131mirafiori forum

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I'm looking for the twin carb set-up on a 16V manifold. Like a fool I let one go a few months ago on eBay UK cos I thought it too expensive for 'untested' carbs  :-\ I'm hoping the seller will relist them.

come on Simon do it,
here you can purchased an new one!
http://www.ricambisport.it/ing/ricambi_auto_sportive_online_store.php?cat=59&id=69
and Weber IDF they are a lot on ebay.
the carburetor sound is great!

Enzo  ;)

 Yes we did tell you at the time  ::) ::) ::) ::)  hindsight uh ..!

Yes Jason, it certainly is.

I have a few issues when looking to swap out my single 34 ADF for twin 40/44 carbs and these are -

a) I'm a purist at heart and my Abarth has always had a single carb, right from the factory, so it would be a shame to change that, but so many 131/twin cam owners have told me to swap it for twin carbs, that the performance/torque advantage is immense and I must admit I love the sound of a 131 with two carbs, so probably the time has come....

b) I'm worried about purchasing the wrong carbs, i.e. with the wrong jets or chokes, which will lead to further expense in correcting. I'm most certainly not a carb expert and am therefore nervous of buying the wrong things. I'm sure it's more complicated than just buying any carb with any old jet in.

c) What about the linkage and cable arrangement? Again this is not going to be 'off the shelf' and all cars will be different won't they?

So, my fellow 131 enthusiasts, please give me the benefit of your experience. Thanks.

Simon

Simon,
I have played around with just about every combination of carb/manifold set up you can imagine!
My latest purchase is a waffle manifold from a 124 Abarth to which I will mount my Jenvey TB and EFI set up and Turtle back air box. ;D

My advice: Keep it original!  :) Now thats something comming from me ;D
I would have the twin choke thats currently fitted profesionally set up on a rolling road, for what your going to gain on fitting a pair of twin 40/45's a correctly set up twin choke will not be far away.
OK sounds will be nice but im sure you will find a shift of torque in the rev range that might be different from your current driving style.
More Fuel requires More Air requires bigger valves with better exhaust, it just goes on and on, im sure FIAT got it right with the set up you have.

If you decide to go the twin route dont worry about linkeage for throttle cables the linkeage unit simply bolts along with the manifold retaining bolts, however you may have to put a longer throttle cable on.
Also when you take the current set up off do not do anything other than clean and wrap in a nice oily cloth as im sure you will want to put them back on in future. :D
Remember to budget 100-150 quid for a decent pair of filters.

Regards
Steve

Simon twin carbs are are a pain in the hole big time my celica has them!
rebuild your 34adf carbie properly & it will be the best i had to do mine twice 2nd time ultrasonic cleaned everything with the proper cleaning fluid & played around with emultion tubes & jets & its grand now the biz ;)

Whilst I like the look of a nicely twin carb'd engine and the sound gets quite addictive, I'm not sure the effort and expense is worth it where performance is concerned Si.

I've gunned my Sport on two occasions against twin carb'd 131 Sports and while one pulled away slowly at higher engine speeds I held the other one easily while maxing out in 3rd and 4th gears. Yes your car has double the number of valves but I wouldn't be too sure you'll get a noticeable improvement in acceleration.

dream on but the man from Ballinakill left ya for dead lol  :D

Yes Brendan has a special engine but I've never competed with it Sid.

I don't remember seeing you there on the other two occasions though....?

Well said fella but my 131 wasnt finished & sure you wouldnt have appreciated a classic Toyota lad would ya?
but its finished now me man ;)

As the car is an Abarth and not a standard sport I think you'll find that twin carbs will make more of a difference. What's the point in having a 16 valve head which allows greater flow and strangling it with a single twin choke carb?

Go for the originality with your car Simon, twintig carbs are Nice but your car is to special to modificate  imho

My current car is my 5th 131 and the 2nd I've fitted IDFs to. I love them, I love the sound and performance, but I'm not that fond of the fuel consumption. My current engine has around 10.5:1 compression, long duration rally cams, extractors and 2" exhaust, I'm using around 14l/100kms, not sure what that is in MPG, it's a fair bit. Lots of people whinge about twincarbs, setting up, tuning, adjusting etc, but if done properly there's no reason they should require any more work than single carbs, I haven't touched mine since I got the jetting right after fitting them, and it's a daily driver. If it's a stock engine, fitting 44IDFs and using the same jetting the factory used will save you stuffing around, it'll just be a matter of getting the linkages sorted out and carbs synchronised. If you do wish to stay with a single carb, but want more performance, a 34ADM weber is what you're after. It's exactly the same as the 34ADF/ADFA, except the main venturies (chokes) are each 3mm larger, 27/29mm instead of stock 24/26mm. Whenever I've fitted them I've simply swapped the venturi/float body, keeping the Fiat top/choke setup and throttlebody. You keep factory linkages, filter etc, and no one would know unless they check the carb model. I bought one recently, it cost me $35, including postage. There's another one on ebay, they come up fairly regularly.
http://www.ebay.com.au/itm/FORD-XE-XF-WEBER-34-ADM-CARBURETOR-84-DA-TB-A5F11-/321352617474?pt=AU_Car_Parts_Accessories&hash=item4ad21bce02
Freight to the northern hemisphere would be quite a bit more though.

Hi All.
I agree with what Sid said leave the Carb alone. I have a 2Litre on Twin Carbs lovely sound
but she is a Bitch on Petrol so I don't drive it too much ;).I am just after buying another
2 Litre with just a single Carb not as fast as the twin Carbs but so much easier on Fuel so
I will be changing some things on the Car but the Single Carb will stay so I can do more
driving this year. Simon hope this helps a little. 8).
      Willie.

Thank you guys for your comments and suggestions. I appreciate them all.

Certainly gives me food for further thought. I'm actually quite surprised that the general consensus is to leave my single carb well alone. It's true that I have been very reluctant to swap to twins mainly because of the poor fuel consumption but people seem to expect an Abarth to have twin carbs and there's often a look of disappointment when I lift the bonnet and there's only one.

Tas, your 14l/100km equates to about 20 mpg.

I must confess to be holding a little back from you all. I actually had the carb overhauled back in Nov 2006 and at the same time it was re-jetted and had the chokes modified/enlarged, so it performs better than a standard 34 ADF anyway. 8)

Thanks again for your feedback.

Hi ho simon , try the rolling road session on 30th see what actually your properly used  abarth is making , worn engine just poring fuel out the exhaust  :-\
 Love the sound off twin carbs thats the problem you drive it different to get the sound , but the first half of a tank
 goes very quick , but drive like your mothers in the car with the second half i can get 33mpg as i had the 131 super as my daily driver with them on in the old days..
  Second choice that ive done twice is bore out the venturi on the adf , just like the ausi ford  falcon carb 34 adf made with bigger venturi , we,ve got 34mm chokes and 23 mm venturi ,   i bore them out to 25mm and 28mm  with a k/n type filter in the original pancake filter and force induction cool air feed .. :) :)
 

Correctly set up twin carbs with a 4 branch manifold should be noticeably more economical than standard.
Expect 24-25mpg against 21mpg.
They must be in perfect order which will require complete dismantling & rebuild.
Eurocarb will advise you on the correct choke size depending on application and can supply the relevant main jet, idle jet & if necessary,chokes.
The remaining jets & holders etc will probably be ok but note their values.
Parts individually do not seem expensive but multiply by 4 and include two gasket sets and your looking at a few hundred pounds.
When set up they are impressive to look at but more so to listen too even at idle which when tweaked correctly can be suprisingly smooth.
Both of my cars have drawn attention over their idling.
  It is worth noting that the noise (more noticably upon acceleration) penetrates the cabin whatever you try and will be too much for a majority of owners.

http://www.ebay.it/itm/Fiat-131-Abarth-collettore-per-carburatori-da-45-48-/371030353614?pt=Ricambi_automobili&hash=item566321e6ce&_uhb=1

 ::)