Datsun 1600 L20B Twin Webers 

Cheers Orlando!...👍

fantastic video i think he needs to do more

Hi Craig. No part 2 just yet, waiting for Danny to make another appearance. I'll make sure I run the camera when he's in next.

Hi Ben, great tip on the pump jets. I've found that they mostly affect high rpm on constant throttle...👍

@@unigroupengineering Interesting. I do a lot of light throttle tuning for better fuel economy and search for midrange torque with ignition mapping. I found AFRs are richer everywhere when you go a size up, even on light cruise. I don't really take the xflow beyond 6.5k, so maybe missed what you've observed. Please share your final jet changes when you do part 2. Theres not much detailed twin weber tuning videos produced these days. At wot, your mains look about right to me, so interested to see what you do to fix.

Hi Ben, What do you run for the bypass for the pumps? I'm finding odd that yours is affected everywhere. Back on this Datsun, my next move was going to be to try another set of tubes, then match them with the mains. As it sits, it's not looking easy. Because if I go smaller mains to clean up lower rpm, upper end is going to get too lean in some spots.

@@unigroupengineering I have a .30 spill valves. The smallest one you can get without blocking it off completely. Don't like doing that cause it uses so much extra fuel. The issue you have is one i only solved with a best compromise. My rich spot is between 3 and 4k at wot. I think its related to progression drilling and cam choice. I managed to get it into the mid 11s, but no better. FYI, it was much worse on smaller chokes. If you can go up a size, it reduces the signal on the mains in this rpm range. Would need the mains revisiting to compensate for the extra cfm at high rpm. I also found emulsions of the same family perform the same at wot. They only make a difference at part throttle acceleration. Good luck finding the answer!

@@bengooch5787 I'll post up the final when we are done. I'm expecting a result like yours though, always a little on the rich side in the middle. This happens because of the refracted wave in the inlet tract without a plenum to equalise it. The inlet charge draws from the carbs, on the way in and also on the way out, causing stand off,, so you get a rich mixture. Nice chatting to you on the matter. I will try to follow this up to see how we finish up.

Apologies, no one that I know of.