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Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341650 Sun Jan 12 2020 01:08 AM
Joined: Feb 2004
Posts: 20,827
H
Boltergeist
"Different strokes- - - - -etc." I'm a firm believer in the slogan Sun Electric Co. used to put on all its test equipment- - - - -"We Test- - -Not Guess"!
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Testing Daytona Universal Carburetor UN2
Hotrod Lincoln #1341655 Sun Jan 12 2020 01:16 AM
Joined: Feb 2016
Posts: 197
C
Gabriel Sandoval
That's a slogan I can get behind. Unfortunately, until a professional tests one of these carbs out, my guess will have to do.

Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341717 Sun Jan 12 2020 03:55 PM
Joined: Nov 2014
Posts: 69
E
Wrench Fetcher
How about installing a O2 sensor in exhaust and using it to monitor mixture. Then tune accordingly.


ESum
Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341720 Sun Jan 12 2020 04:19 PM
Joined: Feb 2004
Posts: 20,827
H
Boltergeist
O2 sensor, vacuum gauge, tachometer, and an accurate record of fuel consumption on at least a 10 mile closed loop test course, and adjust the raw data from several test runs for temperature, atmospheric pressure, and humidity. Some of my really impressive dyno runs turned out to be a fluke of weather, not some magic we conjured up with fuel mixture and ignition timing. One of the best indicators of what's happening in the combustion chamber is an accurate record of exhaust port temperature. On the dyno, we had sets of exhaust manifolds and headers with thermal monitors for each exhaust port.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Testing Daytona Universal Carburetor UN2
ESum #1341726 Sun Jan 12 2020 04:55 PM
Joined: Feb 2016
Posts: 197
C
Gabriel Sandoval
That's a great idea, but probably a bit out of my price range. In any case, my idea is doing what a regular guy would do, getting the results a regular guy would get. The best I can offer is doing a city driving mpg's and a separate Highway mpgs. Though I imagine it wont vary all that much since I only run about 50 mph on the highway. I mentioned before, I was getting 12 mpgs (varied driving) averages with my Rochester, but later that dropped to 10-11 mpgs I attributed to losing fuel when parked for an extended period of time. As soon as the weather improves here in northern California, ill get to the testing.

Last edited by ClassicsR4Me; Sun Jan 12 2020 05:00 PM.
Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341736 Sun Jan 12 2020 05:16 PM
Joined: Feb 2004
Posts: 20,827
H
Boltergeist
Be very careful about not getting that adjustable main jet too lean. Once the fuel/air mixture gets much below that ideal 14.7:1 (stoichiometric) mixture, combustion temperatures spike into the range where engine damage happens very quickly. One night we had a MOPAR 440 tractor pull engine on the dyno, making a final torque pull at 6500 RPM. Apparently, a bolt near the middle of the intake manifold had loosened up for some reason, and one cylinder went very lean due to a vacuum leak. I heard a very slight rattle from the engine, and before I could back off the dyno load and chop the throttle, that piston got a half dollar sized hole burned into it. Of course, the RPM/Torque calculations we made after the fact on that run yielded 714 HP running one 4 barrel carb and gasoline, prior to adjustment for temperature, pressure, and humidity. At those power levels, things happen very quickly.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341851 Mon Jan 13 2020 03:01 AM
Joined: May 2001
Posts: 1,510
W
Shop Shark
Sometimes trial and error is fun. Not for everyone, but it can be fun.

I think one reason the Stovebolt-6 has lasted so long is that it is forgiving. Forgiving for dummies like me.


1948 3/4-Ton 5-Window Flatbed Chevrolet [sandeace.com]

28 Years of Daily Driving but now on hiatus. With a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1341894 Mon Jan 13 2020 03:41 PM
Joined: Feb 2004
Posts: 20,827
H
Boltergeist
I've found over 40-sometning years of doing dyno runs that the "error" part of that process can get terribly expensive. Very few engines run well with an air-cooled crankcase (big hole in the block where a connecting rod used to be!)
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Testing Daytona Universal Carburetor UN2
Hotrod Lincoln #1341896 Mon Jan 13 2020 03:56 PM
Joined: Nov 2002
Posts: 2,062
C
Carburetion specialist
Originally Posted by Hotrod Lincoln
I've found over 40-sometning years of doing dyno runs that the "error" part of that process can get terribly expensive. Very few engines run well with an air-cooled crankcase (big hole in the block where a connecting rod used to be!)
Jerry


Jerry - on the other hand, if one installs a sleeve, then one can convert an inline "six" into a "seven" wink

Jon


Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify
If you truly believe "one size fits all" try walking a mile in your spouse's shoes!
[image]http://www.thecarburetorshop.com/Avatar.jpg[/image]
Re: Testing Daytona Universal Carburetor UN2
ClassicsR4Me #1342266 Wed Jan 15 2020 04:47 AM
Joined: Feb 2016
Posts: 197
C
Gabriel Sandoval
1/15/2020 Update: The weather cleared up for a few hours and I was able to go fill up the tank. I think we might have near the most expensive gas in the nation (northern California). This was at Costco, which is usually about 20 cents cheaper than most places, $3.75 is the average for regular right now at most gasoline shops in town. My initial impressions, and I have to stress, initial impressions on a 30 mile round trip mostly highway driving are: In town, on the low end, about the same or perhaps a little bit more grunt than my Rochester. Smoother power delivery, and less jerking when I let off the gas abruptly. The UN2 helps my 261 idle beautifully at 500 rpms. Perhaps smoother that my Rochester did. I can hardly feel the engine vibrate. One thing I did notice with this carb was that when cranking the engine, I did have to tap the gas slightly to start out even when warm, something I never had to do with my Rochester. Now that might be down to the low rpm setting. I believe I was at 600 with my Rochester. High end driving: it definitely has a bit less grunt at the high end. Now this could be attributed to a few things. One, the air cleaner is noticeably smaller, with the larger heavy duty air cleaner I had on my Rochester, when I would gun it on an uphill in high gear, I would get a beautiful metallic vacuum sound that I loved, and you could hear allot more air going in, something im not noticing with this smaller air cleaner. (I have a paper air cleaner I might try to see if this will remedy the problem) Also, I adjusted the high speed jet without the air cleaner on, this might have something to do with the more sluggish power. I must note, that though it does feel less powerful on the top end, its not greatly noticeable, and there are some things I will try to remedy this. I will call the company and see what kind of customer service they give and what kind of technical advice is at hand. So far, im very content with the carb, with that small downside regarding the air cleaner. Ill definitely try to get some more miles on my truck and post anything I find that has merit announcing (weather permitting). Other than that, just see what its like living with the UN2 day to day, and what kind of gas mileage it gives me, first highway miles, then city driving miles.

Attached Files
Daytona 8.1.jpg (77.15 KB, 144 downloads)
Daytona 8.2.jpg (82.42 KB, 144 downloads)
Daytona 8.3.jpg (72.89 KB, 148 downloads)
Daytona 8.4.jpg (69.52 KB, 155 downloads)
Daytona 8.5.jpg (230.41 KB, 154 downloads)
Last edited by ClassicsR4Me; Fri Jan 17 2020 11:23 PM.
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