Forced induction on a 2.5 Liter 4 cylinder.

Doug Gubbins doug at apogeesys.com
Wed Jun 5 21:40:39 GMT 1996


>>
>4. Super charger - Instant throttle response, Complicated due
>   to the mechanical installation to drive it. If installed with
>   a bypass it could have very smooth transition characteristics
>   from low to high power levels.
>
>I'm still on the vocabulary growth curve so if I'm using the wrong terms 
>please let me know.
>

David,

I don't know if this info will be helpful or relevant to you, but I did want
to make you aware that there are other types of superchargers than the
Rootes blower design that may have characteristics more in keeping with your
objective.

I'm not an engineer, and I drive a Miata. I supercharged it last August with
a Whipple  Autorotor Lysholm compressor. The engine is a MAP multiport EFI,
and the pulley that came with the SC gives me up to 8 psi of boost. My 1.6L
engine is 117 bhp stock. Haven't done any testing, but I'm quite sure I have
50+ more horses. If you don't want that much horsepower, you can install a
bigger pulley, or just don't mash the accelerator as hard. The response is
instantaneous, and very smooth; you can drive it normally with no boost, or
more aggressively with any amount of boost, and the boost comes in at very
low rpms. 

The system has no bypass at all other than the idle air bypass whose inlet
was relocated during installation. As for being complicated, I installed it
myself over a weekend. The "kit" was from Bell Engineering Group, Inc (BEGI)
of San Antonio,  TX, and it came with intercooler, custom tubing, assorted
castings for remounting and relocating throttle body and airflow meter, a
boost-controlled fuel pressure regulator, a piggy-back high pressure fuel
pump, and an MSD ignition retarder which I have since replaced with a J&S
knock sensor so I can run whatever octane and timing settings I want. Price
of the kit was about $2500 at the time, and depending on your enginuity
(sp?) in making things fit together, you could probably obtain the same
components and put it together for considerably less. 

This is Miata-specific, but BEGI's web site has some interesting info about
their induction kits.
The address is http://www.tristero.com/sa/business/bell/index.html.


Doug Gubbins
Apogee Systems, L&H Technologies
Charlotte NC

"There's always another bug..."




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