bolt on upgrades for stock oval 36hp 1200 engine.

[EVfun]

I don't know. I know that a larger (or even no) venturi in the 28 PCI is mentioned in some of the old books I read. I think no venturi upped the main jet to starting point to around 145, if I remember.

The 30 PIC carb is available (a manual choke version of the 1967 Bug 30 PICT.) The venturi and throttle are larger and it should bolt onto the stock intake manifold and accept the stock air cleaner. The intake may need a little porting because you wouldn't want it hanging out into the flow through the larger throttle.

The 30 PIC would lack the correct vacuum connection for the stock Bug 36 horse SVDA carb. A Bus distributor could be used or perhaps the vacuum system on the 30 PIC could be modified to work correctly.

Another concern could be carb icing. I know a 40 horse with a plugged heat riser has more issues with carb ice than a stock 36 horse with a plugged heat riser. Funny, because the 40 horse has intake air preheat. I had to lock that on to make a 40 behave as well as the 36 horse.

A single carb is kinda a weakness with the Bug engines. It needs an exhaust heat riser and that will always be in the process of plugging. Dual singles have their own issues too.
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[TomSimon]

The first challenge with most people wanting to just "bolt on a pair of carburetors and go" is first, getting the sizing right. The second is the fabrication skill to pull off building your own manifolds and fabricating a decent linkage. Do a marginal job at that, and the third, tuning, will prove to be impossible.

You'd essentially be in uncharted territory with a home brewed 28pict or pci set up. As it is, 90% of vw engine modifiers have a hard enough time getting a pair of IDF Webers to run right, and there's a ton of those kits sold and tuned, and lots of advice to be had that will get yo close to a decent running engine.

If you can't 'tune', that is, painstakingly go through all of the tiny little details, sync carburetor linkages, read plugs, play with ignition timing, and tune out flat spots, jet correctly, a guy would be in for an uphill, if not unwinable battle.

On the other hand, if a guy wants to learn to tune, I'd advice a guy start 'getting his beak wet' with what I wrote a few posts earlier, the basics, most would be amazed at the night and day difference you can get out of a low hp engine by jetting for optimal, and timing adjustments. Back in 1982, I played with my stale air 40hp, added nothing more than a big bore kit (which increased compression ratio slightly) and valve job, it ran just ok. I spent a couple weekends tuning on it, and the result was a 40hp than ran as good or better than a 1600sp. Nothing to brag about, but it taught me a valuable lesson about the power of tuning.

An 1100cc 36hp has a single 28mm carb, with such a small hole, has a strong vacuum signal, great for a vacuum advance distributor, and requires a relatively small main jet (a 34pict on a 36hp for instance, has a larger hole, less vacuum signal, which needs a larger main jet than the stock 28pict. The stock 28pct also has an accelerator pump who's 'shot' is sized for long intake runners and 4 cylinders.

Throw on one 28mm carb per cylinder bank, and you've go twice as much air available but halved the vacuum signal, so jetting requirement change (larger main jet) so will the accelerator pump shot, which might need a restriction in the pump circuit.

Webers are so good in this area because they were designed to sold to all sorts of smaller car manufacturers, a given Weber model could be 'adjusted' to work with many different engine sizes and combinations. Designed with replaceable (smaller and larger) venturi, emulsion tubes, idle, main, even accelerator pump bypass jets on some models, which allowed the oem to taylor a Weber for a particular engine, then order thousands of them configured to work 'bolt on'. Same with competitor Dellorto.

When the VW aftermarket started using them, it took guys like Vittone, Berg, Tomlinson and Lieb to figure out what tune to include in a bolt on kit, that would sort work out of the box. You told them what engine size you built, what heads and cam, and the better retailers would get you set up before they shipped your kit.

Getting a vacuum advance distributor to work correctly might require a balance tube plumbed from intake manifold to intake manifold. Even with that, it will still be tricky to recurve the distributor so it will run right. Considering one 2cyl bank at a time, Adjusting the main jets for lower air velocity through a 550cc engine

The other issue could be the accelerator pump in the carb meant for a long running 4 cyl, may squirt too much fuel for tow, 550cc engine pairs.

You could just order a pair of WW okrasa replica heads in a kit w/linkage, get Joe Ruiz to tune the carbs for you, and re-do your top end for around $2k, a bargin.
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2-time NASA Pro Racing Champion, Bonneville 130 Club and 150 Club Memeber, BRS Pro Gas racer

[EVfun]

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[Rome]

Upper pipe bends remind me of the Roger Bursch (Pasadena, Ca) headers for Porsche 356, but those may have had the pipes nearly level instead of the gentle down angles on this 36hp. Plus, 356 heads had differently shaped mounting flanges for the heads, though Mr. Vittone could easily have cut those off and welded on VW ones. Maybe Mr. V had Mr. B make up a one-off header for this 36hp.

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[spencerfvee]

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[spencerfvee]

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