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Re: [turbobike] CBR600F3 first dyno run soon

Dave Schumpert (porsche_boy@vt.edu)
Thu, 08 Apr 1999 11:26:47 +0600

Dave, 
Glad to hear someone is turboing an F3 besides us.  (Virginia Tech Formula
SAE team)  I've been the de facto engine team leader the past two years, and
the best numbers i made were 51 ft-lbs of torque at 9k, and 91 or so hp at
10k.  keep in mind, we're running through a 20mm restrictor, about the size
of a penny.  i'd guess you should make at least 150hp if done right.  we use
a garrett GT15VNT turbo, and it seems to work well for us.  we made positive
boost by 3000rpm, and 40+ ft-lbs from 4500-11,500rpm.  nice fat power band,
although i've really wanted to ditch the restrictor, retune it and really
blow away all the cars at an autocross instead of just barely beating the
fastest ones.  we also run electromotive's TEC-II for fuel injection and
ignition control, and even though it's a bit archaic, it seems to hold its
own and make good power.  this year, we switched to a 3" pickup wheel
instead of a 2", and we ran it up to 13k no problems.  of course, it was
only making 20 ft-lbs at 13k because it was so choked, not to mention the
crap that their coils start to go out to lunch at around 8k.  we run around
7-8psi w/ stock compression as we're trying to eek everything out of a
restricted engine, and want to keep the thermal efficiencies high.  we also
built our own dry sump system, ditched the water to oil cooler, and added an
air to oil cooler.  it's a pretty trick system, it pulls all of the oil
through the turbo w/o 1/2 of it going out the exhaust or better yet, into
the compressor, through the engine, and out the exhaust, and it keeps our
oil pressure at 40psi even in long sweeping right hand corners where
previously the needle would almost fall off the gauge.  we built the dry
sump by using stock F3 oil pump impellers, and CNC'ing the dry sump case.
we also CNC'd the bracket for the dry sump, and purchased the pulleys and
belt.  it seems to work well right now.  we also relocated the pressure
releif valve and oil filter to where the old oil to water cooler used to be
in a trick CNC'd aluminum piece that took way too long to make.  btw, all
those dyno #'s are not corrected, and we're at 3000' of elevation or so. our
MAP reads 95kPa, and STP is 101.3kPa, 25 degrees C.  we have a nice dyne
systems dyno, but it isn't able to do transient runs very well.  hopefully,
if this kid gets off his ass, we'll have full data acq in the next couple of
weeks w/ all the TEC has to spit out (throttle position, MAP, MAT, O2, rpm,
coolant temp, injector duty cycle, and exhaust gas temps as well as whatever
else we feel like logging.  i'll post our final dyno results once we get
them.  good luck with your project.
later,
Dave Schumpert
'95-'98 VT Motorsports FSAE
'73 914 2.0
'83 Suzuki GS550E
www.vt.edu:10021/org/sae


At 09:01 AM 4/9/99 -0400, you wrote:
>Guys,
>    I've got the CBR600 just about done and ready for my first dyno runs
>on April 20th.  Just to remind you, I'm using a garrett t2, blowing
>through the carbs.  I've got a popoff valve on the airbox and it seems
>to be doing its job, if you let off the gas quickly you can feel the
>boost being unloaded.  It was running way rich but I tracked this down
>to too high fuel pressure, 3lbs was pushing the needles open and
>dripping fuel, lowering it to 2 fixed it but I haven't really run it
>since.  Before fixing this I did a burnout in my shop at about 1/3
>throttle and it held 5lbs of boost at about 5-6000 rpm (showing full
>rich on the O2 sensor).
>
>    Anyway, I know the CV carbs are going to be pesky.  Anyone have some
>specific suggestions on needles or spring sizes to start with?  Actually
>any suggestions at all.  I will be running it around my house this
>weekend and will post its behavior next week.  I also have boost, O2,
>fuel pressure, and oil pressure (to the turbo) guages.  I'll be dynoing
>at Starting Line in Waterville, Maine.  Anybody know these guys?
>
>thanks,
>    Dave.
>
>