the right tires will last longer, grip better, and perform in all the weather conditions you'll be driving in. I've ordered tires from Tirerack several times, and highly recommend them.
Remember, your contact patch is essentially just the width of your tires, so wider is better. Try to keep the same outer circumference, no matter what tires you use. Your vehicle's suspension is set up for the stock circumference, and your speedometer is calibrated to tell you the speed based on how far you travel per rotation of the tires. Check the tire size calculator if you're curious as to how new tire sizes will affect your gearing and speedometer reading.
2. Braided brake lines
Most vehicles use rubber hoses to deliver brake fluid to the brakes when you press the pedal. Because your wheels need to move with the suspension and steering components, the lines that connect the brakes to the brake lines need to be flexible. Unfortunately rubber hoses are flexible and stretchy so they absorb some of the pressure sent through them. That decreases brake response and how well you can ‘feel' the brakes working.
Braided stainless steel brake lines address this problem, providing flexible but non-stretchy lines that transfer the maximum amount of pressure you press down on the brake pedal directly to the caliper. They are an inexpensive way to dramatically improve brake feel and response.
Wheels allow for bigger brakes and wider tires, which increases your traction contact patch, giving more grip in all situations. Lighter wheels will also improve handling, acceleration, and braking. My last CRX project was centered entirely around mounting 9″ wide 6ul wheels on it.
4. Coilovers (Springs and Struts)
Car suspension is designed to keep the car's weight distributed as equally as possible between the 4 wheels. Lowering your car will improve aerodynamic efficiency, decrease drag, and improve mileage.
Be cautious lowering your car because driving on public roads still requires ground clearance to avoid bottoming out and damaging any number of components. Tires can also rub against the inside of the fender when going over bumps or turning very hard, and camber changes can cause improper tire wear. Coilovers generally suggest a "kit" of springs and struts (hydraulic shock absorbers) and often allow ride height to be adjusted by moving the perch that holds the spring on the car up or down.
Performance bucket seats grip you more firmly and keep you from having to brace yourself while cornering hard. They hold you right where you belong: behind the wheel. I consider them to be a safety improvement, as well as a psychological performance improvement. You'll certainly feel more in control with race seats than with an old bench seat that doesn't hold you in place at all.
An aggressive camshaft can dramatically increase your engine's performance. It causes the valves to open wider and stay open longer, providing the engine with more fuel and air to burn off.
The downside is that camshafts almost always decrease mileage, and in some cases change the power curve. New camshafts may only increase power output in certain RPM ranges (V8 camshafts commonly increase 3,000rpm-6,000rpm power, while l4 camshafts focus on 6,000rpm to 10,000 rpm output).
7. Limited Slip Differential
Differentials connect your transmission to the axle(s) of the vehicle, and some will limit the speed of one wheel if it does not match the corresponding wheel on the other side. This helps prevent a loss of traction on one wheel when accelerating (and in some cases, an LSD will assist with braking as well) and lets you maximize the traction you have available (see tires, above).
Personally, I love hearing the road, my tires, my exhaust, and all the little wiggles and wobbles created when driving. Carpets and sound-deadening have no place on my vehicles, and are actually fairly heavy. Removing or replacing anything extraneous (such as a can of fix-a-flat instead of a 50-lb spare tire) will improve mileage, acceleration, braking, and handling.
9. Body Panels
Most cars have more weight in the front, which throws off its balance and changes handling characteristics. Ideally, a car should be as close to 50/50 weight from front to rear as possible. A fiberglass or carbon fiber hood may drop 50 lbs from the front of the vehicle, and fenders will help as well.
Adjusting headlights and foglights to point exactly where they belong will increase your visibility and keep you from blinding oncoming drivers with your headlights. Brighter headlights will further increase visibility, and lighter composite buckets are lighter than steel headlight buckets, making the car less front-heavy.
Republished with permission from DrivenDaily.com. Authored by Jesse O'Brien. Photo via the author.