Edelbrock Carburetor Tuning Chart Explained

today we're going to talk about the edelbrock calibration chart for the performer and avs series carburetors how to use it and a couple little tips and tricks on how to read it and how to properly apply it to what you're working on so let's get started right away now before we get started on the calibration chart how to use it with the calibration kit there's a couple of things we have to talk about and if you've watched any of my other tuning videos on the edelbrock carburetor i think you probably know we're going to go next and the first biggest most important thing here is fuel system setup if the fuel system is not set up properly it really doesn't matter how you tune the carburetor or try to tune it you are not going to get the full advantage of it and you're not going to be able to get the calibration out of it that you want you're not going to get the drivability out of it that you want the problem stems from when these things are incorrect in how the fuel system is set up you can't get the carburetor direct react correctly because you're fighting other problems so you know having the correct fuel filters the 100 micron and the 10 micron having a correct fuel pressure or having a pressure regulator at all and having it set at the right psi to start you know making sure the carburetor is in good condition and it's and it's not full of dirt or junk or crap whatever all of those things are super important you have to make sure the other pieces to the puzzle are perfect first before you can really start in on the tuning the other side of this which is absolutely critical in these days with more ethanol in pump gas it's even more so most ignition is more than it should be most folks will set their advance at what the factory setting was back in 1965 or 70 and assume that that's where it needs to be at because the ethanol fuel there and the poor quality of the fuel today you typically need a little bit more advance at initial and most folks don't do that the problem with that is you will get those stumbles those hesitations that rough off idle you know transition and most folks will blame the carburetor on that the carburetor is typically not the problem and that's in that scenario it's typically timing or something else in the fuel system so it's super critical that you get the other pieces correct before you start to do the tuning process on the carburetor if you don't you're just going to keep fighting and you're going to go well this carburetor is a piece of junk it it must not adjust i'm trying to do everything that the charts telling me to do and nothing's working well you have to go back to the basics and always start with the very very simple stuff start with the timing start with the fuel system make sure the filters are in good good order and you don't have something that's clogged up double check your pressure regulator dial it down a little bit if you need to there's a bunch of other things that need to happen here before you can really start so i i it's super important to make this point now because anything you do past this is predicated on the fact that the fuel system is set up correctly and the ignition timing and everything is right so get those right first then we can start on the calibration now let's jump right into the carburetor manual that comes with with every edelbrock avs or performance series carburetor that you buy this is a very very good resource to use and unfortunately i think a lot of folks tend to pitch this thing and don't use it there is a lot of really good information in here of how to set the carburetor up how the fuel system should could look different scenarios for you know adapter plates and and you know fittings for the carburetor the fuel inlet choke settings and all that super critical so before you even start to put the carburetor on the car or start to do any tuning adjusting whatever take a flip through there you'll learn quite a bit of stuff you'll you'll learn what the you know the the factory uh you know the the jets and and rods are in it step up springs all that but all of those are super super important to know because you have to kind of have a baseline of where you're starting before you can get get moving into it so that little book is very very useful don't throw it away you're gonna need it in the future so now let's jump right into the calibration chart if you go online to the edelbrock website put in the part number the carburetor you're working on you'll find some pdf instructions underneath the listing for that carburetor and you can download it and in there it will have your part number carburetor the calibration chart and the reference chart for the rods and jets so i'm going to show you how to use this it's very very simple but there's a couple little things in here that you kind of need to keep in mind when you're doing so so you don't kind of throw off you know the how you're tuning this the first thing to keep in mind with this is to make small adjustments don't jump up way up into it because you think you're really really lean and you need to go really really rich or you're really really rich and you need to go really really lean take small steps and i know it's a little bit more work to do it that way but trust me the results are better because you're not over compensating for something and realizing that you were off in it and maybe you needed to adjust down the fuel pressure maybe the you know there was a spring step up spring that needed to be changed whatever we're just concentrating right now on the rods and jets so make small steps and you'll be in a better place when you're as you're going through the process now when you look at the reference chart here and this is for the 1412 this is the 800 for my 67 chevelle that i'm putting together that 1412 this is the calibration chart for it the center is the base calibration it's what it came from the factory from it's what you always go back to if you're looking to retune this for a different vehicle if you go over here to the the rod and jet reference chart number one is number one here and it will tell you the part number of the metering jet and the rod and what the that that's the base calibration so that's where we're going to start from this shaded area right here in the middle that runs up through there is where you want to stay when you're doing regular type of tuning with these carburetors now it's the optimal space for the tuning and that's where you kind of need to if you can limit yourself into there you'll get good results with the rod and jet combination because they're tuned a little bit better for the cfm of that carburetor now every single one of these that are in the black when you buy a calibration kit all of those combinations to do those are included in that kit so the base calibration is obviously in the carburetor now you already have those all these other ones are in the kit now these ones that are not shaded they're they're in white those are not in the kit if you do go to that calibration or need to you may need to well you will need to buy either a rod or a jet now there's two different modes on this carburetor you've got the power mode and you've got a cruise mode they're exactly how they sound cruz is just off idle you know cruising down the road at 45 miles an hour steady rpm steady on the gas you know you're not up and down you're not hammering it you're not decelerating it's just cruise mode you're just cruising up and down the road power mode is exactly that it's hammer the throttle hit it hard going from zero to sixty zero to seventy going down the drag strip whatever it is that is the power mode it's hammer and wide open give it a ton of gas get it moving so when you are tuning you have to kind of determine where you're having your problems so once you get the carburetor on once you get the fuel system correct once you get the ignition set correctly then go out and take it for a test drive and see what it's doing how is it reacting how is it is it stumbling a little bit off idle is it you know when you hammer the throttle you know going 30 miles per hour and you're trying to get up to you know 70 or 80 to get onto onto the highway or something like that you're getting a little bit of a stumble is it because it's too much fuel or is it because it's too lean that's where you're going to make these adjustments from now let's take that example right there you're trying to get on the highway you hit the gas hard and it gets a little has a little bit of stumble and then it kind of takes off and gets moving there's a couple of things that could be it could be either a rich condition or a lean condition again assuming everything else is set correctly ignition is in good good shape you're getting the correct advance out of the timing we'll assume all that's right so there's if you're doing this by seat of the pants where you're not using an afr gauge to kind of measure what's happening in the exhaust at the time one quick easy way to do is as you hit the throttle look out the rear wheel window if you get a little bit of puff of black smoke the chances are if it's a newer engine and it's not you know got an oil consumption problem that you're probably under a rich condition and you need to go a little bit leaner if you hit the gas and you get moving and you don't see any of that little you know rich or puff of black smoke out the back then you can assume that it's lean so let's take let's take it at that from that step let's say that you're you're tuning for power mode hitting the gas and you're stumbling a little bit and you want to go a little bit richer with the setup so from the base calibration here at one what you're trying to do is move to the right you're moving this way to get richer and you're trying to stay in the shaded calibration area so as we move right we can either go to this calibration setup here which is not included in your calibration kit or the next best step would be up here to number 10 and that would get you one step richer on the power mode and get you the little bit more shot of feel that you need so you know the base calibration here isn't here at 1 so we go down here to 10 and we see that the part number on the main jet is a 1434 from the factory it comes with a 1433 so we know we're going to make a jet change when we come over here it's a 1456 on the rod it's a 1453 from the factory so you're going to make a rod and jet change and just to confirm that it'll tell you over here that it is a number 10 from the base tune is a rod and jet change that's how that calibration chart works so here's the thing once you do once you replace the rod and jet in the carburetor and put it in 10 it's another test trek trip down the road do the exact same thing go try to get on that same highway and see if you have the same thing is it better is it worse did it not do anything at all then you start to make the steps from there and again if you think well it got a little bit better but feels like it just needs a little bit more then continue to move right in that case to keep it in the shaded area and in a black number that's in your calibration kit you'd move over to 13. 13 tells you it's a 1434 you're a 14 34 at number 10 1453 1456 so you're going back to the factory metering rod in there so again now you know at 13 you're going to make a metering rod change and that's it so it's taking those little steps as it continues to get gets better than good you know you're moving in the right direction and you keep moving until it doesn't get any better or it gets worse so in that case if you continue to move down the line you go to 17 and it's not working you know you're getting more black smoke out the back and it's not really improving then go back to 13 and continue to tune now in the case of trying to fix like an off idle stumble always view that as the power mode now i know you're not going from idle to wide open throttle most of the time anyway when you're coming off idle safe from sitting at a stop sign and then proceeding on through the intersection but that is still considered the power mode you can also tune that a little bit in the cruise mode if you like but i typically like to do that in the power mode typically gives it just a little bit more fuel and that's sometimes what you need the other thing with that is you continue to move down the range here and let's say that you finished up here at that number 13 for power mode and you think you know what seat of the pants this thing's it it has good throttle response it's doing everything i want to do next thing you need to do is go back and double check your timing make sure that you're not you can't aren't going to get a little bit better throttle response out of it by giving a little bit more advance you're giving it a little bit more fuel sometimes giving it a little bit more timing will help it out and i'm not talking about making a three to four degree change but maybe a one degree change two degree change will help you move things forward as you're moving from off idle to moving down the road now remember when you're using this tuning chart this is for primary metering it's for the primaries in the carburetor not anything in the rear just you're just tuning the primaries of the carburetor so if you want to make any changes in the secondaries because there are jets in the secondaries of an edelbrock carburetor there is a little metering chart down here to help you figure out what steps you need to take so it will tell you what the stock calibration is in the secondary it'll tell you what the jet part number is if you want to move richer or leaner it will tell you how to do that by one or two stages and how much more rich it's going to be in this the secondaries depending on what jet change you add to it so typically again same type of thing make these in small steps you know if you think you need a little bit more in the secondaries it's not you know accelerating as hard as you want then just go up one stage if it continues to get better then go up to stage two and three and so on so make small steps again it's always going to be the best way to do this now last little thing on this tuning chart i've been asked quite a bit of times you know why are these other numbers out here outside of that gray area if that's where you're trying to stay is within that you know shaded gray area the reason being is all of the rods and jets step up springs that are available in the tuning kit and available from edelbrock these are all mathematical equations of where all that would fit if you combine different rod and jet and step up springs to that equation so they do fall outside of the the optimal area to tune but they're not unreasonable you you can get into an area where you need to go a little bit leaner in the cruise mode you are still trying to push it up in the power mode and you may end up at this number 21. again it'll tell you what the rods and jets are the by the part number and you can make those changes as you need to but there's always that area outside of the norm outside of a regular naturally aspirated engine you know a street car not a big rowdy camshaft not a big you know aggressive high compression big block whatever the case may be sometimes these outlying areas are areas where your knee gonna need to push to and even though that we said in the calibration kit that everything in the black was here they're not all in the shaded area some are partially in the shaded area and some are outside of it it doesn't mean they're not good rod and jet combinations it just means that the optimal area to be is here in the shaded area and when you get outside of it you need to be a little bit more conscious of how you're working with the tuning side of things so for sure print these off before you before you start doing any of the tuning on the carburetor buy yourself the correct calibration you know kit that you're going to need and just kind of look things over a little bit and kind of get used to how this chart's laid out give you a lot of little details here up on the the top give you some you know different understanding of what's going on down here if you forget how you're gonna you know follow the steps in the calibration and then you know pay attention obviously the secondary metering as well but that's a really down and dirty easy way of understanding this and then now you can make the rod and jet changes that you need to facilitate getting this thing tuned now keep in mind also you've got other things within the calibration kit you've got the step up springs and you're going to have to take those into consideration as well so it's just it's a process you're going to continue to move things you know here and there you may make a rod and jet change it gets a little bit better but you feel like you need to you know adjust it because the vacuum's changed in the engine and you need to make a step up spring change no problem make it you know if you you know you start maxing out on the the tuning side or the fuel side of things here and you realize maybe you need a little bit more fuel then maybe it's an accelerator pump change maybe you need to change the squirter in the primary side and get a little bit bigger shot of fuel in there no problem those are all part of the process now i will tell you one other thing about this and i've been very very complementary about afr gauges and i continue to will be it is one of the better tools that you will use to tune a carburetor because it gives you actual live data instead of just kind of guess work which to be very honest see to the pants type tuning is a little bit of guesswork you can guess what it's doing and guess what you're going to need to change it and then you're going to have to figure out did it make it better or make it worse but an afr gauge can also box you into a little bit of a corner if you constantly are looking for perfect numbers on an afr gauge you're always going to struggle get the afr to where you're in whatever mode you're working on if you're working on the power mode and you're looking for more fuel and more aggressive rpm and horsepower out of it then yes you're going to be on the you know that 11 12 and a half to one on the afr side when you're in the cruise mode and you're trying to get it more on the economy side of things then sure shoot for that you know 14.5 or 14.7 if you're going for perfect stoic but don't get wrapped up in it sometimes you need to put the afr gauge away go drive it and determine how it feels if it feels right if it's good throttle response if you're getting good power out of it if you're making power all the way through the rpm range stick with it don't keep trying to fiddle with it trying to get the perfect afr reading you're going to fight yourself with it the entire time and you're going to be more frustrated it's a tool it's not an end-all be-all so use it as that use it to get yourself closer but don't restrict yourself by it so that's basically it that's everything you really need to know about that reference chart in the rod and jet chart and how to kind of tune a carburetor a little bit based on what's happening see the pants wise what's happening in the power mode cruise mode and how to make those changes in the carburetor now again down the road we'll do a live demonstration i'm going to wait and do it on my car and show you how to do this step by step because when we bolt on this 800 cfm on the chevelle i don't have no idea if that base calibration is good i know i'm going to have to tune it i have an idea of where it's going to go but i'm going to take it step by step and we'll show you how to do that but for now if you're doing this on your own that's a really really good place to start but just remember tuning is a process you've got all these little pieces that are working together you've got rods and jets step up springs squirters secondary jets you got timing to worry about you got fuel pressure to worry about all those things take them all into consideration every time you make a change within the system go back and re-verify everything else to make sure you're kind of in the right spot check your engine vacuum check your timing again it's just a process and it is a take does take a little bit of time but at the end of it you're going to get out of it what you want so take your time with it keep good notes let yourself remember or know what you're at if you're you know if you ended up in a certain area on the tuning chart make sure you write that number down put a date by it or something to let you know that that's what you did on that date and then you can always kind of take steps back if you need to or when you start to go tune again because you've changed something else in it you can quickly make those changes so if you have any questions about the tuning chart let me know down in the box below well for sure i'll answer any of those questions that you have calibration kit as well but don't be afraid to do this it's a very very simple process it's just not understood very well and sometimes it gets people a little bit confused but that reference chart tuning chart is absolutely going to get you out of a lot of holes and get you a much better running driving car it's like i said if you have any questions leave them down below please subscribe if you haven't give me a thumbs up if you got something out of the video and uh we will catch you guys on the next one we'll see you

Channel: Muscle Car Solutions

Views: 34,656

Keywords: edelbrock, carburetor, edelbrock carb, carb tuning, edelbrock calibration kit, edelbrock calibration chart, how to tune an edelbrock carb, how to tune a carburetor, tuning, holley carb, edelbrock performer, edelbrock avs, avs2, AVSII, edelbrock carburetor, edelbrock avs2, edelbrock 1406, carb, edelbrock rods and jets, edelbrock carb rebuild, edelbrock 1480 kit, edelbrock AVS2 carburetor, carburetor adjustment, holley carb tuning

Id: GFe3-Br_Z9w

Length: 21min 44sec (1304 seconds)

Published: Sat Nov 14 2020