Larger chokes (venturies) on my Webers? Options

[Eddie914]

I have removed the Weber 40IDC 3A carbs for a rebuild.

They currently have 32mm venturies.

Will larger venturies give more top end power?

The engine is 2.7 from a '77 911. Internals (P/Cs, compression ratio, Cams) are unknown. Bursch Headers with megaphones (with removable baffles).

The car is 90% track. Weighs less than 2100lbs.


Thanks

Eddie

[Eddie914]

I'll do the antipercolation modifications and the put the 40/32s back together with the current jetting. It will be a good baseline for comparison.

I'm not in a big hurry.

When I bought the car last January, it had only been run as an AX car for the last few years. It was suffering from neglect. The owner moved on to a 944 Turbo. The engine experienced a fair amount of low rpm popping and backfiring. After cleaning out the fuel tank, fuel filters, and idle jets, and dialing in the idle mixture, the car ran quite strong.

Two weeks ago I went to a Alfa Romeo lapping day where it rained very, very hard. I have K&N Rainshield air cleaner hats but no engine cover raintray. Before lunch, the engine started running like crap! Missing. stumbling and backfiring. Initially I though it was carburetor related (plugged idle jets or such), but I think spark plug wire arcing was the culprit. New wires are going in this weekend.

I knew the Webers needed a rebuild, so I pulled then apart last night. They were pretty dirty, but I have seen worse.

If you could come up with another set for comparison, that would be great!

The 30th should be lots of fun. I'll take over my motorhome and cook up lunch for anyone who shows up.

Eddie