[Fot] TR6 race engine with 45DCOE triple Webers

[Charly Mitchel]

Marcel, on my TR6 race motor, I run total advance of 37° at 3500 rpm's.  I think that it is about 17° at idle.  It seems to me that when I ran Webbers on my TR6, I was using 40mm chokes.
Charly Mitchel
TR6 #44
----- Original Message ----- 
  From: Van Mulders Marcel via Fot 
  To: fot at autox.team.net 
  Sent: Thursday, December 29, 2016 1:45 PM
  Subject: [Fot] TR6 race engine with 45DCOE triple Webers


  The engine for a friend's TR6 racecar is finished at last and it has run a couple of times now.
  I have a problem with the mixture : the air correction jets are 155, I started with 140 main jets but the mixture was much too lean : AFR was 14 at idle and 17 at 5000 rpm. Even with 180  main jets, the AFR  is still 15 at 4000 - 5000 rpm. The engine is 2720 cc and 12.6 volumetric CR.
  The Webers are secondhand, 45DCOE type 152 and they look as new
  The venturis are 36mm, emulsion tubes are F16, idle jets 55F8 and aux. venturis are 4.5. Pump jets are 40 without a bleed hole. The plugs have a correct colour, no sooting, no signs of overheating. The engine is on a dyno but I didn't risk so far to really load the engine, so the plugs doesn't tell much. The lambda sensor is a wide Bosch sensor, about new and with an Innovate controller. I suppose 180 main jets are already too big. I can't find any air leaks and the spark plugs have all the same colour. Is it possible that 36mm chokes are too big? Any idea's why the mixture can be too lean, even with 180 main jets? Should I suspect the lambda sensor/Innovate controller? What venturis should I start with? 
  Another question : I have no experience about the range of total ignition advance a full race TR6 engine does need.
  Marcel 


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