Classic Alfa Forums

Get your order in for Auto Italia magazine January edition Simon, on sale now I guess as mine arrived in the post last week...issue 251

Thanks Kev. I'm off to order a copy straight away.

Hoping to get the 131 back this week all MOTD and with UK reg so I can drive it on the roads and provide a bit of feedback.

All the best,
Simon

Look forward to it.

Have you got it all road legal yet Simon? Looking forward to a road report!

Hi Julian,
Tom has sorted it out for me thanks. I just had to do the easy bit of putting number plates on it. Tomorrow it will get nice red wheels centres and I will take it for a good drive and report back. Brgds
Simon

Looks great. I've asked Santa for an orange one.......

They look good in Orange.

They look pretty damn good in any colour!

Took the Volumetrico for a drive and the thing that strikes you is that it pulls in any gear from 1500rpm and it is very smooth. You feel the power coming in at 4000rpm.
Stopped in at the garage and as I pulled out the engine died due to an electrical failure. No ignition and no starter.
Power in the battery. Side lights work but not main lights. The fuses all seemed fine. The action of the ignition switch seems a little unusual and I am suspecting the ignition switch has a problem. Not far from home so I got a tow from my son. Here it is parked up: Brgds
Simon

Sounds great, teething troubles aside. The car looks awesome, and you will soon have the little issues sorted.

jobeed wrote:Sounds great, teething troubles aside. The car looks awesome, and you will soon have the little issues sorted.

Ditto Simon.
I think those wheels look great on her as well.
An old friend of mine had two 131 sports in orange. He later fitted the better one with replica Abarth panels.
Great fun on the country lanes.

Hi Guys,

Watching "Narcos" on Netflix and finding it very interesting seeing as I went to Bogota and Medellin around 1990. Scary place. Look what pops up from time to time: Brgds
Simon

I bet it was quite exciting in most of South America in the 90's! I've always quite fancied visiting, but nowadays I don't think that is likely to happen. Still it is the source of one of my favourite jokes! Where about a are the Andes?

Hi Guys,
I suspected the ignition switch was at fault as it felt like the action was a little sloppy but it is fine.
All the fuses were fine but there was no power to half of them.
The battery is fine so I started to trace the power supply. First stop the back of the alternator then across the bulkhead to the starter solenoid. Then I picked up the power feed to the ignition switch and the push connector just before the bulkhead was taped up with very old crispy electrical tape. It suggested the connector had been an issue.
On taking it apart it was burnt: When connected you could restore power to the ignition and starter by wiggling it.
Re-made the joint with a new connector and all is well. Just driven the car home and going out in it now with my son.
Brgds
Simon

Well traced Simon, great when a teething problem is cured.
Top job.

great detective work Simon, nice with the old school stuff that faults can be traced without computers

Hi Guys,
Took the car for a performance run today.
117bhp is the crank HP. The boost from the supercharger seems low but matches the air/fuel ratio. If there was more boost the tuner wants more fuel.

Brgds,
Simon

I'd say that (actual numbers aside) that looks good and typical of a supercharged and sizeable engine Simon.

Very linear torque, and the boost is very predictable and constant.

As a car still on factory spec, probably the first time its had reasonable fuel in it for years, it looks healthy anyway, and a decent starting point.

All you have to do now is crack on!

If you dont mind sharing your bed with horses heads and the discomfort of concrete slippers!

Same comment as Shrew, all that torque will make it very strong in the rev range .

Putting aside the bhp figure, does it feel quick when you drive it?

Hi guys,
The thing that jumps out at me is that the boost is low at 4.5psi.
I am thinking that either the supercharger needs overhauling or the manifold is leaking.
The Lancia Rally 037 Stradale uses 7.5psi (0.5 bar) which is what I was expecting. The 037 car achieves a modest 205bhp but it is 16V and that is at 7200rpm. The CR is the same at 7.5:1.

I have got a book on supercharging and this is a graph for a roots blower with boost limited to 8.0psi. I suspect with a valve. My boost plot is drawn on.
I am going for the easiest thing first which is the pop off valve. This prevents damage to the supercharger in the event of pre-ignition and the subsequent shock wave. It was pretty gummed up so a double whammy making sure it will work and is not leaking.
Next up is to get the water and fairy liquid leak checking fluid in action.

The car is a pleasure to drive Tim. You don't change gear much and Max rpm is 6000. It accelerates quickly. I don't think the gearbox has synchromesh as engine rpm must be correct when changing down.
That's it for now.
All the best,
Simon

Boost is low, even for stock set up i suspect, hence with a low compression to suit forced induction its only making the sort of figures that a good normally aspirated 2.0 of similar era would make i reckon, celica for example, or the lancia and fiat offerings for that matter.

The drawn on graph may well hint at leak, proving that it takes far more revolutions to start making some boost, and even then only just hangs onto it.

But missing material from the charger internals could also produce a similar result i guess.


I hope you can find something simple to cure it mate,

Would i be right in thinking it should be around 160bhp?

the Lancia beta volumex (which is probably nearest thing in comparison, 2.0 8V supercharged) was rated at 135bhp. they were never really that powerful in road trim, the 037 stradale was a bit of a special one off.
I don't think if they are flywheel figures it's that far off really.
pressure looks a tad down though, seem to think around 6psi was the figure..

I was just doing some homework, and found the supermirafiori 2000tc of the era claimed around 115bhp, and as you say kev, the volumetrico 138.

Not much of a bhp gain for nearly half a bar, but then the motors compression does sound on tbe safe side too.

I think there is a lot of scope for improvement here, everything seems present and ready, but needs waking up, Big Time!


I'm sure Simon has just that in mind

Good point Kev. 6psi sounds like it would give me the boost I need for closer to 138bhp.

I do have 2 cars in mind as examples of what can be done Shrew

Lancia Montecarlo with 8V 2 litre, fuel injected, volumetrico blower, eng rpm 7200, blower rpm 8031, boost 17psi - 277bhp

Fiat 124, 8V 2 litre, twin 45 DCOE, Volumex blower, eng rpm 6500, blower rpm 10,214 - 260bhp

Brgds,
Simon

Hi Kev,

Just added your 6psi / 138bhp to my 8V graph and it fits!
If you add the 037 Stradale figures at 7.5psi / 205bhp the point is above the line but perhaps to be expected as it is 16V.

Brgds,

Simon

Hi Guys,

I have sent the supercharger pulley to a specialist shop in Scotland. The existing pulley has 32 teeth and turns the supercharger at 5440rpm with the engine at 6000rpm.
The new pulley will have 23 teeth and rotate the supercharger at 8000rpm with the engine at 6000rpm.

I needed a new supercharger belt tensioner pulley/bearing.
I found out that the Fiat Regata Diesel uses the same pulley/bearing. The pulley manufacturer says it is easy to get all sizes of belts so I am pretty relaxed about that.
I want to be sure not to over-boost the engine so have bought a modern dump valve. I can change the spring in the valve to vary the boost setting at which the valve opens.

The dump valve has a vacuum port on the top which is plumbed into the the manifold behind the carb and in front of the supercharger intake. When you lift on the throttle, the carb butterfly valve shuts and there is a vacuum in front of the supercharger. This opens the dump valve and offloads the supercharger. Helps decrease fuel consumption by reducing the supercharger load when it is not needed. You can vent the dump valve to atmosphere if you like the noise or you can plumb the dump valve vent into the intake between the carb and supercharger to truly offload the supercharger. The next step is to have a valve to augment the vacuum effect and augment the dump valve spring when boost is needed. Pics as follows:

Looking good forward to the results of this mod

Nice one Simon, interesting read.
Cheers.