124 Abarth Stradale factory 44IDF Jetting

ace124 · Post by **ace124** » November 4th, 2009, 11:45 pm

Who can tell me what the factory jetting was for the 44IDF's fitted to the 124 Abarth Stradale?
Help appreciated.

Thank you

Post by **Guy Croft** » November 5th, 2009, 8:48 am

44IDF 20 & 21

choke 36
main 145
air corr 210
emulsion tube F11
idle jet 55
pump jet 40
pump spillback valve 80 (in the bottom of the float chamber)

ace124 · Post by **ace124** » November 5th, 2009, 10:52 am

Thats interesting that they ran 210 air correctors. On 45 DCOE's with a similar spec engine i run air correctors much smaller @ 180 with an Air/Fuel ratio of 12.5-13:1 from 4500-7000 rpm, my mains are 145 with 36mm chokes. Would the fact they are down draught affect top end jetting so much given they are similar size carbs?

Post by **Guy Croft** » November 5th, 2009, 12:18 pm

It would tend to, yes interesting point.

The IDF flow on its own is huge but the downdraft flow of the carb completely mismatches the horizontal flow of the runners on the waffle manifold and this measurably reduces the flow. Obvious really when you think about it, the air has to turn thru 90 deg. I have heard of IDF manifolds being altered to tilt the carbs - presumably for this reason.

Here are some test results from a 124 16v and of a US made IDF manifold on 40 and 44 IDF

GC