In 1967 , while serving in the Army in Germany , I purchased a new 1967 Fiat 850 Coupe . During the 18 months I served in Germany , I Rallied , Solo One , and toured central Europe . " Sophia " performed without a flaw . When I returned to the USA , the 850 Coupe was used in the same manner . The only problem was the lack of power , even after adding Abarth bolt on performance equipment and various other modifications . Today , I want to return to the 850 Coupe scheme . I hope to implant a Fiat 500 Abarth engine with 260 hp , transmission , brakes , wheel and tires , radiator , seats , and the electric wiring . I know that such modifications have been made on the X 1/9 , but have never heard of these modifications on an 850 Coupe . I am looking to obtain , from this forum , any dialogue from members of the forum which would aid in this project . Please no comments on that much hp on such a short wheelbase , I am fully aware it will be a handful . But a Performance Car should be a handful .Thank you for any help you can provide . I am looking forward to your comments .
Fiat 850 Coupe Performance Upgrades
- Thread starter steve b.
- Start date
Alex(Tenerife)
True Classic
Sorry can't help I am not familiar with the 850 but just want to say that this sounds like a fun project and could be a fun car to drive when done.
Anything can be done with sufficient either money or construction skills. I hope some of the guys here can help make your idea a reality
Anything can be done with sufficient either money or construction skills. I hope some of the guys here can help make your idea a reality
kmead
Old enough to know better
This hasn’t been done by anyone yet but other mods have been done which are similar starting with Abarth using both the push rod 124 motor and the twincam 124 motor. A friend of mine had an 850 spider with a 1438cc reverse rotation twin cam in the back. He sold it a few years ago and I don’t know if I have any pics of the engine bay from that car.
There was a 1300cc Suzuki G13B twin cam installed into an 850 Sport Coupe with a VW transmission for sale in the northwest which sold several years ago.
I have also seen a Honda B16 twincam installed in an 850 with the advantage being it is also a CCW motor so they retained the 850 transmission.
In regards to the Fiat 500 Abarth motor, it would be desirable to remove the Air head and substitute the TurboJet head where the engine could be dealt with using fairly standard engine management products versus keeping all the wiring the Air requires.
You might want to read the three completed X swaps of the Abarth Turbo motor you can find in the Best of Xweb Engine Swap threads.
Understand you will need to make considerable sheet metal changes and likely move the fuel tank to the front trunk (not a bad thing from a weight distribution perspective. Transmissions to take plenty of power will need to found, the VW/Audi or Subaru units could work in this instance. Another alternative might be to make it a longitudinal mid engine car again leaning on the VW/Audi and Subaru transaxles.
kmead
Old enough to know better
The Coupe comes standard as a longitudinally oriented engine and transmission with the engine at the rear of the car behind the rear wheels. The 500 is transverse with the engine forward of the front wheels so in the case of the 850 it would now be a mid engine car mounted where the Coupes’ semi trailing suspension arms are now.
Installing the 500 engine transversely will be challenging in an 850 as the 500 is much wider. Fitting the 500 Abarth engine in an X requires a fair amount of engine bay surgery, the 850 would require re-engineering much of the rear of the car. You would likely be best off cutting out all of the interior rear sheet metal and replacing it with the primary structure of the 500 with its suspension in place of the 850 components. I have no doubt it could be done but would be challenging. In the images below you can see the X struts end up just inboard of the 850 rear windows with the top of the struts also nearly inline with the base of the windows.
If I had the money to do a project like this, I would want to keep it as 850 as possible. I would go down the path of the 1050cc version of the engine which produced 70 hp. I would then add the 8 port head ( https://classicperformance-parts.co...2-fiat-127-600-seat-pbs-8-port-cylinder-head/ ) which would allow port injection and then follow Graham Bates ( @ramona300 ) path of supercharging or similar to maximize the power one could elicit from the existing engine arrangement. Graham has kindly documented some of his trails and tribulations here: https://xwebforums.com/forum/index.php?threads/850-sport-coupe-series-2-track-car.28768/
A number of years ago I created these drawings of an 850 overlayed with an X1/9 engine and suspension. Keep in mind a 500 is 1627mm wide, one would need to measure the actual wide of the engine bay.
There is also this thread from here four years ago:
850 Engine swap?
I have seen people switch Honda VTEC into X1/9s and even V8's into 124 Spiders. Has anyone seen any swaps with the 850 Spider? I have looked around and haven't gotten much back since our cars aren't too common. Of course there are the A112 swaps, but I wasn't sure if anyone used something...
xwebforums.com
850 Sedan / X1/9 Engine Swap
New member @Wayne Daudet has a 40 year project 850 standard sedan. I started this thread for him to add details about it. ;)
xwebforums.com
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kmead
Old enough to know better
Some of this has been a recurring discourse
The issue of the transmission given Fiat never had a high horsepower longitudinal rear transaxle remains a stumbling block to keeping it all Fiat. There is an Alfa Romeo Alfasud in Australia which was built, I recall seeing a pic of it a long time ago.
Perhaps that or the Lancia Gamma transaxle could be used to hang the late 500 Abarth motor off of in the rear.
X motor in an 850 Spider?
While driving my 850 yesterday, pedaling as hard as I could (a la Fred Flintstone) to keep up with traffic, I had this fantasy thought about what it would take to drop an X1/9 powertrain into an 850 Spider. Here's the concept: Remove the rear 'seat' (parcel shelf), and stow the folding top...
xwebforums.com
The issue of the transmission given Fiat never had a high horsepower longitudinal rear transaxle remains a stumbling block to keeping it all Fiat. There is an Alfa Romeo Alfasud in Australia which was built, I recall seeing a pic of it a long time ago.
Perhaps that or the Lancia Gamma transaxle could be used to hang the late 500 Abarth motor off of in the rear.
kmead
Old enough to know better
That is an excellent question. I think Graham has come close to finding out.
I haven’t seen a max hp folks have put through one, though there have been some healthy twin cams trying to strip one out. Generally the axle couplings twist out before blowing up the transmission. It was designed for a sub 60 hp engine but has certainly been pushed far beyond that.1
The big issue with this transmission is it is designed for a counter clockwise engine and can’t have components flipped to change that direction which limits the motors you can attach to it (early Honda, Mitsubishi, Fiat and a few others).
Jeff Stich
True Classic
Abarth was using a modified version (5-speed & 6-speed) in the OT1300 & OT1600 race cars which had 105hp & 145+hp respectively.
fiatfactory
Steve Cecchele
It won't so much be a function of Hp that destroys the transmission (i.e. breaks gears and shafts) it will be torque that does the damage...
SteveC
carl
True Classic
It's been a long time, over fifty years, since I autocrossed my 850 coupe but as Jeff mentions, it was the plastic couplers from the axles to the hubs that were the weak link. My first lesson in ride height and cornering was with 850s. I had my coupe and my main competitor had an 850 spider. I had lowered mine and ran negative camber on the rear and ran about even with that guys spider. I later got an 850 spider and was shocked to see it cornered stock as well as or better than my old coupe. Lesson learned!
Clatter
True Classic
A friend did an aircooled VW drivetrain swap to an 850.
This would likely be the most practical way to get a better engine in place for a couple of reasons.
First, they make adaptors for just about any engine,
Second, they can be built to take big powa.
The narrow track of the 850 is the huge challenge.
Even using narrow Beetle rear arms and gearbox, the axles have to be shortened severely.
This puts CVs into sharp angles and binding at small amounts of suspension travel.
Your plan to put in a modern 500 drivetrain would almost surely have to include wide flares or wheels poking way out of the arches if the suspension is going to work well.
This would likely be the most practical way to get a better engine in place for a couple of reasons.
First, they make adaptors for just about any engine,
Second, they can be built to take big powa.
The narrow track of the 850 is the huge challenge.
Even using narrow Beetle rear arms and gearbox, the axles have to be shortened severely.
This puts CVs into sharp angles and binding at small amounts of suspension travel.
Your plan to put in a modern 500 drivetrain would almost surely have to include wide flares or wheels poking way out of the arches if the suspension is going to work well.