Measuring turbo efficiency
06-08-2003, 04:29 PM
#1
Measuring turbo efficiency
Many posts have been written on this subject, and I have added my dosage to the pot as well.
What I want to know is how do all of the turbo's sold get tested. I read where boost is added to the tune, but never any mention of the turbo's efficiency. I did read some time ago someone mentioned their turbo was close to "max ing" out. Not sure what that means.
I cannot speak for all manufacturers, but typically maps are unavailable. So how do we know where on the map we are running. We hear about differing boost levels, but just where on the map are they running. I have read many times about different turbo hybrids been sold with no information except, the normal HP number given. There are so many factors which can change the efficiency of a turbo, and most are discussed here, but almost never understood. We can have the same turbo, but with small changes in engine configuration, the performance of that same turbo can be dramatically diiferent. Exhaust systems and their backpressures is one factor which has huge effects on the turbo's performance. The term turbo performance is usually associated with its tested map, and how far off, or exactly where on that map you are running. In more simple terms, you can run in different parts of the map and produce different amounts of air volume, same boost, same turbo. Usually the change has been in speed, sometimes affected by any number of factors.
When buying a Turbo, your first question before any should be, "do you have the map for this, or have you had it tested, can you provide a map, or how do I know where on the map will I run. Can I buy some sort of measuring device for testing"
Without these questions been asked, all performance info should be questioned and taken at face value.
So, if no maps are available, what good would any device be? Simple, the 3 main factors on a map are, boost(written as a pressure ratio over atmo) and air mass. The third is impellor speed. Measuring air mass is usually out of the question, but the speed can be measured. So now we have 2 points on the map that we can determine where we are. But we have no map to read. Ok, when we run very high levels of boost at WOT, or high boost levels on overrun, 2 turbo terms come into play. 1 is the choke point or choke line, and the other is the surge point or line. Both have damaging effects on turbochargers. Typically when either 2 factors happen, sudden rises in speed occur. In the case of choke, impellor speed, MAP and EXP can be seen to be effected.
So when these guy's tell you their Turbo's are the best, the boost they run and mention something about a turbo map, question them. Its all very simple, but usually clouded in mystery with a pinch of BS. If they cannot supply a map, ask them for a dyno print out of impellor speed with MAP and EXP shown. If any of these is not avialable, you are buying blind. If they sell you something without having any of these parameters recorded, then they probably have mismatched the turbo for the application. If they got it right, then well done. I know some very clever engine experts who still need to measure to apply and understand.
All of the references here have been about a Compressor map. It all starts over with the Turbine Housing, Turbine Impellor trim and much more.
What I want to know is how do all of the turbo's sold get tested. I read where boost is added to the tune, but never any mention of the turbo's efficiency. I did read some time ago someone mentioned their turbo was close to "max ing" out. Not sure what that means.
I cannot speak for all manufacturers, but typically maps are unavailable. So how do we know where on the map we are running. We hear about differing boost levels, but just where on the map are they running. I have read many times about different turbo hybrids been sold with no information except, the normal HP number given. There are so many factors which can change the efficiency of a turbo, and most are discussed here, but almost never understood. We can have the same turbo, but with small changes in engine configuration, the performance of that same turbo can be dramatically diiferent. Exhaust systems and their backpressures is one factor which has huge effects on the turbo's performance. The term turbo performance is usually associated with its tested map, and how far off, or exactly where on that map you are running. In more simple terms, you can run in different parts of the map and produce different amounts of air volume, same boost, same turbo. Usually the change has been in speed, sometimes affected by any number of factors.
When buying a Turbo, your first question before any should be, "do you have the map for this, or have you had it tested, can you provide a map, or how do I know where on the map will I run. Can I buy some sort of measuring device for testing"
Without these questions been asked, all performance info should be questioned and taken at face value.
So, if no maps are available, what good would any device be? Simple, the 3 main factors on a map are, boost(written as a pressure ratio over atmo) and air mass. The third is impellor speed. Measuring air mass is usually out of the question, but the speed can be measured. So now we have 2 points on the map that we can determine where we are. But we have no map to read. Ok, when we run very high levels of boost at WOT, or high boost levels on overrun, 2 turbo terms come into play. 1 is the choke point or choke line, and the other is the surge point or line. Both have damaging effects on turbochargers. Typically when either 2 factors happen, sudden rises in speed occur. In the case of choke, impellor speed, MAP and EXP can be seen to be effected.
So when these guy's tell you their Turbo's are the best, the boost they run and mention something about a turbo map, question them. Its all very simple, but usually clouded in mystery with a pinch of BS. If they cannot supply a map, ask them for a dyno print out of impellor speed with MAP and EXP shown. If any of these is not avialable, you are buying blind. If they sell you something without having any of these parameters recorded, then they probably have mismatched the turbo for the application. If they got it right, then well done. I know some very clever engine experts who still need to measure to apply and understand.
All of the references here have been about a Compressor map. It all starts over with the Turbine Housing, Turbine Impellor trim and much more.
06-08-2003, 11:18 PM
#2
Nordschleife Master
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by m42racer:
<strong> mentioned their turbo was close to "max ing" out. Not sure what that means. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">out of it's efficiency range. i.e. creating more heat than n/e thing.
<a href="http://www.majesticturbo.com/compression.html" target="_blank">http://www.majesticturbo.com/compression.html</a>
I think you are confusing the 'performance' of a turbo (as you put it) with the flow characteristics of a compressor wheel.
<strong> mentioned their turbo was close to "max ing" out. Not sure what that means. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">out of it's efficiency range. i.e. creating more heat than n/e thing.
<a href="http://www.majesticturbo.com/compression.html" target="_blank">http://www.majesticturbo.com/compression.html</a>
I think you are confusing the 'performance' of a turbo (as you put it) with the flow characteristics of a compressor wheel.
06-08-2003, 11:29 PM
#3
Rennlist Member
When I purchased my turbo I didn't get any info on the maps. I still don't know what I have. And it is a little irritating in that I would like to make a change but I don't know what street corner I'm on at the moment 
When I mentioned that I would like to move from 375 to 400 rwhp the vendor stated that all I needed was a port job, intake, headers and exhaust. And 'a lottery ticket in a pear tree' <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" />
My next purchase will be much better informed.
Alan C.
When I mentioned that I would like to move from 375 to 400 rwhp the vendor stated that all I needed was a port job, intake, headers and exhaust. And 'a lottery ticket in a pear tree' <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" />
My next purchase will be much better informed.
Alan C.
06-08-2003, 11:34 PM
#4
Nordschleife Master
I wasn't told what I bought either.
actually I ordered something completely different.
I measured my inducer/exducer and tip heighth with a pair of caliper's and I was told it's a 60-1 hifi.
<img src="http://members.rennlist.com/luke/m3.JPG" alt=" - " />
actually I ordered something completely different.
I measured my inducer/exducer and tip heighth with a pair of caliper's and I was told it's a 60-1 hifi.
<img src="http://members.rennlist.com/luke/m3.JPG" alt=" - " />
06-09-2003, 12:19 AM
#5
Just to let anyone who may be interested, the maps shown on the webb site site linked here are very old. I know this info was released as we no longer consider these combinations as applications we would use. If anyone is using these as reference, should do so with an understanding of their age. From memory, most of what I saw there was from the early 80's.
06-09-2003, 05:31 PM
#6
Nordschleife Master
most compressor wheels's are very old designs <img border="0" title="" alt="[Wink]" src="wink.gif" />
Those maps also match up w/ the maps in my 03' turbonetics catologue that I picked up at the PRI show.
if you'd like a copy, i'd be happy to scan them for you buddy.
In all my numberous phone convo's with employees of both turbonetics , majestic and EVEN the president of RC engineering... those maps are still accurate <img border="0" title="" alt="[Wink]" src="wink.gif" />
just incase you were worried though... this was on that page from the early 80's.
..." Majestic TurboChargers, Inc.
Copyright 1999-2002
Please do not use photos
without permission.
Updated 05/09/2003 "
corky Bell's 'MAXIMUM BOOST' is old.
'ENGINEERED to WIN' is old. ( real old )
the bible is old....
how old are you?
Those maps also match up w/ the maps in my 03' turbonetics catologue that I picked up at the PRI show.
if you'd like a copy, i'd be happy to scan them for you buddy.
In all my numberous phone convo's with employees of both turbonetics , majestic and EVEN the president of RC engineering... those maps are still accurate <img border="0" title="" alt="[Wink]" src="wink.gif" />
just incase you were worried though... this was on that page from the early 80's.
..." Majestic TurboChargers, Inc.
Copyright 1999-2002
Please do not use photos
without permission.
Updated 05/09/2003 "
corky Bell's 'MAXIMUM BOOST' is old.
'ENGINEERED to WIN' is old. ( real old )
the bible is old....
how old are you?
06-09-2003, 05:39 PM
#7
Rennlist Member
You know I have no idea how my turbo is built either. I just know it was the first of it's kind and it's a custom K29. The low, mid and top end pull coupled with the crazy dyno results I didn't care. Then David at Powerhaus had one made for his car. Do wish I was more mechanically inclined though. Can't begin to imagine how much dough I'd save if I could work on it myself.
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06-09-2003, 09:35 PM
#8
Luke,
Thanks or the offer, that nice of you.
I am an applications engineer for a major US Turbo manufacturer, and my responsibilities are to advise and help my customers matching etc Turbo's and components. most of my customers are inthe Diesel area, but the same rules apply.
Thanks anyway.
Any help you need, ask. Unfortunely, I cannot release any maps, as this information is only released when we are contracted to manufacturers.
Thanks or the offer, that nice of you.
I am an applications engineer for a major US Turbo manufacturer, and my responsibilities are to advise and help my customers matching etc Turbo's and components. most of my customers are inthe Diesel area, but the same rules apply.
Thanks anyway.
Any help you need, ask. Unfortunely, I cannot release any maps, as this information is only released when we are contracted to manufacturers.
06-09-2003, 11:27 PM
#10
Not sure what you mean. I would need the part#'s of the wheels etc, and or the part # of the complete assy. I know of no change, unless some component was changed. There are hundreds of comp wheel config's, and housings etc., and turbine wheels as well. The problem that we are often faced with, is the use or misuse of components and complete assy's. Just about every Turbo provider has come up with their own combinations. This has created large # of assy's that are not original part# etc. The aftermarket has asked for many years for assy's and info, but due to the politics of manufacturer's etc, we have not provided the aftermarket with applications. Its been left to businesses to provide solutions, which in most cases have been very poorly matched. alot of the time certain parts are not released to these people, as these parts are propriety to manufacturer's. As I stated earlier, most of these suppliers provide a very old map "close" to what they think they are sellng. Usually, they are nowhere close. Its easy to work in this black area, who can prove them wrong. The only Turbo aftermarket business that could supply parts that were tested in a dyno cell was Rotormaster, but they were absorbed by Garrett many years ago. Good luck with your matching and be careful who you buy from. Even the most well known supplier, works in the grey/close area. My advice to you whenever possible, is to buy assy's with a complete part #. This way you are not buying someones idea of what might work. The new BB Turbo's made in Japan under license are a very good option.
06-09-2003, 11:31 PM
#11
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m42racer,
Do you mean this kind of maps.
<img src="http://www.lindseyracing.com/pics/944stg5compmap.jpg" alt=" - " />
So now I have a map of my turbo (Kokeln), but how do I read it and how do I know if this turbo is more or less efficient/effective than other turbos ?
Do you mean this kind of maps.
<img src="http://www.lindseyracing.com/pics/944stg5compmap.jpg" alt=" - " />
So now I have a map of my turbo (Kokeln), but how do I read it and how do I know if this turbo is more or less efficient/effective than other turbos ?
06-10-2003, 12:11 AM
#12
M42racer,
What would you suggest for a good 325rwhp turbo for the 951?
Using standard Garrett turbo.
And also what would be the perfect compromise between fast spoolup and good top end efficiency when looking at a turbine for the 951? Like a/r and wheel size.
I hope you will educate us with some of your turbo knowledge.
What would you suggest for a good 325rwhp turbo for the 951?
Using standard Garrett turbo.
And also what would be the perfect compromise between fast spoolup and good top end efficiency when looking at a turbine for the 951? Like a/r and wheel size.
I hope you will educate us with some of your turbo knowledge.
06-10-2003, 04:43 AM
#13
Addict
Rennlist Member
Rennlist Member
So I'm a little confused. Please explain as I am not trying to "take you to task" for being arrogant, but if someone with professional experience posts this stuff here, I try to understand their reasoning or at least asses it's value.
1. Why would you open up a thread asking for answers to questions like "where are the maps" when you sound fully qualified - even over qualified with your credentials - to obtain maps the even WE cannot access. Is this to make us aware of the fact that we buy "stage x" turbochargers from tuners without asking questions?
If so, I suppose it is a valid point. But if one were to ask for a map, shouldn't they first need to know something about how to interpret it. Not everyone who wants more performance WANTS or NEEDS to understand pressure ratios and A/R's to know that their turbine is correct for their application nor do they NEED a compressor map to plot where it's efficiency is. That is what they trust their tuner to have addressed in packaging a turbocharger upgrade.
As I understand it, they (tuners) don't nec. give info. out on wheel specifications and the like because it took their time and research to engineer and test compressor wheels/housing and turbine wheel /housing combinations that work best for said engine and that's where they make their $$ which is fair in my opinion. It seems that most participating tuners here including SFR, Guru, Kokeln and Lindsey are willing to release that information to certain inquisitive customers who WANT to understand why these factors help the turbo they bought from them to perform better and who will in return promise not use this information to compete or help others to compete against them. In Luke's case, he reverse engineered his turbo to find out what he had, I had to do the same for mine, but not for the same reason as he. Is this what you are trying help us avoid?
2. Why would how old a compressor map is have anything to do with choosing a compressor wheel? Is that point raised to bring us to the awareness that newer compressor wheel designs will better accomplish what we are after?
1. Why would you open up a thread asking for answers to questions like "where are the maps" when you sound fully qualified - even over qualified with your credentials - to obtain maps the even WE cannot access. Is this to make us aware of the fact that we buy "stage x" turbochargers from tuners without asking questions?
If so, I suppose it is a valid point. But if one were to ask for a map, shouldn't they first need to know something about how to interpret it. Not everyone who wants more performance WANTS or NEEDS to understand pressure ratios and A/R's to know that their turbine is correct for their application nor do they NEED a compressor map to plot where it's efficiency is. That is what they trust their tuner to have addressed in packaging a turbocharger upgrade.
As I understand it, they (tuners) don't nec. give info. out on wheel specifications and the like because it took their time and research to engineer and test compressor wheels/housing and turbine wheel /housing combinations that work best for said engine and that's where they make their $$ which is fair in my opinion. It seems that most participating tuners here including SFR, Guru, Kokeln and Lindsey are willing to release that information to certain inquisitive customers who WANT to understand why these factors help the turbo they bought from them to perform better and who will in return promise not use this information to compete or help others to compete against them. In Luke's case, he reverse engineered his turbo to find out what he had, I had to do the same for mine, but not for the same reason as he. Is this what you are trying help us avoid?
2. Why would how old a compressor map is have anything to do with choosing a compressor wheel? Is that point raised to bring us to the awareness that newer compressor wheel designs will better accomplish what we are after?
06-10-2003, 05:03 PM
#14
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">So I'm a little confused. Please explain as I am not trying to "take you to task" for being arrogant, but if someone with professional experience posts this stuff here, I try to understand their reasoning or at least asses it's value. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Ditto.