Endurance motor

[66brm]

The W110 will give you grief when trying to tune idle with a single carb, I fought it for years in my 1600, eventually a set of 40 idf's made life easier

Were you running 93 octane?
Also, what compression were you running?

91 octane and 8.5 compression, the idle was always set around 1000 as any lower would bounce around like a ported rotary, above 1500 was really torquey up to 4000 then the car would nose over on the power

[Marc]

Had a customer back in the early `80s with a 1756 (old-school, 90x69) with a W-110 and 34PICT-3 in his bus. We were able to trick it into idling acceptably by closing the hole in the throttle plate and fitting a larger pilot jet (g75 in place of g65 IIRC). Even passed the state tailpipe-emissions test, barely...the CO limit applicable was 3%, it was ~2.7

[TOOF]

if I get a 34PICT running well enough will there be a MPG "plus side" over the dual singles? the fewer pit stops the better.

[Marc]

In most cases "all other things being equal" duals will deliver slightly better fuel economy than a single, they're a more efficient way of delivering fuel to cylinder heads that are two feet apart. VW went with a single carb for simplicity and lower production cost, not to maximize fuel economy.
Would the better BSFC of duals offset the gallons per hour consumed, assuming they'll also produce more power at WOT, result in fewer pit stops in a 24-hour period? Probably not - but you should complete more laps, and isn't that the point?