Ported factory headers and upgraded cross/uppipe

[soopersubaru]

 Stoffa said:

no external wastegate for me, no need!! I'll be running my VF36P2018G ;D ;D that Steve Murch made for me, with factory internal gate and an uprated actuator (14psi spring) from a PE1820 (thanks swee)

If it does blow open I'll simply upgrade it with a forge one with a 21psi spring

As i said......Waste gate IS required...Be that external or internal.

[soopersubaru]

 Koom']

[quote name='soopersubaru said:

However Heat is what runs a turbine...

/quote]

If that were true I'd just stick mine in an oven and make it pump out 40psi :

Pressure difference across the turbine is what drives them. Heat being just a part of the perfect gas equation of state;

Which will then lead on to the mass/volume flowrate equations etc etc.

So in summation; heat is important, but so is flow. If you have untidy sections of pipework then you're just loosing flow through bad turbulence.

Did i not say that? clean flow very important! Gas flow pressure is also a factor but primarily to carry heat to the turbine, Pressure is lost as the gases cool after passing energy to the turbine blades.

However heat preservation carried to the turbo is just as if not more important in reducing lag effect...If you measure the temp difference across the turbine one will realise that heat is a considerable drive factor of the reaction type turbine used in turbochargers.

Impulse turbines on the other hand rely on pressure to achieve speed.

[Koom]

 soopersubaru said:

Did i not say that? clean flow very important! Gas flow pressure is also a factor but primarily to carry heat to the turbine, Pressure is lost as the gases cool after passing energy to the turbine blades.

Yes cause heat is the factor doing work on the turbine blade to impart the energy from the fluid to the turbine :

How do you think that heat drives a turbine? Why don't they produce power if you sit them in an oven then?

It is pressure that powers it. If you are loosing heat from your working fluid, then you are loosing pressure due to that equation earlier, so heat is still vitally important as you only have a set amount of energy to work with once it's left the cylinder. But pressure is in no way just there to carry heat to the turbine ???

As the working fluid transfers its energy to the turbine, it experiences a pressure drop (which has a corresponding drop in temperature + the temperature lost through conduction), so it is colder coming out the back end. But that is just the converse to how the air heats up considerably when you compress it, not what is powering the turbine.

[sultan]

I think you're both wrong. Its my foot that drives the turbine

[Jord]

 sultan said:

I think you're both wrong. Its my foot that drives the turbine

Pedal powered turbine? Thats different....

[soopersubaru]

 Koom']

[quote name='soopersubaru said:

Did i not say that? clean flow very important! Gas flow pressure is also a factor but primarily to carry heat to the turbine, Pressure is lost as the gases cool after passing energy to the turbine blades.

/quote]

Yes cause heat is the factor doing work on the turbine blade to impart the energy from the fluid to the turbine :

How do you think that heat drives a turbine? Why don't they produce power if you sit them in an oven then?

It is pressure that powers it. If you are loosing heat from your working fluid, then you are loosing pressure due to that equation earlier, so heat is still vitally important as you only have a set amount of energy to work with once it's left the cylinder. But pressure is in no way just there to carry heat to the turbine ???

As the working fluid transfers its energy to the turbine, it experiences a pressure drop (which has a corresponding drop in temperature + the temperature lost through conduction), so it is colder coming out the back end. But that is just the converse to how the air heats up considerably when you compress it, not what is powering the turbine.

WRONG.................look it up!.. Impulse turbines use pressure with very little temp drop...Reaction turbines utilise both.( I dont think that heat drives the turbine..I Know it does!!

Temp does not drop simply because you drop the pressure in any fluid.

Temp lost through conduction A??.....Good reason to insulate!

OF course the moving fluid imparts motion ..There after Heat runs the reaction type turbine.

Reaction turbine blading is used in turbochargers...Because they impart very little back pressure....Unlike the impulse turbine.

Hi fluid flow with little turbulence as in tuned/aligned/polished internally headers also "frees" up the fluid motion to allow even more heat to be carried more quickly to the turbine rotor....

Don't believe me??.Do a pressure drop check next time on the dyno! At full power!/waste gate open.

You will be quite surprised by the result...And does not relate to your equation at all.

However the temp drop is considerable! This temp drop is not related to the pressure drop by your equation.

The heat loss is due to drive imparted.....Not conduction to anywhere!

if one was to freeze the turbine the pressure drop will increase and the temp drop will decrease...

In your summation this would not occur would it?

In essence headers setup correctly provide less lagg IF insulated well,internally aligned and tuned for pulse width.

Because the fluid flows well...pressure is not affected at all.

[slystiguy]

oh god here we go

[soopersubaru]

 slystiguy said:

oh god here we go

like the last time A? Compressor surging!!! LMAO!!....Compressor entering the surge zone and stalling..IS not compressor surge!

[Koom]

 soopersubaru']

WRONG.................look it up!.. Impulse turbines use pressure with very little temp drop...Reaction turbines utilise both.( I dont think that heat drives the turbine..I Know it does!!

I'm using Wikipedia cause its faster than getting out my thermodynamics notes and text books.

http://en.wikipedia.org/wiki/Turbine

Reaction turbines develop torque by reacting to the gas or fluid's pressure or mass. The pressure of the gas or fluid changes as it passes through the turbine rotor blades

Temp does not drop simply because you drop the pressure in any fluid.

Come on man, I know you know that this statement is about as wrong as saying that Entropy of an isolated system will decrease.

It is the exact same concept as when you compress the air on the other side of the turbocharger. As it is compressed in an adiabatic process, the temperature will go up.

From http://www.gnttype.org/techarea/turbo/turboflow.html;

Tout = Tin + Tin x [-1+(Pout/Pin)0.263]

efficiency

Example: the inlet temperature is 70 deg F, the suction pressure is -0.5 psig (a slight vacuum), the discharge pressure is 19 psig, and the efficiency is 72%. What is the discharge temperature?

Tin= 70 deg F + 460 = 530 deg R

Pin= -0.5 psig + 14.7 = 14.2 psia

Pout= 19 psig + 14.7 = 33.7 psia

Pout/Pin = 33.7/14.2 = 2.373 (this is the compression ratio)

Tout = 530 + 530 x (-1+2.3730.263 ) = 717.8 deg R - 460 = 257.8 deg F

0.72

So the theoretical outlet temperature is 257.8 deg F

Thats just an equation to show what we already know, that hot air comes out of the compressor. So we put intercoolers in.

Its the same when the working fluid passes through the turbine, loosing pressure (cause thats how it works as shown earlier) so therefore there is a corresponding drop in temperature!

Its called Adiabatic Cooling; http://en.wikipedia.org/wiki/Adiabatic_process

Adiabatic cooling occurs when the pressure of a substance is decreased as it does work on its surroundings.

Temp lost through conduction A??.....Good reason to insulate!

I was talking about the turbine as a separate system and the processes that are occuring inside as this is a real system and not a theoretical one with frictionless pulleys and massless ropes Plus it has already been discussed that insulating to save all the available pressure is a good idea.

[quote name='soopersubaru said:

OF course the moving fluid imparts motion ..There after Heat runs the reaction type turbine.

You still haven't given us any information as to why my turbo doesn't make any boost when its sitting in the oven? Especially if heat is what drives it. That little bugger should be spooling away like a mad bastard! Maybe I should build an external combustion engine around the outside of my turbine housing to make it even more efficient ???

[Koom]

 soopersubaru said:

Don't believe me??.Do a pressure drop check next time on the dyno! At full power!/waste gate open.

You will be quite surprised by the result...And does not relate to your equation at all.

Depends entirely on whether you are measuring the Dynamic Pressure, the Stagnation Pressure or just the Static Pressure?

[D-Style]

 slystiguy said:

oh god here we go

+1 I'll just leave this here

[soopersubaru]

Mr Koom.Maybe you can explain this statement then!

Thanks to lower thermal and mechanical stress on the turbine tips, it is possible to boost power quite significantly by increasing the turbine entry temperature (increasing fuel input) which results in an improved mechanical efficiency.

Directly related to the type of radial flow axial turbine used in turbochargers!

Further... Your statement:--Its called Adiabatic Cooling; http://en.wikipedia.org/wiki/Adiabatic_process

Adiabatic cooling occurs when the pressure of a substance is decreased as it does work on its surroundings.

YES have to agree!

However this is not always the case is it?

A fluid carrying heat above its rated pressure/temp relationship is called Superheated..And does not lose temp immediately at the point of pressure drop does it?

Rather this temp transfers its energy as.... kinetic energy in this turbocharger case otherwise known as... Power!......As found in turbines.... Because hot fluid turbines utilise this energy.

[Stoffa]

I'll have a crack even thought theres no reference to where that statement came from as to the accuracy of the statement.....

The tips dont get has hot as the rest of the turbine so its possible increase the boost (which increases fuel input) causing it to run hotter without causing damage to the tips

how did I do?

Koom how many years have you been studying this stuff? and is it part of some mechanical engineering degree? or did I just miss it from bailing out of school after 6th form? haha

[madmike]

 soopersubaru said:

Mr Koom.Maybe you can explain this statement then!

Thanks to lower thermal and mechanical stress on the turbine tips, it is possible to boost power quite significantly by increasing the turbine entry temperature (increasing fuel input) which results in an improved mechanical efficiency.

Directly related to the type of radial flow axial turbine used in turbochargers!

That statement is directly related to tuning for Best flow dynamics into the turbine. using the BEP of the exhaust turbine and compressor turbine is key to running as close as possible to the best points on both curves.

More fuel= more exhaust flow which means more inlet motive power..

HEAT DOES NOT DRIVE THE TURBO... FLOW DOES!!!!!!

The reason heat is kept in is to reduce the pressure lost through exhaust gas cooling pre turbo...

[WRXONP]

One small thing - increasing the fuel to make more heat ??

That seems wrong to me as a lean condition burns hotter and a rich condition burns colder

[soopersubaru]

 WRXONP said:

One small thing - increasing the fuel to make more heat ??

That seems wrong to me as a lean condition burns hotter and a rich condition burns colder

Correct mixture assumed.Turbines are thermal "engines" Simple!

[madmike]

 soopersubaru']

[quote name='WRXONP said:

One small thing - increasing the fuel to make more heat ??

That seems wrong to me as a lean condition burns hotter and a rich condition burns colder

/quote]

Correct mixture assumed.Turbines are thermal "engines" Simple!

WRONG!!!!!!

Turbines use flow dynamics of pressure difference between an area of high pressure and low pressure to generate shaft rotation...

The change in temperature between the high side and the low is a function of the change in pressure.

[WRXONP]

So this thread turned from someone's nice - clean- hard work into a shit fight on who's right and wrong about how a turbo spins

Who caused the shit fight ???

[Stoffa]

Must have been a big weekend on the ekkeys!!

all I wanted was a "look how cool I am" thread

[slystiguy]

if stoffa posts results then it will end the debate to a degree...

[madmike]

 Stoffa said:

Must have been a big weekend on the ekkeys!!

all I wanted was a "look how cool I am" thread

And they do look awesome dude!!!!

[soopersubaru]

With respect Mr Club Captain/ MADMIKE.please read above.

Yes pressure and flow are important.(otherwise no rotation) But heat is also a factor in rotational power in hot fluid turbines.

the temp drop in a turbocharger drive turbine is directly related too this.

It is impossible to lose temp by JUST passing through a pressure drop mechanism.

The gas beyond the pressure drop is termed superheated IF the energy has not been utilised at the point of pressure drop occurrence.

Mr Kooms above reference to compressor side calculations are irrelevant.

To return to the subject:-

Over cutting of headers is not a wise idea as evacuation is minimised some what ( although i have also previously stated in this post!)

[Koom]

 soopersubaru said:

Mr Koom.Maybe you can explain this statement then!

Thanks to lower thermal and mechanical stress on the turbine tips, it is possible to boost power quite significantly by increasing the turbine entry temperature (increasing fuel input) which results in an improved mechanical efficiency.

Directly related to the type of radial flow axial turbine used in turbochargers!

Easy.

Again, from Wiki cause its readily available (http://en.wikipedia.org/wiki/Gas_turbine)

 

As with all cyclic heat engines, higher combustion temperatures can allow for greater efficiencies. However, temperatures are limited by ability of the steel, nickel, ceramic, or other materials that make up the engine to withstand high temperatures and stresses. To combat this many turbines feature complex blade cooling systems.

Just about all the engines that we know in normal everyday use are "Heat" engines. Heat is a driving force behind the thermodynamic cycles that govern them but the mechanical work is still done by the pressure differences. Just study up on some P-V and T-S charts to see how they interact.

Again, heat alone doesn't make turbines move, pressure is what makes them spin.

This comes from the Thermodynamic principles that govern the process of a turbine working. You'll be used to the cycle known as the Otto Cycle which governs the processes of an internal combustion, reciprocating engine. The efficiency of that process can be improved through increasing the compression ratio.

In a gas turbine (as opposed to a steam turbine which is the Rankine Cycle), the Brayton Cycle is loosely followed. I say "loosely" as during the combustion part of the Brayton Cycle, we've gone and stuck a piston engine in there and stolen some of the available energy from the working fluid.

If you look into the efficiency of the Brayton Cycle (gas turbines), the efficiency is also directly effected by the compression ratio but the efficiency is also dictated by the pressure ratio. Seeing as we cannot decrease the outlet pressure (you should already have a free flowing exhaust) we can only effect the inlet pressure. This pressure is the pressure of the gases leaving the cylinder but is also the dynamic pressure which can only be measured if you measure the static pressure (exhaust back-pressure) and the stagnation pressure (or "velocity pressure") and then use Bernoulli's Laws to calculate the total dynamic pressure of the working fluid. The easiest way to increase the dynamic pressure of the gases coming out of the cylinder is by increasing the temperature as this is directly related to the dynamic pressure.

[madmike]

It is impossible to lose temp by JUST passing through a pressure drop mechanism.

How does a refrigeration system work then?

Best you go back and restudy thermo and fluid dynamics.

[Stoffa]

 slystiguy said:

if stoffa posts results then it will end the debate to a degree...

oh boy probably not have my car wired up for another month or so, this could go on for a while