Purchasing a big or twin turbo kit for your car is one thing. Installing them, tuning, and driving the car afterwards are daunting tasks all on their own. Though you’ll get phenomenal results, if you are too ambitious and inexperienced, it will result in a huge headache and most likely a blown engine.
That being said, long past are the days where two smaller turbos are more efficient than one large turbo. Also, twin turbo kits generally require the use of twin piping, intercoolers, and blow-off valves to name a few. Turbo kits vary in overall design, so this may not be the exact case for all. The first thing you must consider when choosing which turbo kit is right for you is your power goals, as they are not universal.
After you have decided on your power goals, and the turbo best suited to accomplish this, you must consider all of the support modifications required for your engine to handle the boost without exploding. Boosted performance does not come cheap, so beware of significantly affordable kits for their quality. Not all aftermarket turbo kits are emissions legal, so do contact your local emissions officials to check before taking the plunge.
A proper turbo kit includes waste gates, intercoolers, oil cooler(s), and blow off valves. Though blow-off valves may conjure up thoughts of that wonderful “hiss” sound, BOVs should recirculate the excess boost back into the intake side of the turbo, resulting in a slight whistle at best.
Installing a big or twin turbo in place of the stock equipment on your car is a popular way to drastically increase performance. Although it’s tempting to cave in to the compulsion of having that extra “go” when you drop your foot on the pedal, the truth is that some people just won’t benefit as much as they might think from this kind of modification. Here are a few important things to note before shelling out the cash for a larger-than-stock turbocharger.
All 50 states now require all vehicles to comply with some sort of emissions standard for licensure. Factory-equipped vehicles are specifically configured to make sure that they meet these standards. If you alter your vehicle from its factory settings you may be required to follow specific rules to make sure your car isn’t putting out any harmful emissions because of its modifications. You’re going to have to brush up on your local and state laws before you do any modifying work on the car to make sure that you’re following all the regulations. Failure to take this step could result in a fine, or even worse, a car that you can’t license because of modifications that don’t fit state standards.
Generally, insurance companies require you to report any engine modification that has a drastic effect on horsepower. The reason for this is that generally, cars that have more power are driven more aggressively than cars that don’t (for obvious reasons). This may seem like an easy thing to skip, but it’s very important that you follow the instructions in your insurance agreement to the letter. If you don’t, your insurance company may deny liability in case of an accident, which leaves you unprotected.
As a rule, an upgrade of this type will automatically void any factory warranty your vehicle carries. Drastically changing your factory equipment in this way can put extra stress on your vehicle’s engine, and your car’s manufacturer will no longer cover it. Make sure you know exactly what you’re getting into when it comes to your car’s warranty before making the switch.
Although you may look forward to your new, bigger turbo dishing out gobs of extra power, the truth is that under most circumstances it will actually have a negative effect on drivability. The larger the turbo, the bigger negative effect it will have on everyday driving. The reason for this is that turbochargers rely on exhaust energy to drive the compressor that pushes extra air into the engine. The larger the turbo, the more exhaust gases it takes to spin the turbine. This means that big turbos simply don’t perform well at low RPMs (an effect called “turbo lag”), which is where most people drive. What a big turbo does best is produce lots of horsepower and higher RPMs, which is great for the drag strip, but terrible in traffic. In addition, upgrading your car’s turbo can have a negative effect on gas mileage which can cost a lot of money in the long run.
There are a number of drawbacks and compromises when going with an aftermarket turbo setup. At low boost almost every engine will react positively, and retain much of its drivability and reliability. Some will even improve efficiency. Consequently, high boost setups mean higher temperatures and stresses that negatively affect reliability. Even when built right, it still requires a vigilant eye and proper maintenance. High boost beckons performance drawbacks such as turbo lag and drivability issues however proper components and tuning remedies these.