SPICA was first implemented on street cars in the late 1960s in response to U.S. emissions requirements. Electronic fuel injection was in its infancy (D-Jetronic was available on 1970s v12 jaguars) and extremely expensive then (and not very reliable). SPICA mechanical fuel injection (initially developed for the Tipo 33 race car from diesel injection systems) was more precise than carburetors so could result in a cleaner burn and lower emissions than Carbs. The Spider started using L-jet EFI fairly shortly after EFI systems started to be widely adopted.
Why SPICA?
Why did Alfa Romeo use their SPICA mechanical fuel injection on Spiders instead of going straight to Bosch electronic fuel injection?
I know why they did for their cars with 1 throttle per cylinder, but Spiders never had one throttle body per cylinder, correct? So, why didn’t they use Bosch’s electronic fuel injection after making the switch from carburetors?
Also, what is the difference in character between the Spiders with SPICA and the ones with electronic fuel injection? Is the sound different? Does SPICA require sportier driving? Is the vibration different? Etc.
I know why they did for their cars with 1 throttle per cylinder, but Spiders never had one throttle body per cylinder, correct? So, why didn’t they use Bosch’s electronic fuel injection after making the switch from carburetors?
Also, what is the difference in character between the Spiders with SPICA and the ones with electronic fuel injection? Is the sound different? Does SPICA require sportier driving? Is the vibration different? Etc.
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Also, the SPICA FI was developed from a diesel pump used by company that Alfa owned. I think they produced truck or tractor diesel motors.
If my memory serves correctly.
Yes. Mechanical fuel injection in general was first developed for diesel engines. It was later that it started being adapted for gas engines. Early mechanical fuel injection was often used on high performance cars like the Mercedes SL (the famous gull wing).Also, the SPICA FI was developed from a diesel pump used by company that Alfa owned. I think they produced truck or tractor diesel motors.
The first production EFI (after Bendix's failed Chrysler experiments in the 1950's) was the Bosch system in Volkswagen 1600 TL in 1968. The Bosch system was actually based on the Bendix's patents from the 1950's which Bosch purchased FROM Bendix -the difference was that transistor reliability had vastly improved in the intervening 10 years allowing Bosch to succeed where Bendix had failed. . That is: the Bendix design worked fine but poor electronic component quality made it impossible to live with.
As Bosch was 'literally' the only EFI available in 1968, ALFA would have had to buy the rights from Bosch and set it up for their engines. Remember however that the Bosch EFI was having its first application in 1968 and SPICA first appeared on a production Alfa for a 1969 model. Given the poor prior history of EFI it would have been a foolish gamble to try in it the same year that VW was trying it. Nobody could know for sure that EFI was actually going to work THIS time.
Mechanical fuel injection however was a mature technology dating back to the 1930's and used extensively in fighter planes in WWII and in expensive Mercedes cars et al in the 1950's and 60's. Further ALFA had a very good MFI system they'd used in diesel vehicles for years and were already using in their gasoline race cars in 1968....
The choice was obvious. By the way, contrary to what OP suggests the SPICA is NOT a throttle-body injector system: each intake port has a dedicated injector just as EFI does. It's a very sophisticated system - not some soviet-style kludge.
The reason that MFI was not common in gasoline vehicles in the 60's comes down to three points: MFI requires sophisticated design and precision machining so it's expensive to make. This limited its use to expensive cars or race cars trying to extract that last bit of extra power. Next, gasoline was cheap and no one cared enough about fuel efficiency to justify the expense in cheap cars and people buying expensive cars could afford the gas. Finally nobody gave a **** about pollution.
So why did EFI overtake and replace MFI in the 70's? Well, the first reason is that EFI is much much cheaper - circuit boards don't require the precision machining of a SPICA pump. Next and ultimately more important of course is that EFI allows more precise monitoring of conditions and measuring of fuel. This includes an O2 sensor necessary for pollution measurement and control. However from a performance standpoint for a street car, I don't believe there would any perceivable improvement in converting a car today from SPICA to a later EFI set up.
As to a difference in sound or character between SPICA and EFI - I have a 1971, and I don't notice any flaws in performance of the system: no cold start problems or hesitation, no flat spots in the power band, so I don't -personally- notice any differences between my SPICA and the EFI cars in my other personal vehicles: they just work. I am told that the first year SPICA's (1969 models) did have some such flaws but they were ironed out in subsequent years.
As Bosch was 'literally' the only EFI available in 1968, ALFA would have had to buy the rights from Bosch and set it up for their engines. Remember however that the Bosch EFI was having its first application in 1968 and SPICA first appeared on a production Alfa for a 1969 model. Given the poor prior history of EFI it would have been a foolish gamble to try in it the same year that VW was trying it. Nobody could know for sure that EFI was actually going to work THIS time.
Mechanical fuel injection however was a mature technology dating back to the 1930's and used extensively in fighter planes in WWII and in expensive Mercedes cars et al in the 1950's and 60's. Further ALFA had a very good MFI system they'd used in diesel vehicles for years and were already using in their gasoline race cars in 1968....
The choice was obvious. By the way, contrary to what OP suggests the SPICA is NOT a throttle-body injector system: each intake port has a dedicated injector just as EFI does. It's a very sophisticated system - not some soviet-style kludge.
The reason that MFI was not common in gasoline vehicles in the 60's comes down to three points: MFI requires sophisticated design and precision machining so it's expensive to make. This limited its use to expensive cars or race cars trying to extract that last bit of extra power. Next, gasoline was cheap and no one cared enough about fuel efficiency to justify the expense in cheap cars and people buying expensive cars could afford the gas. Finally nobody gave a **** about pollution.
So why did EFI overtake and replace MFI in the 70's? Well, the first reason is that EFI is much much cheaper - circuit boards don't require the precision machining of a SPICA pump. Next and ultimately more important of course is that EFI allows more precise monitoring of conditions and measuring of fuel. This includes an O2 sensor necessary for pollution measurement and control. However from a performance standpoint for a street car, I don't believe there would any perceivable improvement in converting a car today from SPICA to a later EFI set up.
As to a difference in sound or character between SPICA and EFI - I have a 1971, and I don't notice any flaws in performance of the system: no cold start problems or hesitation, no flat spots in the power band, so I don't -personally- notice any differences between my SPICA and the EFI cars in my other personal vehicles: they just work. I am told that the first year SPICA's (1969 models) did have some such flaws but they were ironed out in subsequent years.
As far as SPICA performance, it is highly dependent on the year. From '69 to '74 SPICA was steadily improved, rock solid reliable. Starting in '75 Alfa started to detune the system to comply with Fed regulations. By about '81 SPICA's mono-farfalla intake was by most accounts devoid of performance and reliability. The introduction of the Bosch EFI likely saved the Spider from extinction...
The 70s was a terrible decade for cars. What with bump-O-matic bumpers and jumbles of emissions hoses under the hood of most cars. So, it always gives me a smile when I look at the emissions sticker on my spider.SPICA was first implemented on street cars in the late 1960s in response to U.S. emissions requirements.
Interestingly, a Bosch tech had already drawn up an electronic FI back in 1959 !
As with anything new that most didn't understand, it took till 1967 to actually introduce it to the public.
It also added 10% to the price of a VW in 1968.
A backbone of Automotive Electronics - 50 years of Bosch gasoline injection Jetronic
As with anything new that most didn't understand, it took till 1967 to actually introduce it to the public.
It also added 10% to the price of a VW in 1968.
A backbone of Automotive Electronics - 50 years of Bosch gasoline injection Jetronic
Do you own any EFI Alfa’s?The first production EFI (after Bendix's failed Chrysler experiments in the 1950's) was the Bosch system in Volkswagen 1600 TL in 1968. The Bosch system was actually based on the Bendix's patents from the 1950's which Bosch purchased FROM Bendix -the difference was that transistor reliability had vastly improved in the intervening 10 years allowing Bosch to succeed where Bendix had failed. . That is: the Bendix design worked fine but poor electronic component quality made it impossible to live with.
As Bosch was 'literally' the only EFI available in 1968, ALFA would have had to buy the rights from Bosch and set it up for their engines. Remember however that the Bosch EFI was having its first application in 1968 and SPICA first appeared on a production Alfa for a 1969 model. Given the poor prior history of EFI it would have been a foolish gamble to try in it the same year that VW was trying it. Nobody could know for sure that EFI was actually going to work THIS time.
Mechanical fuel injection however was a mature technology dating back to the 1930's and used extensively in fighter planes in WWII and in expensive Mercedes cars et al in the 1950's and 60's. Further ALFA had a very good MFI system they'd used in diesel vehicles for years and were already using in their gasoline race cars in 1968....
The choice was obvious. By the way, contrary to what OP suggests the SPICA is NOT a throttle-body injector system: each intake port has a dedicated injector just as EFI does. It's a very sophisticated system - not some soviet-style kludge.
The reason that MFI was not common in gasoline vehicles in the 60's comes down to three points: MFI requires sophisticated design and precision machining so it's expensive to make. This limited its use to expensive cars or race cars trying to extract that last bit of extra power. Next, gasoline was cheap and no one cared enough about fuel efficiency to justify the expense in cheap cars and people buying expensive cars could afford the gas. Finally nobody gave a **** about pollution.
So why did EFI overtake and replace MFI in the 70's? Well, the first reason is that EFI is much much cheaper - circuit boards don't require the precision machining of a SPICA pump. Next and ultimately more important of course is that EFI allows more precise monitoring of conditions and measuring of fuel. This includes an O2 sensor necessary for pollution measurement and control. However from a performance standpoint for a street car, I don't believe there would any perceivable improvement in converting a car today from SPICA to a later EFI set up.
As to a difference in sound or character between SPICA and EFI - I have a 1971, and I don't notice any flaws in performance of the system: no cold start problems or hesitation, no flat spots in the power band, so I don't -personally- notice any differences between my SPICA and the EFI cars in my other personal vehicles: they just work. I am told that the first year SPICA's (1969 models) did have some such flaws but they were ironed out in subsequent years.
I agree that going from SPICA to L-Jet wouldn’t help performance in any meaningful way, but you would see a bump in performance and reliability going to a fully modern EFI unit with knock monitoring and full control of spark and fuel to each cylinder (plus appropriate tuning). That would allow you to get the most timing and ideal amount of fuel for every cylinder and in all circumstances.The first production EFI (after Bendix's failed Chrysler experiments in the 1950's) was the Bosch system in Volkswagen 1600 TL in 1968. The Bosch system was actually based on the Bendix's patents from the 1950's which Bosch purchased FROM Bendix -the difference was that transistor reliability had vastly improved in the intervening 10 years allowing Bosch to succeed where Bendix had failed. . That is: the Bendix design worked fine but poor electronic component quality made it impossible to live with.
As Bosch was 'literally' the only EFI available in 1968, ALFA would have had to buy the rights from Bosch and set it up for their engines. Remember however that the Bosch EFI was having its first application in 1968 and SPICA first appeared on a production Alfa for a 1969 model. Given the poor prior history of EFI it would have been a foolish gamble to try in it the same year that VW was trying it. Nobody could know for sure that EFI was actually going to work THIS time.
Mechanical fuel injection however was a mature technology dating back to the 1930's and used extensively in fighter planes in WWII and in expensive Mercedes cars et al in the 1950's and 60's. Further ALFA had a very good MFI system they'd used in diesel vehicles for years and were already using in their gasoline race cars in 1968....
The choice was obvious. By the way, contrary to what OP suggests the SPICA is NOT a throttle-body injector system: each intake port has a dedicated injector just as EFI does. It's a very sophisticated system - not some soviet-style kludge.
The reason that MFI was not common in gasoline vehicles in the 60's comes down to three points: MFI requires sophisticated design and precision machining so it's expensive to make. This limited its use to expensive cars or race cars trying to extract that last bit of extra power. Next, gasoline was cheap and no one cared enough about fuel efficiency to justify the expense in cheap cars and people buying expensive cars could afford the gas. Finally nobody gave a **** about pollution.
So why did EFI overtake and replace MFI in the 70's? Well, the first reason is that EFI is much much cheaper - circuit boards don't require the precision machining of a SPICA pump. Next and ultimately more important of course is that EFI allows more precise monitoring of conditions and measuring of fuel. This includes an O2 sensor necessary for pollution measurement and control. However from a performance standpoint for a street car, I don't believe there would any perceivable improvement in converting a car today from SPICA to a later EFI set up.
As to a difference in sound or character between SPICA and EFI - I have a 1971, and I don't notice any flaws in performance of the system: no cold start problems or hesitation, no flat spots in the power band, so I don't -personally- notice any differences between my SPICA and the EFI cars in my other personal vehicles: they just work. I am told that the first year SPICA's (1969 models) did have some such flaws but they were ironed out in subsequent years.
BTW, I see you have an '85 Spider with the L Jetronic system. Did you ever print out and go through the troubleshooting procedure that GHNL has on his signature line?
I just bought the car, and am about to have Jim G do a look over on it, so no. I mean I read through it, but haven’t gone through the steps.BTW, I see you have an '85 Spider with the L Jetronic system. Did you ever print out and go through the troubleshooting procedure that GHNL has on his signature line?
Along the lines of history lessons, I believe some of the German planes in WW2 were mechanically fuel injected which gave them some advantage over carbureted Allied aircraft. For the SPICA system there is this: The Lost Art of Mechanical Fuel Injection
For whatever reason, the website has "Images No Longer Available" . When I first stumbled across this, I downloaded the article in Word format with the photos. If anyone would like a copy, send me a PM and I will provide.
Since this is a fuel system discussion and SPICA was not limited to Spiders, it probably would have been better in the
Carburetors, Fuel Injection & Air Intake
forum. The moderator may consider moving.
For whatever reason, the website has "Images No Longer Available" . When I first stumbled across this, I downloaded the article in Word format with the photos. If anyone would like a copy, send me a PM and I will provide.
Since this is a fuel system discussion and SPICA was not limited to Spiders, it probably would have been better in the
Carburetors, Fuel Injection & Air Intake
forum. The moderator may consider moving.
I didn’t know that forum existed. Though honestly, what I’m mostly interested in is why the character between the Spica and EFI Spiders is supposedly different, as some say. I wanna know how they differ, if they do in fact actually differ. Some say that the car lost a bit of character from the change.Along the lines of history lessons, I believe some of the German planes in WW2 were mechanically fuel injected which gave them some advantage over carbureted Allied aircraft. For the SPICA system there is this: The Lost Art of Mechanical Fuel Injection
For whatever reason, the website has "Images No Longer Available" . When I first stumbled across this, I downloaded the article in Word format with the photos. If anyone would like a copy, send me a PM and I will provide.
Since this is a fuel system discussion and SPICA was not limited to Spiders, it probably would have been better in the
Carburetors, Fuel Injection & Air Intake
forum. The moderator may consider moving.
The spiders built during the SPICA era were in fact somewhat lighter, compared to the series 3 Bosch injected spider. Alfas made during the early 1970s had a superior power to weight ratio, and their performance reflected that. So a stone stock well tuned '72 with SPICA injection will put an S3 Spider in the rearview mirror, but not entirely due to fuel injection type. It's a combination of technology and vehicle weight.
So if some people talk about the "character" of the car they may be referring to outright performance.
So if some people talk about the "character" of the car they may be referring to outright performance.
A lot of manufacturers used mechanical injection during the late 60's and early 70's. Porsche 911's. The BMW 2002TII's.
Then in the late 50's on. The top hp Corvettes had it.
Then in the late 50's on. The top hp Corvettes had it.
Look at their plenums and throttle bodies. A Spica system has equal airflow, or perhaps better, than a pair of Weber DCOEs. The air intake on a Bosch injection Spider is like breathing through a straw.why the character between the Spica and EFI Spiders is supposedly different,
I'm daydreaming about finding a 1982 Bosch Spider, then remove all of the Bosch intake hardware, install a Weber intake manifold and a pair of DCOE throttle bodies with programmable EFI... then I'd have an EFI Spider that sounds like an Alfa.
So the sound differs? See this is what I’m gettin at.Look at their plenums and throttle bodies. A Spica system has equal airflow, or perhaps better, than a pair of Weber DCOEs. The air intake on a Bosch injection Spider is like breathing through a straw.
I'm daydreaming about finding a 1982 Bosch Spider, then remove all of the Bosch intake hardware, install a Weber intake manifold and a pair of DCOE throttle bodies with programmable EFI... then I'd have an EFI Spider that sounds like an Alfa.
I think that the question you're asking is more about the difference in the cars' performance than the difference between the characteristics of the fuel injection systems.
The 1985 Alfa Spider generally doesn't perform as well as the 1971 -1974 Spiders. The difference is that the 1985 car albeit with EFI produces less power than the earlier cars, and it weighs morebecause of the 5 MPH bumper requirements. Additionally the added weight is at the very nose and tail of the car (because that's where the 5 MPH bumpers and their structure were added). Theoretically this affects handling.
Figures for actual weight and horsepower vary all over the map for any given year of Spider because the specifications for US models and European models differ widely after the U.S. started bumper and pollution requirements. Many sites seem to conflate the specifications. Having said that, the figures below seem to match with what I've generally seen over the years.
The 1985 U.S. spec Bosch 2 liter Spider produces SAE 115 horsepower and weighs 2548 pounds
The 1971 U.S. spec SPICA 1750 Spider produces SAE 135horsepower and weighs 2290 pounds
The 1972 U.S. spec SPICA 2 liter Spider produces 129 horsepower and weighs 2403 pounds
NOW: My friend with a Scatpack Challenger laughs at these distinctions, saying that his horsepower varies by 20 depending on the temperature, and the weight difference is "one fat girl and her suitcase".
So these are pretty much differences without any real world distinction - it's like arguing about what size shoes the angels wear when they dance on the head of a pin
The 1985 Alfa Spider generally doesn't perform as well as the 1971 -1974 Spiders. The difference is that the 1985 car albeit with EFI produces less power than the earlier cars, and it weighs more
Figures for actual weight and horsepower vary all over the map for any given year of Spider because the specifications for US models and European models differ widely after the U.S. started bumper and pollution requirements. Many sites seem to conflate the specifications. Having said that, the figures below seem to match with what I've generally seen over the years.
The 1985 U.S. spec Bosch 2 liter Spider produces SAE 115 horsepower and weighs 2548 pounds
The 1971 U.S. spec SPICA 1750 Spider produces SAE 135horsepower and weighs 2290 pounds
The 1972 U.S. spec SPICA 2 liter Spider produces 129 horsepower and weighs 2403 pounds
NOW: My friend with a Scatpack Challenger laughs at these distinctions, saying that his horsepower varies by 20 depending on the temperature, and the weight difference is "one fat girl and her suitcase".
So these are pretty much differences without any real world distinction - it's like arguing about what size shoes the angels wear when they dance on the head of a pin
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