Texx
Super Moderator
Original Article Credit: alan_d
I figured TGTT see's a fair stream of beginners to the car scene so thought id write up a wee 'wiki' sort of guide on what makes a turbo work!
Please note this isnt a technical guide, or a definitive 'how to' its just for those a bit curious as to whats inside one and roughly how they work. Also a shameless plug for danes AWESOME sps manis!
For this example ive disassembled a damaged Blitz K1-200v turbo.
Basically this turbo will help generate 200bhp and 200ft/lb of torque on a well set up Glanza/GT.
Turbos are devices that push air, at speed, into the engine, and help produce more power by pushing more air into the combustion chamber.
The Turbo can do this, by using the exhaust gas that come out of your car to spin a little wheel, almost like a windmill. This little wheel turns another wheel on the opposite side of the turbo at speeds of up to 180,000rpm, and thus can push a lot of air through!
By varying the size of wheels on either side, you can change the 'A/r' ratio (almost like gearing) and produce different characteristics like lots of boost, but only when the car is revving hard, or less boost, but a lot lower down the range, making it not as powerful, but more usable.
the above is a good example - the one on the left is the 200bhp blitz k1, and on the right is the TD04 from an RB5 subaru impreza, which can generate 300bhp roughly.
The exhaust housing (the bit your car pumps exhaust gas into) is much bigger on the td04, so it sits a bit higher making the k1 look smaller, but im sure you get the idea!
again using the glanza as an example, here is a ct9 turbo as commonly found on the EP82 starlet turbo. These have been proven to generate up to 189bhp, but they arnt comfortable doing it , and wont last long. Note the 4 pairs of blades, as opposed to the more aggressive multi blade setup the td04 and k1 use!
If you ever hear of people running a hybrid turbo, they are talking about a modified turbo designed to offer more performance, usually by boring the compressor (front side) housing wider to accommodate a bigger more aggressive wheel like my ct9 hybrid below:
hybrid:
Standard:
the turbo is driven by the exhaust gas coming out of the engine, it is fed through the manifold and through the exhaust wheel of the turbo as you can see below:
the exhaust wheel is connected to the compressor wheel and this spins, sucking and squeezing air in.
The used exhaust gas then spins out the back of the wheel here:
you can see a little flap beside the wheel - this is called a 'wastegate' and is used to control how much exhaust gas gets to spin the turbo up, and in turn controlling how much boost is made. When you lift off the accelerator, this flap opens, and allows the exhaust gas to bypass the exhaust wheel.
heres what it looks like when open:
the more astute among you will notice a crack on the edge of the port. This is BAD! very bad!
what happens is the exhaust gas can leak past the flap, and the turbo wont hold boost steadily as the seal the flap is trying to create is voided.
so now we know roughly how it works, exhaust gas in, spins the wheels, fresh air goes in the front end, and gets compressed and pushed into the engine.
so......
lets look inside the blitz k1-200v
in order to get inside, there will be circlip retainers holding the housings on, these are like circular clips, with holes in them to allow you to squeeze them together and lift them apart.
this will leave you with the housing removed like so:
the rear housing will come off the same way, and it doesnt look as sexy as the front so ill leave it out.
you will then be left with a hub, containing all the bearings and seals, with the two wheels attached.
if we refer back to an earlier picture, you will notice a nut on the front of the compressor wheel, this wheel is normally cut slightly, in order to balance the turbo. Why balance? well, if you imagine your wheels on your car wernt balanced, the wheels will vibrate at speed, so will the turbos wheels, only they travel at up to 180000 rpm, and will quickly destroy the bearings if not balanced, so what the manufacturers do is engrave little nicks onto the centre nut to lighten a heavy side, and thus balance the weight out around the wheel.
see the way the left hand side of the ut isnt perfectly round? thats where weight was removed.
once this nut is removed, youll be able to separate the front compressor wheel and the back exhaust wheel. It will look like this.
front wheel:
note the further cutting into the centre of the wheel as more balance was required.
and the exhaust wheel, complete with the shaft that connects it to the front.
note the different shape. This is because the exhaust wheel is fed gas side on rather than front on, so requires a different shape to spin efficiently.
now if we go back to the compressor wheel, I want to point out what to look for when buying a turbo.
notice that not one blade looks the same????
This is because someone, at some point, has ran the turbo without a filter, and has sucked something small in like grit, or even sand.
because of the speed the wheel spins, it takes ever so little to damage the fragile wheel.
bear in mind that what ever has gone through this, has also gone through the engine. not good.
because something went inside this turbo, it has also knocked the balance off, and in turn ruined the bearings. This causes the wheels to spin and foul against the housings causing markings like below.
The surface should be perfectly smooth and the above clearly isnt, indicating the blades bouncing off the housing at speed. Again not good.
once play starts to develop, it allows oil into places it shouldnt go, and carbon from the exhaust to go into places it shouldnt go either. On the exhaust side, it should look like this:
nice and smooth with no wear.
However, because this turbo is shot, carbon has build up and caused uneven wear:
the assembly will look like this:
you can see the little circlips that hold the housing on here, and the circlip pliers to remove them. You can also see the hub that holds all the bearings, seals, and also pumps the oil to the bearings.
the oil is pushed in one side, and comes out here:
the oil 'floats' the bearing, and slows down the wear on the turbo given how damn hot they get!!!
et voila!
The vital parts to keeping it spinning!
from left:
the end nut that keeps the assembly together
the bearing that has little channels allowing oil to lubricate the shaft (ooerr missus!)
Brass spacers that holds either end of the bearing in position
so there you have it!
Thats whats in the average turbo!
Please note this is only a brief run through to let you see whats inside a turbo. There are entire books written on turbo theory and application. I didnt wanna bore you so just gave a glimpse inside!
I figured TGTT see's a fair stream of beginners to the car scene so thought id write up a wee 'wiki' sort of guide on what makes a turbo work!
Please note this isnt a technical guide, or a definitive 'how to' its just for those a bit curious as to whats inside one and roughly how they work. Also a shameless plug for danes AWESOME sps manis!
For this example ive disassembled a damaged Blitz K1-200v turbo.
Basically this turbo will help generate 200bhp and 200ft/lb of torque on a well set up Glanza/GT.
Turbos are devices that push air, at speed, into the engine, and help produce more power by pushing more air into the combustion chamber.
The Turbo can do this, by using the exhaust gas that come out of your car to spin a little wheel, almost like a windmill. This little wheel turns another wheel on the opposite side of the turbo at speeds of up to 180,000rpm, and thus can push a lot of air through!
By varying the size of wheels on either side, you can change the 'A/r' ratio (almost like gearing) and produce different characteristics like lots of boost, but only when the car is revving hard, or less boost, but a lot lower down the range, making it not as powerful, but more usable.
the above is a good example - the one on the left is the 200bhp blitz k1, and on the right is the TD04 from an RB5 subaru impreza, which can generate 300bhp roughly.
The exhaust housing (the bit your car pumps exhaust gas into) is much bigger on the td04, so it sits a bit higher making the k1 look smaller, but im sure you get the idea!
again using the glanza as an example, here is a ct9 turbo as commonly found on the EP82 starlet turbo. These have been proven to generate up to 189bhp, but they arnt comfortable doing it , and wont last long. Note the 4 pairs of blades, as opposed to the more aggressive multi blade setup the td04 and k1 use!
If you ever hear of people running a hybrid turbo, they are talking about a modified turbo designed to offer more performance, usually by boring the compressor (front side) housing wider to accommodate a bigger more aggressive wheel like my ct9 hybrid below:
hybrid:
Standard:
the turbo is driven by the exhaust gas coming out of the engine, it is fed through the manifold and through the exhaust wheel of the turbo as you can see below:
the exhaust wheel is connected to the compressor wheel and this spins, sucking and squeezing air in.
The used exhaust gas then spins out the back of the wheel here:
you can see a little flap beside the wheel - this is called a 'wastegate' and is used to control how much exhaust gas gets to spin the turbo up, and in turn controlling how much boost is made. When you lift off the accelerator, this flap opens, and allows the exhaust gas to bypass the exhaust wheel.
heres what it looks like when open:
the more astute among you will notice a crack on the edge of the port. This is BAD! very bad!
what happens is the exhaust gas can leak past the flap, and the turbo wont hold boost steadily as the seal the flap is trying to create is voided.
so now we know roughly how it works, exhaust gas in, spins the wheels, fresh air goes in the front end, and gets compressed and pushed into the engine.
so......
lets look inside the blitz k1-200v
in order to get inside, there will be circlip retainers holding the housings on, these are like circular clips, with holes in them to allow you to squeeze them together and lift them apart.
this will leave you with the housing removed like so:
the rear housing will come off the same way, and it doesnt look as sexy as the front so ill leave it out.
you will then be left with a hub, containing all the bearings and seals, with the two wheels attached.
if we refer back to an earlier picture, you will notice a nut on the front of the compressor wheel, this wheel is normally cut slightly, in order to balance the turbo. Why balance? well, if you imagine your wheels on your car wernt balanced, the wheels will vibrate at speed, so will the turbos wheels, only they travel at up to 180000 rpm, and will quickly destroy the bearings if not balanced, so what the manufacturers do is engrave little nicks onto the centre nut to lighten a heavy side, and thus balance the weight out around the wheel.
see the way the left hand side of the ut isnt perfectly round? thats where weight was removed.
once this nut is removed, youll be able to separate the front compressor wheel and the back exhaust wheel. It will look like this.
front wheel:
note the further cutting into the centre of the wheel as more balance was required.
and the exhaust wheel, complete with the shaft that connects it to the front.
note the different shape. This is because the exhaust wheel is fed gas side on rather than front on, so requires a different shape to spin efficiently.
now if we go back to the compressor wheel, I want to point out what to look for when buying a turbo.
notice that not one blade looks the same????
This is because someone, at some point, has ran the turbo without a filter, and has sucked something small in like grit, or even sand.
because of the speed the wheel spins, it takes ever so little to damage the fragile wheel.
bear in mind that what ever has gone through this, has also gone through the engine. not good.
because something went inside this turbo, it has also knocked the balance off, and in turn ruined the bearings. This causes the wheels to spin and foul against the housings causing markings like below.
The surface should be perfectly smooth and the above clearly isnt, indicating the blades bouncing off the housing at speed. Again not good.
once play starts to develop, it allows oil into places it shouldnt go, and carbon from the exhaust to go into places it shouldnt go either. On the exhaust side, it should look like this:
nice and smooth with no wear.
However, because this turbo is shot, carbon has build up and caused uneven wear:
the assembly will look like this:
you can see the little circlips that hold the housing on here, and the circlip pliers to remove them. You can also see the hub that holds all the bearings, seals, and also pumps the oil to the bearings.
the oil is pushed in one side, and comes out here:
the oil 'floats' the bearing, and slows down the wear on the turbo given how damn hot they get!!!
et voila!
The vital parts to keeping it spinning!
from left:
the end nut that keeps the assembly together
the bearing that has little channels allowing oil to lubricate the shaft (ooerr missus!)
Brass spacers that holds either end of the bearing in position
so there you have it!
Thats whats in the average turbo!
Please note this is only a brief run through to let you see whats inside a turbo. There are entire books written on turbo theory and application. I didnt wanna bore you so just gave a glimpse inside!