I've got a turbo Subaru engine in mine, which honestly is too much motor for the car, but a motorcycle motor would be awesome in one of these.
Yes, I don't want to change the character of the car too much, but more engine would be nice, something cool like the supercharger with the weber would be perfect. Brakes are first, fronts are a mess, plus new tires both coming this week.
I loved the little Fiats - I've owned a number of them thru the years - these were the perfect 55mph car (National speed limit at the time) fun to drive, but pretty slow. This one looks like real fun!
I know there are things you can do to get more hp but IIRC these were already turning 5K at 70 - if you could get it there......
Somewhere, I have an old Road & Track special publication that highlighted using a 1.6L out of a 124 (spider or coupe) in the 850. I looked online and could not find an electronic copy but someone may have better Googlefu than me.
Yes, I would love to do a larger Fiat engine, something period correct would do the trick. You have to reverse the direction of rotation if you are keeping the 850 4 speed.
Abarth did twin cam heads for the 850 motors too
brad131a4 (Forum Supporter) said:Have a Fiat repair guy close to me. He used to race these and 124 coupes back in the 70's and 80's. His home shop is full of odd little engine projects he's done over the years. I need to stop by sometime soon. I'll see what he might have as far as go fast parts for the 903.
If you learn of anything he might have, like parts to build a 1050 or PBS parts, I would definitely be interested!
MiniDave said:Abarth did twin cam heads for the 850 motors too
That is pretty cool, but not $4,500 cool
MiniDave said:Abarth did twin cam heads for the 850 motors too
That is pretty cool, but not $4,500 cool
PBS has a big valve ported head with intake for double DCOE's but pretty expensive.
The PBS heads currently available through Scuderia Topilino are nice pieces of kit. They really transform the motors. Of course to run them properly you have to relocate the radiator so the DCOEs fit and if you are swapping the head you should probably up the compression and add a cam......
You can make a genuine 100hp to the wheels with a 1 liter motor with the 8 port head.
Mighty Mouse!!
Got some other projects out of the way, so put the 850 on the lift to see how much work I am in for...... I had ordered pretty much all the brakes as it is hard to trust anything on a 56 year old car. The front calipers were locked up and I had ordered the rebuilt kits but after the hose retainer bolt broke off in the caliper, I decided to just buy new calipers. So new calipers, rotors, pads, hoses, rear shoes, cylinders and a new master and we should be good to go. Hopefully the master comes out without too much difficult.
Body wise not big surprises. The battery box was rusted out and it came out cleanly so I can put in a new bottom piece. There is a gouge in the drivers front outer frame rail, that is not rust, but looks like it hit a curb at some point, so I should be able to cut it out and weld in a patch. Rest of the floor looks good and the crossmember is solid and just a few small patches around some of the drain holes will be required.
Up front it is a little more interesting. There are areas where it is obvious that the underlying panels are originally yellow, but the car and the paint code on the VIN say that the car was blue. The engine compartment seems to have been blue as well but was resprayed the current off white. There was lots of seam sealer in the front trunk and I started scraping it out and now can see what I suspected was the case. The car must have been in a fender bender at some point in it's life, and had a yellow nose, hood and possibly front fenders grafted on. They did not do a horrible job of it, but it could be better and I'll clean it up, weld in new sheet metal where possible and treat it with rust converter and seam sealer and it should be fine. There a couple of small holes in the front trunk floor, all easily patched and overall the rust is pretty minimal by Fiat 850 standards from what I understand.
While I work on getting everything mechanically in order, been researching and going back and forth on how to get more power out of the little engine. Any serious engine modifications are big money (A112 Abarth 1050 engine, PBS 8 port heads, webers, all cost more money that it is worth to double the power of the little 903 engine. I am not looking for anything crazy but one of these with 100 HP would be quite entertaining.
The supercharger idea is pretty cool and reasonably inexpensive, but the guy in Australia that makes these up is AWOL so that is not likely to be a viable option. So while I am working my day job, I have a second computer I use for research. So this popped up on Ebay and was reasonable so I bought it!
So now I will be looking for a small turbo and carburation recommendations, any ideas are appreciated. Goal being to keep it simple, reliable while taking it from 52 HP to closer to 100.
Meanwhile, the brake upgrades are going well.
With help from the hive, I have come up with the recipe for this Spider build. Knowing that I could not keep it stock, but also don't want to change the character of the car too much, it needed to keep the 903 engine, but needed forced induction. After playing around with a baby supercharger, I picked up the 850 turbo manifold and think I have the recipe for my Turbo Spider.
Turbo exhaust manifold for the 903 engine
Air Research T25 turbo- M10 Turbine - M26 AIR .63
Webcon Retroject throttle body (basically a Weber DGV fuel injection replacement for standard Weber two barrel carb)
Classic injection kit with ECU for above Classic Injection DGV kit
Weber top hat plenum designed for turbo boost weber top hat with seals
123 Distributor (with map sensor for retarding timing under boost
Plan now is to finish the brake rebuild, do the minor patches under the car for rust repair, so it can be driven over the spring. The Cromodora CD-4 wheels are being powder coated and have fresh 185/60 R13 tires ready to go. I want to go through the engine and make sure it is all in good share before doing the turbo, so I'll play with it this summer and then do the turbo swap in the fall.
My old 843cc motor was pretty simple. The best cylinder head I had, had been skimmed a few too many times and my static CR was up around 10.5:1 so I found some NOS Borgo forged 64mm pistons and put them in the lathe and cut, what I later considered to be too much off the top. I took the CR down to 8.5:1 which made it a turd off boost. When I do it again I will shoot for a nice even 9.5:1.
I am pleased you are going fuel injection, It really seems to be the only way to do it right. I would inquire if that ECU can handle ignition as well. There isn't much more frustrating than having to have two pieces of tuning software going at the same time when most are set up to do both. Plus it would save more than a few dollars, those 123 units aren't cheap
I built a stout crank girdle for it, but it is one of those things that I have no proof that it did anything.
The throttle body was off a Yamaha Raptor, I used two stock raptor injectors. I used a 36-1 crank trigger with EDIS and a MS2V3 to control it all. The intercooler was located terribly and it heat soaked quickly. I put a GSXR1100 fuel pump in the stock tank, which worked, but now that I know more, might have been less optimal than I thought.
One thing you will quickly find is that normal sized car parts just will not fit in a car this small. I simply could not find a tidy, safe area for an external fuel pump, filter, pressure regulator and return line. That is why I went with the sport bike unit which was internally filtered, regulated and returnless.
As always, verify the health of your motor before proceeding. I cannot tell you how many cars come into the shop for upgrades and modifications that supposedly "run great" but have one or two cylinders reading 60psi on a compression test and have enough piston slap to make 'em sound like an old Kubota tractor. Those motors like to stick their rings when sitting for long periods.
Easy enough things to rebuild though.
Great advice and I'll do a compression check soon. My understanding is that the ECU they run is a Maxxecu Mini, which also supports ignition in the same unit and has a map sensor for boost.
What I like about the Webcon Throttle body is it has all the sensors built into the body for the TPS, air temperature, idle control and MAP sensor.
Since I don't know much about the history of this car, I guess we can find out from the compression readings how healthy the engine is and go from there. If there are any issues, I will build a 903 block with new pistons and measure the head to get a reasonable CR ratio, agree that 9.5:1 would be ideal for this engine and my plans for reasonable boost.
In reply to Trent :
Got this back from the Classic Injection folks.
The ECU runs both fuel and spark. Basically get a standard distributor, lock the shafts together, fit an electronic sensor to act as the trigger source and the ECU does the rest.
Sounds like the easy button for managing fuel and ignition for this project. So I just need to make sure I have a healthy engine and can go from there.
Got back from a business trip and had Christmas in March, got some of my upgrade parts for the 850 Turbo. The little manifold is so tiny and the turbo is as well. I also picked up an Abarth intake, not sure if there is any performance improvement, but it sure looks cool.
So still deciding on whether to use the Webcon Retroject throttle body and then either a Microsquirt or similar small ECU and whether one of these systems can retard the spark well enough under boost to allow me to keep it simple and retain the distributor.
I think MSD makes something that will retard spark under boost. I am sure you would rather have the fuel injection unit do everything and have it programmable. But a separate spark control might make it simpler or provide options.
MSD part 7762
In reply to dherr (Forum Supporter) :
There is some possibility that a prior porting job will make the Abarth manifold unusable. Only remove material from the head when matching these. Hopefully there is enough still there around the flange, I've seen too much removed by a "bigger is always better" person.
123ignition has programmable distributors listed for some Fiats ....
@Turnerx19 it does not appear to be ported as I don't see any grind marks, but not sure what these look like new. I'll match it to the head and not touch the manifold.
This little exhaust manifold is really cool. I guess the turbo is my muffler, as the down pipe turns and exits at the rear bumper, so this should be fun to see how it drives and sounds. I set the manifold on the existing header to see how it positions the turbo. Looks like the guy that built it had it pretty well planned out.
In reply to dherr (Forum Supporter) :
If no one has been in the head you will be surprised how much you take off in the fore-aft axis. my fear is someone has already removed material in the left right axis out towards rectangular.
Not my head, but you are saying that the stock port can be ground out to match the intake, does look like there would be some cutting to get it to match the intake.
@Trent I went back and reread your comments on using the Raptor throttle body injection and that has me thinking that perhaps rather than use the Retroject system, it might be easier and cheaper to use an OEM throttle body, any reason I could not use something like this? Geo Metro 1.0 TBI?
I would assume I could control it with a Megasquirt or similar system.
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