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An engine will run on a HUGE range of AF ratios.
What's your cutoff for too lean?

A tune/flash is not necessary for the mods you mentioned but it would certainly take you out of the markedly lean condition that is factory programmed and not compensated for by any sensors to any big degree.

If the question is staying on the safer side for the engines sake, a tune makes sense. For improved driveability and a decent mid range power boost, for sure.

I would stick to stock air filter as well... one over oiling of the kn filter and the intake tract is gummed up with that sticky residue. And it's hard to beat the quality of the oem piece.
 

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Exactly correct if we are talking about O2-sensor implemented models. Bike of US/Canada region code has no O2 sensor and works in open-loop mode always.
My 2011 has o2 sensor. #31
Font Parallel Engineering Auto part Diagram


I just removed mine and flashed my ecu to remove the the error code.
I believe most bikes have o2 sensors these days especially if equipped with a cat and subject to emission standards.
 

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Please, could you tell me how it works? Values from temp sensors (IAT, ECT) I guess? Or it will be depended on speed of opening TPS?
I don't have the equations, but this is from the 2009 1k manual (the newest manual I have). "Corrective variables" is what I'm talking about. They can only compensate so far....
Rectangle Font Parallel Slope Number
 

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I have a 2023 GSX-R750. Shop installed a Two Brothers exhaust before I purchased (not convinced they flashed the ECU). I just purchased a Akrapovic Megaphone (slip-on) "schwing". I would also like to install a K&N air filter.

Would the bike benifit from a fuel controller with these 2 items?
No, the bike would benefit from being left alone.

Why do you want a K&N air filter? You have to service it properly every 1000 miles or so, why not leave the fit-and-forget paper filter?

Someone had put a K&N into my GSXR, and by the look of it had never serviced it, so dust was getting through into the intake side of the box. I've seen exactly the same thing on other people's bikes. Filters installed by people who don't seem to understand they need cleaning and servicing.

Road use = paper filter. If you had a 15hp bike and used every Watt of its power, then maybe it will make a difference. 150hp at 15k rpm? If you see that on your dial at full throttle, then I'd suggest the nature of your air filter will be the last thing on your mind at that point because you'll be breaking the law and on the lookout for the police, and you will not notice 1hp.

You're more likely to let dust through the filter and see a 10hp drop in power, over time, due to wear, than let more air through and see a gain.

These bikes are rather lean from the factory at lower rpms.
Fuel injection is a closed-loop auto-tuned system to very tight limits and computer controlled. A lambda sensor in the exhaust basically tunes the fuelling of the bike on every single stroke.

I'd trust Suzuki to use its more-than-20-years of experience with bike EFI to have programmed in the ideal tuning controls into the ECU considering everything, including reliability, fuel economy, NVH, rideability, etc..

Please excuse me being somewhat doubtful that a guy with no rolling road, no emissions equipment and no legal means to test the bike across its performance envelope can bodge in a device into the wiring harness and tune the bike to perfection with nothing more than a lap-top and a can of beer by his side.

Also not forgetting that you will screw your warranty by messing with the bike like that. If it blows up after 500 miles and you'd fitted one of those, I'd show you the door and wish you well with your efforts to fix it yourself.

If you want to experience a great bike, then get riding it! Leave alone. ;)
 

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There was an independent test on air filters done several years ago. Granted it was for truck engines, but you can assume the filter media would be the same across the spectrum. K&N filters had the best initial flow and filtered pretty well when fresh. But they were they loaded faster, passed the most and largest particulate, and were the first to failure. I've seen enough testing that I wouldn't use K&N in anything I own.....

Personal opinion on some of these things. Hi-flow air filters, velocity stacks, light weight batteries and other "performance parts". What are people trying to do? I get you want "upgrades" and "more power". But ask yourself this, are you actually using the power you have? I'll guarantee you aren't. Unless you're racing and someone is beating you by tenths of seconds every weekend, why spend the money. It's a waste. Aftermarket exhausts are about the only thing that makes sense because you get a sound and a look/style to go with it. Everything else is so you can talk about it..... which just makes you a poser. But, do what makes you happy. My opinion on it should mean shit to you.
 

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with nothing more than a lap-top and a can of beer by his side.
I agree with your post.
But, You'd be amazed at some of the things I've built or fixed with a bottle of beer in hand and by my side LOL.
Don't underestimate a good beer to 'grease the skids' LOL


There was an independent test on air filters done several years ago. Granted it was for truck engines, but you can assume the filter media would be the same across the spectrum. K&N filters had the best initial flow and filtered pretty well when fresh. But they were they loaded faster, passed the most and largest particulate, and were the first to failure. I've seen enough testing that I wouldn't use K&N in anything I own.....

Personal opinion on some of these things. Hi-flow air filters, velocity stacks, light weight batteries and other "performance parts". What are people trying to do? I get you want "upgrades" and "more power". But ask yourself this, are you actually using the power you have? I'll guarantee you aren't. Unless you're racing and someone is beating you by tenths of seconds every weekend, why spend the money. It's a waste. Aftermarket exhausts are about the only thing that makes sense because you get a sound and a look/style to go with it. Everything else is so you can talk about it..... which just makes you a poser. But, do what makes you happy. My opinion on it should mean shit to you.
Chuck, there used to be a good commercial about when the a certain company talked, people listened.

I read a lot and I try and take in a lot from a lot of posts. And you get to know by reading a lot of posts who makes sense and seems to know what they're talking about.

You sir, and your opinions are top tier. I always make it a point to read your posts. It makes it even better for me having have met you and did those Track Days with you also. I hope to learn more and more from you about this craft.

Thanks,
Todd
 

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Oem manufacturers are limited by stricter and stricter emissions requirements.
Lean mixtures of 17:1 reduce combustion chamber temps and reduce NO2 emissions. (Yeah, I know this sounds wrong but look it up)
Rich mixtures of 12:1 produce more complete combustion and power but increase hydrocarbon emissions.
Trusting the oem to get it right is ok if you leave everything in place and accept that some performance is left on the table for emissions sake.
The video I linked pretty much proves this. It is linked to the part of the video where he shows the dyno results so you don't have to suffer through the whole thing.
A great point he makes is that YES you rarely exploit hp gains at 12000 rpm but a solid 33% increase in horsepower at lower rpms is absolutely noticeable. Also, driveability is markedly improved with a richer than 17:1 a/f ratio. Both in real world and on track smoothness of throttle application.
You really don't know until you try...
 

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Velocity stacks absolutely change power bands... the key is utilize them in such a way to take advantage of this.
By altering the velocity tract length either with a two piece set up or a continuously variable length intact like ferrari and porsche have done, meaningful gains can be had.


Without this, yes, a velocity stack will only work to shift power from one point on the curve to another.
 

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I agree with your post.
But, You'd be amazed at some of the things I've built or fixed with a bottle of beer in hand and by my side LOL.
Don't underestimate a good beer to 'grease the skids' LOL
Oh, gawd, I hope I have not suggested otherwise.

However, in the case of a brand new bike, I think I am on safe ground.

I have a bike frame in the garage waiting for me to bolt things to it. I'm making a custom for my son by transferring parts over from a 20 yr old donor bike, that is if the rear engine mount has not permanently seized to the swing arm axle. Like many in similar circumstances before me, that may well be made better with the technical assistance of several beers.
 

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Oem manufacturers are limited by stricter and stricter emissions requirements.
Lean mixtures of 17:1 reduce combustion chamber temps and reduce NO2 emissions. (Yeah, I know this sounds wrong but look it up)
Rich mixtures of 12:1 produce more complete combustion and power but increase hydrocarbon emissions.
Trusting the oem to get it right is ok if you leave everything in place and accept that some performance is left on the table for emissions sake.
The video I linked pretty much proves this.
Sorry, but I don't agree it proves it at all. You might be right, but 'proves' it, no, not really.

You are assuming that fuelling is constant under all conditions.

When the engine is running cold, a well programmed ECU map will lean off the mixture to increase the exhaust temperature to bring it up to temperature quickly. Blipping it a bit on a rolling road with excess fuel, it will be cooling down.

You might convince me more if you email them and ask them to do the test again - hold the engine under WOT at 5krpm for a minute, then see what the mixture ratio is. Does it change? I'd wager it does.

I would not doubt that the presence of a catalytic converter is a strong motivation to want to get exhaust hotter, but only until it is hot enough. If you 'ride' a bike, not just potter around like a commuter, then I think you might find the map shifts.

I don't know, I can't say, but it's been designed to do 'that', it's been tested and homologated to do 'that', and the bike is under warranty to do 'that', repeatedly, for a very long time. Fiddle with it, and bye bye warranty.

If it was a 20 year old bike in need of fettling, sure, go right ahead (with the beer!! ;) ). A brand new bike needs to be ridden, and ridden gently for the first few thousand miles.

What happened to the other guy here who had an old-stock new bike that wouldn't rev over 12k when it was under 500 miles from new? :oops:

OP here should be doing absolutely nothing to the bike until it's at least run in nicely, means not revving much at all for a good while yet.
 

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Rich mixtures of 12:1 produce more complete combustion and power
I prefere a 13.2-13.7 AFR for WOT and high range revs at high load conditions (determined by MAP values), 14.0-15 AFR for middle range revs under partially load conditions and 12.5-13.5 at the idle or a bit higher. I think a 12 and lower AFR is a fuel wasting and high speed carbon deposit but not the higest power gain at 11:1 compression ratios and higher.
is only good for low compression engines.
I'v got the best gain and minimal carbon deposite with these values.
BTW these mixtures should ignite earlier than with traditional ignition.
.
 

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Yes, that is also a possibility, as the engine is 'relatively' slow at that point, higher fuel mixtures may lead to valve/head coking and loss of unburnt hydrocarbons, so leaning back, like I mentioned, may be for long term reliability.

Suzuki are carrying a lot of liability when these bikes get in the hands of unsympathetic riders who seem to think little of holding an unloaded throttle on the end stop. I think we should respect their 20 year long term knowledge and testing to get this sort of thing right.

A proper explanation and a full understanding of the fuel mapping I am sure would spread light on this, but one internet video of one rolling road test on one bike of unknown preparation, probably removed exhaust components and maybe one of those dastardly filters, well, what it goes to prove is that people's opinions can be unduly biased from seeing a single uncertified youtube video, this is all it proves.
 

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I think we shall agree to disagree as I find I disagree with much of what you say.
Sorry, but I don't agree it proves it at all. You might be right, but 'proves' it, no, not really.

You are assuming that fuelling is constant under all conditions.

When the engine is running cold, a well programmed ECU map will lean off the mixture to increase the exhaust temperature to bring it up to temperature quickly. Blipping it a bit on a rolling road with excess fuel, it will be cooling down.

You might convince me more if you email them and ask them to do the test again - hold the engine under WOT at 5krpm for a minute, then see what the mixture ratio is. Does it change? I'd wager it does.

I would not doubt that the presence of a catalytic converter is a strong motivation to want to get exhaust hotter, but only until it is hot enough. If you 'ride' a bike, not just potter around like a commuter, then I think you might find the map shifts.

I don't know, I can't say, but it's been designed to do 'that', it's been tested and homologated to do 'that', and the bike is under warranty to do 'that', repeatedly, for a very long time. Fiddle with it, and bye bye warranty.

If it was a 20 year old bike in need of fettling, sure, go right ahead (with the beer!! ;) ). A brand new bike needs to be ridden, and ridden gently for the first few thousand miles.

What happened to the other guy here who had an old-stock new bike that wouldn't rev over 12k when it was under 500 miles from new? :oops:

OP here should be doing absolutely nothing to the bike until it's at least run in nicely, means not revving much at all for a good while yet.
None of what I said NEEDS to be done on a brand new engine... yes, let it go through the "break in" period if you like. But a 20yo bike? nooooo... no need to wait that long.
Just getting a flash does not mean you can't ride the bike gently and break in normally either.

Dyno testing is done with the bike properly warmed to temp not cold. Changes at WOT for a minute would be made as the temps increase... but are you WOT on the road or track for a whole 60 seconds as well? Maybe, but not usually. So, I fail to see your point.

I think we will have to agree to disagree... ;)
 

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I prefere a 13.2-13.7 AFR for WOT and high range revs at high load conditions (determined by MAP values), 14.0-15 AFR for middle range revs under partially load conditions and 12.5-13.5 at the idle or a bit higher. I think a 12 and lower AFR is a fuel wasting and high speed carbon deposit but not the higest power gain at 11:1 compression ratios and higher.
is only good for low compression engines.
I'v got the best gain and minimal carbon deposite with these values.
BTW these mixtures should ignite earlier than with traditional ignition.
.
This will really depend on the particular engine and design...
Having tested and tuned a couple engines I've found that there is no IDEAL a/f ratio really for max power. It's just whatever gets you down the road the fastest.
beware of the engine tuner that says he's tuning just for a particular a/f ratio... It's the easiest and most convenient for them but not always the best.
 

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Just for info. Some time ago I made AFR scan for my K6 600 (it has no o2 sensor). I guess is oem flashed but I dont sure about it. So on I got the 15-16 AFR at wide range of revs under no load conditions (on neutral).
 

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A proper explanation and a full understanding of the fuel mapping I am sure would spread light on this, but one internet video of one rolling road test on one bike of unknown preparation, probably removed exhaust components and maybe one of those dastardly filters, well, what it goes to prove is that people's opinions can be unduly biased from seeing a single uncertified youtube video, this is all it proves.
And you are making assumptions... He's tuned and tested and run hundreds of these bikes. Tested them way beyond what the factory intended both on the dyno and track.
And despite the accent, likely has much much greater knowledge than you or I.
 
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