32 adfa jetting for 2L engine

[dinghyguy]

So recently got a spare 32 adfa carb and rebuild kit. It looks to be in good condition and worthy of being used. But if you put a 32 adfa on a 2 l car and it was originally set up for a 1800 (1759cc) it seems to me that everything would be a bit too small, by about 13%. So if you increase the jetting as shown will that make it better?

Part | Main Jet | Idle Jet | Idle Jet solenoid | Emulsion Tube | Air Corrector Jet
Fiat Part # | 73801.* | 74403.* | 74409.* | 61440.* | 77201.*
1759CC | 125/140 | 0.5 | 0.5 | f84/f7 | 170/170
2000 CC | 140/155 | 0.55 | 0.55 | same? | 180/190

sorry for the crappy table formatting......
Of course this seems way too easy.....so suggestion appreciated, including suggestions for changes to emulsion tubes.

cheers
Dinghyguy

[SteinOnkel]

Only way to properly figure this out is on a dyno.

You can get pretty close with a wideband afr and trial and error.

[Nut124]

The carb should work with the same jettings at low/mid power. At top end, where it might actually flow more than the 1800, corrections could be needed.

[dinghyguy]

i agree with both of you, and in fact the 32 adf's on both my 2l cars with the "stock" jetting work reasonably well, but my curiosity makes me think that carb must be unable to deliver enough for the 2l at higher power, in particular off the idle circuits. Now i know i am not the first person to wonder this and i dont have a dyno at home.....but for the cost of some jets i am willing to play, i just expect the system to be non linear (in fact i expect the losses through the 23mm barrel to be higher proportionally for the 2l engine at high rpms/load then for the 1800 (Bernoulli strikes again) so i scaled back my jet values closer to 10% than 13%.

Hmmm, maybe i should go looking at the 32/36 jetting for more information?

cheers
Dinghyguy

[Nut124]

A carb in a shared plenum application like this just measures airflow and adds fuel accordingly.

In a 2L, it should perform identical to what it does in an 1800, until the 2L calls for more flow than the 1800 at the very top end RPM at full power.

Now, IR carbs are a bit different because the flow starts and stops. Common plenum carbs flow more constant.

I would drive it first before buying jets.

[SteinOnkel]

It's all rather shooting shooting broken arrows in the dark...get a wideband afr and go from there.

My philosophy with carbs is keep it stock or go programmable efi.

[wetminkey]

Finally got this scanned,...Here is some Weber re-jetting info that I think will help some of our members with the question of re-jetting:



Please pardon my penciled-in notes-to-self for 5000 ft,...
I think I will post this info in it's own thread, so that it will be more readily available.
I sure hope that it will be of help.
Todd Compton.

[GTRaptor]

I just got a 32/36.. same altitude....

Read your post and was wondering if you already tried those jet sizes...