Dual carb question, Dellorto 40s on a 1.8L to be exact Options

[terrymason]

The problem - The car will go very lean around 2500 rpm, as if the pump jets were too small.

History:
New fuel pump (3.5 PSI to each carb)
55 idle jets
55 pump jets
140 main jets
175 air correctors
These carbs are new to the car, and I'm trying to dial them in.

The car is lean when I first start it (16 / 17 on my air / fuel gauge), but then levels out to a nice 14.7 idle when warmed up. While driving, I can give the car 20% or so of the pedal, and drive up to highway speeds nicely, but when I goose it, it will go very lean (18-22 on my gauge) followed by a series of backfires and loss of power. I started off with 35 pump jets, and have moved up to 55s, which appear to be the most popular around here. I've also adjusted the pump jet linkage, from the nut fully loosened, and moved it in as far as it would go before affecting the main throttle shaft (like 60 turns or something).

What do you guys think, do I need 75 pump jets?

[rhodyguy]

your next decission is which intakes to run. i posed the ? re short vs tall for a f.i 2.0 engine and 40idf. len hoffman said to go with the talls for better top end performance. better power down low with the short intakes. my car is more of a highway runner. i went with the talls. keep us updated with your results. too often, we never hear the end of the story.

k

[jr91472]

Yes please. I want to hear how the 30 vents work. I went with 32s on my 1.8L / Dell combo. Runs really really well, but if 30' are better (IMG:style_emoticons/default/idea.gif)

keep us updated with your results. too often, we never hear the end of the story.

k