79 Spider 2000 - looking into new carb(s)

[callthemall]

About a year and a half ago I got my hands on a 1979 Spider, bone stock. I was told that all work was done by a local mechanic. Alright. Well I've developed carburetor idle issues (typical Fiat, problem after problem haha) I've been fighting this for months now, going anywhere from 3000RPM one minute and 600 - 0 RPM at the next stop sign. While examining the carburetor at idle in my driveway I noticed the butterfly valve stayed close for the most part - leading to excessively high idle. I did just now find that a small white plastic part on the vacuum control for that butterfly valve is broken, and apparently this will cause issues (of course!...) I'm looking into replacing that piece, but I'm also looking into other carburetor options (It is a 79 keep in mind, the worst year for the whole engine in terms of air restrictions and emissions crap).

Before I continue, I want to point out this work was done BEFORE I bought the car. I wouldn't replace anything with less than stock pieces. Anyways..

The carburetor bowl is held on by 4 non-identical screws, 3 being non-matching self-tapping wood screws. Each time I take off the bowl I have to grab a 8mm socket (this is the original screw, but most the threads in the carburetor housing have stripped), a straight-slot screwdriver, a Green Robertson, and a Red Robertson (Did I mention I'm in Canada haha) to get the screws off. The linkage also has 4-6 washers glued together with some black guck, acting as spacers to the accelerator cable. There are a few more little 'modifications' (mostly self-tapping screws) that I can't think of off hand, but the point is, there's quite a bit WRONG with this carburetor, without the emissions stuff.

I have two options right now. Fix up the current carburetor a whatever $$$, or replace it with a much less restrictive carburetor without all the emmissions stuff. My Dad had a 1974 Fiat X1/9 equipped with Dual Weber sidedrafts, and his current race car, a 1986 Honda CRX, also has them equipped. He has been encouraging me to take that route, but after reading Mark's little essay on IDF's I'm a little timid on those right now, since the rest of the engine will remain stock for some time, though I do love the sound of IDFs.....

Has anyone else had problems with their 79 carbs, mainly idling? And what carb upgrades are best recommended for a 79 spider?

Thanks everyone,
Matt.

[narfire]

Matt, go to parts for sale and grab , if still available, the 34 adf for sale. Then source a single plane manifold, about $40-$75.00, and put that on the car. Last year I helped a fellow with a 34 dmsa and single plane intake, and he grinned for days.
The stock carb for the 79 and early 80 were very restrictive compared to the 34. Think they were 28/32 and a ton of crap hanging off the intake side. If emisions are an issue, then I'm not sure what the result will be there.
Chris

[Weelan]

I got my single plane from a '74 spider on ebay for 40 bucks free shipping. I have the 32/36 DFEV carb which I like quite a bit. It growls like mad. (others probably do too, but I love the way these sound too).

Also, are you located in California? Just checking because they require smog stuff to stay(so I've come to understand).

[vandor]

I think you have two options. Either a 32/36DFEV carb on a 1800 manifold, or IDFs
IDFs make a bit more power than a stock FI system, but still they are quite expensive, so you really have to want them to run them.
Once they are dialed in they will work great. My friend has them on his Coupe, and they are super smooth - the problem is many people do not know how to tune them, but on the Fiat forums (esp Mirafiori.com) there are a lot of people who have a lot of IDF experience.

[CajunMike]

+1 on what narfire said. If that 34adf is still for sale pick it up. They sell new for around $500. If not the next best thing is the 32/36 dfev. Several vendors sell them or you can try weber carbs direct. The 34 is a direct bolt up to your stock setup but the poor intake and smog stuff will kill any benefits. The 32/36 will require some modifications but seems to be the popular choice. Dont mess with dual carbs unless you plan to do some other engine modifications and don't have a problem fiddling with constant tuning.

[124JOE]

i was told during my build that i could use the 79 intake with the 32/36 DFEV because the spacer will let it flow
i do have the 1800 intake under it.but for you...
BTW you need a 1" spacer under a 32/36 its from jason miller of millers mule
he also has lightend flywheels
you will see a differance with one of those
some good and some bad

[bobplyler]

I have a 32/36 DFAV on my car. Using the stock manifold with a spacer. It made a HUGE difference.

[DougC]

I have a 32/36 DFAV on my car. Using the stock manifold with a spacer. It made a HUGE difference.

I second this one. It allows you to get rid of the emissions crap, and makes a HUGE difference in power, starting, etc. I have an 1800 manifold sitting here that I didn't put in yet, and the difference was still amazing.

[Kent124]

I have a 32/36 DFAV on my car. Using the stock manifold with a spacer. It made a HUGE difference.

I second this one. It allows you to get rid of the emissions crap, and makes a HUGE difference in power, starting, etc. I have an 1800 manifold sitting here that I didn't put in yet, and the difference was still amazing.

We have a quorum.

With a DFEV and stock manifold you have woken the beast. Add an 1800 intake and 4-2-1 exhaust and the beast comes out of the cave snorting fire.

[124JOE]

I second this one. It allows you to get rid of the emissions crap, and makes a HUGE difference in power, starting, etc. I have an 1800 manifold sitting here that I didn't put in yet, and the difference was still amazing.

take your 1800 manifold and have it gasket matched on the carb end

[callthemall]

Thanks for every bit of info, I'll do further research on all the options!
P.S. I'm in Canada, I only need emissions tests if the car is under 15 or 20 years old, which this is way past haha. I think there is a leak forming in the catalytic converter, don't think anyone will really know if it happens to disappear for a straight pipe

[124JOE]

i bought a headder with down pipe and a stock center section and a ansa muffler

man when i kick in the 36mm secondary it makes me smile