Supercharger info

[Greg Hermann]

>Dan Zorde wrote:
>
>> Thanks for the info so far.  The intent is to generate as much
>> boost as possible, which is why I'd like to know how much boost
>> it can put out before it self destructs (or the engine), so it
>> definitely won't be running slower.
>
>In theory you can get as much boost as you like by using different
>crank:SC drive ratios.
>
>The problem you will have is that the thermal efficiency drops *way*
>off as boost rises, pushing intake temps way up. That, plus the boost,
>will usually push an NA engine into serious detonation unless the CR
>is unusually low. An intercooler helps, water injection helps. (I have
>to agree with the poster who said go turbo for max power or max boost.
>A Roots SC is great for low end power though.)  Not to mention the SC
>will consume more and more crank HP as boost rises, and belt slip will
>become a problem.
>
>HKS, Blitz and Cusco make *crank* pulleys for the 4A-GZE, they replace
>the engine's crank pulley, not the SC pulley. (Yes, this spins the
>water pump faster as well.)
>
>Supposedly the 1991+ Japan-spec SC12 had a smaller pulley on the SC
>unit, also someone on the MR2 list looked into a custom job. Not too
>hard if you didn't mind losing the clutch.
>
>There is also an SC14, which is ~1420 cc displacement. Since you're
>looking at a total custom job, I'd get that instead. I didn't notice
>that you're in Oz before (sorry), you may be able to get the SC14
>off a 1G-GZE. (We don't get that engine in the States.) It's also
>a TRD bolt-on for the Previa engine.
>
>Word is that Eaton is the OEM for these units. Just a rumor I heard,
>but maybe worth looking into. Also Eaton supposedly has newer
>designs that are more efficient, and if you're already looking at a
>full custom job, why not use a better unit?
>
>   Chris C.
>
>Content-Type: application/ms-tnef
>
>Attachment converted: Bear's Den:RE- Supercharger info (????/----) (0000199E)
If you're going total custom, talk to Whipple industries in Fresno, CA.
They are the distributor for Opcon Autorotor screw compressors for
supercharger applications, and have several different sized available.
Also, they have performance curves which they will FAX you in order to get
a proper match--not as simple a thing as one might assume. Screw
compressors are FAR more efficient than Roots blowers, cuz part of the
compression happens internally to the compressor.
                                        Regards, Greg