0.75 = 11.0 AFR 0.86 = 12.6 AFR 0.92 = 13.5 AFR 1.0 = 14.7 AFR 1.15 = 16.9 AFR I pause the video and do the maths so you don't have to :D

This is, by far, the most impressive explanation (and demonstration!) of AFR tuning that I've ever seen. This channel is the cream of the crop.

You can be rich your whole life but you can only be lean once

The reason AFR has a greater effect on an engine than demonstrated here is due to the interaction with ignition timing (fixed for your test) especially for engines that are spark limited (ie run into detonation or pre-ignition before they reach maximum BMEP) Had you run your test at an engine speed closer to peak cylinder filling (ie peak torque) chances are, if you had an ignition timing also optimised for max BMEP, the engine would have started to detonate at the lean AFR settings. So, by running richer, the extra evaporative cooling and additional heat absorption of the greater fuel mass, would reduce the temperature of the charge during the compression event, and allow you to run with an earlier ignition point, which results in a higher mass fraction burn at a smaller average chamber volume, and as a result greater energy transfer to the piston, as opposed to it just going out the exhaust (which is why EGTs fall with advanced ignition angle despite peak combustion gas temperature being higher (effectively you get a higher dynamic expansion ratio)

You explain things so in detail very well done video

I really appreciate your lessons and especially engine tuning contents.

Awesome to share your tune on this part of a ECU...mostly on Dyno!!!!Thanks bro!!

Best afr demonstration ever! A comsummate professional. Hats off.

I love this type of video. I must say I though there would be more of a difference between the lambda's tested. Thank you for posting!!

Such an important topic with massive impact on power and longevity of your expensive engine.

This channel is an amazing tool for beginners! Thank you!

Great video. I would love to take the course to learn how to tune but money is alway on a budget. These videos are much appreciated and love to see more.

This video is an awesome find. I ran my ISF on a Dyno today and asked to show the AFR. The Lambda dipped to as low as 0.79 or so and I could see the dip in the horsepower curve in relation to the Lambda curve. My engine did make less power when below about 0.88. Will have to do some investigation as to why but thank you again for this video.

The most under subscribed channel on KZfaq..

Damn Andre you're making 300+Nm at 2k! Am going to wire in an aftermarket ECU soon and will 100% sub to the courses

Maybe on the next demonstration you can demonstrate for the best lambda reading on methanol and see how wide of a tuning window there is with very little change in torque.

Fantastic job on this video! When needed I will be sure to share with customers for validation ...absolutely no reason to push afr’s as it makes little to no difference in power.

Hi this was very good to see, brilliant thanks, Dave

Amazing stuff man. The demonstration is amazingly easy to understand, though not quite intuitive.

That was awsum guys, I really appreciate and thank you, best video lesson ever.

Why this channel still not 100k subs yet? Should be more than a mil already.

I really enjoyed this. Thank u for the tips.

the clean shaven vs bearded switch threw me there for a second :) great video.

thanks for the explanation and the video

That's an amazing video! I am doing motorcycle tuning and found it very useful

if you could make the same 3 runs with temp. probes in the exhaust and show their data on the screen would be very helpful

Been here since the start thanks for good info man 👍

That's amazing I had no idea a NA engine would care that little. I like how you displayed torque only because it's what is really being measured for one, and is easier to see a difference all across the entire Rev range with torque rather than Power. The tune that I have for my car which is a NA V6 not dissimilar to the 350z engine has a target of .84 lambda at wot.

Aprendo bastante con este canal,muchas gracias por crear contenido de tanta calidad.

Thanks for doing this. I'm finally getting into tuning

Very well done tutorial. Excellent and relevant. I wonder if a lean burning 1.05 to 1.10 ratio, cooled with water injection (x6 individual port water injectors delivering water only) would yield any significant change in power or fuel efficiency? Thank you very much for sharing.

Andre your the boss.. got to lift my hat to you 😎.. excellent content mann..

Absolutly spot on video! Awesome!

Great information. Well Done

Brilliant, thanks for this!

That's some great dyno soft ware he has there. I always try to give the engine the absolute bare minimum fuel and ignition advance that it requires for maximum out put. If you are mapping in each gear timming advance will be a greater value and fuel needs to be leaner in first gear than it does in say eighth gear. One reason is to stretch out fuel consumption as far as possible the other is, it allows the engine to respond much cleaner at lower rpm. One interesting aspect would be to use an multi gas analyser and look at the H.C. reading, it's very telling

Well I just got a $5000 education for 5 minutes of attention

Very good test!!!

Great vids like always👍

Excellent video, thank you

Next time also include EGT curious to see that too

Great demonstration. thing i take away from this basically is the AFR needs to be "correct" for the application. more lean or more rich within that spectrum makes little difference but outside of that either direction results in power loss etc.

I'm impressed with how little difference such a wide variance in AF ratio made. As in virtually no difference! I would not have expected that. It would have been interesting to see a plot of EGT during each of those runs as well...

There is a NACA paper detailing this from a long, long time ago. Look up Technical Report 189 from the mid 1920s.

What an awesome demonstration thanks

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Absolute madman is giving us a class from inside a racecar, too bad regular classes aren't like this

amazing video. I love this

The data do not lie. Good stuff. Thank you!

Absolutely loved this video. Thank you for the education. I do have one question on this. What were you using for fuel?? 10% ethanol?? Ethanol free Gas?? E85??

Explanation was 10/10 but I sometimes I had to rewind the video because I couldn't understand what you were talking about 😂. Apart from your accent the video deserves milion views 👌

Absolutely great !!! Woud you consider next time aquiring EGT as well ? Then we could know how low Lambda has to go to provide sufficient cooling to the combustion chamber and how it compromises output.

perfect , amazing work.

Very good info thanks.

HPA, This is such a great video. I am probably the only one that is interested but it would be great to see a similar test on how efficiency (power/lamba) changes at partial throttle. I really want to know how lean I can run when I have high vacuum.

It would be pretty cool to see the EGT and intake temps overlayed as well.

In my experience A/F ratio is actually more important on light throttle where small variations can make a big difference to driveability. You have successfully busted the myth about A/F ratio being crucial for max power though, neatly demonstrating the BS you hear where the operator says he went up one jet size or increased the fuelling by 2% and suddenly found another ten horsepower. Have you ever tried this with a 2-valve engine? When I was involved in the business I generally found that it was necessary to run these very slightly richer, which I always put down to the less efficient combustion chamber; another effect of 2-valve combustion chambers being that exhaust valves were far harder to decoke due to the resultant much higher exhaust gas temperatures flowing over them (not because of the richer A/F ration which would have the opposite effect, but because of the less efficient combustion causing less of the heat to be turned into kinetic energy). Biggest danger to engines in my experience is not A/F ratio, but when the mapping guy has pointlessly pushed the ignition advance to the very limit and then the car gets a tank full of fuel that is very slightly lower octane than the test fuel. That didn't happen in the days of distributors simply because the timing was wobbling all over the place anyway and to think you could increase advance by half a degree meant you were laughably deluded. Am I giving away my age?

Man, this is some great stuff.

Nice video

Shaved off ten years bro, had me confused at first.

Great Video and info !! Does a turbo charged engine behave the same ??

Very good!

Me gusto el video. lo mejor es usar el AFR que te la misma grafica pero usando el menos combustible posible.

Excellent demonstration.

Very clear and concise explanation! Subscribed! Looks like this NA car is not going to benefit from the dyno tune... probably the fuel consumption can be optimized by running leaner....

Lamda+ignition timing( with lots of resolution) + knock sensor with lots of resulution+ EGTs again with lots of resolution and good response time on a load based dyno... MAN I MISS TUNING CARS

Awesome work. Can you show holding the AFR constant and changing timing?

Interesting. Thanks

Great dmonstration! Could you tell us which fuel quality was used to? Especiali was any Ethanol mixt in? Like at E10 gasoline❓

Super helpful and easily understandable video so thanks for the lesson. My question is, when do we take fuel economy or cyl temperatures into consideration when running a more rich mixture? Is the idea to run in the middle of that AF range or more on the lean/rich end?

Lookin good 2001 Andre :D

Nice explanation. Interesting when many tuners target an AFR of 13.0 or about 0.88 lamda, they are actual not achieving peak power. Which is closer to 0.92 lamda or 13.5 AFR. I realize in their mind this is a safety factor as fuel and conditions do differ. This is merely an observation. Curious if this is consistent across all gasoline engines.

Huge thanks👌

Amazing video, one unrelated question, isn't 200hp for a 350z a little low? Shouldn't it be around 270 or 280 HP at the wheels?

depends on its fuel type, spark ignition if you lean on it, it will make power but run the risk of detonation (localized above the speed of sound events across the piston crown)

Reading the EGT at the same time would have demonstrate this easily. Also, sometimes you don't make more power but the oil get too hot very fast.

Andre went into a time machine at the start

First video I've seen and i hit that sub button and the bell 👌👍

Trying to learn as much as I can. Gotta build that desperately needs a tune. Fueling up top seems to be good about 12.5-11.5:1 afr But down low on rpm and load the afrs are way too lean. Between 19:1 down to 15: at around 3-5k rpms. And most shops w ont touch it because its such an odd build.

How much does the graph change if you change the timing while changing AFR to take advantage of the rich conditions?

whats ideal for boosted applications, can i target 0.8 lambda and call it safe as i dont rly have access to a proper dyno other than virtual dyno wich can be quite finicky

Excellent demonstration but I though max power was near 12.50 natural aspirated not stoichiometric of 1 lambda

Would be nice to see EGTs on all the runs 😁

Hi. I have a question. Rich afr can lead to knocking or not?

Other than that great video I learned a lot

On a serious note, I've heard of people picking up power by running ethanol rich due to ethanol being a fairly oxygenated fuel...would be cool to see this theory quantified.

Hello, this is very interesting but I'm French and I don't understand the all video, can just tell me for you what is the best lambda value for each regime 2000, 2500, 3000 etc ...

i have a turbo car, my dyno run actually show the AFR start around 14.7:1 then full throttle to redline RPM, it starts to drop to around AFR 12.2:1. should i request a tune to have the AFR all the way flat when full throttle til redline?

So on this example, where would you target?

Does overlap effect the a/r value on the wide band sensor?

bro, you gotta have a pair of JNCO jeans on from 00:35 to 2:03! I'd almost bet you do.

Fascinating, does this mostly apply to a forced inducted Engine too??

Can u tell why -100 kpa is open throttle? Like more underpresure in manifold means wider open throttle right?

Great video...thanks

THANKS!

awesome video. just a few questions: what does "eare" and "muicks" mean?

tWould be nice if you showed the EGT in all three cases!

Multi-port fuel injection engines do a two stage process first stage is a 15.0:1 AFR second stage will add just enough fuel to give you a final AFR of 13.5:1 all the first stage does is to clean the intake valve or valves of carbon deposits through the intake port of the head then rest of fuel comes from the direct fuel injection part of the process.

Hello. Is it really for turbo engines, with boost of 2.5 bar? As I know, 0.86 afr, moves to high EGT…

Will the situation of turbocharge engine be the same as NA engine?