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So I know that the Spica to Weber conversion is a popular one, but has anyone done the same going from the Bosch system? I know the Bosch system is technically superior to the Spica system, but the previous owner of this car really managed to hack this system up. With some of the creative wiring done, the parking lights also power up the main relay (and vice versa). It looks like this was done to solve a low voltage problem somewhere in the system. Carbs make life nice and simple. Thoughts? Suggestions?
 

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Its been done, you get a little more HP out of it too, but at the cost of unreliability inherent with carbs.

Carb replacement will run you in the neighborhood of $2000.00 because you will not only have to buy the carb kit, but many of them are designed to work with the SPICA or Other (Correct) intake manifolds so you will have to source one of those and then the real fun would begin with trying to get the throttle linkages to meet up.

My two cents would be to save the money and invest the time to try and get the correct system working again.

Cheers
Martin.
 

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An 86 with Webers will NOT pass any smog or CO2 tests in anystate that knows it's stuff (or has working machines). Here in Lake Tahoe, we don't have to smog cars..so it has been done by a few folks I know. It will work, BUT you need a really good Italian mechanic who knows his stuff. The cost was around 1500 - 2000. Would I do it Hell No..cost is more that it is worth.
 

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I wouldn't do it either, just because carbs don't seem right in a Series 3, even though the European models were all carburettored up to '90. The main reason to use carbs is that they can be tuned to work with high performance mods (i.e. hotter cams) more readily than the stock L-jet EFI.

Once set up the dual carbs are very reliable. Some people have problems with them because they are fitting them to engines that may not be in the best condition to start with, and are often hobbled by worn-out or mismatched ignition systems, the wrong cams, wrong fuel pump and so on.

Scan the many posts on this board and you will get an idea of where reliability issues are to found: generally in cars they were abused or hacked about, and are suffering from 20-30 years of little or deferred maintenance. The cars with EFI systems are just as susceptible to this as any, as evidenced by the many posts, but can be very reliable once all of the various components are refreshed i.e. new fuel pumps, clean/refurbished injectors, new hoses, air leaks eliminated etc.

One thing I would ditch on an L-jet is the ignition ECU and install a good aftermarket distributor.
 

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Repairing chopped up original wiring on any car can be a PITA. It is entirely doable, though. It just takes patience, a VOM, and the ability to follow the wiring schematic.

I had to go through my L-Jet system when I bought my 86 about 4 years ago. Ended up replacing nearly everything, as the car had been sitting in a garage full of bad gas for 9+ years. Ick. Most of the problem was both fuel pumps, but the injectors were shot, as was the time/temp switch for the cold start valve. I also did hoses, fuel pressure regulator, new cold start valve. Very happy now. Runs like a dream.

The Bosch EFI is very efficient, and quite reliable. I question whether changing to carbs helps the horsepower at all, actually. If one wants more HP, it involves starting inside the engine, not by bolting things onto the outside.

You might shop around and find someone that has stripped out the Bosch L-Jet system and buy their un-chopped wiring harness. It could speed things up quite a lot. It's easier than it seems to pull the engine out of the car, clean up the engine bay, install the new harness, and put it all back to rights.
 

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Alfa fitted carburetors to S3 spiders that were sold in Europe - but what do they know?
 

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They knew they didn't have to produce as many EFI specific cylinder heads, manifolds, plenums, and sundry parts therefore making a total retooling and dump of old inventory un-neccisary and thus could use up backstock to save a few bucks.

Nor did they have to add expensive sensors senders computers and extra harnessining, re tool as many certain finishing machines, create an expansive and expensive inventory of basically 'specialty parts' to construct the EFI models, and they didn't have to pass the same level of emissions standards as required in the US market that they so desired.

Basically, the EFI cars were a PITA and more expensive from a production standpoint so they continued selling the archaic parts for carburetted asperation until they simply couldn't anymore because of expended inventory, new corporate ownership, or force of law.

They knew they could get off on the cheap by not converting all the current production models at the time in other words, which was considered 'a good thing' when the book keepers told them they were going under fast.
It was FIAT's dime that took everything over to EFI, not Alfa's.


What they knew is that it was cheaper/more profitable to sell as much of the old design stuff as possible before being forced to spend more and make less on an ever shrinking market.

Large companies call it 'profit engineering'.
 

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I have a friend who has owned, built and raced many Alfa's for almost 50 years who is planning to convert a Series 4 Spider to Webers. He wants to have a car that he can easily troubleshoot when it is not running perfectly.
 

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So I know that the Spica to Weber conversion is a popular one, but has anyone done the same going from the Bosch system? I know the Bosch system is technically superior to the Spica system, but the previous owner of this car really managed to hack this system up. With some of the creative wiring done, the parking lights also power up the main relay (and vice versa). It looks like this was done to solve a low voltage problem somewhere in the system. Carbs make life nice and simple. Thoughts? Suggestions?
I didn't convert my S3 from Bosch to Webers, I swapped my Bosch motor for an earlier European motor and added Webers.

After a failed attempt at great time and expense for a shop to improve performance of the Bosch system to a programmable one, I decided to stop throwing good money after bad and did the swap myself and couldn't be happier I did. I now have a engine I can work on myself devoid of all the computers, wires and hoses that come with a complex system that I don't have the knowledge or inclination to learn to repair when one of it's many components fail.

I don't know the emissions laws in Oregon, but in Texas, a vehicle over 25 years old is not subject to the emissions testing, only safety testing.

Also, it's a clean look under the hood.
 

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Richard Jemison
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Loosing EFI

I decided to stop throwing good money after bad and did the swap myself and couldn't be happier I did. I now have a engine I can work on myself devoid of all the computers, wires and hoses that come with a complex system that I don't have the knowledge or inclination to learn to repair when one of it's many components fail.
I totally agree! This past week I bought a beautiful `91 white spider for my godson.( Body excellent, Interior is perfect (no dash cracks! no upholstery tears) He turns 16 next April, and the consequences of a problem coated (Motronic) FI system isn`t going in his garage.

The engine has seized from long term storage, so it`s coming out and getting a full Euro Weber induction, with improvements.
 

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1986 Alfa with Bosch EFI

I have a 1986 Alfa with a Bosch EFI and was interested in a "how to" if someone would not mind helping. There is no Alfa chapter within 5 hours of me and no local mechanics will work on it. The previous owner ran mostly red wire when rewiring and making a fuel pump switch modification. It's got brand new guards red paint, a new top, and less than 45k miles on it in total, but its a beautiful doorstop, sitting dead in my garage the past 2 years. I won't sell it and cannot afford the EFI woes. The last mechanic got it running for $800 labor + $125 for the new computer. After I paid, he said that it was running but a little bit rough, that he did not know if I had the funds for more work so he stopped. I happily paid and found that only when the gas is to the floor, will it run. In between gears, I have to floor it and smoke the clutch, so there it sits. It's too beautiful and I have too much in it to sell when its not running at a loss, and if it ran, I would NEVER sell it. When I saw Dustin Hoffman drive this car in The Graduate, I had to have one. Then as a child, a neighbor bought a yellow one. Loved it...until he put a single side pipe on it, affixing it to the passenger door with a welding rod, like a motorcycle. It was the 1970's but still quite tacky. Any help would be appreciated. Buying the kit but skittish. This has already been expensive enough that it has hurt my family.
 

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Chuck,
Are you a diy guy? If so, I would go for it. Our '85 spider had every EFI issue in the book. I worked at it for several months and several hundred $$ until I made the switch to twin Webers. In NY we do not have emissions testing prior to 1996. Carbs are simple, L jet is not so simple
 

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I am a diy guy and the eBay user alfa1750 has a kit with a pair of webers, intake manifold, linkages, rubber supports, carburetor support rod, and velocity stacks. Will the distributor need to be replaced or does this kit look complete? In NC, the car is a classic and doesn't need to pass emissions or be inspected any longer. Do you have any pictures? I would like to see what it looks like under the hood converted.
 

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You will need a distributor for a series 2 car. There is a lot of information on the ABB about 123ignition distributors and there are other lower cost options.
Several people have posted details of L-Jet to Weber conversion Alfar7 is one of them. I think that there is a small machining job to be done on the head to fit a carb intake manifold.

Anther option to L-Jet is programmable engine management. Several people have installed Megasquirt with good results. It all depends upon how much fun you want have with a laptop on your passenger seat.
 

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what is the kit going to cost? a grand?

L-jet is not difficult to troubleshoot...I bet you yourself with the help of this BB could get that running for a fraction of the cost of a carb conversion.

as for the last mechanic who charged you 800$ and gave it back running rough, I wouldn't have accepted that lousy service. Was he an alfa mechanic?

Great looking spider graduate btw, looks in really nice condition:)
 
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