High Boost 3800
Supercharger Pulley & Pulley Removal Tool
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(For Eaton M90 units as used in '96 and
later GM vehicles with L67 Series II 3800SC)**
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| The original! We're the
innovators that pioneered the process for removing and installing these supercharger
pulleys unharmed as soon as these cars came to market! Yep - we had the guts to take
on the challenge of removing this press fit pulley when others wouldn't dare! We
perfected the technique and publicly released the tool and pulley in January
1997 after extensive testing
to ensure ease of use and after determining the perfect size for the ideal
balance between low end torque and upper RPM horsepower, all while using 92 octane pump
gas*. Accept no imitations! We are the industry standard.
Thrasher Engineered
Performance - Innovative, Original, Functional, Proven - we get results!
* Pulley size is a balance between low RPM
torque and upper RPM horsepower. With decreasing blower pulley size, the blower
spins faster for a given engine speed. Dyno tests will show that increasing the
blower speed to engine speed ratio (i.e. using a smaller blower pulley) will effectively
shift the power band of the engine toward the lower RPM. Lower RPM torque will
increase but upper RPM horsepower will ultimately suffer due to the intense heat generated
by the relatively low adiabatic efficiency of the roots type blower. With these FWD
vehicles being traction limited (they'll light the tires at ease as you racers well know!)
the pulley must be correctly sized to balance the low speed torque and upper RPM
horsepower.
Photos shown below are of our original
prototype pulley! Yep - it's the one that started it all!
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| Left |
Stock |
7-8 psi (8 @ redline) |
| Right |
3.5" |
10-11+ psi (11+ @ redline) |
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| Here's another shot of the prototype on the right vs. a stock one on the left.
It may be hard to see the difference in diameter in these scanned images, but it
doesn't take much to increase boost! |
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| We have developed the specialized tools to exchange these pulleys on the vehicle! Use
of the proper removal tool places all stress solely between the pulley, the shaft and the
tool itself. No stress is placed on any seal or bearing. Experience has shown us
that most factory pulleys are easily removed without damage, while some fit more tightly
and may be bent during removal. This is obviously a blower with the pulley removed. A half
hour later, and... |
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| The new pulley is on! This photo shows a partially completed installation of an
early production unit from 1997. It's turned on a CNC lathe from a solid steel billet and
was gold
iridated for corrosion protection. (Current production pulleys are powder coated
black.) It was determined that increasing boost significantly beyond 11 psi on this
Eaton M90 blower was detrimental to performance without an intercooler. |
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| This is the completed installation. The original belt is reused - a shorter belt
is not necessary. We are in the process of having the tool quoted for volume
production, and we intend on offering a jobber package of the tool + pulleys to shops and
clubs so that this installation may be done locally. At this point the jobber
pricing structure has not been determined. |
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So how does it feel? Incredible! But don't take our
word for it, you must see for yourself! Throttle response is much improved even with
the stock factory torque convertor and final drive ratio. Torque increases are
evident at all RPM ranges and throttle positions - even light throttle applications are
noticeably quicker. Given max stock boost levels of approximately 8 psi at the shift
points, this pulley will give approximately a 40% increase
to 11+ psi. Of course, maximum boost levels will vary somewhat due to air density,
temperature and rpm. For dyno data, please see our dyno results
page.
(Included is an extremely detailed 12 page
installation manual)Note: Current
production pulleys are powder coated black.
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