Questions tagged [turbocharger]

An exhaust-driven forced-induction device that increases an engine's power output and efficiency.

A turbocharger (technically a turbosupercharger) is a type of device used to increase the and of an . It works by using the engine's flow to drive a turbine, which powers a compressor, which forces more air into each than would otherwise be able to enter. The increased amount of air allows more to be burned, increasing the engine's power and allowing for the use of a smaller, lighter engine. As the air entering the cylinders is already precompressed, the functional ratio of the engine increases (although the compression ratio within the cylinders themselves is typically decreased slightly), making the engine more efficient.

Originally, turbochargers were seen only on vehicles and top-end sports cars; nowadays, however, many automobiles use them due to their power and efficiency advantages. Some holdout manufacturers still produce internal combustion vehicles without turbochargers.

A turbocharger is similar to a mechanical , which drives the compressor from the engine's . A turbocharged engine can be slightly more efficient than a non-turbocharged engine because it uses energy that would otherwise have been wasted out the tailpipe. Turbochargers work best at higher engine speeds; a mechanical supercharger, on the other hand, works well even at low engine speeds.

Image of a turbocharger

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Static vs. Effective compression: Why does higher effective compression not require higher octane gas?

Background I've been trying to do a lot of research on boost lately because I'm planning on running a moderate turbo setup on my daily/light-duty-autox car in the future. I'm trying to get into the physics of things so that when I do my build, I'm…
Annath
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Why do we need to cool air after it leaves a turbocharger?

When we are using a turbocharger to compress the incoming air, the air gets hotter. Usually this hot air is cooled by using an intercooler before it's passed to the engine. What is the reason behind cooling this air? Why can't we pass it as hot…
nivass balu
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Why does a Turbocharger only produce boost when the engine is under load?

Why does a turbocharged car only produce significant boost whilst the engine is under load? Is is something to do with how much exhaust is being produced or is there some kind of valve mechanism that controls this? i.e. running the engine at 3000…
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What happens to a car when it hasn't been driven for 12 years?

I'm hoping that I'll soon be the owner of 2l turbo charged, 4wd hatchback that's been sat in a garage, undriven for over a decade. Trouble is that I won't be able to give it a full inspection until I actually own it (long story!) From other…
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What is an A/R ratio?

I heard the term A/R ratio today while watching a video about turbochargers. What does the term A/R ratio mean? Does it just apply to turbos? If not, what else does it apply to? How is it computed? Why is it important?
Pᴀᴜʟsᴛᴇʀ2
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Turbo equivalent on electric motors

Is there anything functionally equivalent to a turbo for electric motors? Obviously, I am not asking for something that reuses exhaust gases to force in more air, because there are no exhaust gases nor the need for air. What I am asking is if…
sergiol
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How to deal with a hot turbocharger

A piece of advice that seems to be widely accepted is that after a long high-speed run, when the turbocharger is thoroughly hot, you should let the engine idle for a while before stopping it. The reason given is that this allows the extremely hot…
abacus
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What are the various causes of preignition / detonation?

A search on detonation produced some of the causes of detonation, but everything I found says there are other causes, but none list them. The most common listed cause is the air / fuel mixture becoming too hot due to compression by a turbo. When it…
cdunn
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What is overboost?

I've heard the term overboost quite a lot. What is "bad" overboost? What is an overboost problem? What will happen to my turbo engine if I don't fix it? Edit: apparently there is a good type where the engine produces more power for 5 seconds or…
George
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Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

It's a strange dilemma, but if the power of an engine is determined by the difference in pressure between the combustion chamber and the exhaust, it should follow that turbocharging should be equally effective pumping air out the exhaust, than in…
tuskiomi
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Minor boost leak and shrill tone at peak boost: hose clamp, gasket or blow off valve?

Vehicle in question: 2004 Subaru WRX wagon. This weekend, I replaced the intercooler hose (y-shaped upset the intercooler), the throttle body hose and the blowoff valve hose (routes the over boost back to the intake when the throttle closes…
Bob Cross
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My subaru legacy will not boost

I drive a Subaru Legacy Turbocharged GT 2008 model with an EJ20 engine. When I press hard on the acceleration to boost the tachometer upon reaching 4-5 thousand RPM's it starts jerking and there is no acceleration. However, if I accelerate slowly I…
Jamuel
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What is the function of a blow-off valve vs a wastegate?

I am waiting for a 2013 STI and have been looking into upping the performance, but before I go down that road I would like to thoroughly understand the components in a forced induction vehicle. I've done a bit of reading but I'm still confused as to…
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Troubleshooting Low Turbo Boost

I'm starting to suspect that the smoke and low power (I'm pretty sure it is not "limp mode" just a lack of enthusiasm) I'm seeing in our 2002 Jetta TDI (ALH engine with Garret VNT-15 turbocharger) may be a turbo issue. Here's what I'm…
dlu
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what sensors and formula are used to control VGT/VNT turbos?

I want to fit a variable geometry turbo to my car. Its vanes are usually controlled an electrical actuator (otherwise sometimes it's on vacuum). What information is used to to inform the state of the turbo vanes, though - throttle position, intake…
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