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67 M20F Rajay Question


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20 hours ago, TNIndy said:

Sorry for the confusion. The air bleed line is connected to the fuel pump. The two fittings at the air box don't have anything connected. 

The pressure from the intake/box needs to feed pressure to the injector bleed lines and the fuel pump. If your fuel pump and injectors are simply connected together that is effectively doing nothing. You basically have an extension cord plugged into itself and expecting a light to be powered.

Those two open lines should be connected to something otherwise you have a massive boost leak/intake leak.

I cant find a better diagram for you so the text is blurry but it does show it: http://www.kellyaerospace.com/articles/ContinuousFlow.pdf

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21 hours ago, dzeleski said:

Those two open lines should be connected to something otherwise you have a massive boost leak/intake leak.

Need to be connected to the two unconnected AN fittings on the air box.  Should fix the issue.  

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  • 3 weeks later...

We added the two lines and saw a noticeable increase in MP. Unfortunately not as much as the STC shows. at 10,500 ft I'm seeing 24.5". One odd thing is that when I engage the turbo I see an immediate decrease in fuel pressure then it recovers over the next couple minutes. I would expect a drop but not a 60% drop. If I turn the boost pump on it recovers immediately and maintains even if I turn the boost back off quickly.

Thanks for everyone's help. I will continue to look for airflow leaks in an effort to see more boost. 

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Make sure you have all the right hoses and connections.  The original installs can be Frankenstein at best.  I bought new hoses for mine particularly the small rubber hose going from alternate air box on lower cowling to the airbox which is a real pain to get on even with 2 people (I had to cut mine a bit to fit but works great and is highly durable).  Previously it was scat tubing and leaked quite a bit.  Tubing can also collapse if old or weak, somebody else posted that issue awhile back  

Easiest check if you haven’t yet is ensure that you are getting waste gate fully open and closed using the control.  



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