Slant Six - Holley Vs. Weber Side Draft Carburetors
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- เผยแพร่เมื่อ 16 พ.ย. 2021
- A video by a fellow TH-camr from Australia may have the ultimate answer to this debate based on something we observed during a dyno session with a 225 Slant Six.
WILD SLANT SIX - 225 Chrysler Build and Dyno | Iconic Engine Series : • WILD SLANT SIX - 225 C...
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#engines #mopar #265Hemi - ยานยนต์และพาหนะ
I'm going to play devil's advocate- Just watched the Wild Slant Six video and believe the phenomena to be visible condensation in a low pressure area. If the temperature and dew point are close in that dyno room, then the air pressure drop in front of the carbs would chill that air and the moisture in that air would become visible. Something to consider.
Most of the "condensation" is originally from the venturies, watch closer
@@tinkersspeedshop8401 have you ever seen an airplane take off on a cool humid day? A cloud forms over the wings and dissipates at the trailing edge. I have seen it thousands of times with commercial planes, C17s, C141s, and all manner of fighter jets while I was in the USAF. It doesn't happen all the time, only when the conditions are right. C17s have a very high lift wing shape, so they did it far more often than other planes. You can see when a fighter flies through humid patches at the right temp in some videos, because clouds intermittently form over the wings and vanish, like someone is flipping a switch. Its really cool.
Its probably a combination of both reversion and low pressure areas to be noticeable.
He’s trying to justify doing what everyone in America like to do. If the big 3 had used side draft carbs. They would have save Americans millions of gallons of gas.
After using DCOE Webers on small block Chevy cross ram some 20+ years ago, I became a believer in the fantastic tunability that Webers have built into them with the jet stack, individual manifold length, and the ram tubes(velocity stacks) on the mouths of the carbs. You can do virtually anything with these beautiful carbs. When the Chevy was properly tuned with those carbs so many years ago, they would just MOAN when you stepped into them. The sound never failed to draw a crowd and run chills down your spine. A KEY PART of the tuning process is getting the velocity stacks and air cleaners (K&N in my case) the proper length/volume to deal with the "stand off" at the mouth of the carbs that leads to the loss of power or tuning of the torque at the wrong rpm for what you are trying to accomplish with the engine power range. If you combine the above with a header/collector that is set up for the rpm designed to pull the exhaust thru the motor at the proper range, you've got a winner. Good Luck to ya, Tony. Keep the Faith, Tom P.S. Using the Holley with the proper plenum volume is an attempt at the same effect.
That standoff is why the old air cooled vws had such a tall air cleaner assembly, the standoff could be like 5-6"
Will a set up like that work on the strip with an automatic or something more like a close ratio gear box?
I agree I ran triple webber's on my 2.8 datsun 240 z
@@moparsquid Bet that was a nice set-up.......wouldn't you love to have it back today?
If you like the moan of a DCOE, try putting it less than a foot from your ears like it is in my Europa. "We don't need no stinking stereos."
Never heard it called reversion before. When I was younger, it was called "stand-off", and ideally you wanted to be able to have intake trumpets long enough to enclose it if you had the space under the bonnet. Old Minis running a Weber DCOE tend to get quite a bit of standoff also, and i doesn't seem to be detrimental to power or torque output.
Agreed. You adjusted the runner length for the power band area you wanted to run, then the velocity stack length to prevent the reversion outside of the stack.That's why a lot of the Hilborn injectors used such tall stacks.
Well you call wrenches spanners too right? Boot and bonnet rather than trunk and hood.. Different words meaning the same thing depending on what country you live in.
@@SweatyFatGuy Well, yeah...but I've lived in the PA/NJ area for 30 years. Still never heard it called that. Not claiming it's wrong or anything, just odd I'd never come across that term before.
Reversion is just the general term for fuel-air charge coming back up the intake tract, even if it doesn't make it's way all the way outside the motor like the example given here. It's a large part of the reason why a big cam is "choppy" at low rpms and is a really common phenomenon, just not usually a visible one.
I looked up the Ram effect formula in the book “We We’re The Ramchargers”. It relates the length of the from plenum to valve head to the RPM at which the ram effect is desired L (inches)=84,000/RPM. So those stubby manifolds say 6”, are tuned to 14000 RPM. Hence the reversion
For an engine that HP peaks at 5700 RPMs and a way too big 7,500 RPMs cam for the available head flow...
Weber DCOE or Dellorto DHLA is the way to go ultimately. Every aspect of tune is adjustable, including adjustable VENTURI sizes(adjusts velocity wherever you would like it) and fuel EMULSION tube variables for mixture settings high/low, and everywhere in between. 4bbls are just a cheap & convenient way to dump a shit ton of un-atomized fuel in a V8.
Don't talk crap fanboi.
4bbls do atomize the fuel properly.
I can see that because you don't like 4bbls then anyone elso who likes them is ignorant.
The 4bbl dual booster venturi has been out now for at least 50 years - Please! You geese crack me up. You remind me of a those religious idiots that knock at your door on the weekend.
Glenn Everett is awesome. Absolutely a great bloke. Ran a dyno and performance shop but has been firstly tv and now TH-cam for around 10 to 12 years now and an absolute wealth of knowledge on not only aussie cars but many others too.
Are we sure that the cloud isn’t moisture condensing in front of the stacks because of the drop in air pressure changing the point of water vapour saturation at a given temperature? F1 engines have this happen as well when dyno'd
depends on ambient temp and humidity if clouds form in a low pressure area.
Commonly seen as a sheet flashing transiently on the top of airliner wings. Airliners can also produce a water vapor trail from the wingtips or other places where there is transiently a low pressure created.
Usually seen during takeoff or landing with full flaps when higher angles of attack of the wing occur.
Thats how I see it
Webers on an inline motor normally have a very short intake manifold. On a motor that spins fast, like an Alfa Romeo that's probably fine, they run best at high RPM. On a Slant I'm thinking you'd want them longer to match the lower RPM range.
I'm no engineer but I'd bet neither are the folks that designed the Slant Six Weber manifold.
In Australia, we had a (non-slant) straight 6 Hemi from the factory with 3 side-draught Webers. With the Slant having the head leaning to the right and the carb on the left of the engine bay, there should be room for significantly longer manifold runners.
Remember to keep the entire length of the carb and inlet stack in mind.
@@aussiebloke609 the 'hemi 6' was in the vg's on ,
about 69ish from memory,
chyrisler aust was playing with tripple Weber's on 'hemi's' since 68 ish
tbf, the runner length on this Slant is MUCH longer than an Alfa Romeo DCOE runner. The last time I had my hands on a Fiat DCOE intake, the short part of the runner was about an inch long, the long part was about 2" long (the manifold to head surface has a 45 degree angle, it's a straight shot from the tip of the velocity stack to the downward curve to the valve inside the head)
His slant dropped off at 5700 RPMs, a Fiat or Alfa motor will easily rev to 7500, but I don't recommend doing it on a mountain road in Oregon when you're more than 2500 miles from home....
@@alt7488 Yeah, VG was the first hemi 6 - in '70. But the VG Pacer only came in 2 bbl (regular Pacer and E32) and 4 bbl (E34 only)...the 6-pack didn't come along until the '71 VH Charger E38 and E49, and the 225 slants in Oz ('69 VF and before) never came with a multi-carb setup at all. I know there's a fair few Pacers these days with 6 packs (or sometimes just 6-pack badges), but that never came from the factory - even the VH Pacer that hit showrooms alongside the Charger weren't offered with the triple carb setup.
PS: I remember this stuff mostly because my first car when I was a kid was a VG Pacer hardtop, so I really got into the Mopar stuff at the time while I was going to tech. Hard to believe I bought that car for $200. And sold it for $350 a few years later. _AND_ thought I'd gotten a good deal. :-P
Love your show and your style. I'm GM all the way to the ground, but you cannot learn from someone you agree with. Your MOPAR focus, teaches me new things. Thanks, fun stuff.
We forgive you!
Hey man, no doubt these lessons could apply to a stout 292 that oughta put the slants to shame ;)
I enjoy most of your shows, but the educational part is my favorite. I love you sharing your knowledge and experience.
Glen Everett has one of the best channels out there, professionally made videos, yet not a huge amount of subs for the work put into it
The Aussie hemi 6 pack… there’s your starting point
He just got another sub!
That's not reversion. It's the air losing pressure in front of each runner as it gets 'sucked' into the carb. As it loses pressure, the amount of moisture the air can hold decreases; it causes the moisture in the air to condense. What you're seeing is essentially mist. My guess is it was a humid day when they dynoed.
Exactly; fuel backpulses would vary approx. linearly with rpm. Condensation would have more of a threshold at the dew point, which is exactly what you see fairly dramatically above 5500. If you were really interested, you could shoot a laser pointer through it and measure the refraction angle. Gas has a higher refraction index (1.42 vs. 1.33 for water) and will bend the beam more.
Like the vortexes on the wing tips of a fighterjet pulling up like crazy?
I quit my job of 2 years & 3 months to smoke weed on my TH-cam channel full time haha
Yeah I saw that, I am and Aussie like glens stuff , what a strong motor, big torque figure too and I mentioned you and he said he’s a fan and 6000rpm is pretty much there limit. They were using what look to be a healthy budget , with pretty good hardware and internals , interesting discussion 👍👌and something to compare too and see what you’re motor can achieve, using more stock internals and probably smaller budget
Just an FYI, the condition you have described of the cloud caused by reversion is called "fuel standoff." It was very common on VW air-cooled engines with Weber carbs. The solution? Run longer velocity stacks OR use a big air cleaner. Consider what happens at speed on the drag strip when air coming through the grill and radiator blows that cloud of fuel standoff away from the opening of the velocity stacks. Without containing the standoff, the engine will run lean.
That is exactly was I thought. A dyno and real life are two different things. I think a ram air loaded resonance chamber on the carb inlet side is the key to success.
The RamChargers developed a formula for intake runner length. According to the Interweb it is 17.8 cm @10,000 rpm peak torque. Add 4.3 cm for every 1,000 rpm less. So for 5,000 rpm peak torque the length is 15.47" from intake valve to carb butterfly. I see very short intake runners on lots of drag race in line 6's. Wondering if all of those guys are wrong.
They're probably running MPI.
I don't work on cars any longer but I still love watching your video's and learning all the time.
The reversion struck me as well. I immediately started thinking about how to remedy this obvious problem. Glad we have Tony to help work these things out in our heads!
My friend has an engine shop he does many vintage road race motors such as Cosworth BDA and Alfa Romeos....It's very common to see fuel standoff in an Individual runner intake set-up. There is always compromises made in tuning and this standoff usually happens at a lower RPM.
i built a slant 6 in the late 50s and early sixties,i made my own intake out of aluminum and had 3 SU carbs,1 and a half inch off of MGs,no reversion but it was fast, lot of experimentation with different needle in the main jet, tryed th SUs cause they only worked off engine vacuum,,i run SUs on my 77 sportster and 96 inch 84 superglide
I had double SU on a slant too, worked good !
I watch that yesterday, that was a nice slant 6, It reminded me of our Australian built RT Charger with its row of Webbers on a 265 Hemi, just over 300HP and quarter mile time in the mid 14 s . There’s a classic photo of this engine when Chrysler ran it full noise for a crazy amount of hours with the extractors glowing yellow to orange, they checked its durability and didn’t blow up.
I watched the video. Very impressed. That was very interesting to see the fuel spray reversion go in and out of the stacks.
After watching the mentioned vid, it seems that one wants a “box” that the velocity stacks go into to collect those fumes. One could fit an air cleaner there between the collection box and the hood scoop.
That box is quite a common add on on full house modern race spec track cars fitted with Hemi 6's and tripple webbers here in Aus.
In electrical speak we call it a standing wave. Measured as VSWR. Where the tunnel ram is the transmission line.
1960's plymouth Hyper Pak looong runner intake manifold solves the reversion/stand off issue. I built my '67 slant .60 over, 250* cam, 10:1, pistons, Offy intake, and Clifford headers. The Dutra cast irons don't compare for bottom and mid range. I made an alumilum spacer 1.5 inch high to adapt a Holley 4 bbl mounted sideways so that on primaries, the fuel distribution would be more even. New bigger valves and hardened seats with minor matching was done on the heads. Mopar elect ign curved just right and a tightened 904 trans rounded out the build. I'm glad I did all that back in the 1980s when good American parts were still plentiful. Plenty of stories have been generated. My son used it in college or law school and got a few tickets. Oh yeah; it's a 4 door Dart.
I love how you see something that works and say, hell I will do the exact opposite and expect better results.
A few years back a gentleman out west in Montana named Ron McCord was building dirtbike intakes for two strokes and four strokes on this exact principle. It was a specially modified carburetor with a hand built intake and a pulse tube that re-introduced to Pulse on the intake side of the carb needle.
I have a yz250 that does amazing things based on ram effect intake
Power everywhere
I’d like Glenn to to a video on why your engine failed..,
Sorry UTG, us Aussies stay together 😂🚀🇦🇺
I always liked the sound of a slant. I had another straight 6 that was so boring in sound it almost would make me sick on a long drive, but the slant always seemed to have a nice soothing effect as I drove...the perfect motor.
That haze at the end of the stacks is what we call "creating it's own atmosphere"...I thought you'd like that vid.
Watching a "Holley Only" person try and tune in a Weber for the first time is always a treat...
NOPE... that's not an idle speed screw... keep those throttle plates completely closed... and figure it out ;-)
What I have experienced with my car was a revision happening with a restricted exhaust. I run a 514 cubic inch ford with a victor jr. intake and a 1050 dominator. the first time I put this motor in the car I put the exhaust port gaskets on backwards by accident. I didn't notice a fog out side the carburetor because the hood was on. But what I did see was a black soot in the throttle bores. When I change the gaskets and put them on the right way and not restricting the ports the soot went away. also a guy I know had the webber intake and stacks on his hot rod. They worked really well until he put zoomies on the car. After that te car ran like crap. He called webber and they told him the webbers need the scavenging effect from a collector.
I found a Chevy intake with 3 webbers and all the linkage at a pawnshop in 91. I remember they wanted 125 bucks.. I wasn't into cars yet so I had no idea what it really was. Wish I had bought it even just as a paper weight because it just looked so cool.
Is there an intake manifold available in a "split style"? Like a three piece manifold where one piece covers two cylinders and is fed by one 2bbl carb. Or a single flange with six individual runners to use six one bbl carbs? Hey now that I think about it that would be an interesting test item.
Master of machines is awesome! Especially the 413 build.
"Pulsating in Sympathy" Sounds like great name for an album. LOL Great video, Tony!
I just watched that video this morning and noticed the cloud of vapor on the intake stacks too. Also wondered how much more torque would have improved with a set of long tube headers and longer intake stacks. I'm willing to bet there's at least another 15-20 foot pounds of torque to be had if the intake and headers were tuned properly for the power band.
Carburation is neat! Physics is hard... that massive cloud of reversion is probably partially due to cam selection. As I understand it, Webers like a wide lobe separation with a less overlap. The typical rowdy street cam is generally a poor choice for that system. I'm confident those guys know that, but what can you get for a slant without a $$$ custom grind? Sweet engine no matter what.
Can you elaborate on why you think Webers like wide LSA?
Hey Tony what do you think of a 500 cfm holley and Offenhouser intake with a complete stock 68 225?.... still too much or just jet it down
In terms of reversion back in the 70's and 80's there were exhaust built with a "cone" shape on the mating surface to the head that reduced reversion considerably. The other trick for reversion is to have a small groove (circle) cut into the valve as this impeedes reverse flow. Another low budget option is to have a slight mis match in sizes from the exhaust port and the manifold (manifold needs to be bigger than the size of the port). Reversion effects are more pronounced in engines that have "siamese" intake ports, like the classic British Leyland Mini (A Series).
In terms of carbs you also have to bear in mind that on a Weber setup (or dellorto) because you are using an independent runner configuration every cylinder is fed by a single barrell. The setup you have there with the 650 DP means that every cylinder on that engine can "see" the 4 barrels of the holley, in that sense the common plennun approach gives you much more capacity (in cfm) than a weber would ever give you. Webers can be a winner in applications where you want to precisely tune where you want the resonance effect to have an inpact on the power band, and you can do this by adding more lenght to the velocity stacks (trumpets)
Some dual quads like the FOMOCO units for the 427 sideoiler are configured in such a way that every piston is able to draw air from both carbs (8 barrels in total!)
Webers are a little harder to tune right
Bit once you get it on point the throtle response and torque down low is unreal
And they look badass of course
Could reed valves be used with the webbers to prevent the reversion? Works presto good with 2 stroke engines to allow radical porting of the inlet and exhaust ?
Appreciate your decision on using what is available. I would suspect 6 inline carbs would surpass plenum/runner set-up due to the years of development & experience of UJM design alone. Otherwise Hayabusas would have some interesting runner/plenum 4bbl carb set-ups right from the factory. Intake & Exhaust witchcraft got really interesting in the early to late 1950's , especially in the racing motorcycle singles. Thanks for being a car guy who also likes bikes.
Cheers
I kept thinking that either longer intake runners or longer intake stacks would be good for that Oz engine - and I love it. The mopar guys in Oz have the inline 6 265 Hemi Six-Pack OEM engine as an example, with side-draft Webers like those. So I sure see why they like them, once they learn how to tune them.
Hey thanks for talking about this! I observed something similar coming out of the 460 in my f350 a couple days ago while I was playing with then ignition. I was like what the heck was that!?
Also I saw your video on adding extra timing on big bore engines. really put a lot more pep in my truck which previously had some serious lag. Previous owner bored it .040" and Changed the cam but put everything back together stock.
I sat in on the Ramchargers clinic a couple years ago at Carlisle. They talked about a cloud forming when dyne testing a hilborn setup back in the 60's. I think they said it happened depending on stack length. I can't exactly remember though.
Glen Everett Reversion is due to the headers not scavenging at their best. Then I’d play with the stack lengths.
agreed, I would like to see longer stacks on these. The nice thing about Webers is you an change everything on them.
Ive run into reversion in the past. Long runner tubes feeding into a common plenum, then appearing in a large ball above the Holley 4V.
Happened only at a certain RPM, then the ball of fuel appeared to be sucked back into the engine above or below that RPM.
Engine ran fine. The only question was whether the pulse going back out of the carb was collecting additional fuel from the boosters, then would go into the engine with a rich A/F ratio in that narrow RPM range.
I just put the air cleaner cover (still wet with fuel on the bottom) back on and didnt worry about it.
I watched the vid with the Weber's and noted the cloud of reversion you mentioned. As I was watching, I was thing that a trick Yamaha used on their 2 stroke engines might work. In the 70s they put reed valves just down stream of the carburetors to stop this type of back flow. Do you think a similar set up might work on the slant 6?
I remember playing with sidedraft carbs back in the early 90's on short runner manifolds (less than 2") and yeah the reversion was terrible especially at wide open and anything less than full rpm's(6500-9000), the fuel usage was horrendous and the fuel smell made it a constant guessing game of when it was going to catch fire, but add trumpets of sufficient length and or lengthen the runner length and boom the drivability went through the roof and the fuel consumption dropped, add a common air filter or some sort of air box and it got even better.
ITB's are awesome but only if you put in the time as with anything with engines to tune then as a part of a larger system.
I wondered how longer velocity stacks would have changed the dynamics of that Aussie engine when I first saw the video. I have to admit it was VERY impressive! Not sure about its economy on the street. Would love to be able to follow that engine for a year or two and see what happens.
Short intake runners and a lot of overlap will create stand-off until the motor climbs into its powerband. I’d bet the A/F ratio goes rich too, as the column of air picks up even more fuel on its way back into the motor.
Love these Slanty vids...I've only drag raced a slant 6 once... unfortunately and unknowingly against a Indiana State Police 91ish RS Camaro...but that 86 Diplomat was one helluva car
*correction 81 Diplo...bought for $200...drove 6 blocks home from 2 doors down (would only turn left)...straightened frame w/ 30' log chain and 100 yr old oak
Watching the suggested video helped me understand how an intake manifold like the SP2P Werks.
Interesting stuff as always!
Yep we all need variable length inlet manifolds. Ford did it in OZ on their inline 6
Tony I have a question: Did the reversion cloud get smaller and disappear as the slant got up above 5000 rpm?? I would think that it would start ram tuning at some rpm between 5-7 k rpm.
My take on the video is that if anything, the cloud grew with RPM. He didn't run over 6,000. Like a smoggy morning in LA.
If I was building a slant 6, I’d go Triple Webbers.
I saw a guy that installed 6 50mm motorcycle carbs on 240z L28 engine. Not only did it look cooler than hell, it sounded amazing and ran perfect!
i've always wanted to test a "dynamic" ITB setup, not something with a plenum tune intake like the new corvette, but a true stack injection type deal with telescoping velocity stacks, it would be very over the top in the engineering department but to see an intake runner "shrink" like a trombone slide in distance from low RPM to high RPM in trying to achieve the flattest torque curve possible and the best high RPM horsepower output would be astonishing, obviously in the drag racing world this could be compensated with torque converter slip or other gearing measures but just from a hotrod/efficiency POV it would be cool to test
Uncle Tony, webers used on individual runner manifolds often have those reversion clouds hanging above them especially with big overlap cams.
I think you are quite correct in saying the plenum plays a important role in utilizing that reversion in charging the other cylinders.
I think individual runners could often be improved by having a balance tube between cylinders that are opposite in the firing order to take advantage of that reversion rather than as you say letting it go to waste into the atmosphere.
Put baffles or traps in the rear and front of the oil pan. That way under accel and decel the oil won't be pulled away from the pickup. Scrapers around the edge of the oil pan help with windage as well as preventing oil climbing.
Would be interesting to hear what David Vizard has to say on the subject.
I’d like to see you run some Weber’s I love the sound throttle response right threw the rev range on my 265 Hemi I’ve also seen slants at the drag strip with triple Weber’s the sound is amazing
I have been wondering how 6 motorcycle carbs might work on your drag slant .
Love any carb video you do.
I like your theory. In the Weber vid he spent some breath describing how he figured part of the reasoning behind the slant six was for long intake runners. I look forward to finding your theory (and mine) backed up with higher dyno results.
Agreed that the combo is leading to reversion and pulse stand-off. Not uncommon in boat motors where you have worry about carb tuning issues, but also drawing in wet exhaust. Usually because of too much cam and not enough exhaust scavenging at a harmonic RPM ...
What amazed me about that S 6, was that he got 6k rpm out of it. I've never seen one, even hopped up, go above 5k without hitting some wall (I assume flow) and won't go further. I did see that reversion and thought that can't be good for raw power
I paused the video before hearing your answer Tony, the cloud of reversion was helping in a static environment, when on a running vehicle on the track it will get blown away, on the Dyno it can be sucked back in! Just saying I've watched videos of F1 Renault engines doing the same thing starting at around 14,000 RPM. In fact some of the injectors are "outside" the throttle bodies in open air!
Tony. I have seen that cloud form in the airbox of Ferraris. I believe the position of the Webers in the intake runners is important. The intake air pulses have a waveform caused by the rpm, bore/stroke, camshaft timing. It is important to position the Webers at a distance from the intake valve that provides a smooth vacuum signal to the venturi and contains the intake pulse within the Weber + intake runner combination. The intake roar, as a musical note, is affected by the combination. A ragged intake roar is a sign of a mismatch affecting the CFM flow through the engine. Mike
They have to consider that pressure wave on pipelines as well to make sure it, combined with normal pipe pressure don't burst the pipe when they close block valves.
Colin Chapman (owner and mastermind of Lotus) came up with the idea of a resonance chamber on the intake side of his engines back in the sixties. The chambered volume reflects the intake pulse and increased efficiency of engines substantially without parasitic losses. It was mounted on the intake side of the carbs. Truck intake manifolds combine long runners with resonance chambers to increase low end torque as far as I know. According to David Vizard, exhaust resonance chambers increase the scavenging effect without an increase of backpressure. I guess, because of the volume between runners and carb, the slant six intake manifold works somewhat like a resonance chamber.
This cloud is a known danger, actually. In the right conditions, a backfire will ignite this cloud and your engine bay is gone instantaneously. It is why a lot of people running this setup on Austin Healey's and MG's will actually run something that looks like a single cold air intake to the whole thing. If it backfires, it just belches out the nose.
This Offenhauser monifold runners appear to be short vs the ones I have seen at car shows (please note that I have not seen very many). The slant six config. allow the possibility to install very long runners, I’m surprised that Offy made a short runners version like this one we see on the table.
On the oil pan, '79 Dodge Truck slant six had a rear sump, be perfect for this and the Miata, factory part. Question, if you run two headers on slant six or inline six or even a straight 8 does an "H" pipe increase horsepower? We all know it does on "V" engines, but does it matter on inline? I know something that worked really well on inline Toyota were anti-reversionary cones in the exhaust header near where it mounted to the heads. little metal funnels welded in the exhaust header. I seen them for sale as exhaust port torque cones on google. They work!
Question: if you had EXTENDED stacks, could it pull that vapor IN? Maybe 8" horns?
I saw the same thing and immediately thought of reversion. I wonder if a longer stack would have had any effect?
Off topic i know but did ya weigh all those lil' disks that ya drilled out of plan Z ? Why did ya take off the nitrous? (front page pic)cheers.
Go with what you know and are comfortable with. But in terms of the cool factor. Yeah Webers are way cool looking. The first engine I ever remember actually seeing them on was a 343 or 390 in an AMX. Homemade tube intake in a cross ram set up
Do you think if you had longer stacks on it. That fuel would be more likely to be used? On the stack or just longer runners. I assume that would add to the torque as well.
Cam characteristics can also cause some intake reversion. There's a guy on TH-cam who mounted 4 Quadrajet carbs to an Olds V8 cruiser,with all the carbs linked to open simultaniously. An in car camera catches the carbs in action (no hood) as the driver floors it & all 4 carbs open. It sounds great but there's big time reversion (fuel mist sprays the windshield).
All that motor on the dyno needs is a long velocity stack.
How much power you making on the dyno?
Is it possable that the mixture is getting attomized better by pulsing just past carbs and back in again , haven't seen it but sounds like it's attomized fuel , could be part of getting his power curves
I had watched that same video just a cpl days prior. That build is awsum, and it looks super cool, but i do believe the long factory runners were there for a reason. I believe a bit longer runners on his setup would yield absolute excellence, and i bet the sound resonance in those trumpets would be baritone bliss
Tony your thought process reminds me of the old days on how we found that extra H.P.
I saw that same video today and was wondering the same thing. Wonder if longer stacks would help contain that fog.
There was a whole story about this type of thing in the Ramchargers book when they were setting up a 1st gen hemi to run in a Indy car. They had straight stacks on it and had to add the bell on each to keep from fogging the Dyno room.
All for nothing, as one of the first cases of the hemi being banned from racing, because offenhouser complained.
Tony, a while back I had a military 3/4 ton 68 Dodge flight line truck. Full two seat crew cab with 225 slant six and 4 speed with 3 and 4 close. It had a huge rectangular oil pan that was big as a bathtub. Like about 10 quarts big. I don’t know if it was special or if most trucks had one like that. Anyway, one of those with correct pickup and maybe pump would put you ahead of the game. If it doesn’t have a windage tray, there is certainly room for one. Good luck and take care.
I wonder if placing a "reflector" 2 or so inches off the end of the stack would reflect the pulse back. Kinda how reverb works when tuning a guitar amplifier to a room. Just a thought.
i twigged out over the same video...how a cloud of fuel that size can hover in front of a direct vacuum is an enigma.
Here in Australia we had Chrysler Australia playing with the Hemi 265 back in the early 70’s
They had 3 dual side draft Weber’s in a limited production charger six pack
It out run the Ford 351 over the standing quarter in the day ....
No mean feat for a six cylinder against V8
Glen would have been using the same ideas for the 225
This is legendary in Australia
Hey Tony, watch the Renault F1 engine on the dyno that runs fuel injectors at the top of the intake trumpets.
When they are at high rpm you can’t go past atomised fuel rules in the open air.
I know you may know but the 265 hemi six in the E49 charger ran Weber carbs and ruled at Bathurst race in Australia
It did very well against V8
A friend of mine ran a '68 Camaro with a sbc running Webers. I suspect it was for the WOW factor when he opened the hood. However, at the drag strip, it fell flat on it's face. When he tuned the Webers for wide open throttle to run better at the track, the Camaro lost all drivability for the street. He replaced the Webers with a single 4 barrel. Same thing happened when a guy added mechanical Hilborne Fuel injection to his '67 Chevy II. I ran fine on the street but failed miserably at the drag strip.
I wonder what it would do for power if an airbox was built to make the carbs pull air from a common plenum? Seems one wouldn't loose the mixture in the reversion/standoff that way.
I've seen that fog before on indy car dyno motor pulls I always thought it was a good thing. I thing it's also common with the velocity stack style setups that are revving to the moon..
his engine is definite artwork, not sure the reversion is much of anything fuel mix but seeing it would make me want longer trumpets and an air cleaner at least, which might create a self cooling intake situation. I do think the 650 with the jetting, spark plug choices after run reading etc will work as well or better overall.
Does anyone know the LSA of that cam? Jim Inglese recommends 112-114 degrees to minimize if not eliminate reversion.
I witnessed this happening just a couple weeks ago when I was tuning my chainsaw. On a much smaller scale ofc.
I saw the same thing and knew what you were going to talk about as soon as you said you looked up “slant 6” on TH-cam. He made a ton of Power, but you have to wonder how much his mixture might drift around depending on how much fuel gets away and doesn’t get sucked back in to the stacks. By the way, I’ve seen the same above a dual quad setup on a v8, (maybe on Richard Holdener’s channel? I forget). But in that case, the fog only appears at initial dyno load-in (low RPM) and disappeared as soon as the revs came up.
Every time I watch you I learn something and I’m 67 years old
I've noticed that and have concluded that an air filter will help contain that, a deeper velocity stack also helps.