600HP that gets 16MPG with a Holley Tunnel Ram and 2 Holley 660 Carbs

what's going on folks welcome back to the channel so you may be saying what kind of thumbnail was that I'm gonna tell you it's not clickbait I am gonna show you how I was able to get 600 horsepower 16 miles to the gallon with two Holley carbs stay tuned so you might be asking yourself how in the world did you get it 16 miles to the gallon with the tunnel ram and two Holley cars well it's not easy but I can show you detailed ways of going about it and I hope you can get the same results that I did so follow along ok folks so this is part of my secret to success some people may say it's cheating no I say it's taking new technology applying it the old technology so that you can get the best possible result by using those old Holley carburetors you can almost have your cake and eat it too by using this meter why do I say that you can tune your idle circuit you can tune the transfer slot you can tune the main circuit and the power circuit all individual and get great results [Music] [Music] okay so you see me taking the metering blocks off of the Holley carb so what we're going to talk about is the power valve channel restriction okay a lot of people think oh well you just change the Jets and you're good to go well that's the wrong way to tune a Holley carburetor and I'm gonna tell you one all right take for instance I don't know if you can see it but this is a 66 jet main jet right here okay and one of the things about running annular boosters is they run inherently richer compared to down leg boosters and you may ask why is that well it's because you're pulling fuel from six holes or six offices versus just one so the engine is allowing is able to get more fuel from the bowl through the booster itself and thus making it run richer it's not uncommon when you're running in Uhler boosters to have to pull a lot of jet out of the carb just so that you get the air/fuel ratios in the right direction but let's talk about power valve channel restrictions okay when I'm talking about power of our channel restrictions I am talking about these two small offices behind the power valve so let's say you have your wideband air/fuel meter and you're cruising around and you've got this thing running really lean at cruise and you're getting up into the 14s and 15s and the engine is really happy but when you stab the throttle the power valve will open and then it would get additional fuel to the booster through these two holes so depending on whether you're rich or lean will depend on whether you go up or down in these sizes right here now you can see that I have taken these metering blocks drilled and tap them to accept little brass 630 second set screw okay and you can get those from the cast car I think that's the name of the company Yamma Castro and the Castro car yeah and what I do is I will take get some tiny drills i really suggest on getting a a pin vise and a drill set like this right here so that you can tailor you can see how it comes with different drills from 13,000 up to 39,000 okay so you may be saying well Andy how far do I go in drilling this well there's a formula and I will post it down below a finding the area of that Desai's hole in relation to the jet size so when you take this this is a I say I think this is it yeah that drill fits in there so let's take my micrometer make sure that it's zeroed okay so let's see how big this drill bit is okay we're looking at fifty one thousand almost fifty mm right there we'll call that fifty two so when you do the math of the combined area of the power of our channel restriction and the size of the jet it should end up somewhere around a 73 to 74 based off of the math that I did but taking in consideration having annular boosters it's a different ballgame and it works in relation to your high-speed air bleed as well so you've got to get the air bleed correct and one of the ways that you can tell that that is off is like in my case on the dyno the air fuel started out into I think at the beginning of the run it was in the mid to low tens and then it just progressively kept getting richer and richer throughout the RPM range and so that kind of gives you an indication that you need to change your air bleed to try to get that more of a steady-state deal so but yeah this is the key to getting power and mileage out of a Holley carburetor because like I said 99% of the people will just change the jet and call it good because that's the easiest thing to do but like I said in the post when you do that you change the entire fuel curve for the main circuit and when you're in the main circuit using around town your fuel economy just went okay so in changing my channel restrictors out I went from one that was measuring 50 mm or whatever it was to 35,000 that is a huge swinging percentage but given how rich this thing is I've got to make a huge change so we'll see if this is going to be in the right direction I know it's going to lean it out but we just got to find out how much another often overlooked attribute of a Holley carburetor is the auto feed restriction right here because 90% of your time driving around town you're in the transfer slot okay and when you're in the transfer slot you're still taking fuel from the idle circuit okay and so the size of this orifice can determine your fuel economy as well so there's something to keep in mind there one of the cool things that all state carburetor exclusive is the way that they install boosters Jim and the guys at all-state have developed a way to install boosters where they actually thread the booster and install and install this flange nut on here what they do is they drilled the main body countersink it and then they will take and actually screw the booster in place and that is added protection to let you know that that booster is not going to come loose or fall out into your engine one of the many things that I do and it's just for me personally is anytime I take my bowls off and a jet change or whatever if I have new gaskets I always try to replace them I know that the blue gaskets are reusable but for me it's just cheap insurance and knowing that I'm getting a good seal and the reason for that is if you look at this meter and block gasket you can see how it leaves an impression in the gasket and what I've had happen in the past is when I reuse the gasket say the metering block gaskets not exactly in the same spot as where it was before and it'll develop a leak inside here and then you'll end up with tuning issues that you can't figure out so just for peace of mind replace the gasket and another common leak point is right here where the accelerator pump hold is that leaking into the power valve channel and that will cause all kinds of issues okay so I'm doing the rear carb now and I wanted to bring up another topic you know earlier I told you that when you 90% of you're cruising around you're actually using the idle circuit in the transition slot and off the idle circuit because that's where the fuel is delivered from so let me give you an interesting problem that I ran into when I was tuning this tunnel rim setup your mileage may vary so I was able to dial in the perfect idle air fuel ratio I could get this thing to idle almost into the 15 switch for a carbureted engine that is really good and you know and that's all in part two with having a good vacuum advanced setup here with the adjustable pot but the first thing that I noticed with the wideband is as soon as it would come off of idle and get into the transition slaw it would run extremely rich okay and then once you pass through the transition slot and get into the main circuit it would level back out where it needed to be and so I tried forever to figure out a way to tune the transfer slot and I found a Holley carburetor for them I think it's fuel systems I can't remember the exact name but I can't take credit for what I'm getting ready to show you because it wasn't my idea but it's something that I have found and used and used it to great success ever since I found it so anyways on that forum I was looking around and I just happened to run across the guy who had similar issues and they were talking about installing a jet right there because this port on both sides is where the transfer slot gets its fuel and it goes down to the metering plate okay so what I did was drill that out tap it for a 10 30 seconds set screw and pretty much I was able to make another circuit inside the carburetor that wasn't there before and so like I said those guys on that forum they had come up with this and let me tell you it works wonders because I would say 80 to 90% of your fuel economy comes from having this right here dialed in the transfer slot on a tunnel ram setup is everything because when I'm driving around normally with the truck I can be going almost 80 miles an hour on the interstate and still be in the transition slot I haven't even got into the main circuit yet so once again that is something that I would have only been able to find out by having a wide air wide fuel tank a wideband air/fuel meter so you know it has many advantages it's not just a one-dimensional tool what I found is you can dive into the Holley carburetor and let me tell you the engineers who designed this carburetor back in the 50s they were just brilliant because if you dive into this thing and tune each circuit individually like David visored was telling you you can make this thing rival any fuel injection setup out there hands down so just think about that and hope it works out for you so trying to get the perfect airfield ratios the carburetors once again I gotta give TM and home state carburetors Costa instrumental the right direction is for my airplane Rock Ridge and you gotta understand that you're changing a lot your the carburetor there fermentation we're happy with the drivability and 600 rpm and we are still in the transition slot that is something too the cause really phenomenal really and you can get it really good fuel economy if you take the time to dowel in the Ottawa circuit and the transverse loss circuit to a wide-open throttle data log on it what Fairfield Rachel is fine that was a quick under 20 mouth higher than a family I would challenge it like I said it's all in the tune into the barber shir subscribe to the channel thank you later [Music]

Channel: Unity MotorSports Garage

Views: 19,974

Rating: 4.9686027 out of 5

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Id: tMsp7w5gJEk

Length: 18min 33sec (1113 seconds)

Published: Mon May 25 2020