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Pedal Smasher
1973 Opel GT
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3,435 Posts
I'm not a Weber guru, at all. I've done more research on the DGV carb than I have experience tuning them. So, I'm not going to have Rally Bob's vast experience with these carbs but I did have a couple things come to my mind.

1. Your RPM range is very low compared to most vehicles I've heard of running the DGV carb. Just look at the chart that was posted, 3500 RPM isn't even a consideration. The DGV carb is in transition till what, 2000 RPM? What I'm trying to get at, is this: a DGV tuned for your application is going to have to take this into account. We're talking diesel RPMs here. Again, I'm not a Weber guru but this jumped out at me as a significant tuning factor to take into account. I can’t imagine that a carb built to run an engine at 6000 RPM would have the same needs as a carb built to run an engine up to 3500 RPM. Your engine will spend a lot more time at low RPMs and be more sensitive to transition issues as a result I’m thinking, especially if the engine revs rather slowly.

2. The often recommended F66 emulsion tubes, might not be the right emulsion tubes for your application in case this is something that has crossed your mind. You'll need to do a lot of trial and error to tune this carb for your engine. Getting the emulsion tube right could be difficult. Never change multiple things at the same time by the way. Only change one thing at a time and see what impact it had.

What does your intake look like? Even at 3500 RPM, I would think the 38 DGAS is too small for a 4.6L inline 6.
 

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Pedal Smasher
1973 Opel GT
Joined
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3,435 Posts
Ok, the dual fuel bit… that is interesting. Are you running them both at the same time or only one at a time? How is the propane system working?

It’s still worth trying the F66 emulsion tubes. They are the go-to emulsion tubes for our engines, it’s possible they are the right ones to help out with a lean condition. I could be wrong, but my memory is telling me that if someone was running F50’s and struggling with a stumble at lower RPMs, the F66 tubes fixed it. Rally Bob would know more about why the F66 tubes are recommended.
 
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