[twoliterlover]

Gentlemen: Most interesting comments -- some learned and some totally without bais of personal experience. Frankly, I use 45's because my son is involved with many race cars that have 45's as stock set up. That means I have unlimited parts -- venturies, jets, emulsion tubes, etc -- available. But I can't see why 40's wouldn't work as well.

As for Adrian Ratcliff's comment that it makes no difference between Webers and Phh44's I can only say that I KNOW that neither he nor his late mechanical master friend, Richard Jarvis, ever modified their intake manifolds. I never got any difference in performance until I did either. As for Don Peterson's comments on weber use on Mercedes 190SL I have to say there appears to be an astonishing difference with webers and modified intake manifold, but not without the different manifold.

The final design to which I use came through research, determination, and sad experience. I tried everything -- different venturies, jets, etc -- with Webers and the stock solex caruburetor. The results were a waste and even dangerous. I determined finally that the point at which the runners cross over in an untreated solex manifold the extra cross section allows the air to slow down just enough to precipitate out a lot of raw gasoline from what previously had been aerated particles. That raw gas eventually ran out the outside ends of the carburetors or, Lord Forbid, into the cold air box iwhen I developed "gender menders" to allow the factory box to be used on webers. The raw gas would sit in the little trough in the top of the framework connections on the inside edge of the right front fender. It smelled bad, made me carry a fire extinguisher, and quickly ate off the paint under the carburetors. Ever wonder why Phh44's have the two tubes to drain extra raw gas down to below the pan? Even the stock solex set up has that problem when the secondaries start to kick in.

So I studied what Weber said about how their carburetors worked. Instead of the Solex "increasingly wet plenum" theory, Webers use the "faster puff of air carries more aerated gasoline" theory. They suggest individual runners to each cylinder to move air without slowing down.

In fact, subsequent tries proved faster more important that bigger. Thinking of full throat power usage I had Vintage Racing Motors modify an intake manifold for me by "sleeving" it straight through with 45 mm internal diameter auminum pipe, welding up the jackets so I could still use the water passageways (probably not necessary with webers as much as with solex). Over 4500 rpm the engine ran fantastically strong, but it was hard to start, and would hesitate and often almost stall on start of accelleration. The runner size was too big. Unless the air was flowing at full capacity the engine did not carry enough aerated gasoline into the chambers. And there was almost the same raw gas problem that I had with solex intake manifolds with webers. THIS WAS A BAD IDEA.

So I had another intake manifold welded up and then routered out to have smaller but round and equal size diameter runners. Probem was that 26mm was the largest size ball I could pass through the runners. I thought that would be a detriment. But it did not seem to be all that bad. The engine ran fine, used less gas and had more power until at the top end. It did not seem to be better enough for me at full throttle -- maybe better than the old car "dragging" a log experience, but not worth the extra money.

So, I finally got into Hemmings and made call after call to people who advertised as Weber carburetor specialists. Almost uniformly they referred me to the intake manifold specialists in Gilroy who do manifolds for Nascar racers. They were the ones who showed me and explained to me what they had long before come up with for SL 190 intake manifolds. They pointed out the need for the separation of the runners, but suggested only a flat plate be welded in vertically to separate them. That would permit a larger throat and also provide a slight "roll" to the air as it passed into the chamber. In fact, they also suggested I use copper gaskets on intake manifold cut with turned fingers stuck into the air passageway to get the air to spin (haven't done that yet, but mgiht in the future).

And so I started welding in plates. I am happy to say the modified intake manifold DOES MAKE A GREAT IMPROVEMENT, giving both better lower end and top end without raw gas anywhere. Problem, of course, is that the intake manifold cannot be used again with Solex again once it has been modified. Those carburetors each feed two cylinders, not just one, and if you separate the runners only the cylinders to the front side will get enough gas to run decently. Arno will have to keep a special solex intake manifold is he wants to have it for his lousy solex carbs to be "authentic and beautiful" in a concours. Yuk!

But, 40's or 45's is up to you. I use 36mm venturies in my 45's anyway. Should be able to get those into a 40, I would think. I am an old man, but I confess I run my car a bit hotter than I should. It makes me feel young and still the guy my wife used to welcome back and call the "old two liter lover" when I returned from a crisp hot ride, especially with my favorite German music playing on my radio. I guess the name can have many meanings. Lately, I am sorry to say, the emphasis seems to be mainly on "old". I drove my first two liter, the factory demonstrator, on the autobahn in Germany in December 1959. IT HAD WEBERS. It also had a dry sump. I have always hated Alfa for neutering the car when they started to mass produce it for sale. It took almost 30 years of trial and error and effort to get one to perform the way that first one did. I used to be able to pass cars passing cars back then. However, "The older you get, the better you were."

But don't be deceived. While they never will be race cars, they can drift pretty good and make you hold on pretty hard in the corners once you get the engine running like it should. The engine is basically the same engine the 1900 racers used. But I now believe the factory demonstrator had a sportiva engine. I had no prior experience, so I didn't realize then just how great it was. Amazing what a good carburetor set up will do. But don't ignore the need for a dry sump if your are going to corner a two liter long and hard. I've never run Seattle Internation Raceways (now Pacific International Receways) without blowing an engine because the oil would all get shoved away from the sump intake by centrifical force on the old "Indianapolis" turn (now turn two). And I think Adrian will confirm that. He blew one on his red two liter too (and only did a 2.08). Maybe the track was longer then, because even Berlinas can do it in 1.48 now. But, Happy New Year to you all.

Jay