I could take the time to google the differences of an external and interal wastegate, but it would be to complicated of a desciption. So i was wondering if you could tell me why an external is more suitable for high hp applications. Thanks

 

put on your flame suit. and just to help you. go read the FAQ section

 

psh........ thanks........

 

ok, not to be a complete ***, but there is a search function, and something THAT simple doesnt need to be asked again since its been asked 243543543 times... all u guys do when u ask the same thing over and over is make it more time consuming to search for good info...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ForestGreenCiv &raquo;</TD></TR><TR><TD CLASS="quote">psh........ thanks........ </TD></TR></TABLE>

psh dont be lazy

http://www.evans-tuning.com/te....html
http://www.evans-tuning.com/te....html

now you figure it out

 

i understand the basics about them and dont want to go and read something that is goin to take an hour.... i wanted a simple answer... is that too much to ask???

 

if you went to elementary school, it shouldn't take longer than 10 minutes to read this:


Wastegate Sizing:
I have found a common misconception among sizing of wastgate for horsepower goals. Here are my thoughts:

The wastegate sizing is largely dependent upon the boost pressure being regulated, and the exhaust energy from the engine the wastegate is being used upon. The way in which a wastegate works is to regulate the amount of exhaust energy, or exhaust gas that travels into the turbine housing of the turbocharger. At lower boost levels, more exhaust gas is being bypassed to sustain the lower pressure. The reason is that to keep the exhaust flow that goes into the turbine housing to a lower pressure, more exhaust energy is to be bleed from the exhaust manifold. So at lower boost pressures, the size of the wastegate becomes critical in order to regulate the amount of exhaust energy that travels into the turbine housing. The physical size of the wastegate should be larger, or have a larger diaphram and valve to bleed off the most amount of pressure. As higher and higher boost pressure are enabled, less exhaust energy is to be bleed from the system. The wastegate valve is opened less and less, so the physical size of the wastegate (i.e wastegate valve size; ex. 35mm is 35mm valve, etc) being used is to be smaller and smaller.

Besides the amount of boost pressure being regulated, the compression and displacement play a huge role in the amount of exhaust energy available in the exhaust manifold. The greater the displacement and compression, the larger the wastegate size should be used. Its a very simple relationship between boost pressure, displacement and compression ratio of the engine the wastegate is being used upon. A side note, the larger wastegate typically holds boost pressure more stable than the smaller wastegate size. Most, if not all cases of unstable boost is created from poor wastegate placement. If wastegate placement is pre-dictated from the manufactuer, and unstable boost is a problem a larger wastegate should be employed. The Tial 35/38mm wastegate is sufficient for 500-600whp level, which is contradictory to what most turbo Honda's use at higher boost levels.


Turbine housings, exhaust sizing, and backpressure:
Everyone seems to grasp that a larger exhaust on a turbocharger vehicle will gain faster spool up, increased power and thus faster acceleration. Here is the theory behind the phenominon:

The turbine housing is merely a volume for which exhaust gas (energy) is transmitted from the engine, to the turbine blade, then dispelled into the atmosphere. In order to better understand how this works we need to take a look at pressure. Turbines in general work off of a pressure differential. A pressure differential in lamens terms is the ratio of pressure before the turbine blade, and after the turbine blade. The greater the pre-turbine pressure compared to the post-turbine pressure, the greater the amount of work can be transmitted through the turbine/compressor shaft. This is where some engineering comes into play. Work is defined as the integration of force and displacement, keeping force constant. Again in lamens terms this merely means work is the force exterted on an object while taking into account the change in displacement, or position of the object. In relation to turbines, the greater the pressure differential, the greater the amount of work is created. The greater the amount of work created, the greater the amount of energy transmitted through the turbine, into the compressor through the connecting shaft.

To break this down into another small explanation, compressors work off of rpm. The amount of air the compressor is able to "flow", or merely put the lbs/minute the compressor can flow is dictated by the amount compressor blades, angles of the blades, etc. What the compressor uses to "compress" the air through the inlet is based off of how fast the compressor wheel is spun. The rpm at which the compressor blade has to be spun to "compress" the air varys from turbo to turbo from the different compressor blade characteristics. Another critical aspect of the compressor is the physical size and weight of the blade. The larger the blade, more amount of energy must be transmitted to allow the shaft to spin to the rpm at which the compressor can compress the air. In engineering terms rotating mass is called inertia, so smaller turbos have smaller inertia demands, larger compressors have larger inertia demands. To bring the focus back on the turbine side of things, the increased inertia demands more energy to be supplied from the turbine. The greater the pressure differential discussed above, the greater the amount of work that be be supplied to overcome the inertia effects of the compressor.

Now looking at the exhaust, or post turbine the larger the exhaust, the larger the pressure differential can become. The increase in area of the exhaust, gives the exhaust gas much more room to expand. Hot gas has only one goal, to expand as quickly as possible. The goal pre-turbine is to focus the energy into the turbine to carry as much energy as possible. As the exhaust expands the energy disspates, so the goal post turbine (i.e exhaust) is to have the largest area possible for the gas to expand. Looking at the immediate exit of the turbine housing, the downpipe, the exhaust gas is traveling at a very high rate of speed. The exhaust gas is expanding rapidly, and is in a very turbulence state from being flung from the turbine. At this point having a 3" downpipe becomes critical since the exhaust gas is both in a turbulent state, and is expanding. In turbulence, the expansion of an area the turbulence is forced to become more laminar (although this doesnt happen very quickly). Also the increased area allows the gas to expand rapidly, allowing the energy in the exhaust gas to dissapate quickly and letting the pressure created by the exit from the turbine housing to drop. Essentially you are creating a greater pressure drop.

Looking at the turbine housing the sizing becomes a critical part in how the pressure differential is created. Take for instance the .48 A/R housing. Changing turbine A/R has many effects. By going to a larger turbine A/R, the turbo comes up on boost at a higher engine speed, the flow capacity of the turbine is increased and less flow is wastegated, there is less engine backpressure, and engine volumetric efficiency is increased resulting in more overall power. The .48 A/R is able to create the pressure differential at a much lower engine rpm, giving the compressor ability to make its maximum rpm speed sooner. As the engine rpm climbs, the pressure differential is lowered due to the physical volume of the housing size becoming a restriction on the post turbine side. As the housing size is increased, it take greater engine rpm speed (greater exhaust energy) to spool up the turbine, but the pressure differential is less effected by the physical volume of the housing. If you are after maximum midrange gains smaller housings are essentially, if top end gains are essential larger housing are essential. Selecting the powerband of the engine is essentially dictacted through the housing size, and the turbine physical characterisitics.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ForestGreenCiv &raquo;</TD></TR><TR><TD CLASS="quote">i understand the basics about them and dont want to go and read something that is goin to take an hour.... i wanted a simple answer... is that too much to ask??? </TD></TR></TABLE>

Internal WG advantage
compactness
quiet because it dumps into DP
built into the turbine housing

Internal WG disadvantage
boost creep
limited to less than 20psi anything above that an i suggest a external. (please other posted dont say **** about evo and dsm's and blah blah blah im giving the guy a rundown)

External WG advantage
performance
good boost control
doesnt deal with backpressure downstream of the turbine
different sizes

External WG disadvantages
size
loud-when not plumbed back into exhaust stream


theres more to it but thoses are the basics. honestly i suggest you read and LEARN. learning never killed anyone and its good for you




Modified by tony413 at 11:23 PM 10/30/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by esedulerp5tenin &raquo;</TD></TR><TR><TD CLASS="quote">

if you went to elementary school, it shouldn't take longer than 10 minutes to read this:

.</TD></TR></TABLE>

do not cut and paste from the links i have provided the op can stop being lazy and read. besides he has already made it clear that the language is not clear enough for him.

 

why you guys got to hate... [freak]... i was just being a nice guy and eveyone got to treat me like im [freak]ing 2... thanks No more posts.... i get the picture then......

CLOSED!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ForestGreenCiv &raquo;</TD></TR><TR><TD CLASS="quote"> why you guys got to hate... [freak]... i was just being a nice guy and eveyone got to treat me like im [freak]ing 2... thanks No more posts.... i get the picture then......

CLOSED!!!!</TD></TR></TABLE>

why do you insist on not reading and learning

i hope you get it, its dumb to refuse to read and learn because you dont want to. thats why people are hating on you. you have to want to learn forself otherwise you can just have your tuner or build do the job for you.

 

uh i know how to learn... i have a 3.0gpa and i know a **** ton about hondas... I have never boosted a car but have many diesel pickups and semis that have internal waste gates, thats all i was wondering. was it hard to type a couple advantages and disadvantages about them. thats all i wanted to know. if i wanted to go to a encycolopedia and read 4 pages i would have. but you yourself posted up advantages and disadvantages... and thats all i wanted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ForestGreenCiv &raquo;</TD></TR><TR><TD CLASS="quote">uh i know how to learn... i have a 3.0gpa and i know a **** ton about hondas... I have never boosted a car but have many diesel pickups and semis that have internal waste gates, thats all i was wondering. was it hard to type a couple advantages and disadvantages about them. thats all i wanted to know. if i wanted to go to a encycolopedia and read 4 pages i would have. but you yourself posted up advantages and disadvantages... and thats all i wanted. </TD></TR></TABLE>

ok gasolines and deisels are who different animals.

gas = combustion
diesel = compression

the reason diesels run 30psi on an internal WG because its cheap and boost creep is not an issue. diesel are primo for boost and high CR gasoline engine not so much