Every car owner at some point feels the desire for more power. Whether it's burning rubber off the line at a stoplight or mashing the throttle to pass someone on the highway, the rush of acceleration is a thrill that everyone wants to feel in their vehicle.
In the past, a custom project to beef up a car's power figures would usually involve dropping in a bigger engine. Not so today, when bolting on a pair of turbochargers has become all the rage. Even modern commuter cars use turbos to improve power and efficiency simultaneously, so why not mount a pair of snails onto every sports car from the past?
But in reality, any method of creating forced induction presents just as many problems as any other complex engineering system. Keep scrolling for 15 details that make no sense about twin-turbos.
Modders who bolt huge turbos onto their engines do it because they want to enjoy the performance benefits of forced induction. They usually focus on producing as much boost as possible to bump horsepower up in a big way—though efficiency can also be improved upon with twin-turbos as well. But all that boost can seriously damage an engine.
One of the most ridiculous ways that people ruin their cars by installing twin-turbos comes about because they simply take up a lot of space. Especially when choosing huge snails like the duo above, the entire car has to be modified to deal with size alone, which can take energy and finances away from making sure the rest of the car can handle the turbos.
13 Too Much Horsepower
Texas-based tuners Hennessey Performance made a name for themselves bolting twin-turbos onto anything they could get their hands on, starting way back with the first-generation Viper and its V10 engine. The firm now plans to release their Venom F5 supercar, which will be powered by a 7.6-liter monster with two turbos about as big as a Civic's engine. But 1,500 horsepower really isn't necessary.
One hilarious little detail about twin-turbos is that many of them aren't actually twin-turbos. Some marketing genius realized a few years back that twin-turbos sound cooler than twin-scroll turbos, which is what most cars use these days. But twin-scroll turbos are really just one turbo with two exhaust inlets to pick up on exhaust pulses better.
One way to handle turbo lag with a twin-turbo setup is to set up a sequential turbo system, where one smaller turbocharger spools up faster for low-RPM power and then the second, larger turbo spools up for high-end grunt. But this complex system can result in more work (and complexity) than it's worth—plus, two big turbos is more fun for burning rubber and bumping off the redline.
10 V Engines
Twin-turbos are ideal for V-shaped engines like the V4, V6, and V8—though plenty of people have even bolted them onto a V10 or V12. Having two turbos allows the exhaust and intake routing to remain on each side of the engine, rather than having to be connected, then rerouted to the turbos. But the size and complexity of such a setup is a nightmare to maintain and work on.
9 Inline Engines
It would seem like twin-turbochargers wouldn't be ideal for an inline engine, like the straight-sixes that BMW has famously pioneered for decades. And yet, the 335i that debuted as part of the E92 generation did exactly that. The reason was that BMW needed to keep their reputation for low-end torque alive, though the problems quickly mounted with the setup.
8 Smaller Is Better?
Most modders who install twin-turbos on their project cars typically go for the "bigger is better" approach, which results in complex engine bays and huge horsepower figures. But in reality, having smaller turbos may be better, since they can spool up quicker and increase boost faster. And with today's machining technology putting out products with super tight tolerances, turbos can spin faster and faster.
7 Heat Problems
Any car that uses an internal combustion engine requires extensive engineering to manage the heat produced by exploding fuel and air. But for turbocharged cars, heat issues become even more important. When the turbos compress the air, it heats up in a big way—meanwhile, they're using hot exhaust to do so. Intercooler setups can help mitigate the problem, just adding another piece onto an already complex system.
Huge intercoolers mounted just behind a car's grill are usually the best way to recognize a project that's been twin-turbocharged. All that hot air created by the turbos needs to be cooled down, so the intercoolers are routed between the turbos and the intake manifold. But intercoolers just add weight and take up crucial space in an engine bay.
5 Turbo Lag
Turbochargers offer improved efficiency because they use exhaust gasses to compress air going into the engine. But this creates the famous problem of turbo lag that twin-turbos try to mitigate. Normally aspirated and supercharged engines don't deal with this problem, though, so maybe just building up the powerplant in another direction would be a better bet for most modders.
4 Wastegate Pressure
Most modern cars have turbochargers these days because they improve power and efficiency. The trade-off has always been complexity and reliability, though. Older turbocharged cars were built with less exacting techniques, resulting in turbos that heated up too quickly and destroyed themselves. Another main point of failure is the wastegate, which can dump pressure when the engine stops revving or changes gears.
3 Traction Control
Traction control may be the bane of performance drivers everywhere, but the reason most cars are equipped with the system is that it saves lives. But modern traction control systems will kill the fun of a twin-turbo project quite quickly, preventing the engine from revving enough to build up serious boost.
The Camaro above—with its huge twin-turbos making a hood impossible to mount—looks awesome doing a massive burnout. As inconvenient as the car now may be for everday use, since a bird could wreak havoc on the engine bay, just imagine how many tires this monster would go through on a single trip to the grocery store.
Japanese cars from the 1990s really helped create today's craze for turbochargers, especially twin-turbos. Models like the Nissan 300ZX and Mitsubishi 3000GT could be had with turbos bolted on to create serious power for their time. These cars are still relatively desirable today, though their insanely complex engine bays are definitely holding values down.
Sources: Wikipedia, Engineering Explained, and X-Engineer.