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T25G PSI limits, paint temp limits.
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Rohan 84ET
- Posts: 1429
- Joined: Thu Feb 08, 2007 9:51 pm
- Location: Adelaide, South Australia
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Ben Hewitson
- Posts: 1136
- Joined: Tue Aug 08, 2006 9:19 am
- Location: Adelaide, SA.
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yeah. exhaust flow spins the turbine. think of it in different terms. Gasses flow like liquids in controled environments like this.
ok. i'm going to break this down in ultra simple terms.. nad no-one from another website better hassle me over this either
if you can imagine a paddle wheel in a river turning a shaft that in turn is connected to a flour mill wheel.. hang in there guys.... the water flows down the river and forces the wheel to move. the amount of torque on the wheel is determined by the radius of the wheel and the speed that the river is flowing (turning moment comes into this, but i'm not going into it today without my physics books)
what determins the speed of the shaft in the mill is the speed of the paddle/turbine wheel in the river.
if the river is saw 6m wide and the paddle wheel is 1m wide then there is a certain amount of water that just flows past and thus there is less energy to turn the wheel.
if the river was 2m wide and the wheel was 1m wide then most of the waters energy would be used to turn the wheel and it wouldn't flow around.
as you can already see there are a number of issues you can do to make the paddle wheel spin faster and these include, speeding up the water flow, concentrating it so that ALL flow goes to pushing the wheel, etc..
if you have a certain flow of water than the best way is to squeeze it down to a narrow throught just before the wheel so that all its energy is converted down a narrow path and thus increasing its speed. that way the waters energy is forced over the wheel and you get the maximum amount of energy transfered into torque.
the downside ofthis is that the water could be flowing too fast and it spills over the edge or it causes a choke effect down stream becasue of reduced flow. so you'll need a path around the water wheel to let this excess energy escape into the river down stream.
this is pretty much what a turbo does. except you can encrease the flow with higher revs and load as well as making the exhaust manifold near the turbo as hot as possible so it creates the most amount of velocity.. if you have too much choke or back pressure you increase the amount of space around the wheel to allow the gas to pass by and if you have too much and you want to control the speed of the wheel you'll need to bypasss it with a wastegate...
hope you understand turbo's and water wheels a little better now.
HewiB
ok. i'm going to break this down in ultra simple terms.. nad no-one from another website better hassle me over this either
if you can imagine a paddle wheel in a river turning a shaft that in turn is connected to a flour mill wheel.. hang in there guys.... the water flows down the river and forces the wheel to move. the amount of torque on the wheel is determined by the radius of the wheel and the speed that the river is flowing (turning moment comes into this, but i'm not going into it today without my physics books)
what determins the speed of the shaft in the mill is the speed of the paddle/turbine wheel in the river.
if the river is saw 6m wide and the paddle wheel is 1m wide then there is a certain amount of water that just flows past and thus there is less energy to turn the wheel.
if the river was 2m wide and the wheel was 1m wide then most of the waters energy would be used to turn the wheel and it wouldn't flow around.
as you can already see there are a number of issues you can do to make the paddle wheel spin faster and these include, speeding up the water flow, concentrating it so that ALL flow goes to pushing the wheel, etc..
if you have a certain flow of water than the best way is to squeeze it down to a narrow throught just before the wheel so that all its energy is converted down a narrow path and thus increasing its speed. that way the waters energy is forced over the wheel and you get the maximum amount of energy transfered into torque.
the downside ofthis is that the water could be flowing too fast and it spills over the edge or it causes a choke effect down stream becasue of reduced flow. so you'll need a path around the water wheel to let this excess energy escape into the river down stream.
this is pretty much what a turbo does. except you can encrease the flow with higher revs and load as well as making the exhaust manifold near the turbo as hot as possible so it creates the most amount of velocity.. if you have too much choke or back pressure you increase the amount of space around the wheel to allow the gas to pass by and if you have too much and you want to control the speed of the wheel you'll need to bypasss it with a wastegate...
hope you understand turbo's and water wheels a little better now.
HewiB
Uncie-G wrote: As for the drift steering wheel, if you use this combined with earthing kit at the same time the overall road feel and torque steer gets reduced.
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Rohan 84ET
- Posts: 1429
- Joined: Thu Feb 08, 2007 9:51 pm
- Location: Adelaide, South Australia
haha sure do, you ever been up to Bridgewater in the Hills mate?
haha, theres a large mill there.
connected to a restaurant.
which sells Petaluma wines,
Petaluma winery is right beside my house
but yes, do understand it now, cheers mate.
The T25G Turbine housing is possibly a little bit too large for the Turbine inside it, and alot of gas is passing by and not spooling the turbine, so by replacing the large in-effective turbine housing to a smaller A/R.49 one of a T25, you are reducing the path in which gas has to pass by, and forcing it to spool the turbine, making quicker spool times, more boost earlier.
should i expect the Turbo to get much much hotter than usual?
haha, theres a large mill there.
connected to a restaurant.
which sells Petaluma wines,
Petaluma winery is right beside my house
but yes, do understand it now, cheers mate.
The T25G Turbine housing is possibly a little bit too large for the Turbine inside it, and alot of gas is passing by and not spooling the turbine, so by replacing the large in-effective turbine housing to a smaller A/R.49 one of a T25, you are reducing the path in which gas has to pass by, and forcing it to spool the turbine, making quicker spool times, more boost earlier.
should i expect the Turbo to get much much hotter than usual?
Last edited by Rohan 84ET on Fri Jun 08, 2007 9:02 am, edited 1 time in total.
ET coming back from the dead.
SAVE ME JEBAS!
SAVE ME JEBAS!
To wrap it up a little better, think of it this way. If you have one of those 'whirly bird' roof ventilators, the thing turns because there is a flow of air passing through it. The reason there is a flow of air is because there is a pressure difference between the air in the roof and the air outside (air in the roof under greater pressure being released into outside air with lower pressure) the greater this pressure difference the faster the 'bird' will spin.
Same thing with the turbo, the greater the pressure difference between the exhaust manifold and the dump pipe + exhaust, the faster the gasses will pass through the turbine making it spin. So the idea of most all mods is to increase the pressure across the turbo.
And we all know that hot air/exhaust takes up more volume than cool air/exhaust, so the idea is to keep the exhaust pre turbo as hot as possible and the exhaust runners as short as practicle to keep temp/volume as high as it can be.
Now, the exhaust housing of the turbo has a set orfice that the exhaust gasses pass through, and it the size of this which detremines how hard the turbo will spin for a given flow. Given all the upgrade turbos we are using on our engines are off bigger engines, the exhaust housing is optimized for its original application. So when it comes down to it, our little engines will have to rev harder to make the same exhasut flow in order for the bigger turbos to make boost.
Easiest way of looking at this is all turbos need a certain amount of exhaust flow (engine power) to make them spool. Take the original engines (that the turbo came from) max power, divide by 6, and this is approx the amount of power N/A you will have to make to get it to start boosting.
So, 130kw (T25/CA18) divide by 6 = 22kw. N/A, the E15ET will make around this power at 2.2k-2.5k rpm WOT, so boost should come on around there.
T28 SR20 GTiR 165-180kw divide by 6 = 27-30kw so you need 2.7k-3.2krpm to get it to spool.
The effect of putting a smaller exhaust housing onto a turbo will reduce the amount of power (exhuast flow) required to make it generate boost.
The thing to remember is that the smaller the housing is, the less exhaust flow potential it wll have. In other words, exhaust housing size will be a limiting factor on how much power your engine can make!
Unless you run a external gate. =7]
Damo
Same thing with the turbo, the greater the pressure difference between the exhaust manifold and the dump pipe + exhaust, the faster the gasses will pass through the turbine making it spin. So the idea of most all mods is to increase the pressure across the turbo.
And we all know that hot air/exhaust takes up more volume than cool air/exhaust, so the idea is to keep the exhaust pre turbo as hot as possible and the exhaust runners as short as practicle to keep temp/volume as high as it can be.
Now, the exhaust housing of the turbo has a set orfice that the exhaust gasses pass through, and it the size of this which detremines how hard the turbo will spin for a given flow. Given all the upgrade turbos we are using on our engines are off bigger engines, the exhaust housing is optimized for its original application. So when it comes down to it, our little engines will have to rev harder to make the same exhasut flow in order for the bigger turbos to make boost.
Easiest way of looking at this is all turbos need a certain amount of exhaust flow (engine power) to make them spool. Take the original engines (that the turbo came from) max power, divide by 6, and this is approx the amount of power N/A you will have to make to get it to start boosting.
So, 130kw (T25/CA18) divide by 6 = 22kw. N/A, the E15ET will make around this power at 2.2k-2.5k rpm WOT, so boost should come on around there.
T28 SR20 GTiR 165-180kw divide by 6 = 27-30kw so you need 2.7k-3.2krpm to get it to spool.
The effect of putting a smaller exhaust housing onto a turbo will reduce the amount of power (exhuast flow) required to make it generate boost.
The thing to remember is that the smaller the housing is, the less exhaust flow potential it wll have. In other words, exhaust housing size will be a limiting factor on how much power your engine can make!
Unless you run a external gate. =7]
Damo
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Rohan 84ET
- Posts: 1429
- Joined: Thu Feb 08, 2007 9:51 pm
- Location: Adelaide, South Australia
righty O, well 130-140fwkw's is good enough for me to aim for, and thats what Ben is sitting on with his T25G/T25 turbo.
i just wanted to grasp the general idea a bit better, thank you all.
theres alot of things i will need to do to my car before i ever have to worry about how my engine is being limited.
btw, was that a no to havin a crack at ma I/C pipework ben?
i just wanted to grasp the general idea a bit better, thank you all.
theres alot of things i will need to do to my car before i ever have to worry about how my engine is being limited.
btw, was that a no to havin a crack at ma I/C pipework ben?
ET coming back from the dead.
SAVE ME JEBAS!
SAVE ME JEBAS!
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Ben Hewitson
- Posts: 1136
- Joined: Tue Aug 08, 2006 9:19 am
- Location: Adelaide, SA.
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s1380akuma
- Posts: 4
- Joined: Mon Jun 04, 2007 6:33 pm
- Location: Adelaide
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re T25G psi
My good friends at Tilbrook Auto and Dyno say that safely a 25G will only produce good power upto 14psi on a 2L motor anything after that is a waste and only shortens the life of the turbo.
Live life sideways or die laughin trying to get there.....