IDF dimensions

The forum for all of your technical questions on your classic FIAT autos
User avatar
mille club
Posts: 1893
Joined: Wed Aug 24, 2016 8:13 am
Last Name:

Re: IDF dimensions

Post by friedman » Sun Sep 08, 2019 8:04 am

It does sound odd, you would think a carb venturi would be bored consistent all the way through from top to bottom and adjustments made with the removable venturi. I don't have a 44 to make any measurements for you and my 40s are currently bolted to my X.
Carl in Virginia
75 spider
83 Bertone
User avatar
Posts: 681
Joined: Sat Mar 19, 2016 10:40 pm
Last Name: Truscott
First Name: Andy

Re: IDF dimensions

Post by atruscott » Sun Sep 08, 2019 9:01 am

I’ll measure some carbs later. I’ve got Italian made Weber 40 and 44, along with Spanish made Weber 40 and 44, on the shelf.
1960 Autobianchi Bianchina Transformabile
1970 238 Camper OHV
1974 124 Wagon TC
1974 124 Special TC
1975 124 Sport Coupe
1976 124 Sport Spider (The Racer)
1981 Spider 2000 (The Resurrected)
1985 Pininfarina Azzurra
2017 124 Spider Abarth Elaborazione
User avatar
Posts: 811
Joined: Sun Jan 24, 2016 11:31 am
Last Name: Cecchele
First Name: Steve

Re: IDF dimensions

Post by fiatfactory » Sat Oct 12, 2019 5:31 am

I just happen to be overhauling a set of IDF13/15's and also a set of 44IDF20/21's this weekend... and dug out my inside dividers and measured the ID of the throats just below the butterfly plates. (not measuring the slight chamfer at the very base of the carb throat)

40IDF 13/15 measure 40.15mm I.D.
20191012_173541.jpg (623.79 KiB) Viewed 103 times
20191012_173722.jpg (886.66 KiB) Viewed 103 times

44IDF 20/21 measure 44.20mm I.D.
20191012_173845.jpg (590.19 KiB) Viewed 103 times
20191012_174059.jpg (1.42 MiB) Viewed 103 times
maybe the EMPI /Chinese copies are smaller?

but it looks to me like 40mm in Italian is actually 40mm...

What do the auxiliary venturis look like on the set that you thought were 44's?
The aux venturi design of the 44's is much less restrictive than the 40's

Post Reply

Who is online

Users browsing this forum: No registered users and 5 guests