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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,274
Hi Nathan,
The HFS has a smaller diameter hot side turbine wheel than the 7006 so it is forced to spin faster under a given volume of exhaust gasses blowing through it.
It also has a different shape and design compressor wheel that blows a whole bunch more air than the 7006, and the inlet to the compressor housing is .5" larger in diameter and then venturied down to the same diameter as the 7006.

The result is the 7006 and HFS come on about the same in my car which also has B&B headers, garretson long neck intercooler, 1 bar wastegate spring, IA auto fuel head, Brian Leask adjustable control pressure regulator, and powerhaus group B cams. And the HFS holds boost at sustained high rpms where the 7006 looses boost pressure or runs out of breath in that same situation.

The HFS can really take advantage of a larger intake manifold, larger ports, and longer duration cam, and make lots more top end horsepower than the 7006.
It is a really good turbo. Kevin did a great job making that one.

From my experience, the K27 7006 boost pressure would eventually drop at sustained increasing high rpms like when you are wide open accelerating in 3rd gear. In 1st gear it didn't seem to drop in boost like in 3rd, but 1st goes by so fast it would be hard to notice anyway. 2nd gear goes by quick too and i just don't remember if boost dropped much at high rpms, but i definately noticed it in 3rd while approaching 6800rpm. Never done that in 4th because, lol.. there's no where to do it safely in south florida with all the trafffic here.. that would be over 150mph and kinda crazy.
With the HFS the boost doesn't seem to ever drop in those situations, it just holds full boost all time and the engine sounds meaner while doing it and before you know it you are going scary fast.
...and we like that kind of excitement now, don't we.
i sure never get tired of the rush!

Jim
Old 07-15-2008, 02:17 PM
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