Hi All,
I am chasing some information on jet sizing for a set of twin 45 weber DCOE 13’s.
They are going onto a reasonably worked A15 motor that is used as a race motor.

They currently have the following;

Choke/venturi – 36mm
Air Correction – 160
Emulsion Tube – F16
Main Jet - 125
Idler Jet – 40F9

Any who has some experience with setting up webers for a race motor would be great to hear from.

Cheers.

first i would of said 36mm is much to big, generally people running twin webers they run 40 DCOE's....
First suggestion would be to get your hands on a weber book
i have this one http://www.ebay.com.au/itm/WEBER-CARB ... 4839c6611f#ht_2164wt_1270
which has a genera'll guide in the back of it...
Depending on how much its worked i would assume one having the carb jetted etc perfectly which from my knowledge is best achieved by a dyno tune with some pro carby ppl.
Otherwise your best to talk to member Clyons and im pretty sure he is still rebuilding them, dont knwo him personally but seems to have a high rap on here with his carby rebuild service, i would guess he'd be able to point you in the right direction...

Thinking about building a new motor for next year John??

What size carby's are on that A12 you have now?

Stock1200,
I have a similar weber book which is great reading. The book says to run 40mm webers and 30/32mm chokes which is nice for a sunday drive.

Lemonhead,
I have got 40mm dellortos on the A12 at the moment. Not really thinking about running a bigger motor next year.
This other motor is in pieces and is a long way from being put together unless i win the lotto.
I picked up the 45 webers in question at the right price...

our friends in Japan choose to run 40's on 10s and 12s and 45's on 14/15s so they should be ok..
I don't know the numbers though

Have you thought about running the 45's on the A12?

In the 80's I use to race an A12ish motor with 45's on it, worked well, I know of a few other people who are doing it today, ok for race, not much good for around town driving.
I'll see if I still have the choke size that I use to use written down somewhere.

Something to think about for you...

That's what i would of thought, around the 30 mm mark... I would contact a Carby specialist and book in a dyno tune if and when the engine is built that the carbs are going on.... Not cheap but definitely worth it.
I'm running a single 45 DCOE on my mild A12, seems to work OK with 30mm chokes in it, but im getting back firing out of the carb when blipping the accelerator changing down gears :S but that's a different story haha.

Thanks for the advice.
I will have a think about running the 45's on the A12. Only problem is i won't be getting 30 mile to the gallon anyone...

What are "DCOE 13’s"???

45 DCOE are fine for A12 good for 6400 RPM as long as jetted correctly (most important: use 32mm venturies, or 34mm for A12 GX engine)

On a "worked" A15 use 34 mm venturis
For a Sunday Drive A15 use 32 mm venturis
For a race A15 36 mm venturis might be OK, as long as you are keeping it revved up.

Click Carburetor Sizing

Thanks DDGonzal.
Notes straight from the weber book I have;

"The prefix number on the DCOE, e.g., 40 DCOE, is the diameter of the throttle plate (the throttle bore) in mm; DC means doppio corpo (double throat); O means orizzontale (horizontal); E means it is a die cast carburetor; and the number or number and letter suffix is the variation type (e.g., 40 DCOE151). An example of a 40 DCOE"

The suffix I have is 13 - just another variation of the DCOE.