You are such a very clever man, with a way of explaining things so people like myself can understand, many thanks for sharing 😊

Great work. Next week Steve explains all about Quantum Mechanics in 20 minutes and instantly the the whole world understands. Your delivery and explanations are exemplary!

Excellent video and explanation. A useful addition to the data logging is a throttle position potentiometer and engine RPM you can then correlate butterfly position with readings etc. I have one on my Dellorto 40 equipped escort along with the AEM gauge. Once you know the cross over from progression to main jet position it is very useful to set up the jetting across the full range.

Very much looking forward to the tuning based on AFR data, thanks for all your work.

You are very knowledgeable and talented in so many different areas. It is good watching your videos. Keep them coming.

This is the best SU AFR video ever! I have a Volvo P1800S with dual SUs and installing an AEM AFR,

Its funny i dont have a car with a carburetor but just love to watch all of your videos... You explain things in a very simple way that most of us thought it was a rocket science during the days... And i really appreciate the artistic side of it changing your background/setting from time to time...

Excellent we wait see the next video with carb tuning

You re searching the perfection of everything.. .. thumbs up !!

Great instructional video. Cheers Steve 👍

Awesome! This is exactly what I was looking for! Any one of these relatively simple steps would have hung me up completely. I want to have my carb. perfectly tuned and don't want to be guessing at it. I have the exact same gauge so this is perfect.

I was thinking of recording a video showing my revs / speed whilst data logging to help dial in my idle to main jet transition. I'm using the same AFR setup as you, so your guide has been very helpful. Thanks for sharing.

Interesting to see the carb performance in the form of a graph. Much more precise than looking at the gauge! I wonder what will be involved in putting it right? Looking forward to the sequel.

Stephan, I reckon that's a better than fantastic video !!!!!. I followed your procedure for the main part with a different spreadsheet program but it worked tremendously . Now I just need to work out if I can also record engine revs at the same time. I'm doing this on a 1978 Triumph TR7 4 cylinder with absolutely no engine management so this is just a great help. regards kippy

This is really good stuff, I can’t wait for the next video!

Interesting, I have a Jeep 258 with a Weber 38/38. Bought an Innovative LM-2 (I didn't want a gauge) and after logging, found that I was running VERY lean, much like yours, spikes in the 22's!! It will almost always spike in some places, but not that bad!! I replaced the 4.0 Aux Vent to 4.5, helped a ton, stabilized alot of that back/forth/up/down you see. Can't wait to watch your next vid on this. I found it easier to go a tad rich, and work my way out of the hole. It may sound funny to go through all this for a Jeep, but people spend more money on stupid "upgrades", without knowing where their carb stands!!! I've already noticed a HUGE difference in performance. I would also note, it's addictive, lol. And your right about small things. I like the Jeep a tad rich from idle, better low end TQ, it seems. But for a Mini, it may be different, they are polar opposites, lol. But AFR Theories are abundant in this field. Great vid as usual!!!

Superb, helpful as always.

Looking forward to seeing how you address these issues Steve, very interesting.

Class A Effort for producing the video and analyzing the Ratios. However 10:1 on a Naturally aspirated engine with low compression it's excessively rich. I've experienced peak power with conservative EGT approximately 12.6 to 13.1, however ignition timing is key and vastly affects the mixture at WOT. Thanks again for your informative video.

High tech to help a classic car running better. Maybe i should do that to my own "old sporty". Your golden Mini on a rainy road is a nice yellow submarine.😉

that's super informative . I there any way to record the RPM data as well ? and align the data with the AFR data . this way you can tell exactly when and where your engine needs more or less fuel ?

looking forward to this series of tuning with AFR gauge. also would be good if you could explain if you know WHEN you need twin carby or bigger carburettor or what the symptom for a carby too large would have (lack of signal i think i've heard) thanks again for great tutorials.

Excellent, will get a wideband!

Sir.... Again... You are the best... Um still fighting with the transition from idles too mains.. with my Webers 40 in my BMW 2002.... Its slughish on low rpm at full throtle.... It looks rich... I dont have an afr.... Sir you are the best....

And now for a decent carburator, a Weber! (But something tells me you did do that already)

Thank you for sharing your knowledge and experience, much appreciated. I will soon be fitting a Spartan 2 dual Wideband AFR gauge and am having problems finding a Windows based grapher and Serial port app. Have you any suggestions which one I could use? This is on a PC.

Steve..... what is the MacBook graphing tool you mentioned? Fabulous video by the way. I'm implementing this on our MGC for tuning purposes.

Very good videos Steve, thanks for sharing your knowledge and time with us. I was just wondering if you could clarify that when you looked at the log file, there was 9 sets of numbers, did you shorten the list down to that as there would really be hundreds if not thousands to import into a spreadsheet? When you import the excel data into the graphic tool, there appears to be a lot more sets of numbers which then formed the graph. I assume that's the case as the graph could not show so much detail from 9 sets of numbers, but wanted to make sure i wasn't missing something.

Thanks for the explanation. I use a Macbook as well, can you tell me which serial app and graph app you were using?

I had an AFR gauge on my Clubman Mini when I first got her back on the road. Unfortunately the exhaust sensors that the kit used were a very poor quality and I ended up using three sensors! I lost interest in the kit and stopped buying the sensors, I should've simply bought a genuine Bosch one from Ebay. I ended up putting her on a rolling road and custom shaped a needle to give a good fuel supply. The AFR gauge is a very useful tool when you can't get access to a rolling road, just make sure you buy a good quality exhuast sensor!

Great info. 👍 I wonder if dual side draft DCOE Weber's carburetors would fit in that mini.

PLEASE do not let the gauge "warm up" before starting the engine. Thiis is the #1 cause of wideband sensor failures. The CERAMIC element of the sensor "warms up" to about 680C/1250F ( glowing orange hot ). When hit with a blast of (relatively ) cold start-up exhaust, it cracks just like when trowing cold water on a hot windshield. The cracks grow and spread the same way. 1st the destroy the calibration of the sensor, with air leaks. Then the sensors get flakey. OFten showing full rich or full lean, intermittently. Then, the cracks hit something vital; and, the sensor does the way of the dinosaurs.

very good and cool, I have an afr setup in my mini, but im not sure if my version can log the same

I would like to try this system on Classic Motorcycles. Where can I but the meter from? Many thanks! Norman

Very interesting video. Have you think to replace SU- carburetor with Mikuni HSR-series carburetor. HSR flows much more than SU and it is modern design. HSR swap is almost bolt on.

You should consider using any simple ecu, like speeduino, that would allow you to hook rpm and afr wires to ecu and obtain an afr vs rpm log and analyse it much easily

This will take some time for me to repeat😎incidentally, where you located? I was thinking Spain? Bob

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anyone found a grapher tool for windows

Great video but I'd like to add that you are actually adding an unnecessary step. After you remove the header and blank lines from the log file, it is already valid CSV, in a more conventional format even. A single data point with no comma and then a newline (with dos, unix, or old school macintosh EOL encoding) describes a single column of ascii encoded numeric data, which any spreadsheet can convert for you. For extra points, open the serial port with a python script or something, and every time you receive a value from the serial port, you write the value comma the timestamp comma whatever other data you can interface with, maybe a tps data point if you are into such things, or a digital vacuum sensor reading. then you have quite instantly a very useful graph that tells you a ton - extra extra points, hook in a python graphing library and get realtime graphing while still logging data.

twin su

love the ability to document the Values, but i hate Excel and all this fiddling with the Computer. So sadly useless for me. :-(

Indrukwekkend !

You have some great and helpful videos, except when you talk about expected/optimal AFRs. In one about SUs you say it should be in 14s under all conditions. Can you say hand grenade??? And here you expect it to be in 11s under hard acceleration. That’s way too fat. And the graphs don’t have time or RPM indicated (I understand why, but makes interpretation difficult) but the series of up-down appears to be typical acceleration-shift-acceleration-shift, or just accel-decel-accel-decel, should always be dead lean as revs drop. Please rethink your AFR expectations, I am seeing them repeated by others and they are confusing people.

eish i wonder what IQ do you have. very close to that of SIR I Newton. sometimes give us basics of electronics. M.B.S MOSHITOA ( S AFRICA)