compresser A/R
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From: La Porte, IN, United States
compresser A/R
whats considered to be a big and small A/R for the compresser housing? i read that a big A/R is for low boost and small A/R is for high boost. what would be about in the middle of the two?
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Re: compresser A/R (Jedi Jake)
The difference between the A/R is how your powerband will build. The smaller the A/R The lower you powerband will be. The bigger your A/R , the higher your powerband and so on. You change A/R to shift your power curve. You can run whatever boost you like with any A/R size. I use to run 48PSI with a .58 A/R on a T72 but it just fell off to much at high RPM so I went bigger on the A/R to shift my power curve farther out.
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Re: compresser A/R (PHDZINE)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PHDZINE »</TD></TR><TR><TD CLASS="quote">I use to run 48PSI </TD></TR></TABLE>
weak....
Good explanation though
weak....
Good explanation though
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Re: compresser A/R (Schister66)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 »</TD></TR><TR><TD CLASS="quote">
weak....
Good explanation though</TD></TR></TABLE>
Good explanation of turbine housings, but not compressor housings like the OP had asked. To be honest, there really isn't that much of a difference in compressor housings, just baller status (give the appearance of a larger turbo). From what I've heard, larger a/r housings are supposed to be used on low boost apps to get better efficiency, and smaller a/r housings on high boost apps. But like I stated, it's really not that much of a difference. I always go with E cover housings if I can to save space if there is a tight fit. You can always request E cover housings on most turbos.
weak....
Good explanation though</TD></TR></TABLE>
Good explanation of turbine housings, but not compressor housings like the OP had asked. To be honest, there really isn't that much of a difference in compressor housings, just baller status (give the appearance of a larger turbo). From what I've heard, larger a/r housings are supposed to be used on low boost apps to get better efficiency, and smaller a/r housings on high boost apps. But like I stated, it's really not that much of a difference. I always go with E cover housings if I can to save space if there is a tight fit. You can always request E cover housings on most turbos.
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Re: compresser A/R (nebulight)
Oops...I over looked the Compressor housing part...but I don't agree with you on the A/R housing not making a diffrence on the compressor side. If it did't make a difference...all the manufacture should just use the .50 A/R compressor housing that they make but thats just my opinion. 
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Re: compresser A/R (nebulight)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nebulight »</TD></TR><TR><TD CLASS="quote">
Good explanation of turbine housings, but not compressor housings like the OP had asked. To be honest, there really isn't that much of a difference in compressor housings, just baller status (give the appearance of a larger turbo). From what I've heard, larger a/r housings are supposed to be used on low boost apps to get better efficiency, and smaller a/r housings on high boost apps. But like I stated, it's really not that much of a difference. I always go with E cover housings if I can to save space if there is a tight fit. You can always request E cover housings on most turbos.</TD></TR></TABLE>
Compressor housings do make the difference on powerbands. Garrett has some good Tech on this on their website - check it out, its a good read. A turbo will make or break a setup, so to say that a bigger a/r on the compressor is just to "look" cooler, than you're in this for the wrong reasons.
Good explanation of turbine housings, but not compressor housings like the OP had asked. To be honest, there really isn't that much of a difference in compressor housings, just baller status (give the appearance of a larger turbo). From what I've heard, larger a/r housings are supposed to be used on low boost apps to get better efficiency, and smaller a/r housings on high boost apps. But like I stated, it's really not that much of a difference. I always go with E cover housings if I can to save space if there is a tight fit. You can always request E cover housings on most turbos.</TD></TR></TABLE>
Compressor housings do make the difference on powerbands. Garrett has some good Tech on this on their website - check it out, its a good read. A turbo will make or break a setup, so to say that a bigger a/r on the compressor is just to "look" cooler, than you're in this for the wrong reasons.
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Re: compresser A/R (Dunn@ITS)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dunn@ITS »</TD></TR><TR><TD CLASS="quote">
Compressor housings do make the difference on powerbands. Garrett has some good Tech on this on their website - check it out, its a good read. A turbo will make or break a setup, so to say that a bigger a/r on the compressor is just to "look" cooler, than you're in this for the wrong reasons.</TD></TR></TABLE>
Taken from Garrett's website:
Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.
Compressor housings do make the difference on powerbands. Garrett has some good Tech on this on their website - check it out, its a good read. A turbo will make or break a setup, so to say that a bigger a/r on the compressor is just to "look" cooler, than you're in this for the wrong reasons.</TD></TR></TABLE>
Taken from Garrett's website:
Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.
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Maybe I am reading differently than you, but it does say to optimize the performance for high boost applications (which is common when shooting for 400 - 600whp).
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status" 
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status"
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Re: (Dunn@ITS)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dunn@ITS »</TD></TR><TR><TD CLASS="quote">Maybe I am reading differently than you, but it does say to optimize the performance for high boost applications (which is common when shooting for 400 - 600whp).
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status" </TD></TR></TABLE>
The thing is they don't make compressor housings with a large number of A/R's. You don't have the choice of a .40, .70, or 1.00 A/R TO4S, it's primarily just a .70 A/R housing. If it made a significant difference at ALL, you would see many different comp covers cast.
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status"
</TD></TR></TABLE>The thing is they don't make compressor housings with a large number of A/R's. You don't have the choice of a .40, .70, or 1.00 A/R TO4S, it's primarily just a .70 A/R housing. If it made a significant difference at ALL, you would see many different comp covers cast.
Re: (Dunn@ITS)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dunn@ITS »</TD></TR><TR><TD CLASS="quote">Maybe I am reading differently than you, but it does say to optimize the performance for high boost applications (which is common when shooting for 400 - 600whp).
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status" </TD></TR></TABLE>
True. But it does depend upon the application. In many cases for street Honda use, unless there is a LARGE HP difference needed, it will not make THAT much of a difference more than just spacing issue. If top end is needed, and the compressor wheel is large enough, it is recommended to get the larger compressor cover.
Guess it comes down to the application whether its worth to actually change it up or not, t3/t4 I wouldnt worry about it, you wouldn't notice.
But atleast for me, I'll be looking to optimize its efficiency and ignore the "baller status"
</TD></TR></TABLE>True. But it does depend upon the application. In many cases for street Honda use, unless there is a LARGE HP difference needed, it will not make THAT much of a difference more than just spacing issue. If top end is needed, and the compressor wheel is large enough, it is recommended to get the larger compressor cover.
Re: (Jedi Jake)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jedi Jake »</TD></TR><TR><TD CLASS="quote">so basically the size really doesnt matter when it comes to performance?</TD></TR></TABLE>
I wouldn't say that so generally as a rule of thumb. Most of these cover sizes "b", "E", or "S" really depend upon volume of CFM flow used (not velocity, that is different), as well as the size of the exducer used. When you get to over 80mm to 85mm and up in the exducer of the compressor wheel, typically that is for a higher CFM volume turbo that is used for top end, and you want to be able to extract as much as possible from that exducer. These are when the larger compressor covers are generally used. Depending upon use, on some compressor wheels, the larger compressor covers don't assist with the amount of CFM velocity that may be needed to assist in an application, simply higher end power in the upper 1500rpms of the powerband. HOWEVER, in a "b" cover, because velocity of the channel in the compressor cover stays high, it does help with some spool characteristics with a larger exducer in the lower part of the powerband. Though it does depend upon the wheel used. I built plenty of "b" cover turbochargers that uses a slightly larger compressor exducer and wheel combination that can fit in either a "B" or "S", but because of the person's purpose, the smaller E and B covers help spool the larger exducer a little faster than it would in an S cover. This gives them a little bit of an option of having a little assistance in a larger power application, while still staying in a compact size. But the drawback of the smaller cover become apparent because it doesn't allow for as much CFM VOLUME at the higher rpm ranges (above 8000 in our case), that allows the larger exducers to stretch their legs of efficiency a bit in the top end. As a result, top end power creation becomes a little stunted.
So again, its not a "general" rule of thumb.
I hope that made some sense. I'm busy watching GT Speed World Challange..
Modified by TheShodan at 8:27 PM 3/25/2007
Modified by TheShodan at 8:48 PM 3/25/2007
I wouldn't say that so generally as a rule of thumb. Most of these cover sizes "b", "E", or "S" really depend upon volume of CFM flow used (not velocity, that is different), as well as the size of the exducer used. When you get to over 80mm to 85mm and up in the exducer of the compressor wheel, typically that is for a higher CFM volume turbo that is used for top end, and you want to be able to extract as much as possible from that exducer. These are when the larger compressor covers are generally used. Depending upon use, on some compressor wheels, the larger compressor covers don't assist with the amount of CFM velocity that may be needed to assist in an application, simply higher end power in the upper 1500rpms of the powerband. HOWEVER, in a "b" cover, because velocity of the channel in the compressor cover stays high, it does help with some spool characteristics with a larger exducer in the lower part of the powerband. Though it does depend upon the wheel used. I built plenty of "b" cover turbochargers that uses a slightly larger compressor exducer and wheel combination that can fit in either a "B" or "S", but because of the person's purpose, the smaller E and B covers help spool the larger exducer a little faster than it would in an S cover. This gives them a little bit of an option of having a little assistance in a larger power application, while still staying in a compact size. But the drawback of the smaller cover become apparent because it doesn't allow for as much CFM VOLUME at the higher rpm ranges (above 8000 in our case), that allows the larger exducers to stretch their legs of efficiency a bit in the top end. As a result, top end power creation becomes a little stunted.
So again, its not a "general" rule of thumb.
I hope that made some sense. I'm busy watching GT Speed World Challange..
Modified by TheShodan at 8:27 PM 3/25/2007
Modified by TheShodan at 8:48 PM 3/25/2007
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From: La Porte, IN, United States
Re: (TheShodan)
what does "CFM" mean? and what do you mean by "B" "E" and "S" cover sizing? if you tell me what all that means then ill be able to understand the last post thanx
thanx
Re: (Jedi Jake)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jedi Jake »</TD></TR><TR><TD CLASS="quote">what does "CFM" mean? and what do you mean by "B" "E" and "S" cover sizing? if you tell me what all that means then ill be able to understand the last post thanx</TD></TR></TABLE>
This will take a while. There are 3 main classes of turbo compressor housings, and one or 2 larger ones. please check out this definition:
CFM is Cubic Feet per Minute; a measurement of volume over time. It has no considerations as to what gas it pertains to nor the density of the gas. CFM is strictly a rate of volume measurement. But within that volume of gas, and in our case – air, we can evaluate the quality of the air and its ability to transfer heat. Every molecule of air has a mass, and this mass has the ability to absorb or emit energy; also known as transferring heat. If we count the number molecules for a given volume we obtain the density of the air (mass/volume).
If we pack more molecules of air into a given volume, increasing the density, we have more mass per volume and the ability to transfer heat increases. Consequently, the reverse applies also.
At sea level, the density remains fairly constant and we calculate the CFM using a heat transfer equation:
CFM = Q /(Cp * r * DT)
Where:
CFM = Cubic Feet per Minute
Q = Heat Transferred (kW)
Cp = Specific Heat of Air
r = Density
DT = Change in Temperature
If the specific heat of air and the density are held constant (eg. sea level), the equation then becomes simplified:
CFM = 3160 * Q (kW) / DT (°F)
or
CFM = 1760 * Q (kW)/ DT (°C)
I simply can't be more definitive than that.
As for the Cover sizes, you need to do a little searching. Its not that hard.
thanx</TD></TR></TABLE>This will take a while. There are 3 main classes of turbo compressor housings, and one or 2 larger ones. please check out this definition:
CFM is Cubic Feet per Minute; a measurement of volume over time. It has no considerations as to what gas it pertains to nor the density of the gas. CFM is strictly a rate of volume measurement. But within that volume of gas, and in our case – air, we can evaluate the quality of the air and its ability to transfer heat. Every molecule of air has a mass, and this mass has the ability to absorb or emit energy; also known as transferring heat. If we count the number molecules for a given volume we obtain the density of the air (mass/volume).
If we pack more molecules of air into a given volume, increasing the density, we have more mass per volume and the ability to transfer heat increases. Consequently, the reverse applies also.
At sea level, the density remains fairly constant and we calculate the CFM using a heat transfer equation:
CFM = Q /(Cp * r * DT)
Where:
CFM = Cubic Feet per Minute
Q = Heat Transferred (kW)
Cp = Specific Heat of Air
r = Density
DT = Change in Temperature
If the specific heat of air and the density are held constant (eg. sea level), the equation then becomes simplified:
CFM = 3160 * Q (kW) / DT (°F)
or
CFM = 1760 * Q (kW)/ DT (°C)
I simply can't be more definitive than that.
As for the Cover sizes, you need to do a little searching. Its not that hard.
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Re: (TheShodan)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheShodan »</TD></TR><TR><TD CLASS="quote">
True. But it does depend upon the application. In many cases for street Honda use, unless there is a LARGE HP difference needed, it will not make THAT much of a difference more than just spacing issue. If top end is needed, and the compressor wheel is large enough, it is recommended to get the larger compressor cover.</TD></TR></TABLE>
Hmmm so I guess its a bigger than my idea of "big" hp cars. Understood. I just didn't like the idea that a bigger compressor shroud = looking cool. I'm sure Garrett makes things for a reason.
What kind of a specific difference does a ported shroud hold? I have heard so many people say its really not a big deal and other say they wouldn't run without it.
True. But it does depend upon the application. In many cases for street Honda use, unless there is a LARGE HP difference needed, it will not make THAT much of a difference more than just spacing issue. If top end is needed, and the compressor wheel is large enough, it is recommended to get the larger compressor cover.</TD></TR></TABLE>
Hmmm so I guess its a bigger than my idea of "big" hp cars. Understood. I just didn't like the idea that a bigger compressor shroud = looking cool. I'm sure Garrett makes things for a reason.
What kind of a specific difference does a ported shroud hold? I have heard so many people say its really not a big deal and other say they wouldn't run without it.
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