3.2 Build EFI N42 / MN47

[DuffyMahoney]

How close are they synced now?  Are you removing linkage to do that? Are dog bones the exact same lenght?  

[madkaw]

1 hour ago, DuffyMahoney said:

How close are they synced now?  Are you removing linkage to do that? Are dog bones the exact same lenght?  

I’m using cable control on the linkage. So the issue with them is the cascading effect of using cable on one ITB that has direct linkage to the other two . It causes #1 ITB to open up sooner no matter how I try to adjust . I also have #4 port that doesn’t flow as much air as the rest . Maybe a butterfly issue - slightly off.

I would go with rod linkage but I’m pushing it for time to make it to ZCON . 
I’ve tried syncing the best I can at lower TPS by just holding throttle open with cable adjustment and calibrating 3-6 . 
Once I’m around 12+ TPS - AFRS blend much better .

As far as #4 - I  will address this with injection trim . It’s just light cruise where I have to pull some fuel . 
I’d love to try the rod linkage but I’ll have to see how much time I have . It won’t help with the center ITB . I’ll have to take it off and see about doing something with the throttle plate . Again -  it much time for that right now 

[DuffyMahoney]

Linkage is what I am calling the small arms between throttle bodies and the shafts.  

 

You need to remove everything connecting each throttle to the overhead bar.  Then sync.  Then check again once hot.

 

Also blip each throttle, see if they stick or bind once hot.  

You should have the cable going to a cam on the overhead bar.  If that isn't what you are doing, I would highly suggest that route.  

Setting butterflys is extremely difficult to do perfectly.  I would print the 3D file I posted for syncing, then set each off the car.  Then put each in an oven to 185 and check each again.  

 

Do you have an injector company in your town? Have them checked for flow matching?  

 

[DuffyMahoney]

I really think you should move to an overhead bar.  

[madkaw]

On 9/4/2025 at 12:03 PM, DuffyMahoney said:

I really think you should move to an overhead bar.  

I will do this -eventually. I did pull the center ITB and tested the flow past the butterfly using a vacuum cleaner . Not sure thats an appropriate testing method but the sync tool showed same flow between the two ports. So maybe my issue with 4 is a porting of that intake runner at low flow. At this point I did another valve adjustment -cold- and I did end up finding small adjustments needed, so we will see if that changes anything. Meanwhile I am going to use injector trim to even things up the best I can before Zcon.