Weber Emulsion tubes differences

[356robo]

Before final assembly after rebuild, I'd like to know how an F1 emulsion tube would differ from the oft recommended F26.

Engine is 2.2, E cams, S pistons, slightly ported heads.

Webers currently have 30 venturis, 125 mains, 55 idles, and 185 air corrections, F1 Emulsion tubes.

F1's are rarely mentioned in set ups as above. How would F1's differ with F26's in performance?

I am more interest in low end torque rather than high R's.

Thanks in advance,

Rob

[1976 TN Porsche]

Talk to Paul Abbott at Performance Oriented ( 1Quicks ) here on Pelican.

[T77911S]

here is a chart someone else posted.

[356robo]

I've seen that chart, but F1 is not shown and I've learned though reading threads that the numbering system for Emulsion Tubes has no real logic.

I've not been able to find anything that describes the difference between an F1 and F26 tube.

Rob

[1976 TN Porsche]

Free Bump.

[Steve@Rennsport]

Hi Rob,

I looked through all the factory Weber books I have and found no operating references for the F1 emulsion tubes. They are listed in the parts manual, however I see no application for those anywhere in the Weber or Porsche books.

These aren't even in the table of suggestions for emulsion tube selection.

Remember,......these are matched to the camshafts (intake manifold vacuum characteristics) so one choose emulsion tubes based on cams, venturies, and displacement.

[chris_seven]

F1 Emulsion Tubes were used in the Weber IDTP 3C/3C1 fitted to the 1969 MY 2.0 litre 911T and the European 1971 2.2 911T.

They will give different progression to the F26.

Details of both tubes as follows:



F1 Part No. 61440.150

A: 4.5, B:2.75, C:1 X 100, D: 1 X 100, E:2 X 140, F:2 X 100

F26 Part No. 61440.151

A: 4.5, B:2.75, C:1 X 100, D: 2 X 100, E:4 X 140, F:4 X 100


I would think about changing venturis to 32 and may be 130/135 mains and F26 emulsion tubes

[1QuickS]

A picture of F1 and F26 with F1 on the left. I think the F1 would provide a richer main circuit fuel delivery due to fewer holes. I agree with Chris that the F26 is probably the better E-tube as they were used on the standard 911s prior to emissions concerns affecting carb jetting. I also agree with the 32mm main venturi change but if you want low end torque then the 30's would provide more than the 32s.

[krk]

fwiw, in my weber book (Haynes), I can see the F1 used as original equipment on the 911T and the 914/6 on "40 IDTP 3C/1" carbs. It was true of the last 914/6 I had, and I believe true on the current one.

I know.... not a lot of info. I did scan all the list for any other use of F1, and it didn't show up in that book.

kim.