Talked to Tom Langdon yesterday evening and he says it is adviceble to let the heated colant water go through the intake heatplate wich should give a better heating effect and results in better carb/engine performance!Tom said that his solution is the best one. On the other hand its posseble to connect 2 copper tubes from the exhaust manifold to the intake manifold and there will be less work to do. This is why ! WHY YOU NEED TO HEAT YOUR INLET MANIFOLD The most frequent complaint I have is from members who complain that since they've installed their multiple carbs, the engine hesitates and stumbles at low speed on initial acceleration even after warm-up. The most blamed culprit is the darn Rochester Carburetor. Usually it is falsely accused! Usually while installing dual exhaust manifolds or headers, the production exhaust heat supply to the inlet manifold is eliminated because (except Edmunds Inlet Manifolds and Clifford's) there is no provision or instructions to provide heat...Why?? I don't know and could only guess. In any event heat will be required to achieve good driving response and reasonable fuel economy. Here's why: As liquid fuel enters the manifold from the carburetor, the vacuum vaporizes the fuel and causes a chilling effect on the walls of the manifold much like the chilling effect of spraying an aerosol on your skin. Now you have a cold manifold. If you do not have a continuous supply of heat the manifold will remain cold and even build frost under some conditions. At this point, if an acceleration is attempted, the vacuum will drop, fuel will no longer vaporize, and will in fact condense on the cold manifold walls until they are fully saturated with wet fuel - this takes about three seconds, during which time no fuel is going into the engine (and thus no power or a "sag"). After the walls are fully saturated with fuel the air flow finally picks up this ultra rich mixture and floods some of the cylinders but not all of them because liquid fuel is notoriously bad for equal distribution. More fuel (bigger jets) will only slightly help this problem and actually worsen the over rich condition and spark plug fouling and fuel economy. The solution: Moderate, and continuous heat supply to keep the walls of the inlet manifold warm and the fuel in vapor form. Exhaust heat is fast but requires a butterfly valve in one manifold to force the exhaust flow. Water heat is slower but very clean and not corrosive to aluminum manifolds. This method utilizes the water pump to continuously supply warm water to a passage underneath the manifold. (See attached drawing.) It is sometimes necessary to weld a tube to the manifold, but be sure to obtain intimate contact between the coolant and the manifold wall or floor. Simply tack welding a closed wall pipe to the bottom of the manifold will not result in sufficient heat transfer. According Tom langdons advice i need to ask about your experiences with both solutions.
Interesting article. Someday I will have the dual carb setup, and then I can reflect back on this conversation...
A good thread to look up on dual carb set us is fla54chevy3100 He has a pictures on hint and tips for the 235 that fantastic. try it.
Heated Intake As the Fenton dual exhaust manifold actually reduces power , I see no need to go this route but I do agree that water heating the dual intake manifold is the way to go , DO NOT use the suggested plastic 'T's though ~ use brass ones . FWIW , the Fenton split exhaust manifold is a Racing part so it's screws up the exhaust flow until the engine is really wound up , 3,000 RPM's & above . at normal driving RPMs , 600 ~ 3,200 , it causes bogging & flat spots off idle . I know they " look cool " but I don't have stuff that looks cool and make the engine run worse , that's counter productive in my book . FWIW , YMMV , IMO , etc. , blah , blah , blah .
Looks good Looks good but makes life worse........who does that remind me o...... Nothing dear, I'm just online checking for a valentines present for you! Got to go guys, been caught
Sometimes using a Ford water heated carb spacer is an easy way to get heat to the carb base. They were use on 1 bbl, 2 bbl, and 4 bbl carbs and they used the Holley bolt pattern. One of the heater hoses just passed through this base plate so on a dual set up the hose could run to the first carb and out the back of it to the second carb and then on to the heater. They are about an inch thick so linkage might need tweaking and I do not know the spacing of the mount stud holes or throttle bore size on the one bbl carb. I'd bet it's close enough to work with a little custom fitting. Besides, if it was a direct bolt on I wouldn't want to mess with it---no fun.
Dual exhaust solution. Hey Nate The split headers setup is not really a must. A better engine performance is most wanted and therefore you can combine the dual carb setup in a fine way with the original GM single exhaust outlet. The heatplate fits at the bottem of the GM exhaustflange to.The coolant water connections that Tom Langdon recommends are a good way to go and it makes carb idling in the stationary lower ranges even more stable when engine coolant is on temp at 160- 180 Fahrenheit. The total water sirquit gets a bit longer and maybe that gives even a better engine cooling effect to ? The mini H.E.I. and a new type of engineplugs with gap 60 improves some more to. I need our forum members to tell there experiences with one way or the other ! . P.S. It should be fun to measure Volkers engine rpm on different ranges as he used a different setup and welded his exhaust pipes upper parts together into one. I `ll get back to you guys with pics and a report when everything is installed and ready to drive my truck. Until so long.
