What needs to be done to a fiat 128 1300 Engine before turbo charging it.
This is exactly the question I asked myself a few years ago (except for a 1500 engine).
The X is very underpowered and I am living in a region where having AC is mandatory most of the year. If you think a non-AC X is slow, try one with the AC running.
I wanted a performance upgrade but not a race car; in other words very streetable, fun, reliable, and 'sporty' with the AC on.
As
@Bjorn Nilson said, the cost to build a high performance NA SOHC is far more than it's worth. Not to mention the other trade offs it brings (decreased reliability and a peaky power band with little torque are just two examples). And it really won't get you all that far into the "performance" realm.
@fastx19's suggestion of a complete swap to a "modern" drivetrain (e.g. Honda, Toyota, Mazda, VW) is the ultimate route. But it is a huge task to accomplish. And more costly than I wanted to invest in a cheap car. I really liked the idea of using a Uno Turbo drivetrain due to the simplicity of installing it, providing enough power to be fun, while still reliable. However finding a UT engine/trans here in the USA is very rare. And purchasing one in Europe and shipping it here is quite costly. But the UT concept got me interested in seeing what might be done with adding a turbo to the original X engine (1500 in my case).
Many years ago I looked into turbocharging in general. Unfortunately in those days there really wasn't much development for it and it simply had not evolved enough. The results were very discouraging to say the least. However fast forward to today, where we have the benefit of years of OEM development utilizing turbochargers in mainstream production vehicles, and things are very different. Add to that how the aftermarket has embraced the turbo and the concept becomes a viable option. So I did a ton of research to find out if adding a turbo to the X might be a realistic possibility for me.
As it has been said, it really depends on what your goals are. In my case I wanted to keep the overall cost below the other "performance" options. I wanted it to provide enough of a power increase to make driving the X fun (with AC), but still be reliable. And I wanted it to be very "drivable" on regular roads; meaning a wide power band with plenty of torque. The best answer would be retaining a stock engine (more on that later), adding a small turbo, keeping the boost below 10 PSI, use a aftermarket (standalone) ECU, improve the engine cooling/thermal management, and source affordable components to build it from. That came in the form of a turbo and exhaust manifold from a UT (which was not too difficult to find at a good price), the "MicroSquirt" ECU from MegaSquirt, commonly available sensors/triggers/ignition (GM, Ford, VW), and some generic aftermarket accessories (BOV, WG actuator, intercooler, oil cooler, large radiator, MLS head gasket, studs, etc). The expectations - based on the experiences of others - is around 130+ HP and a ton of midrange torque.
The X's SOHC has some characteristics that are not beneficial in a high performance NA build, but actually advantageous for a boosted build. Such as its low compression ratio, pistons with thick crowns and ring landings, and heavy but strong internal components. I decided to rebuild the engine and in the process perform a few things to give it the best chance of surviving. A couple of keys to that are getting all of the tolerances correct for a boosted application, using a MLS head gasket and head studs, basic "blueprinting" of all systems to assure everything works correctly, and proper assembly techniques. I believe the stock crank, rods, and pistons, along with the original oil squirters in the rods, will be good so long as the boost level is kept reasonable as I mentioned. Likewise the standard bearings and oil system are fine provided they are in good condition and properly toleranced. A couple of good upgrades I would recommend over stock are a Euro spec X1/9 cam and stainless valves. For now I have the stock valves (I just want to see how they hold up first), but direct replacement SS valves are available at a very reasonable price. Detonation is the real killer with a boosted application. So keeping things cool, having a conservative and accurate tune, and limiting the boost are vital.
My turbo build is still in progress but based on the expenses so far, and the cost of a few remaining items, the total will be under $2000 for the complete engine and related components. But keep in mind that I do all of my own work so that does not include labor. Naturally the sky's the limit on cost if you want to go all out; the greater the boost level you run, the more you will need to replace stock components for ungraded ones. However the real limiting factor with the SOHC is the restrictive head design....trying to force more boost through it will exponentially elevate charge temps and detonation will result. So there is a limit to what can be done.
The thread linked below was started about the time I began researching this concept. It offers a lot of good discussion about what's needed. I haven't documented my whole turbo build but I will once I get it completed and can offer some actual results and outcomes.
EDIT: This thread started out talking about air flow and a intercooler. But it has grown as there is a lot more really great turbo related information to be learned from our members. So I changed the title and want to open up the discussion to any/all things relating to a turbo on a X1/9. In...
xwebforums.com
. And not cleaning his bores. I know he didn't clean them because of the scratches on the pistons. I want to make sure because I dont want to have 30min of fun and the to start all over again.
