WW on a stock truck
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From: NW Arkansas
Here is an easy question.
Does the E99 wheel flow the same amount of air as the L99 wheel?
Are you reducing surge with the E99 b/c you are moving less air? or are you moving air more effieciently?
With the larger exhaust housing I think the L99 would be a better choice..ASSUMING that the E99 flows less air.
Set me straight guys!
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From: Fulltime RVer
Can anyone identify the compressor wheel in this picture? It's an E99=WW compressor wheel, and please note that this wheel has some full height blades which have a full "Inducer" diameter and that some of the blades are reduced height and have a reduced "Inducer" diameter. The parameters in this picture are used in my discussion below and in one of the quotes I give below.
The Inducer acts kind of like a conventional fan blade and it pulls air molecules into the turbo inlet. The Exducer acts kind of like a centrifuge and it slings the air molecules into the compressor housing. This slinging action increases the average kinetic ENERGY of the air molecules.
Air pressure is proportional to the average kinetic ENERGY of the air molecules divided by the volume that the air molecules are forced to occupy. This volume varies as the air is forced through the convoluted geometry of the compressor housing, but the final volumes that count for producing engine HP are the intake manifold and cylinder volumes.
To generate a given BP in the intake manifold requires an even higher pressure in the smaller volume of the compressor housing where the air first enters the compressor housing from the compressor wheel, and this is where compressor wheel stall occurs which in turn causes turbo surge.
The classic chuffa, chuffa, chirp, chirp, and chugga, chugga noises are due to turbo surge and are caused by repeating compressor stalls which allow a momentary back flow of boost air which is then followed by a rapid recompression because the throttle is still being applied so that the turbine still has drive pressure. As indicated in my surge graph discussion the only way to minimize this type of surge (yes there are other types of surge as well) is to let off the throttle some when you hear it and downshift to a lower gear.
I've done some analysis which indicates that compressor wheel stall can occur due to an excessive angle of attack on the Inducer portion of the blades and also possibly due to the tips of the Inducer portion of the blades going trans-sonic which causes turbulence and flow separation. The different blade characteristics of the E99 wheel compared to the L99.5 wheel help to circumvent both of these effects which is why the E99 wheel has much better surge control than a L99.5 wheel and this general effect is true independent of using a stock compressor housing or the ATS version.
The above is my "plain and simple" explanation for why the E99 wheel is the best choice for surge control no matter what compressor housing you use. Some day I'll start a general interest turbo thread which includes a summary of my analysis and anyone else can join in and give their viewpoints on turbos. In closing I'll give some direct "quotes" from various sources, and since people keep posting that this or that turbo doesn't EVER surge I'll start with a quote from Dennis of ITP fame...
"There have been people that had problems with surge with the BB turbo. It depends on how hot your programming (chip) is, how much load you're pulling, and altitude seems to be a factor for those with surge issues and the BB turbo.
Keep in mind that EVERY turbo can experience surge/stall, even those with aftermarket compressor wheels and housings. The aftermarket devices serve to move the point of surge/stall to an operating condition where you won't theoretically get your truck...(rpm too low or boost too high, etc.)...but it can still surge. Dennis Schroeder Owner - ITP Diesel, L.L.C"
"Two key parts of a compressor are the inducer and the exducer. The inducer is the part of the wheel that first takes a "bite" of ambient air. The exducer is the part of the wheel that "shoots" the air (now compressed) out of the turbo."
"Surge is a fluttering sound, several times per second, when the compressor "spits out" more air than the engine can swallow, which causes a backup of air at the intake and it actually creates reverse-flowing pressure waves that can be very damaging to the turbo. You want to avoid surge at all costs. The compressor stalls and surges in and out of stall until external changes are imposed."
"There is a common myth in the automotive world about so called "wastegate chatter", the sound is commonly described as a chipmunk or a rattlesnake. The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo."
The Inducer acts kind of like a conventional fan blade and it pulls air molecules into the turbo inlet. The Exducer acts kind of like a centrifuge and it slings the air molecules into the compressor housing. This slinging action increases the average kinetic ENERGY of the air molecules.
Air pressure is proportional to the average kinetic ENERGY of the air molecules divided by the volume that the air molecules are forced to occupy. This volume varies as the air is forced through the convoluted geometry of the compressor housing, but the final volumes that count for producing engine HP are the intake manifold and cylinder volumes.
To generate a given BP in the intake manifold requires an even higher pressure in the smaller volume of the compressor housing where the air first enters the compressor housing from the compressor wheel, and this is where compressor wheel stall occurs which in turn causes turbo surge.
The classic chuffa, chuffa, chirp, chirp, and chugga, chugga noises are due to turbo surge and are caused by repeating compressor stalls which allow a momentary back flow of boost air which is then followed by a rapid recompression because the throttle is still being applied so that the turbine still has drive pressure. As indicated in my surge graph discussion the only way to minimize this type of surge (yes there are other types of surge as well) is to let off the throttle some when you hear it and downshift to a lower gear.
I've done some analysis which indicates that compressor wheel stall can occur due to an excessive angle of attack on the Inducer portion of the blades and also possibly due to the tips of the Inducer portion of the blades going trans-sonic which causes turbulence and flow separation. The different blade characteristics of the E99 wheel compared to the L99.5 wheel help to circumvent both of these effects which is why the E99 wheel has much better surge control than a L99.5 wheel and this general effect is true independent of using a stock compressor housing or the ATS version.
The above is my "plain and simple" explanation for why the E99 wheel is the best choice for surge control no matter what compressor housing you use. Some day I'll start a general interest turbo thread which includes a summary of my analysis and anyone else can join in and give their viewpoints on turbos. In closing I'll give some direct "quotes" from various sources, and since people keep posting that this or that turbo doesn't EVER surge I'll start with a quote from Dennis of ITP fame...
"There have been people that had problems with surge with the BB turbo. It depends on how hot your programming (chip) is, how much load you're pulling, and altitude seems to be a factor for those with surge issues and the BB turbo.
Keep in mind that EVERY turbo can experience surge/stall, even those with aftermarket compressor wheels and housings. The aftermarket devices serve to move the point of surge/stall to an operating condition where you won't theoretically get your truck...(rpm too low or boost too high, etc.)...but it can still surge. Dennis Schroeder Owner - ITP Diesel, L.L.C"
"Two key parts of a compressor are the inducer and the exducer. The inducer is the part of the wheel that first takes a "bite" of ambient air. The exducer is the part of the wheel that "shoots" the air (now compressed) out of the turbo."
"Surge is a fluttering sound, several times per second, when the compressor "spits out" more air than the engine can swallow, which causes a backup of air at the intake and it actually creates reverse-flowing pressure waves that can be very damaging to the turbo. You want to avoid surge at all costs. The compressor stalls and surges in and out of stall until external changes are imposed."
"There is a common myth in the automotive world about so called "wastegate chatter", the sound is commonly described as a chipmunk or a rattlesnake. The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo."
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Posting Guru
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From: NW Arkansas
Can anyone identify the compressor wheel in this picture? It's an E99=WW compressor wheel, and please note that this wheel has some full height blades which have a full "Inducer" diameter and that some of the blades are reduced height and have a reduced "Inducer" diameter. The parameters in this picture are used in my discussion below and in one of the quotes I give below.
The Inducer acts kind of like a conventional fan blade and it pulls air molecules into the turbo inlet. The Exducer acts kind of like a centrifuge and it slings the air molecules into the compressor housing. This slinging action increases the average kinetic ENERGY of the air molecules.
Air pressure is proportional to the average kinetic ENERGY of the air molecules divided by the volume that the air molecules are forced to occupy. This volume varies as the air is forced through the convoluted geometry of the compressor housing, but the final volumes that count for producing engine HP are the intake manifold and cylinder volumes.
To generate a given BP in the intake manifold requires an even higher pressure in the smaller volume of the compressor housing where the air first enters the compressor housing from the compressor wheel, and this is where compressor wheel stall occurs which in turn causes turbo surge.
The classic chuffa, chuffa, chirp, chirp, and chugga, chugga noises are due to turbo surge and are caused by repeating compressor stalls which allow a momentary back flow of boost air which is then followed by a rapid recompression because the throttle is still being applied so that the turbine still has drive pressure. As indicated in my surge graph discussion the only way to minimize this type of surge (yes there are other types of surge as well) is to let off the throttle some when you hear it and downshift to a lower gear.
I've done some analysis which indicates that compressor wheel stall can occur due to an excessive angle of attack on the Inducer portion of the blades and also possibly due to the tips of the Inducer portion of the blades going trans-sonic which causes turbulence and flow separation. The different blade characteristics of the E99 wheel compared to the L99.5 wheel help to circumvent both of these effects which is why the E99 wheel has much better surge control than a L99.5 wheel and this general effect is true independent of using a stock compressor housing or the ATS version.
The above is my "plain and simple" explanation for why the E99 wheel is the best choice for surge control no matter what compressor housing you use. Some day I'll start a general interest turbo thread which includes a summary of my analysis and anyone else can join in and give their viewpoints on turbos. In closing I'll give some direct "quotes" from various sources, and since people keep posting that this or that turbo doesn't EVER surge I'll start with a quote from Dennis of ITP fame...
"There have been people that had problems with surge with the BB turbo. It depends on how hot your programming (chip) is, how much load you're pulling, and altitude seems to be a factor for those with surge issues and the BB turbo.
Keep in mind that EVERY turbo can experience surge/stall, even those with aftermarket compressor wheels and housings. The aftermarket devices serve to move the point of surge/stall to an operating condition where you won't theoretically get your truck...(rpm too low or boost too high, etc.)...but it can still surge. Dennis Schroeder Owner - ITP Diesel, L.L.C"
"Two key parts of a compressor are the inducer and the exducer. The inducer is the part of the wheel that first takes a "bite" of ambient air. The exducer is the part of the wheel that "shoots" the air (now compressed) out of the turbo."
"Surge is a fluttering sound, several times per second, when the compressor "spits out" more air than the engine can swallow, which causes a backup of air at the intake and it actually creates reverse-flowing pressure waves that can be very damaging to the turbo. You want to avoid surge at all costs. The compressor stalls and surges in and out of stall until external changes are imposed."
"There is a common myth in the automotive world about so called "wastegate chatter", the sound is commonly described as a chipmunk or a rattlesnake. The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo."
The Inducer acts kind of like a conventional fan blade and it pulls air molecules into the turbo inlet. The Exducer acts kind of like a centrifuge and it slings the air molecules into the compressor housing. This slinging action increases the average kinetic ENERGY of the air molecules.
Air pressure is proportional to the average kinetic ENERGY of the air molecules divided by the volume that the air molecules are forced to occupy. This volume varies as the air is forced through the convoluted geometry of the compressor housing, but the final volumes that count for producing engine HP are the intake manifold and cylinder volumes.
To generate a given BP in the intake manifold requires an even higher pressure in the smaller volume of the compressor housing where the air first enters the compressor housing from the compressor wheel, and this is where compressor wheel stall occurs which in turn causes turbo surge.
The classic chuffa, chuffa, chirp, chirp, and chugga, chugga noises are due to turbo surge and are caused by repeating compressor stalls which allow a momentary back flow of boost air which is then followed by a rapid recompression because the throttle is still being applied so that the turbine still has drive pressure. As indicated in my surge graph discussion the only way to minimize this type of surge (yes there are other types of surge as well) is to let off the throttle some when you hear it and downshift to a lower gear.
I've done some analysis which indicates that compressor wheel stall can occur due to an excessive angle of attack on the Inducer portion of the blades and also possibly due to the tips of the Inducer portion of the blades going trans-sonic which causes turbulence and flow separation. The different blade characteristics of the E99 wheel compared to the L99.5 wheel help to circumvent both of these effects which is why the E99 wheel has much better surge control than a L99.5 wheel and this general effect is true independent of using a stock compressor housing or the ATS version.
The above is my "plain and simple" explanation for why the E99 wheel is the best choice for surge control no matter what compressor housing you use. Some day I'll start a general interest turbo thread which includes a summary of my analysis and anyone else can join in and give their viewpoints on turbos. In closing I'll give some direct "quotes" from various sources, and since people keep posting that this or that turbo doesn't EVER surge I'll start with a quote from Dennis of ITP fame...
"There have been people that had problems with surge with the BB turbo. It depends on how hot your programming (chip) is, how much load you're pulling, and altitude seems to be a factor for those with surge issues and the BB turbo.
Keep in mind that EVERY turbo can experience surge/stall, even those with aftermarket compressor wheels and housings. The aftermarket devices serve to move the point of surge/stall to an operating condition where you won't theoretically get your truck...(rpm too low or boost too high, etc.)...but it can still surge. Dennis Schroeder Owner - ITP Diesel, L.L.C"
"Two key parts of a compressor are the inducer and the exducer. The inducer is the part of the wheel that first takes a "bite" of ambient air. The exducer is the part of the wheel that "shoots" the air (now compressed) out of the turbo."
"Surge is a fluttering sound, several times per second, when the compressor "spits out" more air than the engine can swallow, which causes a backup of air at the intake and it actually creates reverse-flowing pressure waves that can be very damaging to the turbo. You want to avoid surge at all costs. The compressor stalls and surges in and out of stall until external changes are imposed."
"There is a common myth in the automotive world about so called "wastegate chatter", the sound is commonly described as a chipmunk or a rattlesnake. The noise is in fact the air compressed by the turbo passing back through the compressor housing of the turbo."
OK.. I understand all of what your saying. but the question remains...
Are you reducing surge with the E99 b/c you are moving less air? or are you moving air more effieciently?
..... I doubt that with ATS exhaust and compressor housings on a stock wheel with a DP Tuner that I will be battling surge when towing 22-28k gross.
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From: Fulltime RVer
...at 2,800 RPM where you get max HP surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP with the E99 wheel than you'll get with the L99.5 wheel!...
Here's how a compressor map is measured. There's a bench test in which the compressor wheel is spun with an external motor at a fixed rpm and data is first taken with the turbo outlet wide open. This determines the maximum air flow and a single data point on the "choke line" for the given wheel rpm.
Then the turbo outlet is gradually closed off to reduce the air flow while the wheel rpm is held constant. Eventually the compressor stalls and this determines a single data point on the "surge line" for the given wheel rpm. This test is then repeated for a number of fixed wheel rpms and the outlet-to-inlet pressure ratio is measured for each and is plotted versus inlet MAF lb/min for each constant wheel rpm speed line, and that's how a compressor map is generated.
Here's what I did get from ATS...
"The ATS 4 inch Ported Shroud Compressor Housing has been designed to increase your turbos life expectancy by eliminating compressor surge. If you have ever towed with a 1999.5 or newer Powerstroke, you've undoubtedly experienced compressor surge and flutter (which occurs between 1800-2200 RPM). When performance products are added to increase horsepower, the compressor wheel accelerates faster and compressor surge and flutter becomes more apparent and damaging to your turbo. An opening wastegate, a bad torque converter, or a loose cover plate are a few of the excuses in which people mistake for the compressor surge noise. Say goodbye to the mysterious noises with the ATS Ported Shroud. The ATS Ported Shroud Compressor Housing is designed with A 4” intake and exclusive inducer bleed ring. Utilizing A 4” intake results in a 13% increase in choke flow, allowing more air to flow into the compressor Wheel. Inducer bleed acts to broaden the range of the compressor wheel, smooth out air flow, and eliminate turbo compressor surge."
Except for the 4" diameter the only other "number" they provide is... "results in a 13% increase in choke flow" but as I discuss below this is irrelevant when it comes to towing!
The ATS statement... "13% increase in choke flow" ...pertains to the part of the compressor map bench test where ..."the turbo outlet is wide open"...and since the "choke line" is on the opposite side of the compressor map from the "surge line" this statement is totally irrelevant for the conditions of towing up a hill! I'm assuming here that you've read the link I gave to a compressor map?
Here's what I got from Garrett in addition to their compressor maps...
"A Ported Shroud compressor is a feature that is incorporated into the compressor housing. It functions to move the surge line further to the left by allowing some airflow to exit the wheel through the port to keep surge from occurring. This provides additional useable range and allows a larger compressor to be used for higher flow requirements without risking running the compressor into a dangerous surge condition. The presence of the ported shroud usually has a minor negative impact on compressor efficiency."
As correctly stated by Garrett ..."It functions to move the surge line further to the left" and if the ATS does this as well it can also provide some additional air flow near the surge line compared to a stock compressor housing. But it would sure be nice if ATS provided a compressor map to guarantee this improvement instead of their meaningless statement about improved choke flow!
Based on my analysis (and I've done a lot of it) my conclusions are...
1) Everything else being equal all types of "Ported Shroud" compressor housings should provide some additional air flow near the surge line compared to a stock compressor housing.
2) As demonstrated by its superior surge control in stock compressor housings the E99 wheel combats surge by different mechanisms than are operative in "Ported Shroud" compressor housings.
3) Using a E99 vs a L99.5 wheel in a "Ported Shroud" compressor housings will provide at least as much and possibly more MAF when you operate near the surge line with the engine RPM in the vicinity for maximum HP.
Why are you so sure that your choice of a DP+ATS+L99.5 wheel will NEVER surge? Maybe it will and maybe it won't, but using a E99 wheel can only help and not hurt! Did you read this quote?
"There have been people that had problems with surge with the BB turbo. It depends on how hot your programming (chip) is, how much load you're pulling, and altitude seems to be a factor for those with surge issues and the BB turbo.
Keep in mind that EVERY turbo can experience surge/stall, even those with aftermarket compressor wheels and housings. The aftermarket devices serve to move the point of surge/stall to an operating condition where you won't theoretically get your truck...(rpm too low or boost too high, etc.)...but it can still surge. Dennis Schroeder Owner - ITP Diesel, L.L.C"
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Joined: Feb 2007
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From: Dallas-Ft. Worth
Something's wrong then. Everyone and I mean EVERYONE sees 1-3psi less boost with the WW than the late wheel. With the stock late wheel and ATS I'm getting 29-30psi with stock injectors on the van turbo with 1.15 A/R exh housing. I've NEVER seen those numbers with any other turbo configuration. I have seen close to 28, but that was before I went to the WW. Once I did, I would get 26-27, and that was it. I don't know what the issue is, but once again, the real world is conflicting with your analysis, Gene. Unless the lb/min measurement is it... Maybe the late wheel peaks higher, but the WW maintains more in the middle?????
Man, it's just like old times, isn't it??
Man, it's just like old times, isn't it??
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From: Fulltime RVer
As I described in the bench test to measure the compressor map the turbine shaft is driven by an external motor. To measure a given point on the surge line you apply an external source of HP to drive the turbine shaft so as to maintain a constant compressor wheel rpm as you progressively restrict the turbo outlet to make the compressor work harder and harder to produce an ever increasing pressure ratio until the compressor wheel stalls.
I think the choice of exhaust housing is about trading off turbo lag versus maximum EGT and the choice of compressor wheel and the compressor housing determines the surge line on a compressor map, and that these are basically independent choices.
The choice of exhaust housing does determine how much or little throttle needs to be applied to generate a given drive HP to the turbine shaft, but the same turbine shaft drive HP will cause surge for the same BP and MAF no matter what exhaust housing you use.
Would you care to venture a guess/estimate as to how much turbine shaft drive HP is required to say generate a BP=28 psi? This isn't a trick question and I pondered it for awhile before I figured out how to derive an equation to calculate it.
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From: Fulltime RVer
Your above statements are 100% consistent with what I've posted several times on this thread and on other FTE threads for several years. For example in post #28 I on this thread I said...
The smaller reduced height blades of the E99 wheel have a lesser pitch angle and this means that the BP for a E99 wheel flattens out at higher RPM and it gives about the same BP=26 psi at 3,200 RPM as it does at 2,800 RPM.
In post #28 I also said...
...at 2,800 RPM where you get max HP surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP with the E99 wheel than you'll get with the L99.5 wheel!...
...As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!...
...As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!...
Remember that a boost gauge reads in psi not in HP. If you want a HP gauge you have to measure the parameters in this equation which is a simplified version that only applies to straight summer blend #2 diesel...
FWHP={(39.4)(VE)(ED)(RPM)(AAP+BP)(ER)(TE)}/(MAT+459.67) HP
VE=Volumetric Efficiency ratio 0 to 1
ED=Engine Displacement ft^3
RPM=Revolutions/min
AAP=Atmospheric Air Pressure psi
BP=Boost Pressure psi
ER=Equivalence Ratio 0 to 1
ER=AFRS/AFR
AFRS=Air Fuel Ratio Stoichiometric
AFR=Air Fuel Ratio
AFR=MAF/MFF
MAF=Mass Air Flow lb/min
MFF=Mass Fuel Flow lb/min
TE=Thermodynamic Efficiency ratio 0 to 1
MAT=Manifold Air Temperature F
On my CAT C7 I've got a VMS 240 CL made by SilverLeaf Electronics, Inc. VMS 240 CL | SilverLeaf Electronics, Inc. , and it plugs into the data link port to access data from the engine ECM and tranny ECM so I can measure every thing I need to calculate FWHP and here's an example calculation...
FWHP={(39.4)(.84)(0.25566 )(2,200)(14.7+28)(0.6)(0.37)}/(127+459.67)=300.8 HP
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