Fiat 124 Spider Forum banner

1 - 18 of 18 Posts

·
Administrator
Joined
·
1,928 Posts
Discussion Starter #1
I reached out to my contacts at FCA last week to get some technical information regarding this engine to share with the community. I'm sure some of you that were involved in the 500 Abarth groups are more familiar with it, but I figured I'd keep this thread updated as new information comes in.

So far, the first tidbit of information I got was that the 1.4L Multiair in this car is part of the FIRE engine family. FIRE stands for "Fully Integrated Robotised Engine." This is a distinction from the Tigershark engine family, which powers the Fiat 500X and also has multiair.
 

·
Registered
Joined
·
1,930 Posts
My very first car - back in Scotland - was a Fiat Uno 45. It was on a 'H' plate so probably a 1990 model. There were two versions of the Uno 45 - mine had the 'FIRE' engine - 995cc and all of 45 horsepower - hence the model designation. Compared with the non-FIRE engine, my car was much quicker (OK - that's all relative), and it was absolutely bullet proof - I did everything in a 17 year old's arsenal to destroy it and it kept on plugging away.

Loved that car.

Can't believe they are sill using the 'FIRE' designation.
 

·
Registered
Joined
·
1,111 Posts

·
Administrator
Joined
·
1,928 Posts
Discussion Starter #6
I've received some additional information!

Innovative MultiAir® cylinder head
Unlike engines that rely on direct action from fixed lobes on the camshaft to control intake valve opening and closing, MultiAir is an electro-hydraulic system that can control intake air, cylinder by cylinder and stroke by stroke depending on the demands from the standard electronic throttle control (ETC) system.

Actual opening of the valves is achieved by hydraulic fluid running through a narrow passage that is controlled by a dual-action solenoid (one for each cylinder). When the solenoid is closed, under highway speeds or full acceleration, intake valves are fully opened much like a traditional engine for maximum power. At lower speeds, the solenoid opens, allowing oil to bypass the passage, decoupling the valves. This allows for infinite control of the valves and the amount of fresh air into the cylinders, reducing wasted energy that is common with fixed intake camshaft lobes.

Spent exhaust gases are released through traditional lobes on the camshaft and exit through a cast stainless steel exhaust manifold.

Ignition is through a single output, coil-on-plug system. Spark plugs are dual precious metal for durability.
Fuel delivery is sequential, multi-port, electronic, with injectors located to direct the fuel spray at the intake valves in a wide spray pattern that increases fuel atomization and enhances complete combustion for a smooth driving experience.

MultiAir technology on normally-aspirated 1.4-liter engines helps boost torque and contributes to greater fuel efficiency.
 

·
Registered
Joined
·
1,155 Posts
I know it says 'hydraulic' in the above, but it is engine oil, isn't it (technically, of course, hydraulic)? I'm actually curious why they used an iron block instead of aluminum, but I have several guesses why (durability for potential increased output, and the size is small enough that a weight reduction using aluminum would not be worth the engineering exercise?).
 

·
Super Moderator
Joined
·
949 Posts
I think your speculation is spot on. Contemporary cast iron is hardly the stuff they use to make horseshoes. It has many advantages that probably outweigh aluminum.
Best regards
Pet
 

·
Registered
Joined
·
1,111 Posts
Would using the cast iron block also help lead to the claimed "near 50/50" weight distribution of the car? All other things being equal, an aluminum block would lighten the front of the car.

Steve.
 

·
Administrator
Joined
·
1,928 Posts
Discussion Starter #12
Front of the car is too heavy. 54%/46% The MIATA hast about 52/48 with a 2l engine.
What is the weight distribution once you put an adult male passenger in the driver seat?
 

·
Registered
Joined
·
114 Posts
Did you find out? Would it offset the slightly heavier front? I find the Abarth a little twitchy when cornering.
 

·
Registered
Joined
·
413 Posts
I think your speculation is spot on. Contemporary cast iron is hardly the stuff they use to make horseshoes. It has many advantages that probably outweigh aluminum.
Best regards
Pet
Bottom line: cost. The other (reasonable) way to do the block is aluminum with steel or iron sleeves. That's more complicated to manufacture, and the aluminum is more expensive. Using an aluminum bedplate does shave some weight. Since the only significant advantage to using aluminum would be the shaved weight, I guess they figured it wasn't worth it. If it were a straight-up race car, they'd probably have nore seriously considered it.
 

·
Registered
Joined
·
413 Posts
What is the weight distribution once you put an adult male passenger in the driver seat?
From the cutaway views I've seen, it looks like the passengers are almost right in the middle. When Isaiah drove our 124 on the Solo2 course with an instructor, and when I drove with him as a passenger, we both noticed that the handling balance didn't seem changed at all.
 

·
Registered
Joined
·
114 Posts
Yes you're right. I didn't notice any changes either. Passengers are centre. I've notice a change since sound deadening the trunk - 5 kilos. It feels a lot more planted, smooth. I'm thinking of removing it though.
 

·
Administrator
Joined
·
1,928 Posts
Discussion Starter #17
From the cutaway views I've seen, it looks like the passengers are almost right in the middle. When Isaiah drove our 124 on the Solo2 course with an instructor, and when I drove with him as a passenger, we both noticed that the handling balance didn't seem changed at all.
Reason I mentioned it was because it looked like the seat is a little rearward of the center location. With a driver, the weight would be shifted slightly to the rear.



That was in response to the notion that the front of the car is too heavy. I don't think a couple of percent difference in weight distribution is going to be that consequential.
 

·
Registered
Joined
·
114 Posts
It is well balanced and the seats positioned centre, slightly to the rear would counter balance the long nose. But I can feel a difference with the extra 5-6 kilos in the trunk, evenly distributed. I think I prefer it before though so might remove a couple of pieces.
 
1 - 18 of 18 Posts
Top