The Ultimate Vacuum Advance Video Part 1

so do you want the ultimate vacuum advanced video stay tuned because you're going to get it it is unlike anything else welcome back to the channel everybody so when I make the claim of being the ultimate vacuum advanced video that means that is pretty serious territory because they've been some good videos put out on vacuum advanced but for me making it the claim of the ultimate that's it's got to be over the top so let's first talk about vacuum advanced and what it does vacuum advanced is not a new thing check this out I have two books here on the hood of Casper that are very near and dear to my heart one is this motor Tuna manual right here from 1946 my granddad gave me this and it was like literally one of my first auto mechanic books that I ever got so let's see what it says about vacuum advance because 1946 do you think they know a lot about vacuum advances I don't know let's see I'm going to read you what it says right here when the engine is operated under part throttle there is vacuum in the intake manifold and consequently the charge taken into the cylinder is not so highly compressed lower compression means a lower rate of flame spread and the cylinder as spark occurs with lower compression in the cylinder the spark must enter the cylinder earlier in the cycle so that the mixture can be ignited burn and give up its power to the piston if the spark occurs earlier in the cycle that is if there are some additional spark advanced full burning of the charge and maximum economy is achieved now check that out this is 1946 so let's think about this in modern-day terms this is a vacuum advanced canister off of a Mallory distributor in the modern-day world your ECM computer controls your timing correct and when you build a high performance engine that's feeling ejected what do you do you go and get a tune put in the computer and it changes the timing curve appropriately like it's needed guess what this does the same thing as what your computer does in your car late model car it provides additional spark advance based off of the needs of the engine okay now the key is the tune is being able to adjust this to give the engine what is really required and so when I first got into talking about vacuum advances and trying to figure out how to make them work I was clueless you know I would hook it up you always hear the terms ported and manifold well first of all you need to understand why is there two choices okay going back to consequently around 1970 68 70 71 it was discovered that the vacuum advance all had manifold vacuum up until that point it was discovered that by having the vacuum advance on a manifold source created higher emissions so thus you get into a quantum if you give up your fuel economy by going to a ported vacuum source you're going to get better admissions and if you go to ported your drivability is going to be reduced so you need to understand that getting good fuel economy is not always conducive to emissions there are two separate entities ported and manifold vacuum is not really too much of a debate because prior to 1968 everything was manifold vacuum but to talk on the subject a lot more I'm going to let you hear the guy that taught me how to set up vacuum advance that's David Weiser okay so here I am at David shop hey David you're around good hey man so I just started a video of while ago you know everybody this is the one and only David Weiser he is like yeah I hear you got my email interesting so David what I'm doing is uh I did a video outside talking about back to me Dennis Vance and distributors and I want to tell the story about how using your method I was able to get like thirty five to forty percent more fuel economy out of my truck okay so I'm sitting here with my good buddy and mental Dave advisor and this right here has probably one of the most misunderstood stories and history and the world of hot rodding but if you get this right you can take your hot rod that's getting single-digit fuel economy and believe it or not you can get better fuel economy than some of these late model cars that are out here on the road today and David is the man that's going to tell you how to do that because I applied his theory and trust me it works they would tell me about your how do you use this with this to get well good fuel economy but cannot history with vacuum advance go way back yeah right now I've always understood because it was common knowledge back then you know Ashley I got into the motor racing business in nineteen sixty right yeah most of the people listening to this weren't even born right what a lot wasn't either so I'm part of that so the thing is is back team advanced was the need for vacuum the bunch was being accepted normal technology and that right there was some engines that didn't use it for instance stop confer s only used mechanical abundance that's because they wanted to bring the car right before Lucas another distributor right right and so and a lot of people raced with just the Cooper S distributor I know they're on a road course for the mini you're very rarely off the throttle and fuel mileage is no nation for i right so it got to be well racing games don't use back in the bunch all right well guess what when you're in a traffic jam that's a little different to being brushing demonstrated front after sister o abs and letter quite the right engine situation right so the thing is is I would tell people yes that's right much race engines don't buy yeah then you know what we nearly every damn successful racing in these days has biked through but the night gala flag comes out he won't feel funny bright the only way you're gonna get it is to have the advanced the ng one arms know what you think you're going to give it right right what wait when I have somebody walk in that door and they say well I want this my engine and it's that's irrelevant yeah I know what you want it's what it is you was right right and let me tell you this little story so when I first met David we got on the topic somehow no they're talking about back you in advance and he told me this method that too used to set up a vacuum advance and I'm sitting there listening to this thinking it's so simple it's like it's the smacking you in the face and it involves using one of these right here so David tell everybody how we can get into the ballpark of plotting out a graph of what your engine needs up using this and a level piece of road well the biggest folks that's right especially what we're at so you may have to do a little bit of edgy in your reading what you're doing right you'll get a very good idea I mean you need a good buddy to the yes I mean these things I cube it all on the dyno where I brought the load over nicely and then this appeal and everything what timing and carburetor adjustments gives the least right let's say that just an average guy and we've got a straight piece of road and we've got a relatively streetable famine attention cry I'm not talking about an all-out race car no we're talking about a street strip like yeah and wrong edit to 8200 yeah but it take this way the method works on my truck and you know what kind of engine etiquette that's what it's up at the upper end of the scale that's a 9/10 racing engine yeah it's this disguised as a sheet don't pay any attention so what you do is set the cruise control your foot well this is the way I do it now this Andy's got variations on this and I think by the time he's finished what he's doing he'll have more experience doing this than I do that's because I've got access to the dyno yeah he's yeah that's right his dyno testing time is only a fraction of what it's like probably had a hundred or maybe a thousand of wheels yeah but next what you do is go down the freeway with just the mechanical bus and you put black human funds hooked up to this kind of home piece of vacuum hose rest on inside the cockpit of the home or is it so much it is it's a money back right and what you do is you set the cruise control and look at the vacuum you've got on your back engage but you need a back yeah I'm gonna round over the carburetor with the vacuum gauge like yeah it's like this and you will slowly pump or suck the air out of the back you can while you're trying to maintain a steady speed if say well the nozzle how the well yeah whose control should we had cruise control right and what you do ppand pulling this advancing right and of course if it makes more horsepower the cruise control close the throttle that's right so the vacuum on the vacuum gauge goes up as far so you keep on sucking in advance on that distributor until the backing gauge wouldn't go up any more that's right actually don't be the result you know Dan note what that vacuum is you know what the vacuum is here the RPM that you're traveling at yep and you write that thing right after you've done that for several points you take your back in the pen and you look at the advance get on a distributor machine you have this you're never seen or you can do it the time in life yep we've got you look at the Advanta minute you can do the mechanical of the time and luck with their vacuum you can do it but you sit there and watch it and bring it back up to the RP and what and see actually how much advance report to go down and bring right say 50 miles an hour and high gear you'll probably find that it's about 40 degrees some engines it could be more if the engine has a really good burn right combustion efficiency is high it could be as high as 50 degrees that's all right people say that it's gonna detonate well no it's not you're barely filling the cylinder that's right right now guys under no-load here let me let me say something here I need that most people don't know that yeah this I get yes good stuff here people assume this mixtures we gonna melt the Indian Day right well that's only if it's a little bit too rude yeah if you start getting really really high mixture ratios by law therefore not much feel like on our mini engine we go up to 22 to 1 that's right right the combustion was so cool because there's such a little amount of fuel use you could always put your hand in there right right the combustion temperature dropped I can't remember what it was but it's something like 400 degrees you aren't gonna melt a piston yeah there's no so so and it's not gonna detonate because the octane requirement for that is down so low 60 or 70 off to run on air right yeah ground everything that octane is when you put your foot on the gas the backroom goes away yeah right so all right that's how you get your vacuum events and what you do is you build a curve yeah for it and then you cool then you call performance distributors and they will go through all their end and see what's the nearest one yeah now I understand that if they don't have the exact thing that you're really high professor yeah right that they can fudge one so that it does what you report but it costs a lot more money right now what what I did on my truck for personal reference going down the road I chose 30 miles an hour as one reference point I did it again at 50 miles an hour and then at 70 miles an hour and the reason why you do that is because the engine is under different loads at that different speed so you can get a better understanding an idea of what's required and you will see it what were the figures our bonds figures that you report those I'm at nearly fifty degrees that's like 48 50 degrees 50 yeah 50 miles an hour and 50 60 and 70 yeah it was it at 70 it will actually go more it can take more it'll go up to probably about 51 you have to pretty healthy size 10 min that much yeah that's probably why yeah but your vacuum advance Nev sheets youring that's right it's not a canned tune yeah it has to look by the way good viewer I got to drive on this truck you can start off from the play here yeah he put it through the paces he was able to take off from high gear at a stop sign and you can watch that video I'll put a link to it right up here you see you'll see it and you can watch David actually drive my truck and you'll see the kind of drivability that we're talking about so what what's the whole point of all of this for 90% of you guys out there gals who have a hot rod I'm just throwing this away and not using this or not hooking it up you're giving up 35 to 40% of your fuel economy I'm wearing you're bourgie but yes that's the most important thing I'm polluted in the world right because when you're running those really rich mixtures that accelerates more wear okay that's one of my favorite topic that's one of the biggest negative arguments on the world let's clear all the here but 40 vacuum only exists because of emission regulations hang out like I was in the era when 40 vacuum came in and had to develop ignition systems and or engines that required to have certain circumstances and regulations met the biggest problem we had back in the day was that at idle with manifold vacuum the throttle is closed so much that to get the charge to burn you had to have it richer now this doesn't mean you have more fuel what it meant was it was Richard still less fuel than you would have had if you didn't have any background well this caused a lot of emissions apart right so to cut this what they what the idea was that if we opened the throttle and let more air in we will have a more combustible mixture all right but now we've got a free am i right how do you get rid of that you the ignition and go right so you don't want imported back you don't want manifold vacuum and I look the only way to get around it is to have ported vacuum that is no vacuum hits that distributor until the throttle is open it's not an idle anymore that's right but as soon as that porting vacuum as soon as that butterfly passes that ported back deal it might as well be manifold back then because that ports connected to the manifold that's right all you are doing reported vacuum is preventing the engine from having enough ignition timing to have such a low air requirement that the mixture is too rich for clean combustion right every engine these days what road engine should have manifold vacuum and get a really good distributor an ignition system which lights off the chart now I've now give you an example here back in the day typically 12 and 1/2 to 13 to one mixture ratio at idle showing 18 to 20 inches of vacuum was it yeah these days with what we've got going now everything just right I can run fifteen to one that's exactly where that hurt groans and one other side benefit that we haven't even touched on when you have a high compression street engine guess what it wants to run hot right well when you have a vacuum advance hook to manifold vacuum and you're giving it additional time and guess what it runs a lot cooler at idle it actually solved an overheating issue by having this on our truck so just another point to have it do we have anything else to tell these guys anything that they can have in park - I don't know that you need to check out part two I don't know where am I going to get to it because we've got to get our engine to the dynoed but I promise you everything that we've just talked about you're going to get to see it in practical terms in real life and we will show you that next time on the unity motorsports garage this is Andy that's david bazar de legend catch you later [Music]

Channel: Unity MotorSports Garage

Views: 56,923

Keywords: Hot rod tips, Vacuum Advance, David Vizard, Unity Motorsports garage, improved fuel mileage

Id: U7-zpnP0y18

Length: 21min 19sec (1279 seconds)

Published: Mon Jul 13 2020