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      10-17-2011, 03:17 PM   #21
pbonsalb
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Drives: 08 E90 M3, 99 E36 M3 Turbo
Join Date: Feb 2011
Location: Concord, NH

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Quote:
Originally Posted by img View Post
I think the part about the Vortec blower making less torque than
the HKS is pure myth, maybe even sales pitch by the guys selling
those blowers. I just downloaded a bunch of files from the Dyno
Database (www.bmwdynodatabase.com) and when you compare the same
boost and same octane, the Vortec has far more torque than the HKS
blowers. Down low where it really counts, the Vortec has as much
as 40ft/lbs more torque than either of those kits. The only way I
could get the graphs to show more torque on the HKS blowers than
the Vortec, was to compare against cars with 1.5-2.0 PSI less
boost.

It was hard to get an apples-apples comparison with the ASA blower
since there's only one entry in the DynoDB for this type of
blower. From what I saw, the ASA might have more torque than the
Vortec up to a point. But just like the HKS, the ASA blower dyno
chart showed it falling apart above 7000 RPMs. The power dropped
like a rock at that point.

I'll send links to the Dyno DB files I used in case anybody wants
to do their own analysis.
Yes, different boost levels may be required on different blowers for the same power and there is nothing wrong with that. In the turbo world, this is very common. You can run a very small and very responsive turbo and bring the boost in earlier and make more torque sooner, but choke out on the top end and not make as much peak power. Or you can run a massive turbo and need much less boost to make the same power, but the torque will arrive later even if it is ultimately more torque. I am not going to compare a GT30R at 12 psi to a GT35R at 12 psi -- I'll compare the GT30R at 16 psi to the GT35R at 12 psi. While a centrifugal supercharger is not motivated by exhaust gas energy like a turbo, it does have a centrifugal and an impeller and boost will take more or less time to arrive depending on the size of each.

ESS used to run the ASA blower (on the E46 M3 before the days of the E9X M3), but changed to the Vortech since it works pretty well over a broader power range and that helps with upgradeability of the kits. ESS made more midrange power with the compact and high speed ASA planetary gear drive blower than with the larger and slower Vortech fixed gear drive blower.
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