Say I may have a line on a carb'd car with this particular engine in it, and I wanted to get the output up to somewhere between European standard and NA Miata 1.6. So around 90-ish horsies.
How much of an engine rebuild am I looking at? I know about the 1.6L "option" that requires parts that aren't that easy to find and/or have to come from Europe. That might be a little more than I'd be willing to throw at the car for now. Is this doable with more carbs, possbily a shaved head (for the engine, not the owner) and the usual exhaust + header? Or am I looking much deeper into the engine?
And yes, I know the answer is K-swap, but for right now I want to figure out if it's halfway feasible to add another car I really like to the stable or if I'm back to looking for turboable NA Miatas, unicorn CRX Si and similar stuff.
My '74 X had close to 120 at the crank (1500 swapped in). To get there was a bit of work, it had HC Pistons, a ported and matched head, cam, header, light flywheel, and dual Weber 40DCNFs. And it was built by Steve Hoelscher who knows his way around a Fiat engine. It was a blast to drive and I owned and autocrossed for 10 years. Selling it was a sad day.
edit. I should also point out that it sounded incredible and rev'd like crazy.
Guess it wasn't that hard to figure what model Fiat I'm considering 
.
I do know the US model's lower compression - at least for a lot of the carb'd models - is one of the major issues with these cars. I was just wondering if it would be even feasible to hit 90-100bhp without bottom end work. It looks like the options would either be to get a carb'd model - might be easier to do a more radical cam, but would need dual Webers - or get an FI model, which starts out with more power already but limits the choice of cam before I have to megasquirt it.
I think 90 is reasonable without getting into the bottom end. I would scroll through the "Ultimate SOHC" thread by fiatfactory over on XWeb.
I'm slowly getting ready to put together another motor for our 128. Going injected X19 1500 bottom end with stock pistons, the Chinese Tipo 39.5mm/31mm big valve head, a vick 37/71 cam, and a modified Punto GT intake so I can use modern injectors with the MS that's currently in the car. I think this combo is good for about 9.5:1 compression, but I don't recall the exact figure off the top of my head. 90-100hp would be enough for the little 128. 
I don't know anything about the engine in question...but is it really worth trying to avoid bottom end work with a low compression engine? Yank it, drop in some new slugs and now you've got fresh bearings and rings to go with that head.
ddavidv
PowerDork
1/28/21 1:08 p.m.
There's things you can do with pistons, cams and heads, but...
The most impressive one I ever drove was one with a turbo on a bone stock 1.5 EFI model. Used a old Subaru 1.8 turbo because it was small. Fast spool up. Could run about 12 psi until the stock clutch slipped.
Keith Tanner said:
I don't know anything about the engine in question...but is it really worth trying to avoid bottom end work with a low compression engine? Yank it, drop in some new slugs and now you've got fresh bearings and rings to go with that head.
Part of the reason for this thread was to find out if it's doable and worth it. One of the Fiat-specific vendors is selling complete heads - with cam and everything - that are milled for a pretty significant bump in compression already. Of course it would be nice to have the bottom end redone, balanced and fitted with high compression pistons, but I was wondering if that would make more sense as the second stage.
Of course with that level of mods we're also getting close to me wanting proper engine management with a knock sensor because I'm not sure I'm up to tuning carbs and ignition that well after bumping the static compression by almost two full points.
ddavidv said:
There's things you can do with pistons, cams and heads, but...
The most impressive one I ever drove was one with a turbo on a bone stock 1.5 EFI model. Used a old Subaru 1.8 turbo because it was small. Fast spool up. Could run about 12 psi until the stock clutch slipped.
Dropping in the Uno Turbo engine with all the attached bits used to be quite a common modification on these in Europe, and there isn't much of a reason to not try this on the 1.5L. My main concern would be heat management though. But "turbo all the things" has a certain ring to if I'd be able to find a turbo manifold. After all, the FI version has similarly turbo friendly compression as the Miata does (around 9:1).
Of course at that point we're also in the land of Megasquirt if I want this car to hold together for longer than an Auto-X run.
BoxheadTim (Forum Supporter) said:
Keith Tanner said:
I don't know anything about the engine in question...but is it really worth trying to avoid bottom end work with a low compression engine? Yank it, drop in some new slugs and now you've got fresh bearings and rings to go with that head.
Part of the reason for this thread was to find out if it's doable and worth it. One of the Fiat-specific vendors is selling complete heads - with cam and everything - that are milled for a pretty significant bump in compression already. Of course it would be nice to have the bottom end redone, balanced and fitted with high compression pistons, but I was wondering if that would make more sense as the second stage.
Of course with that level of mods we're also getting close to me wanting proper engine management with a knock sensor because I'm not sure I'm up to tuning carbs and ignition that well after bumping the static compression by almost two full points.
I guess it depends on how hard-core you want to get with the bottom end. Don't bother balancing. Just yank the pistons, give the bore a quick ball hone and drop the new ones in. Change out the main bearings and button up. It's more work than just swapping in a shiny new head but not exponentially so if you restrain yourself. You can certainly fall down a rabbit hole but you don't have to.
In reply to Keith Tanner :
That's a good point. ISTR that the high compression pistons are only available in an oversize, so a trip to the machine shop would be necessary. Which then opens lots of rabbit holes "while I'm in there".
Wiseco will make custom pistons in any size you want. Same price.
In reply to Keith Tanner :
Looks like this vendor is able to get the pistons in other bore sizes as well.
Come to think of it it's probably a good idea to pull the motor and at least place bearings etc. Apparently 1980 was 40 years ago, even though it doesn't feel like it.
BoxheadTim, I'm certainly not a guru but the processes are well known. I'm going to build a 1500 pretty much to what you are inquiring, 85-90 whp. The US FI 1500 is about 64 whp. They also have more torque than hp, which is nice for the street - I rarely use 1st gear. The standard approach is a complete exhaust change, modified head/cam, n.a. in the 10.1-10.5 compression range and a few other little changes. The fuel injection on mine was recently redone and the bottom is solid. I haven't checked the compression yet but the head was recently off and it feels rock solid. If the cylinders are scored etc. I'll rethink it and would probably up it to a 1580 while in there but I doubt it needs anything in the block, fingers crossed. I imagine you're referring to MWB for the head/cam.
I have a 4-2-2 exhaust but a 4-2-1 is fine and lighter. After the head I'll install a lightened flywheel/clutch, etc..
I've pulled around 300 lbs. so far and it's not the same car. Getting some Avon ZZS 18/55/13s and 7.5 lb. 13x6 wheels, both from England. I have very high quality (Dallara copies) fiberglass doors, frunk, roof, and engine compartment but not sure if they will go on this X as it is in really nice condition. I REALLY lucked out on this X.
After all of that I will decide if it is enough power. If I stay with the Lampredi lump an aftermarket ECU/injection system and block work gets expensive for the extra 15- 20 hp.
Here is mine with -270lbs., lots more to pull but not sure how much farther I'll go as it's a street car. Maybe another 100lbs. while retaining the ac. I'll get coilovers soon to drop it just a bit.
In reply to BoxheadTim (Forum Supporter) :
Late to this post as I was working on my X tonight. The bottom end of these engines are nearly unbreakable. my MegaSquirted 9.2/1 compression car with a home made tri-Y header must be nearly 100 HP at the crank. I do need a dyno run, but I have been to busy driving it. Just a head swap is a good place to start. If it has good looking oil and decent pressure I would not worry about the bottom. They are not high oil pressure engines, they don't need to be. Oil pressure should roughly equal RPM until the relief valve opens about 60psi. The MegaSquirt adds power only because the original Bosch air flow meter is extremely restrictive. Above 100 HP the transaxle/clutch are the weak links. Warning, 1st gear turns the reverse idler, so you cannot down shift into 1st, as the idler is stationary in all other gears. With the stock X1/9 final drive ratio that is not an issue ever. I changes to a slightly longer one from a Ritmo, and it will still lug away in 2nd almost everywhere. As Hasbro noted there is a lot of wheight removeable from the original configuration, and the difference is marked. If you are comfortable in the driving position there is nothing better that a 1500 X1/9. Avoid the 1300s, it isn't the engine at fault.
In reply to Keith Tanner :
They are Cromodora CD31s, 13x5.5. Hard to find. The next wheels will be 6 or 6 and 1/2" wide.
In reply to amg_rx7 (Forum Supporter) :
I do. My younger self owned a couple of them. Of course I've grown a tad, err, wider since then but not taller.
In reply to Hasbro (Forum Supporter) :
I was going to ask you for a build thread link, but I already found it over on xweb.
In reply to BoxheadTim (Forum Supporter) :
Here's a good quick rundown for a street f.i.1500. This is from a pm from a guy that I really respect.
I know what EFI kit you are talking about, I think it is from VAS (Vics). That is basically the same as what I'm describing. And a good example of why I said don't buy from the vendors; you can assemble the same kit for well under a grand.
Really all you need is a engine machine shop to build your own performance head. The valve sizes on the stock head are good. I know the "big valve" thing is popular, but it has been proven to me by several experts that it is actually a mistake to go to bigger valves on these engines (the stock ones are already quite large for the engine's design)....unless you are building a 'race' only engine that will run constantly at redline with no bottom end, and a huge induction system, etc. Certainly not a street engine. Many guys just don't understand the theory and design aspects, and go for what sounds cool based on what others say online. So a standard valve job is all you need. But have the machine shop mill off quite a bit from the surface of the head to up the compression. The details for how much to remove have been established on the forum.
Porting is similar to the valves; you don't want to do too much for a street engine. Basically clean up any casting imperfections and make sure the mating surfaces are a smooth transition between the head and intake manifold. This can also be done by many standard shops.
By increasing the compression at the head, you can retain the stock pistons. So if the bottom end is in good condition then no need to modify it.
Definitely get a better cam. The best option is the Euro spec late 1500 version. Unfortunately it's become hard to find them any more. But MWB offers a clone at a very decent price (one of the few good deals from the typical vendors). I have one for one of my X's.
A header can be found from a few sources. The very best street version is no longer being made. It came from ANSA, and could be had with a matching exhaust system (muffler, etc). Those headers come up used now and then, but sadly none of the new parts sources have ever cloned it (I cannot understand why, it is by far the best design). The next best option is from VAS.
With the EFI mods we talked about, the head mods described above, the cam and a header/exhaust, you will have about the highest performance SOHC engine possible that is streetable (drivable). It is very tempting to go further with more extreme mods, yielding higher top-end numbers. But it will not be good to actually live with anywhere other than the race track.
Along with these performance mods I'd recommend upgrading the cooling system and adding a oil cooler. There will be a very noticeable difference with this setup. Although the actual power increase won't be HUGE. To get more than that you will need to either install a completely different engine or add a turbo (which will require different mods).
In reply to BoxheadTim (Forum Supporter) :
I sorta fit. 6'2", 180 lbs., EEE feet. I found the seat to very comfortable but am currently driving seatless to get lower. Just a UHaul furniture blanket wrapped around some plastic storage lids.
It fits similar to a Europa but Italian style, which is different (worth watching);
https://www.youtube.com/watch?v=4LiAKSXpXX4&feature=emb_logo
In reply to Hasbro (Forum Supporter) :
Thanks, that's very helpful. When I looked at the VAS aftermarket EFI I looked at the ECU thinking "well, this looks very familiar". It looks like Megasquirt might be a better option in the longer run as some of the options I'm looking into (assuming I can pull of a car I don't have to sweep up) would be a pain in the posterior to tune on carbs. I'm surprised what options are (still) available for these engines, but then again, they made a ton of them.
Re the fitment, the one thing I never checked because my ownership of them predated my interest in track driving is if I actually fit in the car with a helmet on at 5'11".
I am 5'10" & 32" inseam. Here I am with my helmet, and the stock 1981 seat which is pretty high off the floor.
This dude in England is having his street 1500 built to a 1600(1580?). According to the shop they should get 130 hp. That's about the most I've heard for street without using a bigger Lampredi. The builder (highly regarded) claims he could get 150 from it but for track only.
