hkestes41 Posted February 13, 2019 Report Posted February 13, 2019 30 minutes ago, sser2 said: This is completely wrong. Multiple carbs indeed increase power, but only at steady high speed. The tradeoff is deteriorated performance at low speed and poor acceleration. This is because with 2 carbs the air flow speed at each venturi is only 1/2 compared to single carb, resulting in poor fuel atomization at lower speeds. Increased air flow increases power only at the expense of higher fuel consumption, so there is no better fuel economy. Fuel economy is worse with multiple carbs because more fuel gets into cylinders in liquid form due to poor atomization. This liquid fuel does not burn and is wasted into exhaust. Again a very broad brush you are painting with. If the original carb was at or close to the upper end of the capacity of the engine then yes the issues you point to could indeed occur with an additional carb added to the mix. However if the opposite is true and the original carb is at or near the bottom of the capacity of the engine a second carb as long as the combined do not exceed the capacity will absolutely increase performance and can and did in my case increase fuel economy. This is especially true if you help open the breathing on the exhaust side. Look at all the production vehicles (cars, bikes, planes etc) that well paid and very educated engineers have designed with multiple carbs. Were these engines only efficient at high speeds and show poor acceleration? Do all those drag cars with multiple carbs exhibit poor acceleration? 1 Quote
Adam H P15 D30 Posted February 13, 2019 Report Posted February 13, 2019 1 hour ago, sser2 said: This is completely wrong. Multiple carbs indeed increase power, but only at steady high speed. The tradeoff is deteriorated performance at low speed and poor acceleration. This is because with 2 carbs the air flow speed at each venturi is only 1/2 compared to single carb, resulting in poor fuel atomization at lower speeds. Increased air flow increases power only at the expense of higher fuel consumption, so there is no better fuel economy. Fuel economy is worse with multiple carbs because more fuel gets into cylinders in liquid form due to poor atomization. This liquid fuel does not burn and is wasted into exhaust. My expierence with adding dual carbs and headers is the exact opposite of what you describe. Quote
sser2 Posted February 13, 2019 Report Posted February 13, 2019 1 hour ago, hkestes41 said: Look at all the production vehicles (cars, bikes, planes etc) that well paid and very educated engineers have designed with multiple carbs. Were these engines only efficient at high speeds and show poor acceleration? Do all those drag cars with multiple carbs exhibit poor acceleration? Very educated engineers equipped virtually all NORMAL (I mean not racing) cars not with multiple carbs, but with double barrel sequential open carbs. In drag racing, they don't accelerate like you would do in normal driving. Engine is raced to top speed before car even starts moving. This is poor example to prove your point. Quote
JBNeal Posted February 13, 2019 Report Posted February 13, 2019 The big flatheads in heavy duty trucks had two single bbl carbs and split exhaust for a reason...these trucks were not speed demons but needed to produce power at launch throughout the engine speed range...these carburetors were designed and adjusted to work well this way. And it's these adjustments that are key to making the dual induction work. With increased fuel consumption, fuel economy will begin to drop, but properly adjusted induction with increased exhaust will generate more power to the pavement. As a side note, I recently upgraded the exhaust on my Dodge Cummins from 3.5" to 4"...after several thousand miles, I could see that my economy had decreased by about 1 mpg, but passing at speed rarely required a downshift as putting my right foot into it motivated that beast very quickly...LOTS of fun that way 1 1 Quote
Matt Wilson Posted February 13, 2019 Report Posted February 13, 2019 39 minutes ago, JBNeal said: The big flatheads in heavy duty trucks had two single bbl carbs and split exhaust for a reason...these trucks were not speed demons but needed to produce power at launch throughout the engine speed range...these carburetors were designed and adjusted to work well this way. And it's these adjustments that are key to making the dual induction work. With increased fuel consumption, fuel economy will begin to drop, but properly adjusted induction with increased exhaust will generate more power to the pavement. As a side note, I recently upgraded the exhaust on my Dodge Cummins from 3.5" to 4"...after several thousand miles, I could see that my economy had decreased by about 1 mpg, but passing at speed rarely required a downshift as putting my right foot into it motivated that beast very quickly...LOTS of fun that way I was about to bring up the same point. If dual carbs and dual exhaust didn't make any difference for low and mid-range rpms, Dodge would not have equipped the flatheads in multi-ton trucks with these features. 1 Quote
hkestes41 Posted February 13, 2019 Report Posted February 13, 2019 (edited) 1 hour ago, sser2 said: Very educated engineers equipped virtually all NORMAL (I mean not racing) cars not with multiple carbs, but with double barrel sequential open carbs. In drag racing, they don't accelerate like you would do in normal driving. Engine is raced to top speed before car even starts moving. This is poor example to prove your point. Wrong again. Your exact quote was "Multiple carbs indeed increase power, but only at steady high speed. The tradeoff is deteriorated performance at low speed and poor acceleration." Drag racing is the ultimate acceleration test of a vehicle. It starts from a dead stop and accelerates for a 1/4 mile. Yes the RPMs are brought up prior to launch, but it is in no way "steady high speed" it is full on acceleration. Below is just a partial list of the normal factory equipped domestic cars that have had multiple carbs not to mention foreign cars. The following is a listing of multiple carburetor manifolds used by USA manufacturers as original equipment compiled by The Carburetor Shop. We believe all information presented to be correct, however, the listing is not complete. We would welcome documented additions and/or corrections. Make Years Engine Application Casting number Material Type Buick 1941 248 40, 50 Cast iron 2x2 Buick 1941 320 60, 70, 90 Cast iron 2x2 Buick 1942 248 40, 50 1326503-2 Cast iron 2x2 Buick 1942 320 60, 70, 90 Cast iron 2x2 Buick 1964 425 1370316 Cast iron 2x4 Buick 1965 425 1370316 Cast iron 2x4 Buick 1966 425 1370316 Cast iron 2x4 Cadillac 1930-1937 452 2x1 Cadillac 1931-1937 368 2x1 Cadillac 1938-1940 431 2x2 Cadillac 1955 331 El Dorado 1463205 Cast iron 2x4 Cadillac 1956 365 El Dorado 1464580 Cast iron 2x4 Cadillac 1957 1469263 Cast iron 2x4 Cadillac 1957 365 El Dorado 1465950 Cast iron 2x4 Cadillac 1958 365 El Dorado 1469689 Cast iron 3x2 Cadillac 1959 390 El Dorado 1472225 Cast iron 3x2 Cadillac 1960 390 El Dorado 3512080 Cast iron 3x2 Chevrolet 1953 235 Corvette Aluminum 3x1 Chevrolet 1954 235 Corvette Aluminum 3x1 Chevrolet 1956 283 3731394 Aluminum 2x4 Chevrolet 1957 283 3739653 Aluminum 2x4 Chevrolet 1958 283 3739653 Aluminum 2x4 Chevrolet 1959 283 3739653 Aluminum 2x4 Chevrolet 1960 283 3739653 Aluminum 2x4 Chevrolet 1961 283 3739653 Aluminum 2x4 Chevrolet 1958 348 3749948 Cast iron 3x2 Chevrolet 1959 348 3749948 Cast iron 3x2 Chevrolet 1960 348 3749948 Cast iron 3x2 Chevrolet 1961 348 3749948 Cast iron 3x2 Chevrolet 1962 409 3814881 Aluminum 2x4 Chevrolet 1963 409 3814881 Aluminum 2x4 Chevrolet 1964 409 3814881 Aluminum 2x4 Chevrolet 1965 409 3814881 Aluminum 2x4 Chevrolet 1963 396 Z-11 3830623 Aluminum 2x4 Chevrolet 1967 427 400 HP 3894382 Aluminum 3x2 Chevrolet 1967 427 435 HP 3894374 Aluminum 3x2 Chevrolet 1968 427 400 HP 3937795 Aluminum 3x2 Chevrolet 1968 427 435 HP 3919852 Aluminum 3x2 Chevrolet 1969 427 400 HP 3937795 Aluminum 3x2 Chevrolet 1969 427 435 HP 3937797 Aluminum 3x2 Chevrolet 1969 302 Z-28 (cross ram) 5841130 Aluminum 2x4 Chrysler 1959 413 300-E 2264877 Cast iron 2x4 Chrysler 1960 413 300-F 2264877 Cast iron 2x4 Chrysler 1961 413 300-G 2264877 Cast iron 2x4 Chrysler 1962 413 300-H 2264877 Cast iron 2x4 Chrysler 1963 413 300-J (right side) 2129985 Aluminum 2x4 Chrysler 1963 413 300-J (left side) 2129987 Aluminum 2x4 Chrysler 1964 413 300-K (right side) 2129985 Aluminum 2x4 Chrysler 1964 413 300-K (left side) 2129987 Aluminum 2x4 Dodge 1956 D-500 (early) 1733878 Cast iron 2x4 Dodge 1956 D-500 (late) 1733978 Cast iron 2x4 Duesenberg 1931 420 (Supercharged) 2x2 Duesenberg 1932 420 (Racing only) 2x2 Ford 1956 EDB-9424-C Aluminum 2x4 Ford 1956 312 (experimental) ECZ-9424-C Aluminum 2x4 Ford 1957 312 ECG-9424-D Aluminum 2x4 Ford 1963 406 None Aluminum 3x2 Ford 1963 427 Low riser C3AE-9425-H Aluminum 2x4 Ford 1963 427 C3AE-9425-K Aluminum 2x4 Ford 1967 427 C7AE-9424-A Aluminum 2x4 Hudson 1952 232 Wasp Cast iron 2x1 Hudson 1952 262 Super Wasp Cast iron 2x1 Hudson 1952 308 Hornet 307184 Cast iron 2x1 Hudson 1953 202 Jet Cast iron 2x1 Hudson 1953 308 Hornet 307184 Cast iron 2x1 Hudson 1954 202 Jet Cast iron 2x1 Hudson 1954 262 Wasp, Super Wasp Cast iron 2x1 Hudson 1954 308 Hornet 307184 Cast iron 2x1 Hudson 1955 202 Jet Cast iron 2x1 Hudson 1955 308 Hornet 5325118 Cast iron 2x1 Hudson 1956 308 Hornet 5325118 Cast iron 2x1 Mopar 1634285 Cast iron 2x4 Mopar 1956 315 500 'A' Option 1735917 Aluminum 2x4 Mopar 1957 315 500 'A' Option 1735917 Aluminum 2x4 Mopar 1957 318 'C' body 1822004 Cast iron 2x4 Mopar 1958 318 'C' body 1822004 Cast iron 2x4 Mopar 1958 350 'C' body 1827899 Cast iron 2x4 Mopar 1958 383 'C' body 1827899 Cast iron 2x4 Mopar 1959 350 'C' body 1827899 Cast iron 2x4 Mopar 1959 383 'C' body 1827899 Cast iron 2x4 Mopar 1959 413 385 H.P. 1854817 Cast iron 2x4 Mopar 1960 350 'C' body 1827899 Cast iron 2x4 Mopar 1960 383 'C' body 1827899 Cast iron 2x4 Mopar 1960 413 385 H.P. 1854817 Cast iron 2x4 Mopar 1961 350 'C' body 1827899 Cast iron 2x4 Mopar 1961 383 'C' body 1827899 Cast iron 2x4 Mopar 1961 383 'C' body (left side) 1947162 Aluminum 2x4 Mopar 1961 383 'C' body (right side) 1947163 Aluminum 2x4 Mopar 1961 413 385 H.P. 1854817 Cast iron 2x4 Mopar 1961 413 'C' body (left side) 1947162 Aluminum 2x4 Mopar 1961 413 'C' body (right side) 1947163 Aluminum 2x4 Mopar 1962 383 'C' body 1827899 Cast iron 2x4 Mopar 1962 413 385 H.P. 1854817 Cast iron 2x4 Mopar 1962 413 'B' body max 2402726 Aluminum 2x4 Mopar 1963 426 'B' body max 2402726 Aluminum 2x4 Mopar 1963 426 'B' body max perform II 2402728 Aluminum 2x4 Mopar 1964 426 'B' body max perform 2402720 Aluminum 2x4 Mopar 1964 426 'B' body S/S strip - 2468045 Aluminum 2x4 Mopar 1965 426 'B' body S/S strip - 2536900 Magnesium 2x4 Mopar 1966 426 'B' body hemi w/Carter 2531921 Cast iron 2x4 Mopar 1966 426 'B' body hemi w/Holley 2946278 2x4 Mopar 1967 426 NASCAR 2536900 Magnesium 2x4 Mopar 1967 426 W/marking 'DPCD' 2780543,4 2x4 Mopar 1967 426 W/pentastar (late) 2780543,4 2x4 Mopar 1968 426 2536900 Magnesium 2x4 Mopar 1968 426 W/pentastar 2780543,4 2x4 Mopar 1969 426 W/pentastar 2780543,4 2x4 Mopar 1969 440 'B' body (Edelbrock) 3412046 Aluminum 3x2 Mopar 1970 440 'B' body (Edelbrock) 3412046 Aluminum 3x2 Mopar 1970 340 'E' body (Edelbrock) 3418681 Aluminum 3x2 Mopar 1970 426 W/pentastar 2780543,4 2x4 Mopar 1970 440 'B', 'C', 'E' body 2946275 Cast iron 3x2 Mopar 1970 440 'B', 'C', 'E' body 2946276 Cast iron 3x2 Mopar 1971 426 W/pentastar 2780543,4 2x4 Mopar 1971 440 'B', 'C', 'E' body 2946276 Cast iron 3x2 Mopar 1972 440 'B', 'C', 'E' body 2946276 Cast iron 3x2 Nash 1951 235 5160 2x1 Nash 1952 252 Healy 2x1 Nash 1952 252 Jetfire 2x1 Nash 1953 252 Healy 2x1 Nash 1953 252 Jetfire 2x1 Nash 1954 252 Jetfire 2x1 Nash 1955 195 5540 2x1 Nash 1955 252 Jetfire 2x1 Nash 1956 252 Ambassador 2x1 Oldsmobile 1957 371 J-2 571145 Cast iron 3x2 Oldsmobile 1958 371 J-2 571145 Cast iron 3x2 Oldsmobile 1966 400 442(3 versions AL,AU,AZ) 393238 Cast iron 3x2 Packard 1955 352 440856 Cast iron 2x4 Packard 1956 374 440856 Cast iron 2x4 Plymouth 1956 (over the counter) 1732479 Cast iron 2x4 Plymouth 1956 1735919 Aluminum 2x4 Plymouth 1956 303 Fury 1733878 Aluminum 2x4 Plymouth 1957 303 Fury 1733878 Aluminum 2x4 Plymouth 1957 318 1822004 Cast iron 2x4 Pontiac 1956 316 (production) 523554 Cast iron 2x4 Pontiac 1956 316 (developmental) D-32960 Cast iron 2x4 Pontiac 1957 347 528533 Cast iron 3x2 Pontiac 1958 370 529371 Cast iron 3x2 Pontiac 1959 389 532422 Cast iron 3x2 Pontiac 1960 389 (Late production) 535552 Cast iron 3x2 Pontiac 1960 389 (Early production) 536194 Cast iron 3x2 Pontiac 1961 389 538202 Cast iron 3x2 Pontiac 1961 389 Super duty 540510 Aluminum 3x2 Pontiac 1961 421 Super duty 542991 Aluminum 2x4 Pontiac 1962 389 541690 Cast iron 3x2 Pontiac 1962 421 541690 Cast iron 3x2 Pontiac 1962 421 Super duty 542991 Aluminum 2x4 Pontiac 1962 421 (over the counter) 54299 Aluminum 2x4 Pontiac 1962 421 Super duty 9770319 Aluminum 2x4 Pontiac 1962 421 Super duty 9770859 Aluminum 2x4 Pontiac 1963 389 9770275 Cast iron 3x2 Pontiac 1963 421 9770275 Cast iron 3x2 Pontiac 1963 421 Super duty 9770859 Aluminum 2x4 Pontiac 1963 421 Super duty 9772128 Aluminum 2x4 Pontiac 1963 421 Super duty 9772598 Aluminum 2x4 Pontiac 1964 389 9775088 Cast iron 3x2 Pontiac 1964 421 9775088 Cast iron 3x2 Pontiac 1965 389 9778818 Cast iron 3x2 Pontiac 1965 421 9778818 Cast iron 3x2 Pontiac 1966 389 9782898 Cast iron 3x2 Pontiac 1966 421 9782898 Cast iron 3x2 Pontiac 1969 303 RA V 478489 Aluminum 2x4 Pontiac 1969 303 RA V 546235 Aluminum 2x4 Studebaker 1962 304 1555811 Aluminum 2x4 Edited February 13, 2019 by hkestes41 1 Quote
55 Fargo Posted February 13, 2019 Report Posted February 13, 2019 (edited) 10 hours ago, sser2 said: This is completely wrong. Multiple carbs indeed increase power, but only at steady high speed. The tradeoff is deteriorated performance at low speed and poor acceleration. This is because with 2 carbs the air flow speed at each venturi is only 1/2 compared to single carb, resulting in poor fuel atomization at lower speeds. Increased air flow increases power only at the expense of higher fuel consumption, so there is no better fuel economy. Fuel economy is worse with multiple carbs because more fuel gets into cylinders in liquid form due to poor atomization. This liquid fuel does not burn and is wasted into exhaust. Im not sure where you are doing your research. But on these engines with siamesed intake ports you are "full of misinformation " to say it nicely. A single carb is the least efficient method of fuel distribution with a design such as this. Cyls 3 and 4 run rich and cyls 1 and 6 much leaner. Now aint that fuel distribution efficiency? Oh its adequate, but its not more efficient at all. the most efficient is a carb for each intake port all 3 balanced to provide the best fuel distribution and atomization for each set of cylinders per port. Multi carbs good only at high speeds and WOT? I think you missed the boat on this. They are great in all ranges on this engine. Better fuel distribution to all 3 ports and much more efficient fuel atomization. No problem you can believe what you want, but the reality is quite the opposite of what you are claiming. I can go on much further to refute your claims and to demonstrate how a multi carb set up works more efficiently in all ranges, the benefits and the increased HP and fuel economy. However you would come up with some reason contrary, its quite evident you dont like multi carb setups and better exhaust flow for your own uninformed reasons. I believe others have also stated their responses in disagreement to your beliefs. Edited February 13, 2019 by 55 Fargo 1 Quote
Adam H P15 D30 Posted February 13, 2019 Report Posted February 13, 2019 11 hours ago, sser2 said: Very educated engineers equipped virtually all NORMAL (I mean not racing) cars not with multiple carbs, but with double barrel sequential open carbs. In drag racing, they don't accelerate like you would do in normal driving. Engine is raced to top speed before car even starts moving. This is poor example to prove your point. I'm not sure where you are getting your information but you are comparing modern engines with basically antique/obsolete technology. I agree that with modern vehicles it is very difficult to improve on the stock intake/exhaust because there was actually "engineering" involved with their design. In the earlier years these engines were engineered just enough (not much) to meet target specifications. Once met no further engineering was needed. Even the factory offered upgraded intakes and exhausts among other items during the muscle car years and even before. Examples would be the Super Stock Dodges, 300 Hemis, GTO's........ Now for late models - In the late 90's Ford lowered the hood lines of the Mustang, by doing so the Cobra intake was pancaked and the car was released to the public without meeting it's advertised HP. Subsequently there was a recall that replaced the intake with a hand ported one and replacing the exhaust with a more free flowing system, thereby increasing the HP to the advertised amount, so it does improve things. Technology improves over time also, look at what people called high performance cars in the 80's verses today. A 81 fuel injected vette made 150hp in California, now 600+ and better mileage / driveability also. When I was racing Pontiacs in the 90's, if I dropped the hammer at max RPM as you state above I would have left parts at the lights. Please understand multiple carbs, especially on these long Siamesed port engines, do make improvements all around with the only downside is a bit more tuning. I have done it and witnessed it first hand, you? 2 Quote
Frank Elder Posted February 13, 2019 Report Posted February 13, 2019 Lets make this even simpler......single carb spaced over the center port feeds that port rich, the the 2 pistons in the middle receiving the lions share of the fuel. The 2 outer ports are lean and do not run as well as the center port due to lack of fuel. It runs well but not efficiently, nor has it reached its potential in horsepower. However by placing 2 carbs of the same size as the stock carb between ports all ports get fed the same amount of fuel thus improving both horsepower and mileage.....as if it was being fed by one carb efficiently. Headers or some form of split manifolds are needed to to round out the package so the engine may breathe at its best. I never change the cam because I am not a rumpity rappity raspy guy.....I like quiet cars. Quote
HotRodTractor Posted February 13, 2019 Report Posted February 13, 2019 Dodge's own literature states the dual carb, dual exhaust option on a 265ci flathead increases power and economy. Coincidentally, the flat 6 with dual carbs and dual exhaust has more power than the V8 Hemi in 1954. Quote
greg g Posted February 13, 2019 Report Posted February 13, 2019 (edited) 6 hours ago, Frank Elder said: Lets make this even simpler......single carb spaced over the center port feeds that port rich, the the 2 pistons in the middle receiving the lions share of the fuel. The 2 outer ports are lean and do not run as well as the center port due to lack of fuel. It runs well but not efficiently, nor has it reached its potential in horsepower. However by placing 2 carbs of the same size as the stock carb between ports all ports get fed the same amount of fuel thus improving both horsepower and mileage.....as if it was being fed by one carb efficiently. Headers or some form of split manifolds are needed to to round out the package so the engine may breathe at its best. I never change the cam because I am not a rumpity rappity raspy guy.....I like quiet cars. Ok! Wait a minute. I see this argument all the time. Not picking on Frank but the air fuel mixture is set in the carb. It then gets delivered to the manifold and gets sucked to which ever port is calling for it. If the mixture is correct as it enters the manifold, how can it change to a leaner mix in a closed tube? If it gets leaner where does the gas go?? Seems to me unless air is entering some where south of the carburetor. I will stipulate the center intake might be provided a fuller charge because the fuel air has to travel a shorter and more direct path to the cylinder but if all cylinders are pumping equal volumes the charge would be the volume and contain the same amount of gas. I can see were a second carb shortens the distance and may make the system more efficient but since each carb is only half the cfms based on bernullis principles and venturies effect both charges might actually be leaner than that provided the single carb. Things that make you go hmmmm. And if distance were a critical factor please explain the long runners on slant sixes and the long ram intakes on the 413 dual 4 BBL intakes. Edited February 13, 2019 by greg g 1 Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 (edited) Greg part of the reason could be this. This is not pressurized fuel injection system. So yes atomized fuel enters the plenum and is drawn into the intake manifold. Which 2 cylinders do you think might receive the most or best balance? If you said cyls 3/4 give yourself a correct mark. Cyls 1,2 5,6 get there's too obviously but not as effecient as 3 and 4. The runners on a slant 6 very long and balanced supplying to 6 ports and with a puny 1 bbl very asthmatic. Different movie altogether compared to a siamesed flathead intake and ports. I dunno Greg do you think a1 bbl intake supplies fuel to all the cyls in an equal fashion? I sure dont believe so. I could be off my beliefs but dont think so. If a center carb feeding 3 siamesed ports were great we would all have 4bbl single carbs for more power and perf as you see a lot on hopped slant 6s.. Edited February 14, 2019 by 55 Fargo Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 This about says it all. Great tutorial on this topic. 1 Quote
greg g Posted February 14, 2019 Report Posted February 14, 2019 (edited) So let's consider dual carbs for single cyinder engines. Re read, I stipulated that three and four are probably best served and most efficiently provided for. But if number 1 and 6 are pumping the same amount of air they must by the principles of fluid Dynamics get the same intake charge assuming valve timing and intake valve timing lift and duration are the same. Is it possible that some fuel falls out of the vapor state sure. If it's significant where does it go. Does it pool in the intake?? If it does might this not allow the pooled fuel to cause the rear cylinders to run rich under acceleration? And conversely do the front cylinders run rich while braking?? It's like tire rubber. We know it wears off our tires and others tires but shouldn't it accumulate at the side of the road? Other than chunks of truck tires, you don't see rubber laying around. Where does it go? Edited February 14, 2019 by greg g 1 Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 30 minutes ago, greg g said: So let's consider dual carbs for single cyinder engines. Re read, I stipulated that three and four are probably best served and most efficiently provided for. But if number 1 and 6 are pumping the same amount of air they must by the principles of fluid Dynamics get the same intake charge assuming valve timing and intake valve timing lift and duration are the same. Is it possible that some fuel falls out of the vapor state sure. If it's significant where does it go. Does it pool in the intake?? If it does might this not allow the pooled fuel to cause the rear cylinders to run rich under acceleration? And conversely do the front cylinders run rich while braking?? It's like tire rubber. We know it wears off our tires and others tires but shouldn't it accumulate at the side of the road? Other than chunks of truck tires, you don't see rubber laying around. Where does it go? That settles it Greg pull off your dual intake and go to a 1 carb setup. Heck even better get a 2 bbl to 1bbl adapter and a Langdon carb. Geesh are you the new Devils advocate..lol Quote
Frank Elder Posted February 14, 2019 Report Posted February 14, 2019 It does not have time to pool in the intake........it gets sucked greedily into the center port. Quote
rallyace Posted February 14, 2019 Report Posted February 14, 2019 Well, all I can say is this has made for some interesting reading with my morning cup of coffee. 1 Quote
MackTheFinger Posted February 14, 2019 Report Posted February 14, 2019 Seems to me that deferring to Mr. Asche and Mr. Kingsbury's experience is worth more than all the wool-gathering and head scratching the rest of us might do. It would be interesting to see actual fuel mixture data from each cylinder, though. 1 Quote
Don Coatney Posted February 14, 2019 Report Posted February 14, 2019 On 2/12/2019 at 9:22 PM, sser2 said: Exhaust performance 1 Exhaust performance 2 Exhaust performance 3 Just from top of Google search list. Larger exhaust improves performance at high engine speed, especially at speeds approaching top rpm. At low to normal driving speeds, there is no improvement or deterioration. Dynamic performance (acceleration) may suffer. Now I'd like to see evidence for souped exhaust making difference at normal driving. I would like to see or hear evidence of a flathead 6 turning 6000 RPM's 1 Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 53 minutes ago, Don Coatney said: I would like to see or hear evidence of a flathead 6 turning 6000 RPM's Well here is 1 turning 5500 revving no load. But I guess it would take another 500 to impress you. I suggest you Call George Asche to discuss a 6 k RPM redline possibility. 1 Quote
MackTheFinger Posted February 14, 2019 Report Posted February 14, 2019 On 2/12/2019 at 3:44 PM, normanpitkin said: my 41 on boxing day ,BUT before all the modifications! That is the best sounding exhaust ever!!! Quote
Adam H P15 D30 Posted February 14, 2019 Report Posted February 14, 2019 (edited) 58 minutes ago, 55 Fargo said: Well here is 1 turning 5500 revving no load. But I guess it would take another 500 to impress you. I suggest you Call George Asche to discuss a 6 k RPM redline possibility. I'm not saying it can or can't but I could snap a Briggs&Stratton to 6k with no load. It sure seems like this "Velociraptor" struggles a bit to get there.... Edited February 14, 2019 by Adam H P15 D30 1 Quote
Matt Wilson Posted February 14, 2019 Report Posted February 14, 2019 (edited) I spoke to George Asche last Friday and he told me about someone he knew many years ago who got a 265 up to 7200 rpm during turns in races. Stock crank, rods, rod bolts, etc, except the guy had to modify the bearing oiling configuration by cutting grooves in the rod bearing halves and cutting grooves in the main bearing journals (not the main bearings themselves, as they already have grooves, but the main journals). It had some power boosting mods or else the engine wouldn't rev that high, but the engine was capable of taking those revs repeatedly. George also tells a story about cruising from Salt Lake City to Los Angeles in 1953, averaging between 4000 and 4500 rpm for 9 hours straight. Again, there may have been some intake and exhaust mods, but he says it was otherwise stock, and was either a 251 or a 265. He also had a 265 that he routinely took up to 6000 rpm during races, again with power mods, but stock crank, rods, pistons, etc. Maybe not proof, as we're not there to see it ourselves, but I tend to believe George. I've also read about tractor pull competitors using 265s and other Chrysler flatheads and taking them up to 6000 rpm and beyond, with mods of course. Edited February 14, 2019 by Matt Wilson Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 (edited) 1 hour ago, Adam H P15 D30 said: I'm not saying it can or can't but I could snap a Briggs&Stratton to 6k with no load. It sure seems like this "Velociraptor" struggles a bit to get there.... Well its a race engine and no load. What kinda redline you gettin? Better yet Adam how bout a video if your flattie runnin. And not a HF clone engine running to 6 grand. Edited February 14, 2019 by 55 Fargo Quote
55 Fargo Posted February 14, 2019 Report Posted February 14, 2019 Its very clear why Tim Kingsbury and a number of others stay away from this Forum. Most likely time to lock this useless thread. Good rittens.. 1 1 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.