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1971 240z ITB install


DuffyMahoney

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No throttle blade on any carb or throttle body that I have seen is designed to seat 100%.  On carbs that I have rebuilt you can see damage from people trying.  

 

I got it to run and idle down, but butterflys stick almost fully.  I will fix it right and get an IAC that closes 90-100%.  Really I want the IAC off after it's warm.  

 

OEMs that do ITB use a large balance log just like this, bmw etc.. 

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6 hours ago, Derek said:

 

In theory the butterfly's should be closed at idle and all of your idle air controlled by the valve. 6 butterflies slightly cracked is not a dependable metering method for the air. It can also build up gunk over time but I doubt that will ever be a problem with Mr " I can eat of my motor because it's so clean" :)

 

Yes I'm jealous . 
 

in theory yes but in practice no. You want enough base idle in the butterfly to have a low idle and then the stepper goes from there. Today’s efi is much better and I am sure Duffy’s stand alone is more than capable of quick response but I spent most of the 80’s-90’s cleaning throttle plates and setting base idle to keep every car running a BOSCH fuel system from start stalling in the morning. Saab and Volvo were the worst.  

 

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Porsche/Mercedes round pin connectors should be the same. They were used everywhere on those cars in the 80’s I can try to double check tomorrow. I think I actually have one at work in a box of connectors.  Look for Mercedes idle motor it temp sensor connector housings

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PCV question. This isn’t a debate about the need for a PCV vs a catch can. I want true postive vent. I decided I want to use my exhaust to pull the fumes out, to keep the dirty fumes out of my intake. But since I have Fujitsubo. I have true dual exhaust. Is plumbing to one good enough? Should I still use the stock check valve? I would guess it holds back a tiny bit of pressure before popping open?

My plan was to weld this bung at a 45 just past my o2 bungs on my exhaust. With the stock check valve in line.

91057026_10157359568848985_7028320041208643584_o.jpg

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