| Jeff,
That's good advice, but I think this problem was there prior to my changing the intake. I've been trying to sort out my low rpm MAP readings being higher than expected. My readings may be "normal" for the p-port engine, or I may have a leak, or ???. I changed the vacuum plumbing during the intake change. I'll try changing that back and see if that helps. I had a problem with #1 rotor dropping out at low rpm before changing to the new TB intake. Now its still there, only at a higher rpm.
As for the possibility of one TB not working properly, I doubt that could be the problem as they are extremely simple devices consisting of the body, a shaft, and a butterfly. The shaft is solid so it services all three TB's at once, there's no adjustment. I can look into each bore and see the butterfly operate. The only complicated part, if you could call it that, would be the fuel injector and I've swapped/changed it twice with no improvement.
I'm wondering if there may be something going on with the diodes that Tracy had us install in each injector. Since I changed the injector connectors, this one possibly may have ended up without a diode. I'll verify that #1 primary injector has a diode tomorrow.
Mark S. On Thu, Mar 22, 2012 at 6:58 PM, Jeff Whaley <jwhaley@datacast.com> wrote:
Well Mark, I'm no expert but I always look at what I modified last for clues to what might be wrong now.
Is it possible that 2:3 new TBs are working great and one is not?
Just a thought ... Jeff
From: Mark Steitle <msteitle@gmail.com>
Subject: Re: [FlyRotary] Re: #1 rotor cutting out
Date: Thu, 22 Mar 2012 16:32:44 -0500
Kelly,
Yes, the slide throttle is history, mainly because,
1) I concluded that the location of the primary injectors being upstream from the slide was causing puddling of the fuel and surging, and hence poor low speed/idle characteristics, although this was not a problem at mid to WOT. I could have relocated the primary injectors but there were other issues as well (see 2 through 5)
2) I suspected cross-feed from one port to the next during low throttle operations, although I couldn't verify that was happening I felt it may be contributing to the rough operation mentioned above,
3) It dripped fuel upon shutdown, not a lot, but it caused me some concern,
4) the nature of the design prevented me from balancing the individual rotors, and
5) it required a modest force to operate; the new TB's are silk smooth.
I located a triple-set of like-new 46mm 1 BBL throttle bodies from a Sea Doo or snowmobile that looked like would work with very little modification. It required a new throttle shaft to be fabricated since it was one piece and the spacing was wrong for the 20B, but Bob Darrah and his Bridgeport were happy to help me with that. I'm very happy with the end result.
The nature of the p-port necessitated the TB's to be located very close to the ports, else I would have gone with a larger single TB feeding into an airbox like most have done. Not sure that wouldn't work here, but I've read that with the p-port engine the TB should be as close as possible to the ports. These TB's have the injector bungs cast into the body just downstream of the butterfly, exactly as I needed. Low end performance has improved considerably. I just need to figure out why the #1 rotor cuts out in mid-range.
Mark S.
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