Weber IDA40 venturi and jets?

[Allen Henderson]

Engine builders,

I am building the following engine:
2.4 liters
Solex Cams
2.4S heads
From "2.2" 84mm 911E 9.1:1 P/Cs
SSIs
Dansk sport exhaust
Stock '67 "normal" intakes will be ported to carbs and heads ~40mm/36mm
Anyone having experience with a similar engine please provide:
Venturi size
Main Jet
Air Correction Jet
Idle jet
Emulssion tube
recommendations.
Any bets on dyno HP?
Thanks!
-Allen-

[jhora]

A start would be:

............2.2L....2.4L
Venturi....30......32
Main......125......135
Idle.........55......55
AC.........180......180
Etube.....F26......F26

[speedo]

The changes you make will likely be to the chokes and the main jets. Get yourself (or borrow) an LM-1 which will allow you to measure the air-fuel ratio. Weld a bung in the drivers heat exchanger after the collector. You might go as high as 34 on the chokes and 140-145 on the mains. You will want to keep track of the AFR and be careful not to go lean on your new engine. Keep it ~13.3-8 and you will be happy.

Speedo

[1QuickS]

I have a 2.25 twin plug with S cams and 10.1:1. I've used 32's and 34's and I wouldn't go back to the 32's.

[marankie]

My 914-6GTR has a similar motor set up for track and street.
34mm venturis, 150 mains, 160 AC, 60 Idle F3, tall secondaries. Carefully ported, headers by George. Good power all thru range both with megaphones and modified muffler. Probably 220 HP. Enjoy.

[Allen Henderson]

My 914-6GTR has a similar motor set up for track and street.
34mm venturis, 150 mains, 160 AC, 60 Idle F3, tall secondaries. Carefully ported, headers by George. Good power all thru range both with megaphones and modified muffler. Probably 220 HP. Enjoy.

Great info. thanks. I'm pondering 32 versus 34 mm venturis.

Do you know on the head side, the size the intake manifolds were ported to, actually mm? The heads are, of course, 36mm intake. "S" manilfolds are 36mm on their bottom, I'm guessing yours were ported to 36mm? Thanks again.

-Allen-

[turbochad]

If you go to the larger 34mm venturis you may want to try using 906 style tall auxiliary venturis. I have them on my 2.7RS motor with large 36mm venturis and they help offset the larger vent size.

[Allen Henderson]

from lots of folks including Richard at PMO I am going

Venturi 32
Main 135
Idle 60
AC 180, which are std. on my IDAs
Etube F3

I am not building a race engine or going for all out HP in which case I would have probably gone with 34mm venturi. I'll post my dyno results in a few months. Thanks.

-Allen-