We all want to work on our own cars. A lot of people gained knowledge and became interested in cars when they purchased their first car or shared quality father and son time working on project cars. As much as the home mechanic or DIY’er wants to do everything possible to their own car, some things are better left to professionals. 1) Tuning and dyno tuning. Although it’s easy to get hand-held programmers with pre-modified power curves for your engine, tuning should always be left to the professionals. Some systems such as the AEM EMS, Apex’I S-AFC NEO, and HP Tuners can be used by the do-it-yourselfer. The problem with tuning engines yourself is that there is no dynamometer to measure horsepower at the wheels. There is also the issue of catastrophically damaging your engine. For the cost of a handheld tune, most tuners will squeeze every last available bit of power to the wheels. The best part is, you have an experienced tuner (and not just you trying to learn everything at once) coupled with a dyno so you can visually see the results being produced. If the tuner blows your engine, the shop should have insurance that covers it. If you blow your own engine, you’re on your own. You also can’t get a speeding ticket for trying to data log and tune at high speeds.
Gear changes are done for many reasons. Faster acceleration, better cruising RPM, or to be able to crawl on rocks and go off-roading better. Changing gears is not too difficult for the home mechanic, but there is too much room for error. Professional rear end specialists will be able to set-up a new set of gears in half the time, with none of the headache being transferred to you. The wrost thing for a home mechanic is to shim and set-up a new gear set only to have howl, whine, grinding, or bearing noises when finished. Leave it to a professional so the parts and labor are covered under warranty and you don’t have to get messy.
Cams, Timing chains and gears, lifters, rockers, heads, and everything else associated with the top end or even bottom end should be installed by a professional. Why? They do it all the time. It’s the same as tuning. Being able to do the work and doing the work professionally are two different things. If you’re building an engine on a stand and have all the time and resources in the world including an experienced helper go for it! If this is your daily driver and you need your car to go to work, have a professional do the job quickly and accurately. Sometimes paying for the time and experience outweighs the savings. Bonus if your mechanic can install the cam and then dyno tune it before you pick it up.
A lot of people do their own lift kits, which is fine - until the alignment technician gets the vehicle. Not knowing how much the kit adjusts the ride height or how it’s adjusted causes major headaches to the technician. Some kits require extended or shortened tie-rods which customers skimp out on and the technician has no idea it’s required unless it’s too late. If you really can’t afford to pay a technician to drop or lift your ride, at least consult with an alignment technician first and bring all of the documentation that accompanies the kit with you to the alignment. Don’t skimp on the extras. Return them if they are not needed. Your alignment technician will thank you!
We all want huge turbos and superchargers under the hood of the car. This is a gray area for the home mechanic. This isn’t a bolt-on affair no matter what the item description is on eBay. Adding forced induction is serious business. Not only are there a lot of components to install, but there is also tuning that must be completed before the car can run efficiently and safely. Having a professional install a forced induction kit will leave your mind at ease. Blowing an engine is possible, but having a professional install it and tune it before you pick it up ensures a safe gain in power.
Too many times people try to install wings, body kits, or wheel tubs, or even subframe connectors and seem to mess things up. Let a qualified body shop install and paint your paints at the same time. Let a professional install your tub. Let an experienced welder install your subframe connectors. With these mods, you can’t be perfect on your first try, and why attempt it for the first time on your own car?
If this is your first “attempt” at building a transmission whether automatic or manual, it’s best left to a professional. The price will be substantially higher, but with the price you’ll also receive a warranty and a guarantee at specific horsepower rating. Although building a transmission might seem like a feasible task, when it comes to high horsepower applications, professional builders know best. They know how to properly disassemble, clean, prepare, and rebuild your transmission to handle the increase in power your car has. If you build a transmission yourself and something goes wrong, you’re on your own. If a shop built it, you can tow your car in or ship your transmission back for warranty work.
Adding horsepower through a bottle has been common for street and strip racers alike for decades. The best option when adding nitrous oxide to your vehicle is to go to a specialist who designs and installs systems for a living. With so many “universal” kits, and generic parts, it’s easy to install a system that sprays too much, too little, at the wrong moment, or at the wrong temperature. In order to guarantee safe and successful gains in power through a bottle, a professional is recommended. Nitrous can either safely add a burst of power or damage your engine.
This might not be considered a performance modification but nevertheless a lot of street/strip cars have window tint. Do-it-yourself tint is highly frowned upon because of the difficulty, quality of available materials, and lack of a warranty or guarantee. Window tinting is inevitable, especially in the street/strip crowd. Even family sedans have it to block the hot sun from children’s eyes. Professional tint will always look cleaner, adhere better, have a guaranteed transparency (so you pass inspection), and guarantee workmanship. Tint shops also use professional and commercial products as opposed to what is available to consumers.
Fabrication is hit or miss. Either you’re a really good welder or you are not. For the average DIY home mechanic, welding anything of importance and safety such as roll cages or exhaust systems should be left to professionals. Fitting can be performed at home, but when it comes to the quality of the welds, seek professional assistance. A roll cage could save your life, so it better be safe enough to ride in. Welding exhaust work off the car is easier than on the car, but if the work is needed on the car, a skilled welder can ensure a leak-free seam.