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[turbobike] turbo GS550E???

Dave Schumpert (porsche_boy@vt.edu)
Wed, 24 Feb 1999 02:24:40 +0500

Rick,
being that i'm still trying to get my 1983 Suzuki GS550E running, this is a
bit premature, but i was wondering if anyone has ever turbocharged a GS550
of any sorts?  i've heard from my friend that they are really reliable
stock, but i've had my 3rd gear (6th driven) loose it's dawgs, and the same
happened to another friend of mine.  the reason i ask is that i've built
several   turbo CBR600F2's in the past for our Formula SAE team that were
fuel injected and turbocharged, intercooler and yes, RESTRICTED! due to
those damned FSAE rules.  oh well, we were still i believe to be one of the
three fastest cars at competition last year even though i ran my program
from 1997 due to several dyno grenades and a lack of testing.  we managed to
make around 95hp corrected w/ about 7psi, no intercooler, and the stock
astronomical compression ratio of 11.6 to one.  one school last year made
92hp to the rear wheels.  i believe it was UW madison with a turbocharged,
and I'm betting intercooled F3, i think.  that's 102.2 if you use the 10%
formula for finding crankshaft or more typically engine hp after adding the
10% loss through the tire and chain.  the most we've ever made is 95hp
corrected in 1992 with a fast by ferraci ninja 600, an intercooler, and a
warner-ishi RHB5 turbo with a compressor impeller that was designed for a
1.0 liter car engine.  i think we made the same in 1997 with our F2, and we
never got a complete dyno run in 1998 with our new F3  (new to us, anyways,
w/ a ported head, a first for us) and new Garrett GT15VNT w/o a normal
wastegate.  instead, it used variable turibine vanes to control the boost.
very trick, but also very heavy.  i would have liked to strap our car to the
dynojet at competition, but the line was like 3 hours long and we wanted
beer and food badly, especially those not on engine team.  keep in mind,
this is through a SINGLE 20mm restrictor, not 4 36mm mikunis.  i don't want
to venture a guess as to how much power we could make unrestricted, but i'd
really like to find out this summer.  run like 20psi with a BIG intercooler.
i'm guessing close to 200hp corrected at the output shaft.  what do you
think?  also, if you want one of my dyno graphs from 1997, let me know.  we
made like 52 ft-lbs of torque in 1997, and probobally more last year.  we
also made 40+ from 4500-11,500rpm.  nice ayer's rock powerband that's easy
to drive on an autocross course.  also, what compression ratio do you
reccomend for 100 octane race gas, a 600cc motor with essentially no redline
but slightly weak rods (the nemesis of the F2), and around 10psi of boost
max.?  i'm guessing around 10 to 1 to keep the the thermal efficicency up as
high as possible, but i'm not sure.  soundls like you have more experience
with playing with the compression ratio than we do.  i've done engine work
the past two years, and been on the Formula SAE team for the past four, but
i still have yet to break the magic 100hp barrier.  please let me know what
you think about a turbo Suzuki GS550E, max hp on an unrestricted F2, and the
best turbocharged compression ratio.  thanks.  also, my crank is presently
severly frozen in the bottom end of my motor.  i think i dropped a bearing
when i put the engine back together while waiting for the gear, and the
bearing fell between the crank and another bearing, but i don't know.  i've
put 100ft-lbs on the end of the crank to no avail.  the cams move and are
fine, but i'd have to break the cam chain to split the case and look inside.
any ideas/suggestions?
later,
Dave Schumpert
'95-'98 VT Motorsports
'73 914 2.0
'83 Suzuki GS550E