The old AlfaSud plant were the last 159 was built is very close if not next door to the aviation division.
I acknowledge and understand the history of the two plants and the radial engines alfa romeo built under the leader ship of Ugo Gobbarto were splendid examples of engineering.
The travails of this Enigmatic car continue! To be fair, it is not of Alfa's making - damn. It has more to do with the way I chose to modify my car. The manifold cats have gone. They are the metal type and clearly can withstand much higher temperatures. Although I knew the twin cats below the car are Ceramic and thus lower temperature, I felt as they are some distance away from the engine, they would probably cope ok. It was the output of the twin cats that appeared to be the problem as they form a "Clarinet Reed" for the gases exhausting into the central section where the resonator is. After my modifications, the higher power level was causing extreme droning @ ~ 2500 rpm.
I fitted a Supersprint central section which has no resonator and sure enough, the drone disappeared. But this resulted in a cacophony of noise emanating from the rear boxes. Cue new rear boxes - a lot worse, although both the sound and acceleration from 3000 rpm is brilliant. But impossible to live with at below.
My worst fears seemed to be confirmed - a new cat would be needed. And Supersprints is not cheap. So having bitten the bullet, contacted Supersprint Technical Department. By this time, the Cat had been ordered, but I had the daunting prospect of having to buy yet another pair of rear boxes as the new ones seemed incapable of handling the power. I wanted Supersprints assurance theirs, which would complete my system once the cat is installed, would handle the extra power. I quoted a figure of 350hp as a target figure. I even picked up a brand new Alfa Nearside Box cheaply, fearing I would end up going back to theirs. It confused me, the Alfa boxes handle the lower revs well, but break up at higher revs, the new ones handle higher revs, but break up at lower ones.
I needed Help.
That's where S.S. tech dept. came in. I laid it out as baldly as I could and within the space of the weekend I had a comprehensive reply.
"It's not your rear silencers that are your problem, it's your cat". Brilliant, so at least I had a second opinion supporting my view about the Alfa Twin Cat".
But not for the reason I believed. Quote:- "I would be very surprised if there are any cells left in them". They are 500 CPI (Cells per inch) and very restrictive.
So to shorten a long story, having a spare twin cat in the garage - which I was intending to take to the dump - I got a garden chair to sit on, a 10mm. piece of stainless pipe, an eight pound club hammer and drove the pipe through the cat. Initially it was very reluctant but eventually smashed my way through. A quick check below and sure enough, there were pieces of the Ceramic Cat on the garage floor.
I picked up, what clearly had been part of the outer matrix, which was very hard. The initial strength must have been this outer screen/matrix. However, along with it on the floor was part of the inner honeycombe. Inspecting that revealed it was almost of a dust consistency - extremely crumbly. One could rub a small lump between two fingers and it quickly fell to dust/coarse powder.
So, full marks to the Supersprint tech guy for pointing me in this direction. I don't think the "Reed" helps, but if my twin cat has collapsed cells, it certainly would contribute to my problem.
Funnily enough, after a quick blast to get out into mainstream traffic flow, from a junction yesterday, the exhaust system appears to have got a little less "Rackety". It's not the way it should be. But it seems a bit quieter. And although my doubts about my new rear boxes remain, the throttle response is such that, blipping the throttle a little on down shifts brings an exhaust note that reminds me of my old twin cam Berlina and her Dellorto carburettors.
Funny - the tricks the mind can play on perceptions!!!!!!!