Epiphany?

[slabghost]

Another point is that the stock carbs don't have added heat so why would a single carb? I haven't seen one inline four motorcycle with any heat added to the carbs or throttle bodies.

 

[dan filipi]

I've been piecing together in my head the information posted through the years about Tom's carb, heat and all.....
It is interesting that Tom insists manifold heat is a must with the specific dft he sells.... as if he is aware of it's extremely rich idle problem and lack of a simple way to lean it. Hmm.
That is the way I see it, since the true mix screw that would solve the problem doesn't exist on his carb.
Interesting.

 

[slabghost]

It is my belief that many of the car carbs were designed to use the heat because the intake manifolds were heated.

 

[Dusterdude]

Question,what does the mix screw on the dft do if it doesnt affect mixture?

 

[canuckxxxx]

I have to put myself in the Tom Langdon camp here. The DFT is a car carb which is designed to work on a heated manifold.

When I put my new DFT carb on my bike with no heat to the manifold it bogged and hesitated just like Tom had warned. :head bang: It was so bad it was pretty well unrideable. :shock: It became clear to me, early on, that a heated manifold was the way to go. :yes: When I put a good, high volume manifold heating system on, the bike ran as desired; no bogging, no hesitation, returned to a steady idle when throttle closed. That is with the jets that came with the carb. I took the power valve off as soon as I got the carb, based on Joe's recommendation but, in retrospect, it may have run fine with it left in. Wish there was room for the electric choke...would have been nice to keep that too.

I have not had to tinker or fiddle with my fuel system since I completed the system about a year and a half ago. I changed some jets early on but right now the jets that are in my carb are the ones that came with it. Bike always starts and runs the same every time. :Egyptian:

Adding heat is a very simple thing to add if you are using the Type IV manifold. You have to form a coolant chamber to the bottom of the manifold and then you have to route coolant through it. If you read "Canuckxxxx Single Carb Built" thread you will see how simple it is for anyone to do. Do that, take your new carb out of the box, stick it on the bike and go for a ride. :moped:

Now, Joe, would you please list all the mods that you have made to the carb on Hooch to get it to run properly and how many hours you have spent doing it? :whip:

Which do you think is the simplest, most practical route for the average Oldwinger who wants the simplicity of a single carb?

Brian

 

[slabghost]

I suppose it depends on the individual and personal goals in play. If the idea is to use the carb as is then I agree the motor must be adapted to the carb by adding heat. However as has been reported by most going this route. There is no performance gain and you lose mileage. If this is acceptable then yes go that route. If your goals are a bit higher and you want better power and throttle response and close to stock mileage then the carb must be adapted or chosen to be adjustable.
Joe had better than stock power and throttle response early on and could have called it good. His bike would have run like a champ. However each improvement he made simply encouraged him to make it even better. His goal is to get the most performance from his bike with the mods he's installed. I think he's met his goal but I've thought so many times before.
Average guy new to old tech who is pretty sure he can tell a screwdriver from a wrench should probably just stay with the stock carbs for their simplicity. Simplicity there is the manual covers pretty much every issue with them. :builder:

 

[joedrum]

hmmm ok good ? ...as for time in it ...that's a hands down loser on my part ...i have many mucho and any extreme word for time in the scc...my only defense here is ...i had no idea what i was doing :smilie_happy: ...i could realize that the problem was it was too rich ...but fixing it led to a lot of dead ends or other discounts that never seemed to lead to being dialed in right ....most all cars use heat in manifold ...even bikes like the 1500 goldwing dressers ....this does present a wider window of running ok when things are not dial in good or dial in half good. either way ...it comes at a price though power is lost ...you don't have to dive too far to figure out cold charge has more power ...other things in a carbs favor is no fi system atomizes gas charge better than an carb ...heat's purpose is to keep moisture in air from making ice in a carburetor ...if no moisture in air there will be no icing at ground level ...even on top of a mountain ....

so to me heat is used by mass production to curb problems of difference conditions a car or bike can be in ....plain and simple ....

as far as power valve brian i doubt it would work on oldwing that is too rich in idle circuit already ...its job is to richen the charge from a to lean condition the carb was set up for .....in my opinion ...you were already bogging without one ...adding it would flood the carb in my opinion

as for mix screw it meters gas and air in the idle circuit but the mix is predetermine so in effect it just meters volume and not really a mix screw like a real carb should have .....dft and all epa carbs have set air bleeds and a gas jet can be changed ...and this is the only adjustment there is at idle ....completely dumb as idle is the most challenging part of dialing in a carb ...if it isn't right the next step won't be either ...that's where bogs and pops come from is poor idle .....

ive proven to myself there is 60mpg in a oldwing ....do i think im perfect? no cause like most ...i have worked with just a few of the parts available to the weber system ....its not webers fault they were slaughtered by epa and had to make non carbs ....

epa is full of it ...well dial in carbs are extremely cleaner than the epa junk carb masterpieces out there ....even oldwings are a example of epa junk running products ...the carbs leak in motor ...are never up to par in most cases ...and as it seems through hooch not very good at mpg either ...too many things involve in there operation and total lack of adjustments to stay up with it ...cv vacuum carbs are a nightmare of engineering ..this was all epa inspired by mandate ...

so to answer your ? brian ...ive got a lot of time in the dft ...i also know this carb completely as in regards to oldwings and very happy i did so ....

i pretty much consider hooch as king SCC now ...not only is way more powerful than stock carb bike ...it gets better mpg also ...facts are facts ..i post facts if ones don't want to believe that ...and think im like a cm guy so be it .....im not going to care much

sheesh dang near doubling mpg is huge ...it makes no difference if its heated or not ....i know or not can get 60mpg in conditions i went 120 miles in plain and simple the best mpg figures ive ever seen on oldwing post ever.....no matter what induction system is used :thanks:

 

[joedrum]

let me add one thing jetting ...hooches jetting is twice as big as what the carbs come with ...hooch has some big jets in it but some are smaller ...this is probably not right but ill try sizes

idlle gas .035....primary gas .130...primary air bleed .160....secondary idle gas .o90 secondary gas .160 air bleed .160....

this is huge jetting yet it gets 60mpg at times ....this is way better than yours brian so set up is everything ....no way would hooch run like it dose with the jets that were for a slow turning low flow car motor ..simply no way

and the other fact is most all the the mpg is in the idle and off idle circuit hooch has prove that to me :thanks:

 

[dan filipi]

Joe has spent an incredible amount of time modding the dft and I commend him for that.
His efforts have gotten to the bottom of this carb and helped in prompting this thread, which I believe has gotten to the real reason heat is needed.
When you have as much time as we have in this carb studying it and what little documentation there is available on it, this whole idea of what is truly happening makes sense.

When you look at the fact that fuel injectors do not introduce fuel in a vapor form, you've basically put that notion to rest.
Evidently an engine burns a mist of fuel, not vapor or at least not only vapor. My guess is with pure vapor detonation would be an issue. An engine needs a burn that expands, not an explosion.

Anyway, all of the ideas and requirements to a successful single carb installation that have been posted in the past are being looked at and we will continue to pick them apart to present the truth.
A Dodge Colt 1.6 liter I had got 45 mpg average. With that size engine in the 4 door car it had to be floored to drive it.
I see no reason that a bike with a smaller engine and weighs much less, cannot do much better than 45 mpg, which is after all, closer to the mpg that a stock rack gets with no external heat added.

 

[Steve83]

The way I see it, carbs and injectors both introduce atomized fuel into the combustion chambers. During the compression stroke, the mixture is rapidly heated, evaporating the majority of the fuel. Once the engine is warm, the heat from the intake port and valve, and the interior of the cylinder will evaporate even more of the fuel. Heat=evaporation, cold=condensation. Flowing air makes cold, compressing air makes heat.

 

[slabghost]

Steve83 » Sun Dec 06, 2015 1:57 pm[/url]":7ommiv7j]
The way I see it, carbs and injectors both introduce atomized fuel into the combustion chambers. During the compression stroke, the mixture is rapidly heated, evaporating the majority of the fuel. Once the engine is warm, the heat from the intake port and valve, and the interior of the cylinder will evaporate even more of the fuel. Heat=evaporation, cold=condensation. Flowing air makes cold, compressing air makes heat.

Ideally speaking you are correct. However. If you pour water on a flame heated rock you get steam right? It is almost instantly vaporized. Since gasoline vaporizes at much lower temperatures the same happens if it's sprayed into a heated chamber. Effect is the same. a small cup of water creates a big cloud of steam. A tiny amount of fuel is expanded to a large volume of vapor that is confined in a small space ( the runners and manifold).Vaporizing the fuel leans the charge by making a small amount require a large area. Injectors spray atomized fuel directly into the chamber as the piston is dropping ( creating a pull of vacuum). At this point fuel under high pressure is suddenly in a low pressure state which in effect cools it. Maintaining it's atomized state. Then it is compressed and forced to fill the entire chamber. It is then fired and as it burns it expands forcing the piston to move away.
Cold cannot equal condensation without humidity. Airflow alone does not cool at all. Touch the airline from a compressed air tank to a sand blaster in use. The flow is huge but the line does not cool. Cooling or heating is achieved where pressures change. Sudden drop will cool but sudden increase adds heat .

 

[slabghost]

While this has strayed just a bit :0fftopic: . Which is that the primary reason for heating intake manifolds is to maintain their integrity. I want to bring this point home once again as it should be a consideration in all of the single carb conversions. This is likely why the use of the type 4 vw plenum serves so well. Once the leaks are chased down and sealed they stay sealed. Because the hose connections allow the intake to fit the motor cold or hot. Solid metal one piece intake manifolds must be heated sufficiently to expand with the motor or they will fail. Through cracks or snapped bolts or??It's enough to add heat to the plenum if you just want the stovebolt carb to work. That is entirely insufficient though to maintain the structural integrity of a one piece manifold. Some sort of expansion joints must be used or heat evenly applied to the entire manifold.

Okay then back to the discussion of fuels and the effects of temperature. :thanks:

 

[canuckxxxx]

Was babysitting grand kids all day but back now.

Interesting discussion opcorn: . The primary, low speed jet in my DFT is a #50, that came with carb, and it gives me best idle at about 1 1/2 turns out for the idle mixture screw. Which is about right for the DFT, according to Weber tuning instructions. My plugs are a very light tan color.

I think I read somewhere that Joe uses a #35 primary low speed jet in his :shock: . This seems way too small. But are you saying that with heat turned off, this would work OK. Or are there a bunch of carb mods needed...if so what are they?

Brian

 

[slabghost]

Joe has done a lot of modification to his carb. Read Hooch get's a new fuel source thread. He lists everything he's done including the stuff that didn't help.

A very long read as it took him a long time and a number of tries to get it where it is.

viewtopic.php?f=107&t=6565

 

[joedrum]

well brian as we have talked before on this my dft carb is bigger than the tom carb ...my carb flows much more air than 32-32 tom carb ...not sure why completely but hooch has always been way rich at idle ...ive never had tan plugs on hooch ....so theres a difference here ...

so im not saying that a 35 jet would work for you ....i can tell you that the idle circuit is gone on hooch and now provides fresh air under the throttle plate at mix screw spot ...and a 35 gas jet now feeds the off idle circuit and also double duty as idle circuit too ...and this is where the huge boost in mpg came from along with a steady idle .....hope that explains it good ....past this the jetting goes completely the other way and is huge over what the carb came with ....

 

[ekvh]

Another factor no one has addressed here is water vapor in the air. Basic science says that when matter changes states, energy is consumed. There's always some water in the atmospheric air, sometimes lots of water , sometimes not. The higher the humidity, the greater the chance for icing to occur. I think it's referred to as icing because at temps of around 50 degrees and less, we often see frost appearing on the outside of the intakes or on the throttle shaft areas of the carbs. For frost to occur, it needs to be near 32 degrees F. My understanding is that it happens because in the Venturi the liquid gas is being turned into a vapor (small gas droplets.) This extracts heat from the air which is drawn in along with the fuel. Extracting the heat lowers the temperature. Evaporating water through a cotton cloth drops the temperature 20 degrees F approx. So it is the fuel evaporating that drops the temperature in the Venturi and beyond it and can cause water droplets to condense out of the air, especially when humid, and begin collecting on the sides of the walls in the same way as cooler temps cause rain to condense and drop from the sky. You're turning a liquid fuel to a gas, which in turn turns a gas water vapor to a liquid. This can cause rough running when warming up as it gets pulled along the sides and into the combustion chamber. Heat was added only when cold. If you add heat when the engine and runners are at the right temp, you'll lose power as Slab says because less air will get in. I think they called them dash pots when I was a kid. They were simply a spring in a vent above the exhaust manifold that when warmed up expanded to close off a vent tube from the exhaust manigold. If they stuck open and allowed heat all the time, the motor would run poorly. The 1500's used them.

So maybe the answer is D, all of the above.

One big advantage fuel injection can have over carbureted is the ability to adjust fuel ratios based on humidity, air temp, and air pressure. I still like messing with carbs though.

 

[canuckxxxx]

Eric, are you referring to the warn air coming off a shroud around the exhaust manifold that warmed the air coming into the intake. I remember those, but I also remember looking at an intake manifold from a SB Chevy. There was an exhaust cross-over from one head to the other and heated the intake manifold. I don't think there was any control over that flow.

I think most stock car intakes are heated. :heat: On the other hand I don't think aftermarket intakes like Edelbrock have any provision for heat. Maybe performance carbs don't need heat. :headscratch:

Brian

 

[joedrum]

ok eric is rather spot on in my opinion ...i have talked the same thing in the hooch fuel source thread ...takes water to make ice....in my opinion no amount of heat can take the water out of the air before the motor need it ....so even on FI injection the fuel is adjusted to the air quality ....this dosnt fix the air ....the motor will burn or run compromised and mpg is effected ....just like hooch was on the night trip home during mpg testing .....FI is a gasoline form of forced induction and it also leaves out the process of proper atomization of gas and air ...this is usually looked over as not needed ...well that's a big mistake in my opinion and it compromises the fuel charge from the get go....common sense tells you it cant be important in a carb and not important in FI set ups .....so in my opinion FI set ups are compromised from the get go ...and in my opinion there's no way it provides the best gas charge ....

i was reading over at ngw ...the steve ...has FI going on project .....he is complaining that under load his motor gives up ...and he cant figure why ...to me its properly atomized gas and air is the problem ...at this state the charge is sloppy and not prepared good to operate at high rpm ....on a carb set up preparation starts before the motor ...with SCC setups with its longer runners ...it for sure prepares atomize gas and air charge before and better than all other systems if everything is dialed in right on carb and carb itself is matched for motor size with it passage size in circuits and jetted right ....a carb is ahead of the game over all system out there in my opinion ...and is self regulated by motor draw on carb ....modern techs scoff at this process for FI ...but me ..im the other way ...this is all natural ...needs no high pressure forced pump for gas solenoids for each piston ..sensors for everything to regulate ,,,and its behind the game always like cv carbs and proper atomizing is not happening ....

so far id say hooch has best mpg reading for a oldwing 4 ive ever read about ...its gas charge is perfect under good conditions 1 ft before the motor needs it. so its ever ready ....dose it have down sides .....yes icing can be a problem the longer the runners the better charge prep and the more icing likelihood .....but as hooch has shown me even its worst is better than most best ...so im good with that 45.7mpg aint bad in rough conditions ....

the high rpm is primo on hooch ...there's no drop off from high rpm demands what so ever ...its gas charge is prepared naturally over a longer travel ....this doesn't delay things it actually increases response all the way down to idle with huge torque over other set ups ...im sorry my way doesn't match the commonly pushed systems out there and also i like what is considered a lesser system ...but i assure you i know what im doing as ive really ironed this all out with mucho hrs of time in the deal...as jpwinger said ...best running bike hes ever heard ...jpwinger is no fool with words and has owned oldwings for decades at least 4 or more ...has three right now i think ...2 here in florida .....

its hard to argue with mpg testing ....i will stand there ..and it basically dose all this with one moving parts ...the throttle plates .......ill take this set up over multi port late acting induction system that gets less mpg .......only discount is rather people think im lying ...oh well i cant control that ... :thanks:

 

[canuckxxxx]

Joe, FI does a great job of atomizing the fuel by spraying the gas, under high pressure, through a fine nozzle, right into the air stream. Much better than a carb that is drawing gas in at atmospheric pressure.

The whole auto industry is FI and nobody wants to go back to carbs.IMO

As far as doubters go; the best way to shut them up is to post some performance numbers such as a time slip from a 1/4 mile run. There must be some drag strips in Florida. An ET in the 11s with a top speed over 100mph would shut them right up.

As far as gas mileage I would suggest doing a closed loop of about 130 miles to eliminate any influence from wind or hills. Anything over 50 mpg would be amazing.

Brian

 

[slabghost]

Let's clarify the terminology.
atomized is a mist of tiny droplets. Like the mist from a rattle can of paint.
Vapor is the fumes from the solvents of the paint evaporating.
These are terms for the states of materials and are not interchangeable.
Ice is water in a solid state. We simply call it water in liquid form. When forced through a small opening it becomes a spray. A smaller opening is a mist. At this level we can say it is atomized. A fine spray of it on your hand will barely make it feel damp. The same amount applied to a hot surface will likely form a cloud large enough to obscure vision temporarily as steam.
These are terms used to describe specific states or forms of materials. No one asks for a drink of ice or steam. But both can be water.

Discussions here rely on accurate descriptions. We cannot hear smell or feel what is present at each others place. We rely on descriptions of issues to form possible solutions. :thanks: