2.0L Carburetor Options

[argonaut]

If I end up keeping my 75 and put the 2.0L motor in it, I'm wondering what the best streetable carb is. I would like decent cold start, idle and part throttle response. I've only ever built auto motors with single 2bbl or 4bbl carbs (or fuel injected) before, never run multiple carbs. However I have also owned and tuned several inline 4 motorcycles with individual carbs. So while it seems that a single carb is easier to setup, I'm not afraid of duals if it provides better performance.

Dual Carbs: I've done reading on this site and the guy-croft site where it has been said that the dual 40mm IDFs are suitable for 1.6L displacement but not for 2.0L. So are people using dual 44mm or 48mm IDFs instead? Or is there another size or type of dual carbs that can be used on an aftermarket manifold?

Single Carb: I've seen the 34 ADF and the 32/36 DFV discussed and available for sale. Seems like the 32/36 would be a better street carb with its smaller primary. I have no interest in trying to run one of the synchronous carbs.

Obviously a single carb would be drastically cheaper. So that is a factor too.

[So Cal Mark]

if you run IDFs on a 2L you need 44s. 32/36s work really well for all around use

[argonaut]

Okay, from what I've been able to find online the 44s should flow around 290cfm and the 32/36 DFV around 270cfm. So that sounds about right.

The 32/36 does sound cheaper and easier. Couple more questions:

Does the 32/36 DFV have a ported vacuum port available for running the distributor's vacuum advance? is it the port just above the idle mixture screw?

Are there any significant differences between the 32/36 DFV and the Holley 5200? From what I've been able to find the 72-74 5200s look pretty darn similar to the original webers and are, in theory, set up for a similar 2.0L application.

[argonaut]

Also, what about side draft 40mm or 45mm DCOE's? I see that Pierce Manifolds has a kit for a decent price. Do they fit on LHD cars?

[fiatfactory]

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[argonaut]

SteveC,
Thanks for all the data! I see it there under your data from CA Performance 1991 it has the Weber 44 IDF listed as 292.3 cfm. As you say I also assume that is for a single venturi, which is the number that I am interested in.

I guess you could say that I'm trying to determine the flow rate per venturi (or half of the total rating) when looking at the IDFs, DCOEs, etc because that is all that is available to a single cylinder when filling. Versus the single carb in which which both venturis feed each cylinder when filling.

For a quick comparative check I'm looking at relative cross sectional area of each: 44^2 versus 32^2+36^2. While the 44 has about 30mm^2 less cross section it does have the advantage of much less surface area. Without dusting off my physical book I would think that each of these carbs would have similar flow capacity.

All this total flow capacity is great for WOT condition but since mine will be a street car not a race car total flow is not really my only design factor. It's more of a baseline really.

[baltobernie]

Are you changing anything besides carburetion? For a stock motor, the 32/36 DFEV is the easy choice; electric choke, disti vacuum, and "safety in numbers" i.e. popular, so you don't need to learn jetting, etc. on your own.

[argonaut]

Approx 9.8:1 compression. 1.8L intake manifold. 4-2-1 exhaust manifold. Stock camshafts now but considering a mild intake camshaft at some point. Nothing too exotic.

[So Cal Mark]

you'd be better off with a 32/36 with that setup

[argonaut]

That's what I'm going to go with.

Thanks for everyone's input!

[fiatfactory]

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[toplessexpat]

Just to mire this slightly. The ADLs are most excellent carbs. Both the 36 and 38. I've got the 38ADL with electric choke put on it, running in progressive form (apparently people ran them synchronous too...!). Great carb, and ADF parts fit.

[argonaut]

I have seen where people recommend the ADL carbs but how do I get my hands on one? I can't find anyone selling them. I saw one on an overseas eBay for $600. Are they worth that much?

Are they really worth it for a stockish street motor?

[131]

I have seen where people recommend the ADL carbs but how do I get my hands on one?

34ADM, they used them in their 100s of 1000s on 4.1l 6 cylinder Fords in Oz. The same as the ADF except each venturi is 3mm larger and they ran an electric choke. A great carb on a Fiat 2l.

http://www.ebay.com.au/itm/ADM-Weber-Re ... SwwbdWGZ0A

http://www.ebay.com.au/itm/RECO-FORD-FA ... SwLVZVyKdJ

[toplessexpat]

The ADM is a great idea!

I'm running a 38ADL on a street car. It's great, and likely to be surplus when I pop dual 44s on.

In general the 36 and 38 ADLs are pretty rare - keep an eye on flea-bay, and asking the Europeans.