AMS Billet K16's go 133.3mph at the strip
#48
10-26-2009 | 10:22 PM
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Umm, why are we talking "boost" at all? Shorthand? It's airflow that matters, boost is a measure of restriction in the intake is how I see it. Run a less restrictive intake and if shaft speed isn't increased boost goes DOWN. We don't see this on turbos because we have W/G that compensate. You DO see it on shaft driven superchargers. It does make a difference though since the added speed to maintain the set boost will move the efficiency around. Make sense? I could give a real world example but I doubt anyone wants to hear about belt driven blowers on Mustangs ;-) Airflow is power, not "boost".
IMO what's important is how much air it moves, how quickly it begins moving that air, how much exhaust restriction it presents, and how efficient it is over the power band of the motor. Since we're all talking pretty much the same motors here displacement is the same but intercoolers, exhaust, and even intake piping can make big differences too. Frank, Martin, and Earl are spot on... Since these turbos use the same housings with modified guts then the name doesn't sound so bad - gotta' call them something and knowing you don't have to redo a ton of stuff to bolt them on is nice :-)
IMO what's important is how much air it moves, how quickly it begins moving that air, how much exhaust restriction it presents, and how efficient it is over the power band of the motor. Since we're all talking pretty much the same motors here displacement is the same but intercoolers, exhaust, and even intake piping can make big differences too. Frank, Martin, and Earl are spot on... Since these turbos use the same housings with modified guts then the name doesn't sound so bad - gotta' call them something and knowing you don't have to redo a ton of stuff to bolt them on is nice :-)
#49
10-26-2009 | 10:30 PM
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Mike
[edit] Martin, I just read your post. Kinda jumped the gun there. This sounds very impressive.
Last edited by Zippy; 10-26-2009 at 10:37 PM.
#51
10-27-2009 | 07:02 AM
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^To add, the billet wheels have extended tip technology, longer blades for a given diameter (the blades extend further into the hub of the compressor due to material strength and machining process) and they're presumably lighter than a standard 16g compressor wheel upgrade. All of this allows them to continue shining (maintaining efficiency) as the pressure ratio and mass flow goes up.
ttboost,
You're right its not a straight K16 but you could call it a K16/billet 46mm or something along those lines to keep in line with the K16/16g or K24/18g nomenclature.
ttboost,
You're right its not a straight K16 but you could call it a K16/billet 46mm or something along those lines to keep in line with the K16/16g or K24/18g nomenclature.
I'd like to see flow rates for all the K16's hybrids compared?
#52
10-27-2009 | 07:28 AM
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I'd be interested to know if these flow more than the latest 24/18g (44lbs/min).
#53
10-27-2009 | 11:00 AM
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Here's the problem with looking at just the flow rate of the compressor wheel. If we stuck a GT35R compressor wheel in there that flowed 65lbs/min would that mean the car would make 1400 hp? No! 1 lb/min of air is capable of supporting roughly 10.5 hp. Looking at the 24/18g that is rated at 44lbs/min (462 hp per comp wheel), how many are making 925 crank horsepower (780whp)? Everything has to be matched to take advantage of the available flow. The turbine size has to be matched to keep back pressure low and the rest of the engine combination also has to be matched. That's why just putting on huge turbo's doesn't always mean the car will make a ton of power or be amazingly fast. It's about the right combination of all the parts.
Like BLKMGK said, boost is just a restriction of airflow. Put the same size turbo on a more efficient engine or larger engine that can take in more airflow and you'll have to run a higher shaft speed to maintain boost. A GT35R can make 30psi of boost on a 2.0L 4 cylinder but it might struggle to make 15psi of boost on an efficient 4.0L V8. Since we're talking about the same engine on the 996 with similar bolt on mods I'm using the boost figures on K16 based turbos as a relative reference.
So in short while compressor wheel flow numbers may sound impressive, it's not always a great way to compare turbo to turbo unless you know all the variables. I'm working on getting some figures for the compressor wheel and I'll post up when I get them for reference.
-Martin Musial
Last edited by AMS; 10-27-2009 at 11:16 AM.
