I Hate My Throttle Body

Brian Martinez

Originally published February 1996

Well folks. in December I left everyone with a brief summation of my flight test experience with my Q-200 experimental. When I first started conceptualizing the engine installation. there was a lot of positive press concerning the Ellison Throttle Body Injector (TBI). The TBI was a very nicely made component, lighter, smaller, simpler. and supposedly more efficient. Little did I know what I would experience in 1995. As I told you before, engine readings for flight with the Ellison TBI installed were as follows:

RPMMANIFOLD PRESSIAS (MPH)
027-----
100011-----
170018-----
225025125-130

Pnor to liftoff the RPM would roll back from the 2300 static maximum to 2250 and remain there abouts during flight. During the recent holidays I removed the Ellison TBI and replaced it with the standard Marvel Schebler carburetor for a one to one comparison under static conditions. The prop remained the Props Inc. type used previously. The results are as follows:

RPMMANIFOLD PRESSIAS (MPH)
027.5Static
100010Static
120011.5Static
130012Static
140013.8Static
160017Static
170018Static
223027Static

In case you don't do math, I just got 2 inches of mercury back!!!!! During the past year, my aircraft has served as a Ellison TBI test bed. This was not my intention. My Ellison TBI in good condition is currently for sale. For the price of $900.00 OBO I will be happy to provide anyone with the EFS-3 TBI for engines 100-150 HP with an unused factory plenum box (a $300 value). As soon as the Marvel Schebler installation is complete we will see what the new performance looks like in flight. Go ahead Norm, hit me with that cold water again...l love my airplane...l hate my airplane.

Related Articles:

Brian Martinez's Q-200 Flies!

Q-200 Flight Test Summary


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Contents of The Leading Edge and these web pages are the viewpoints of the authors. No claim is made and no liability is assumed, expressed or implied as to the technical accuracy or safety of the material presented. The viewpoints expressed are not necessarily those of Chapter 1000 or the Experimental Aircraft Association.
Revised -- 22 February 1997