How does a turbo work ?
Discussion
Hi Guys,
I'm thinking of getting a Mitsubishi GTO/3000GT Twin turbo over the next couple of months and this car has, at the name states "twin turbo's".
But how does a turbo work, who can explain in plain simple English what it does and how it does it, bearing in mind i'm a total carnoob if it comes to technicall stuff (and English isn't my first language).
With my celica GT (n/a) i just wait untill the motor is at temperature when it's cold in the morning before i "start enjoying it", but i've heard that with turbo's you have to wait for some boostlevel or something before you can use it, and after using it goes down and has to recharge, or am i just talking jibbajabba at the moment.
A Turbo is a turbine with two halves, one half (the hot side) is driven off the exhaust gasses (hense lag as low revs etc. = less gas to spin the turbo). The cold side of the turbo takes air in from the outside world and forces (=forced induction) it into the combustion chambers of the engine, normally via a cooler to make sure the air is cold.
With a Turbo it's even more important that you wait for oil temp to come up as turbos spin a lot faster than engines (e.g. 80,000rpm), they don't tend to enjoy being thrashed from cold.
ETA - bugger, google would have been a lot quicker.
With a Turbo it's even more important that you wait for oil temp to come up as turbos spin a lot faster than engines (e.g. 80,000rpm), they don't tend to enjoy being thrashed from cold.
ETA - bugger, google would have been a lot quicker.
Edited by AngryS3Owner on Thursday 17th April 08:27
To burn fuel, you need air in the cylinders. The more fuel you can burn, the bigger the bang, and the more power you get, however a cylinder can only pull in a volume of air equal to it's own size. A turbo allows the engine to supply squashed up (and therefore more for the same size cylinder) air to the engine. With the appropriate matching amount of fuel, a bigger bang happens and more power is produced.
A turbo charger pumps and squashes this air using a spinning impellor in the inlet of the engine. The power to spin the impellor is provided by another impellor on the other end of the shaft that is powered by the speed of the exhaust gases escaping out of the engine.
A turbo charger pumps and squashes this air using a spinning impellor in the inlet of the engine. The power to spin the impellor is provided by another impellor on the other end of the shaft that is powered by the speed of the exhaust gases escaping out of the engine.
Think of it as 2 water wheels on an axle seperated by a wall, on one side the wheel has water flowing over it (exhaust gases) this turns the wheel.
On the other side you've got another water wheel (intake), except it's in a level slow flowing canal, when the water flows over the other wheel (exhaust) it turns the intake wheel, this pushes the water along faster than it was previously flowing.
Now if you replace the water with air you can then put more fuel in per 'bang' as the increased flow compresses the air meaning you can get more in the cylinder.
As a result of this, the bigger your wheel is the longer it takes to spin up to speed, this is called 'turbo lag', the way you feel it is when you accelerate but the turbo isn't spinning fast enough yet to produce all the power, so it's slow and then all of a sudden speeds up.
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
On the other side you've got another water wheel (intake), except it's in a level slow flowing canal, when the water flows over the other wheel (exhaust) it turns the intake wheel, this pushes the water along faster than it was previously flowing.
Now if you replace the water with air you can then put more fuel in per 'bang' as the increased flow compresses the air meaning you can get more in the cylinder.
As a result of this, the bigger your wheel is the longer it takes to spin up to speed, this is called 'turbo lag', the way you feel it is when you accelerate but the turbo isn't spinning fast enough yet to produce all the power, so it's slow and then all of a sudden speeds up.
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
Silent1 said:
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
But not on the 3000GT/GTO - they are on each bank of the V and the same size, they aren't sequential. Relatively small turbos though so lag is minimal.Sorry if that's too simple
even easier...
It is basically a fan which is powered by the exhorst fumes. One side spins as the fumes push it around and the other side is used to shove lots of nice air into the engine to make lots of lovely power!
Downside is turbo lag, although twin turbos or low pressure turbos solve this.
Upside - shed loads of power, reliable, shed loads of power and the turbo lag can be massivly entertaining! Did I mention shed loads of power?
It is basically a fan which is powered by the exhorst fumes. One side spins as the fumes push it around and the other side is used to shove lots of nice air into the engine to make lots of lovely power!
Downside is turbo lag, although twin turbos or low pressure turbos solve this.
Upside - shed loads of power, reliable, shed loads of power and the turbo lag can be massivly entertaining! Did I mention shed loads of power?
Silent1 said:
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
Twin turbo.Sorry if that's too simple
MarkK said:
But not on the 3000GT/GTO - they are on each bank of the V and the same size, they aren't sequential. Relatively small turbos though so lag is minimal.
Bi-turbo.I hope reading the HowStuff Works it gives you more info than this thread....as Im sure you are now confussed to hell!
By the way...GT3000 is a great car! Had one for 4 years, only problem I had was the head gasket went. Loads of power, dont be put off by people telling you that it has too much electronics....its no less than an EVO.
If you want the ideal solution....go Single
By the way...GT3000 is a great car! Had one for 4 years, only problem I had was the head gasket went. Loads of power, dont be put off by people telling you that it has too much electronics....its no less than an EVO.
If you want the ideal solution....go Single
nats1rt said:
Silent1 said:
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
Twin turbo.Sorry if that's too simple
MarkK said:
But not on the 3000GT/GTO - they are on each bank of the V and the same size, they aren't sequential. Relatively small turbos though so lag is minimal.
Bi-turbo.
Medic-one said:
i've heard that with turbo's you have to wait for some boostlevel or something before you can use it, and after using it goes down and has to recharge, or am i just talking jibbajabba at the moment.
Speaking genericly about all turbo cars in general here - It just means that when you put your foot down it can take a second for the engine to reach full boost/power, it doesn't really go down again unless you lift off the throttle. You will tend to find that the engine feels quite flat below a certain RPM, say 2 or 2.5k as the turbo doesn't really work well below this speed. Day to day driving it probably doesn't matter much because as you plan ahead you make sure you're in the right gear if you need some power.Haven't driven a GTO myself but have been a passenger in one, pretty fast cars and very grippy!
Good luck!
nats1rt said:
Silent1 said:
Twin turbos get around this by having a very small turbo that kicks in whilst the bigger turbo is still going too slow to be useful.
Sorry if that's too simple
Twin turbo.Sorry if that's too simple
MarkK said:
But not on the 3000GT/GTO - they are on each bank of the V and the same size, they aren't sequential. Relatively small turbos though so lag is minimal.
Bi-turbo.To break it down:
The example of small turbo and large turbo is called Sequential Twin Turbo, this is a relatively rare setup as it's quite complicated, being used on a only a few production vehicles, the only ones I can think of off the top of my head are the Mazda FD RX7, Toyota Supra TT MkIV, Porsche 959, Subaru Legacy B4 and Mazda JC Cosmo.
The example of two identical sized turbos is more correctly called parallel twin turbos, these are just about obligatory on V engines but are also found on some straight sixes like the RB26DETT in the old Skyline GT-Rs and Alpina B10 BiTurbo.
The final example, which is extremely rare for road cars but common on aircraft, (and the odd diesel) is series, or staged, turbocharging where you basically have one turbo blowing into another one, which is mainly useful at high altitudes where the air is thin and needs to be compressed to very high pressure levels.
Road_Terrorist said:
The example of small turbo and large turbo is called Sequential Twin Turbo, this is a relatively rare setup as it's quite complicated, being used on a only a few production vehicles, the only ones I can think of off the top of my head are the Mazda FD RX7, Toyota Supra TT MkIV, Porsche 959, Subaru Legacy B4 and Mazda JC Cosmo.
I'm starting to think everyone just ignores what I write, ah well nevermind 
All the new BMW *35i engines are sequential twin turbos.
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