Lotus Elan

Weber 45 application numbers

PostPost by: S2Jay » Fri Apr 19, 2024 7:57 pm

A friend had a set of 45 DCOE 9, I thought maybe I could use these on my stroker twincam. So we checked & discovered that the mounting spacing is different & so cannot be used [w/o a lot of silly impractical modification – since nearly anything can be made possible].
So, 1. Does anyone know what the correct number would be for a 1706 cc stroker T/C?

2. Then I noticed that Weber Carbs as new are being advertised on eBay, etc for ~ 180 usd.
Looking at the close up pics, it can be seen on the carb body that these carbs are not made by Weber, but by “Lantech”, which is of course a Chinese company. Does anyone know anything about these? Are these good/bad, etc? Would other Weber tuning parts interchange?

3. What is a good source for new/used/rebuilt Webers?
just looking for clues at the scene....
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PostPost by: StressCraxx » Fri Apr 19, 2024 8:54 pm

I have a pair of 45DCOE on my twincam powered 23.
The engine is about 1640cc with big cams. Power is from about 3K to 8200 with 188 hp. It's great fun on the loud pedal and sounds great.

The low speed circuit suffers from low vacuum, so driveability is poor until 3K when the main circuit comes in.

So the question is, is this a race motor, a street motor or something in between? Twin 40s for the street, and you can use up to 36mm chokes which is the lower end of the choke size of the '45s. I would suggest you ask your engine builder for his recommendations before you start throwing money and time at it. Time on the dyno with someone who knows webers well could be your friend and save you grief....

Most used webers are very tired and leaky. DCO9s are over 60 years old!

Here is a source for new:
https://www.piercemanifolds.com/WEBER_4 ... 00.060.htm

Avoid the Chinese made copies, usually sold on web pages as "ECON" Buyer beware. They are about 1/2 cost of the real deal.

If your vacuum is below 18" low speed circuit tuning is a challenge. Same with finding the right emulsion tubes for the main circuit. If your intake ports are not properly matched, you may not get the desired effect. Same goes for the exhaust. Consider the engine is an air pumping system and everything matters from the intake snorkel, airbox, carbs, head, exhaust are part of the overall system. Simple things like the position of the header flange openings mated to the head so the bottom of the exhaust flange openings were flush with the exhuast ports gave me 3 free HP on the dyno.

Suggest you join "Sidedraft Central" and do some reading. Keith Franck has done some great work. https://vintagetechnologygarage.groups.io/g/sidedraft
There is no cure for Lotus, only treatment.
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