Technical Performance in a 1300 X

[wildcat_lgf]

Hi everyone, I did a search but didn't have much luck.

I've had a few X's, and after a short break from restoring Fiats I have an option on a very tidy 1978 X1/9. I know they are not the most popular version, but it was my first car and I think they look the best of any of the X's (stripey seats, engine cover, spilt bumpers, front spoiler etc).

I am trying to decide what is the best route to upgrade it - and I'm on a budget.

I would like to achieve ~120hp from the 1300 engine. Is this likely / possible on a budget? I would be interested to hear from those who have modified their original engines. I have a copy of Project X1/9 and a couple other similar books (most of which look expensive modifications!)

Obviously I would have to do something with the 4spd box? Ideas?

I also have a very rusty Mk 1 Uno T (160k km). that I will use the brakes etc off. I would like to avoid the cost of the transplant (I don't know that much about turbo engines) and I figure it might be more valuable in "standard" form? Ideas?

Sorry for the ramble

From what I know:
Intake valves need upsizing...say 39/31 (I/E)?
New exhaust manifold and exhaust
Cam?
Lightened flywheel
Clutch upgrade?
etc.

Thanks in advance

 

[jimbro1000]

This is somewhat dangerous territory as everyone has an opinion and if you want proper performance you need to talk to a specialist who will do the work for you. There is nothing to stop you doing the work yourself but be prepared for a lot of disappointment before you get it right.

Back to the original question though.

First of all definitely use the Uno Turbo front calipers (and frames) as they are hugely superior to the original X1/9 items.

120-130bhp is not unheard of from a 1300 *but* it may not be driveable on the road due to how it performs at low revs.

Larger intake valves are a must, these are a serious impediment to performance at the top-end of the rev range. Exhaust valves are ok but still need properly cutting, seating, polishing, etc.

You need a decent set of manifolds, the exact nature of which is going to depend on everything else.

The cam profile like the manifolds depends on the other components but a fairly aggressive profile will be needed.

The lightened flywheel isn't 100% necessary but will help unlock some of the performance. Just keep in mind that a flywheel can be too light especially for road use. The clutch should be upgraded but stay away from paddle clutches, you can get really good "organic" clutches that will far out-perform the original spec *and* avoid the on/off nature of a paddle clutch.

If you want a 120/130bhp engine you should definitely look at the bottom end of the engine too. Not necessarily for major work but definitely to ensure you have good straight rods, undamaged pistons and good shells. Any deficiencies here will lead to a very short engine life. If you want to do it properly it needs a but of lightening and balancing. We've had over 400bhp out of one of these bottom ends, the basic structure is good and the original rods can take some punishment.

Back to my original point:
Work out what kind of performance you want from the engine (I'm guessing fast road usage) and talk to a specialist about the options.

If you're on a budget you're likely to end up looking at a twin-carb setup and that is going to make 120bhp about the top of what you are going to get.

Decide what you want you're rev-limit to be - every 500rpm above normal is going to cost and the cost goes up exponentially. An engine that revs solid to 8500-9000 rpm with a redline at 7500-8000 rpm is more than adequate.

Decide where you want the power, an engine that gives more torque across the range without lots of zoom at the top end is likely to be more practical but doesn't lend itself so well to the engine design. However the lack of 16v head means the top end can struggle if too much is expected of it and the costs of porting it to do so can get expensive.

The cam profile will follow from the choice of induction and power band. The exhaust manifold will need to match the choice of cam profile. The inlet manifold obviously needs to match the choice of induction *and* cam profile.

One last word of warning - the blocks on these engines, as already mentioned are very good. However there is a problem with the blocks distorting over time when exposed to heat (ie prolonged heavy load or overheating). A good block will just rev and keep doing so. A poor block will run but as the revs go up it will soak up the power.

The 1300 block isn't as prone as the later engines but it still happens. The only way to tell a good block from a poor one is to check the crank alignment before you start - if it is off you shouldn't try using the block for a modified engine. If it is straight it needs to go in a kiln for a proper heat cycle and then check the crank alignment, if it is off then again, don't use it. If it comes out straight you have a good block that will not let you down and will let you get as much power as the rest of the components will allow.

At the 120bhp end of the possible upgrades the block distortion problem isn't too bad but it can still haunt you when trying to get the best out of the engine.

Finally don't expect Uno Turbo performance, the power figures might be the same but you will not get turbo levels of torque (the turbo should give between 30% and 50% more peak torque compared with an NA engine for the same peak power at normal rev ranges).

 

[wildcat_lgf]

thanks jimbro...as always your posts are well detailed and very useful.

I see what you mean regarding drivability of the car...yes a fast road car is where I'm heading - 7500rpm redline should be sufficient

Twin carb setup is what I was thinking, with modified cam...sounds like I should have a chat with our local Fiat experts before I get too far.

I'll definately change over the brakes - Uno T for the front and 125 on the rear (from memory) and upgrade the suspension a bit first.

Once I have the suspension, brakes sorted...I may be tempted to go the Uno T route, but would need a few extra bits and pieces.

I read in Project X1/9 that converting a 4spd box to 5spd is very difficult...has anyone had experience with it? Otherwise in future I could be needing a whole new case?

 

[jimbro1000]

It is most definitely easier to simply obtain a 5-speed box and use that but keep in mind that early 1300s don't have clearance on the lhs rear swing arm to accomodate the extra length of the 5-speed box. You should check first to see if your swingarm has a notch missing for this very purpose, if not then you will need a 5-speed swing arm as well.

Don't forget that the 5-speed box uses a different driveshaft mounting as well (a flange instead of cup) so you would need the shafts to match. Your Uno Turbo uses the same arrangement but with an intermediate shaft across the engine to the rhs.

If you are happy with a 7500 rpm rev limit then you would be looking at minimal bottom end work and spend your money on the headwork instead. You might need higher compression to get what you want and ideally that means new pistons.

Keep in mind that 130bhp would be 100bhp/litre, something that is hard to achieve with an 8v head. 120bhp is much easier to get to. If you do go for higher compression you should also consider increasing the bore of the cylinders at the same time as more cc's means more torque which is what you are going to need to get what you want. Anything between 100bhp and 120bhp is a good achievement with the 1300 engine for a budget build.

If it is a road car you are going to want downdraught carbs, not sidedraught as there isn't really enough space without sacrificing some (or all) of the rear luggage area. Keep in mind that bigger is also not necessarily better with carbs. You really need to have the head tested for flow on a bench to work out what the optimum flow rates are like and how much gas flow you are likely to see at any given revs.

I used to have a 1300 engine in my race car that did pretty much all of the above but revved well beyond 7500 rpm. Peak figure on a dyno was about the 135bhp mark. It took a lot of work to get there too. Twin 40 DCOE carbs, an original Abarth camshaft and exhaust system, a moderately ported head and some fancy work at the bottom end to increase the bore (seriously overbored with liners added, custom pistons and a lot of balancing). Sadly I didn't commission the work myself and bought it like this only to find the engine builder had taken a short cut to maximise profit and left out a couple of vital steps.

If you're in the UK then consider contacting these people: either of Guy Croft, Mario Grech-Xerri. Both have a lot of experience with the older fiat engines, Guy Croft especially. They are not cheap though, you do get what you pay for all the same. There is also Avanti cars but not everyone gets along with them. I would recommend Wolfdirect Racing as well but they have stopped working on Fiat engines to concentrate on other things. Beyond that you are looking at Europe and eastern Europe for suppliers of "off-the-shelf" parts.