Logging your carburettors behaviuor -AFR- and analysis

[Music] hello folks and welcome to the channel or welcome back to the channel and in this video we're going to do something completely different it is not going to be very greasy or very labor intensive we're going to register the afr values on a mini while we're driving it and the whole purpose for that is to be able to tune the carburetor now we are not going to tune the carburetor in this specific video that will be later but i'm going to show you on how you can capture the afr values from an afr gauge on how you can import it into a graph and we will be doing this by driving the car in different regimes idling acceleration wide open and cruising and along all these moments i'm going to capture the data of the efr gauge you've seen me installing the fr gauge some time ago and if you want to see how that goes please refer to that video but in this video we're going to actually use that gauge and use that data and at the end of the video we're going to analyze what's happening with this carburetor on this mini and the method i'm going to show you is something that everybody can do if you have an afr gauge you don't need expensive software to analyze anything and you'll see that during this video and we're going to practice this on a classic mini with a su hif44 carburetor but it's applicable to any classic car with a carburetor it doesn't really matter if it's an su or something else or the lordo or even a weber it doesn't really matter the analysis will be a little bit different of what the cause could be for misalignment of misadjustment or mistuning and i think here a critical word foul tuning a lot of people referred to tuning a carburetor but in fact what they really mean is adjusting the carburetor because all what they do is adjust the idle mixture with the idle mixture screw and the idle rpms and that's about all they do and that to me is not tuning but tuning a carburetor is really all about getting it fit for purpose and it means changing the jets the air jets the fuel jets the emulsion tubes the needles all that to match it to your specific driving conditions and you might have seen in my previous video that i talked a lot about the stoichiometric value 14.7 parts of air versus one part of fuel as the most optimum ratio for burning all the fuel and that is still the case and nothing has changed on that however there should be no misunderstanding that you don't want to maintain that's tokyo value during acceleration you might want to go to a 10 to 1 ratio because you need more fuel for acceleration especially for wide open you're probably going to be sitting at 10 to 1. and the same thing is true then for cruising and even for idle maybe your engine isn't running all that well on a 14.7 to 1 ratio on idle maybe you want to give it a little bit more richness so you're always going to have these small little differences on that so and that's why it's so important to test drive the car and to be able to measure the afr while you're doing so of course if you'll have lots of money you can take it to a dyno and all these things can be tested on a dyno but you don't need to go to a dyno if you have an afr gauge and you can drive the car on the road you can test it yourself if you understand the carburetor you can analyze the curves that you get from the afr gauge and then you can actually start working on the carburetor we're going to do this on this hif44su cobra not in this video because first of all i need to analyze it so enough talk so now let's get on with what we're gonna need and then we're gonna install it on the car and we're gonna start running it some people claim that looking at the spark books and the state of the sparkplex tell you all about the state of the engine well there is some truth to it but it's by certainly no means to actually verify how good the carburetor performs and how good the tuning is of the carburetor it tells you that in average you're running too rich or you're running too lean based on that color and it's all about what it tells you but it doesn't tell you anything about acceleration it doesn't say anything about cruising it doesn't say anything about wide open or even idle so yes using a spark plug it's an indication but certainly not a means to tune your carburetor in the previous video we installed the afr gauge and cabled it up to the monitoring port or the logging port and i installed the db9 connector for logging the data into the place where the ashtray used to be so now i can just connect my cable to that port and that's the port where i'm going to connect my laptop or my mac to to start logging the data to do this job you're going to need a couple of tools but you don't need a whole bunch of tools you're going to need a windows laptop or a mac it doesn't really matter i'm using a mac because that's what i like and that's what i have and you're gonna need a cable now most laptops or macs today don't have serial connections anymore and this is a serial connection it's a db9 and you don't find these plugs on your laptops anymore so what you typically find is a usb connector and you can get these cables these are converter cables from usb to rs232 or usb to serial they're very cheap they run about two euros two dollars a piece and they are very helpful and this is what you're going to need so we're going to hook up a usb port on the laptop with this cable to the monitoring port of the afr gauge this is the circuit diagram of the actual aem gauge but it could as well be another gauge and it might be a little bit different you have one big connector here which is going to your sensor and i've shown you that on how all that is installed in my previous video and then you have another connector right here which is already hooked up to the gauge itself and it comes out with a whole bunch of wires now to record any data from that um you need to have a serial connection and a serial connection terminates typically on a dp9 connector that doesn't come with it you have to get this from a hardware store or a computer store or electronics component store they are very cheap i installed the db9 connector in my case a female one on my dashboard and i have a cable going from that one to my laptop or my mac removable of course and that's where the two connectors pull up together the actual db9 needs only two signals it needs a pin number two and this is spin number two and these pins are numbered actually on the connector themselves and that's where you're going to get the data from the actual gauge itself and of course you're also going to need another connector on that which is the ground which is pin number five on the db9 and that's all you're going to need to it and over those two wires you will now be able to receive the afr readings from the gauge as soon as the gauge is running you also will need your laptop because you're going to use your laptop or your mac to log all the data and you're going to need a couple of applications you're going to need a grapher application and you're going to need a terminal application that is communicating with the serial port and saving the data these applications are very cheap in fact they are for free in most cases or even embedded in your operating system of your specific device i'm going to give you in a few minutes a couple of examples on how i'm doing it and then you can figure that out for yourself if you have something similar or you want to use something else it's easy very easy to do before we can start recording the values that have been transmitted by the gauge to our application be it on a mac or be it on the laptop we'll have to set the communications application to a very specific bald rate or the speed of that communication the amount of data bits the parity bit and of course the stop bits you need to set this because otherwise your application will not understand what the gauge is sending you now that might depend a bit from gauge to gauge but for this specific age it is 9600 eight data bits no parity and one stop it and now the application or the terminal or whatever you want to call it can now receive the data from the gauge as soon as the gauge is powered on but keep in mind that the format in which we're going to get the afr readings is something like this and you can see that 14.7 that's going to be the actual afr reading of that moment in time and you're going to get a whole bunch of readings one after the other but that is followed by a carriage return and a line feed and the character general line feed is something we'll have to remove later in a text editor before we go in to import that log file into our excel spreadsheet or into a graphic tool now let's have a look on our terminal program on how we're going to set that one up there are many applications that are available to be used as a terminal for serial communications i'm using what we call a serial app on my mac but on a windows pc you will find as well multiple applications that can do exactly the same so it doesn't really matter as long as the application can communicate over the serial port so let me open this up and then we'll see what happens so when i open it up you can see immediately that what i see here there is a usb 2 port and that's the port i'm going to use that's where my cable is plugged in so i'm going to select it and then we open it up if i remove my cable you will see that it will say disconnected see that right here it says disconnected if i put my cable back up it will say connected right now it's important to set the terminal to the proper line speed and line coding as we've seen before on the gauge itself because that's what the setting is on the gauge so we're going to go to settings and then we go to line coding and here you would set the ball right that you would desire now in our case we know it's 9600 so let's select that one eight data bits no parity one stop bit and you don't need no flow control at all because we only have two wires ground any received data and that's about it there's nothing more we need to do on this and now we're about ready the next thing we're going to do is to log all what it's incoming so we start the log and now it's going to save that anything that comes in now from the gauge will be stored on the log file on your pc or laptop and that's it so now we could crank up the engine basically and start running so we've got the laptop and i turned it on already so i'm gonna hook up my usb port and then hook it up to my monitoring point of my afr gauge i'm sorry i should wear my glasses because without glasses i don't see nothing so that's one side which is hooked up and i should hook up the second part now to the probe here and that should go like this there we go it's now connected so now i can start my um monitoring program which is this uh serial application i'm gonna start to log all right so that's all set up and ready to go now i'm gonna crank up the engine uh the gauge will warm up first now as soon as i turn on the power you see all the lines appearing on the screen that is the gauge warming up so it's going to scroll through until it's completed it's warming up phase um so as you can see it's still rolling through now it's done so if i start now the engine you will see actually the values coming up on the screen so i'm going to start it and now you see the numbers scrolling on the screen and these are the different afr values that we have and as you can see this is now running a little bit rich but it varies a bit [Music] all right so let's shut it down and take it for a test pen [Music] i'm going to take the car for a test run so we can record all the batteries i'm going to let it set idle i'm going to start the log then i will accelerate through all the gears one two three and four then i will cruise a bit and then i do a wide open and then i let the throttle go and that's going to be the sequence of testing the weather is terrible it rains like hell okay it is what it is and then we'll see how it goes and once we are back we then look at the actual figures and we graph it out on a graph and see how good or how bad it is right so i'm going to start recording now and i'm going to set up the laptop and the weather is awful but that's okay the engine is warmed up or almost take off we're gonna accelerate through the gears and then uh we'll see what it does for us so now i'm going to four gear so this is cruising and now we're gonna go right over [Music] and i'm gonna go all right so i'm gonna stop my logging all right that's it so we are back from our test right and we took the card through the different stages we had it on idle we had acceleration first second third fourth gear then we did a wide open and now we let the throttle go i would have loved to go to an uphill climb but i didn't do it this time the weather is just too bad to go there but i'll do that next time but we got everything recorded so my file is now here and now i'm going to change the file name so i then i can process it so let me show you on how that works now that we have a log file stored on our desktop by the gauge as soon as we stopped of course logging we can't really use the dot log extension so we'll have to rename that file doesn't matter but let's say we're going to rename it to afr1 dot text afr dot text i think now it should be good enough and now we have actually a text file now that the file name is changed now we're going to convert it a bit so we don't have the line feeds and carriage returns anymore we have it all nicely separated with commas that will make it easier for importation into an excel spreadsheet or a graphic tool so let me do that if you open up our text file which is actually the log file you will see all the afr values one after the other and that format is not all that suitable for importing it as a csv file into any grapher tool or even in excel so therefore we have to change that we will remove all the line feeds and carriage return to a comma so we can create a csv file we also have some other information on the top here that we don't need so i'm going to delete this and now i'm going to replace the line feeding carriage return in this document so i'm going to go to an edit i will go to find and replace and i will be looking for carriage return and you can find this by a pattern and here's the pattern and then you go for uh line break or carriage return but i don't need it there of course i needed it on the top one and i'm going to replace it with a comma oops that's not a comma that is a comma and i'm going to replace them all and there we go now we have the proper format the afr value separated with commas and now we can import this very easily into a spreadsheet or a grapher so i'm going to open up a spreadsheet now so i can show you on how that goes so we open up an excel spreadsheet and we're going to open it up from our desktop where we had our afr text file i'm going to open that up and here um it says that already that it's delimited it has seen it already with commas i'm just going to say next the separation is a comma if they say next it's general and then we'll finish it and now we should have that in our spreadsheet see now we have all these columns and now we can actually use this into a graph if you wanted to use the graphs from excel and now all that is done so now i can import it into the graphic tool let's import the file nnc so i will open up this grapher and this is a grapher that comes for free it's called the z grapher so i'm going to import the data here you have our file with all our values that we measured so now i'm going to open up this grapher which i have over here and this is a free grapher by the way it's an app for your mac and i'm going to import the data from that file and here it is so let's open that up and immediately you will see that the data comes in and now you can actually see the curve uh when we were accelerating the different gears when we were kind of kind of cruising along we did that for a while and then we went actually wide open and you can see what happens in wide open we actually go very lean and then we go back down to uh more rich but as you can see this whole curve uh doesn't make a lot of sense for a good calibrated carburetor you can see and at the start we were running a bit on idle in fact quite lean on idle around 16 then we took off and as soon as we depressed the throttle you could see that we went extremely lean and then after that the throttle reacted to it or the carburetor reactor to it we got a little bit of a richer mixture 12.9 and then it was kind of and we were in first gear accelerating and now you can see we have the short acceleration here but then it really became lean again and and then we actually shifted up again to the second gear we went a bit rich again but then it build it up lean again and we move to third gear and then eventually we moved up to the fourth gear and again it was very hesitating the car to accelerate each time and that is obviously because of this very lean area here it picks up after that so it's a bit of reluctance and then it picks up with a richer mixture and then we started to accelerate a bit and then we started to cruise um for a while which is kind of all right it's kind of like where it should be 14-7 in average it's going up and down a bit so it shouldn't be doing that really this probably is indication that something is really not right with the carburetor and then i decided to go wide open now as soon as we decided to go wide open you could see that you know although i floored the gas pedal we went extremely lean so the carburetor wasn't able to feed the fuel to the engine not enough at all it but it recovered it took a while of hesitance and then it recovered shortly after that over at this point but you can see how that is actually going up and down so it is almost like the the the uh the piston in the carburetor in the su is actually opening up now and then it drops down again and opens up again and you know it's like a yo-yo effect so yeah there is some issues with this i'm gonna work now out this graph a bit more and mark the different zones for you so you can actually see on how to interpret these graphs so when we started the car we saw some very lean mixture initially for picking up speed and it wasn't good then we got a little bit of more rich mixture and then it started climbing in again in the very lean area and this symptom uh happened across all the shifts so the second the third and even the fourth gear there was always some form of reluctance uh to pick up speed and then it actually happened shortly after that and that's because of the lean mixture as you can see on the graph but once we were at cruising speed things started to stabilize a bit and you can see that in the blue curve there we see the cruising curve and that's kind of all right but still there's a bit of oscillation and i think this is all related to the same problem but once i went to wide open we again ended up in a very lean mixture initially and then go into more rich but then oscillating between very lean and rich up and down and the rich wasn't really all that rich because i would have expected at least a 10 to one ratio so there is something really wrong on that carburetor most likely on that damper something is wrong or the needle or the jet itself and then when i backed off uh power then i let the throttle go uh then we ended up lean which is okay but that's about the only thing which is all right so folks we're nearing the end of this video and you have seen on how you can capture the performance of your carburetor how well or how badly it's tuned with some very simple tools by a terminal on your laptop or your macbook log in the files and then using a grapher and a test right you can really see what's going on with your carburetor and on this specific car it wasn't very good so in the next video we're going to tune all this and make it better so keep watching bye

Channel: D3Sshooter

Views: 26,703

Keywords: mini, classic, afr, testing, logging, data, analysis, carburettor, stoichiometric, curve, grapher, how to log data, AEM, 30-0300, gauge, X-series, UEGO, BOSCH LSU4.9, SU, hif44, tuning

Id: 4DoFYbPNuzE

Length: 23min 39sec (1419 seconds)

Published: Sat Sep 26 2020