This came up, as it does, in the course of looking for something else: Eight motorcycle-style Dell'Ortos (presumably SS1-42s) on a Cadillac V8 (presumably a 331). http://www.lastopenroad.com/burtsblog56.html "Also took a bike ride out to Jay Leno's garage once again for a looksee at what's new or progressing inside and to congratulate Jay on his new, car-guy (and gal) TV show. He was busy with a tour-bus-full of people from Apple (they all looked like they were barely out of high school!) but I saw a lot of neat stuff and was once again captivated by a strange and wonderful "racecar that never was" on Jay's floor. I'll hopefully be doing a pictorial story on it for Vintage Motorsport, so I don't want to give too much away, but suffice to say it was created out of thin air right there in the LA area back in 1952-'53, and it is one of the most amazing, ingenious and advanced vehicles of that era I have ever seen. No, really. Like how about a spaceframe ch***is, a cleverly-located, fully articulated DeDion rear suspension, 4 wheel disc brakes (aircraft, I think, and inboard at the rear!), a Cad/Lasalle-based rear transaxle (!!!) and a big ole Cadillac V8 sporting no less than EIGHT Dellorto motorcycle carbs working off a common float bowl! Plus impeccably machined, knurled-nut valve-cover hold-downs that double as crankcase breathers. Wow! "There's more, too. Pretty damn incredible for a 1953 'homebuilt', even if it never turned a wheel in anger. Watch for the story." Interestingly, I haven't been able to find anything else on the car or the engine anywhere on the internet. The motorcycle-carbs-on-a-car-engine thing has a certain following right now, generally on at best OT-ish builds. The idea is that carbs for a 1200cc bike engine spinning at 12500rpm would be just about right for a 2000cc car engine at 7500rpm. Moreover, a rack of modern Keihin CVs can be had for a lot less money than a pair of Weber DCOEs, and there are downdraft versions if your engine configuration wants it. I'm not sure when such high-winding motorbike engines first became commonly available, or how far back that approach would therefore have been viable. Into our era, or just after? The common float bowl idea — I wonder if and how well that worked — reminds me of a past rabbit hole: https://www.jalopyjournal.com/forum/threads/bendix-stromberg-aircraft-carb-ruminations.1281920/. Subsequent reflection would suggest that SUs might not be the best for that: their whole point is that they maintain constant vacuum. So motorbike CV carbs wouldn't work either. But good old round- or flat-slide motorbike carbs might be perfect. It gets towards fuel injection controlled by pneumatic rather than electronic means. Air logic sounds like a running shoe, but that'd be pretty much what it is.
I’d like to know more about the mystery car too! I can’t see any dates on that blog post @Ned Ludd referenced, is it a week old, a year old or ten years ago?
Interesting. Reminds me of a guy who slapped a landmower carb on his Ford 302 OT ride. Incredibly, it worked and he also managed over 40 mpg!
Back in the 60's Ak Miller wrote a long article for Hot Rod called "Horsing Around With The Mustang 6" I believe he ended up installing 4 Honda 450 carbs on the engine. He said it responded like fuel injection.
Ned, your search history must be 'interesting' in the best possible way for the stuff you come up with! I watched a video about NASCAR stuff a while back and the guy was talking about how they wanted to feel the inlet pulses, not just read sensor data. They built an intake with a port you could stick your finger in. It was violent at idle and nobody was willing to risk their finger at higher RPM. This came about due to injecting oil into the exhaust and seeing it 'climb' through the combustion chamber into the intake tract in a short time. I'd hazard that cam timing (overlap) would be critical to getting good results on IR carbs. Talk about carbs that you might find interesting. www.youtube.com/watch?v=0rZGps4zS-A
In that article, the little integral intake Ford 200" six had four sidedraft carb flanges brazed onto it; this allowed trying various two-carb and four-carb setups. Ak tried a pair of Brit car SUs, which worked well and then a pair of H-D Tillotson carbs, "More flat spots than a shaker full of dice." jack vines
The problem with motorcycle carbs is that they can't take pressurized fuel delivery, being designed for gravity feed. The 'common float bowl' is just a way to eliminate that pressure.
t Thanks for posting the link. Very informative. He does say that even wth high-speed photography the fuel comes out like “a fire hose” and is not mixing with air. It is “aerated but no atomized”. I’ve seen this watching vids of dyno testing on Nick’s Garage YT channel. They typically have a camera mounted right above the carb, and the fuel is just dumping into the carb barrels at higher rpm. I was just shocked to see that, and feel there has to be a lot of room for improvement, but obviously, I’m no expert.
For true, the '60s Ak Miller article, along with the others I remember from back in the day, made mention of the above and emphasized a fuel pressure regulator was required to run motorcycle carbs. jack vnes
I think remote float bowl carbs when mounted in cars change the fuel level around the main jet a lot when cornering. That can make the effective jetting change a lot too. Raise or lower the float level in a regular carb .5" and see what happens. https://elantrikbits.com/nusite/wp-content/uploads/2017/06/1-sump-diagram-01sc.jpg
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