Datsun Roadster Forum-311s.org

I have seen a lot of pictures of weber DCOEs on 1600s. I haven't seen a lot of discussion about the jetting. While I was talking to Jason, I knew of a program that was available but it was a DOS program and my laptop cannot run it anymore. So I searched, and came across a nifty website that has the jetting program. I am sharing it here:

https://www.carbparts.eu/calc/

Clever. Premo is my go to guy, but that site was pretty good Good find

In order to tune your webers you MUST understand how they work. I watched this guy's videos on youtube: D3Sshooter

Look for his weber carb videos and watch them all. It takes a bit of time but when you are done, you will understand how they work and then you can start to tune them.

Also: install a wide band O2 sensor. You need to know what is going on downstream of the air pump once the fuel has been burned.

tjp wrote: Sat Jul 03, 2021 5:22 pm In order to tune your webers you MUST understand how they work. I watched this guy's videos on youtube: D3Sshooter

Look for his weber carb videos and watch them all. It takes a bit of time but when you are done, you will understand how they work and then you can start to tune them.

Also: install a wide band O2 sensor. You need to know what is going on downstream of the air pump once the fuel has been burned.

Thanks
Does it apply equally to Mikunis?

A quick web search showed up a few sites for Mikuni/Solex jetting: -
https://www.rmcarburetors.net/Tuning%20Tips.htm
https://www.upgrademotoring.com/perform ... ations.htm
No recommendation just search results

While those give sample jettings, the page that I shared is dynamic - you can alter the parameters and get suggested jettings. Like I said, I haven't seen much discussion of jetting, and I have no doubt that a lot of the cars could benefit from some changes.

spl310,
I like it. Once it gives the suggested jets you can select the jet or the configurable item and it gives a little summary of what is that item's role.
This informative is especially useful when you are trying to tackle a specific issue.
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Click on picture for a full view.
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I have an R16 stroker with 40mm DCOEs and it's running well now after 2 years of screwing around. I love that site listed above and wish I had known about sooner but it's a bit late. Here's what I'm running now for reference. Timing 35 degrees BTDC. F9emulsion tube, 140 MJ, 180 Air jet, F9-55 idle jet. Takes about a mile to warm up and then runs very crisply and strong. Make sure your idle is around 1000 rpm or lower if possible. Too high of an idle will cause the car to "run on" when you shut it off. Also use a phenolic spacer between the carbs and intake manifold and it helps to have a heat shield of some sort. Float bowls will boil fuel without heat protection.