What, does it have some sort of mini-gearbox? How the F does it spin "faster"? The compressor side does not "spool" so to speak, you spool the turbine side up, and it just so happens the compressor is connected to it.

 

the WW,,,it moves less air.less resistent on the wheel..so it takes less exhaust and lower temps to spin the wheel..it need to spin faster to make up the diff (lack of air)to reach the same boost level as the stock wheel.....

 

like i said i am a plumber, you want to know how a chiller, boiler, works i can help when it comes to my truck little lost. that is why i ask you guys. sorry

 

you said it would help with turbo surge. not sure i know what you mean by that

 

1) In a stock 99.5 GTP38 turbo at the 2,800 RPM for maximum HP a WW=E99 wheel produces a 2 psi higher "surge free" BP (26 vs 24 psi) and flows more MAF than a L99.5 wheel does. For towing grades at 2,800 RPM and below the WW=E99 wheel is by far the best choice!

2) At a 3,200 RPM a L99.5 wheel produces a 2 psi higher BP (28 vs 26 psi) compared to a WW=E99 wheel, but this is somewhat meaningless because this RPM is on the back side of the HP vs RPM curve!

3) For those with an ATS housing who claim that a L99.5 wheel is a better choice than a WW=E99 wheel I'd like to know just what those claims are based on? Have you ever seen a compressor map for an ATS housing with either a L99.5 wheel or a WW=E99 wheel installed? A GTP38R uses a ported compressor housing that's similar to the one ATS uses and the GTP38R uses a compressor wheel that's very similar to the WW=E99 wheel and I think that's a good enough reason to prefer a WW=E99 wheel over a L99.5 wheel in an ATS housing!

4) I've posted many times on this issue but my latest post # 27 here... https://www.ford-trucks.com/forums/8...ml#post7228722 ...is a good place to start and note that the "Banks surge line" is the one for a WW=E99 wheel in a stock turbo. For even more details see my posts starting with post #28 here... https://www.ford-trucks.com/forums/8...k-truck-2.html .

 

so it would be a help to me when towing

 

yes because the surge has been moved out of reach with the WW in place...

 

Well...I think Im clear now,after aquiring all this knowledge I think Ill keep my WW in with my ATS housing....

 

so how hard is this to change? my turbo will be off the truck figured it would be a good time.

 

If you tow a load up a grade with a stock turbo and you've added a HP chip and you push the throttle too hard while in too high of a gear you'll hear strange noises like... chuffa, chuffa, chirp, chirp, and chugga, chugga which are due to turbo surge and these noises 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.

Unless you install a WW=E99 wheel the only way to minimize this type of surge is to let off the throttle some when you hear it and downshift to a lower gear. The problem is that you can get some mild surge without hearing these noises and over time this mild surge does damage to your turbo bearing!

The Inducer portion of a compressor wheel acts kind of like a conventional fan blade and it pulls air molecules into the turbo inlet. The Exducer portion 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 BP and 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 blades and this is where compressor wheel stall occurs which in turn causes turbo surge.

A WW=E99 wheel counters this surge by employing 2 different types of blades so that when one type stalls the other type doesn't and those blade types continue to produce boost pressure. The L99.5 wheel only has one type of blade and when those blades stall you get a sudden onset of severe surge!

A compressor map is measured using 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 compressor 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.