 Larger Venturi for Zenith TIN40 on a 2.4L? |
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| Tdskip |
 Oct 21 2025, 04:25 PM
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Advanced Member  Group: Members Posts: 3,747 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None 
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The 74 914/6 build has a 2.4 L MFI engine in it that came to me running Zenith 40 TIN.
I spoke with a Zenith specialist and he said that a 34m Venturi would be a bette match for that engine displacement and it’s an easy change to make along with some jetting changes etc. This seems a whole lot more cost effective than going to Weber 40ida that are $3,000 +/- just for cores. Anyone here have experience with this they can share? Thanks! |
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| porschetub |
Oct 22 2025, 04:14 PM
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Advanced Member Group: Members Posts: 4,945 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
QUOTE(Tdskip @ Oct 22 2025, 10:25 AM)  The 74 914/6 build has a 2.4 L MFI engine in it that came to me running Zenith 40 TIN. I spoke with a Zenith specialist and he said that a 34m Venturi would be a bette match for that engine displacement and it’s an easy change to make along with some jetting changes etc. This seems a whole lot more cost effective than going to Weber 40ida that are $3,000 +/- just for cores. Anyone here have experience with this they can share? Thanks! Tom I have 2.2T motor , I went to 30mm vents ,125mains and 52 idles runs/starts great ,tryed 32mm vents but bottom end power was weak but top end strong ,too much lose of vacuum to work and fussy to tune. In your case you may find the MFI cams could make a differance but I don't exactly know,cheers. |
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Posts in this topic
Tdskip Larger Venturi for Zenith TIN40 on a 2.4L? Oct 21 2025, 04:25 PM
930cabman I have twice overcarburatored Porsche engines. Onc... Oct 21 2025, 05:53 PM
Superhawk996
I have twice overcarburatored Porsche engines. On... Oct 21 2025, 07:08 PM rgalla9146 All three 2.4 engines came with MFI. Do you know i... Oct 21 2025, 07:33 PM Tdskip Thanks for all of the responses.
Not looking to ... Oct 22 2025, 04:43 AM rgalla9146 Quick edit here.
The 911 T in 1973 changed mid-yea... Oct 22 2025, 07:22 AM Ninja
Thanks for all of the responses.
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