As a matter of fact, did YOU googled the word stoichiometric?to be safe 12.1:1-12.7:1 is slightly rich, i mean slightly. This way you wont burn holes in pistons. 14.1:1 is lean period. my dyno guy shut my run down at 9000 rpm's cause he didn't want me to blow my motor on the dyno. Google the word "stoicheometric" it is the optimum A/F ratio for an internal combustion engine. Then you can form your own opinion about what A/F ratio you want for your bike
.......I have to know how tuning OUTSIDE of the "best power ratio" will give more top speed?Best power ratio is around 12.7/1, but that ratio won´t give maximum achievable top speed. Going towards stoichiometric will.
stoicheometric is where it will get the best combustion and is a general term that changes with selected fuel use. methanol is around 6.4:1, ethanol is around 9:1, e85 ethanol is around 9.8:1 only problem is that most of us are using an A/F sensor that is calibrated to gasoline. best power usually occurs at around .88 to .89 lambda which on gasoline is around 13 to 1.(14.7 x .88) on e85 like I run in my gsxr .88 lambda is around 8.6 to 1 but will still read 13 to 1 on most a/f gauges because the gauge is taking the lambda reading from the sensor and converting it to an a/f for gasoline. some A/f meters allow you to change the fuel that it uses for its calculation. anyway enough of that, many things effect a/f so there is no right answer but from my time on the dyno I have found that a good place to start to tune to on pump gas and many of the VP race fuels is around 12.9-13:1. on e85 ethanol around 12.6-12.7:1. all of these readings are taken on an A/f meter calibrated for gasoline. 12:1 is way too rich and will probable cost the bike 10+ hp on a naturally aspirated engine. turbo and nitrous will be very happy and safe at 12:1 but not a NA engine. your best bet is to take it to a compitant tuner and you will know its right.
yep:thumbsup: But to the threadstarter though just tune it to 12.9 and you will be real close. If its a street bike you may want it a lot closer to stoich in the crusing areas of the map(part throttle) to save on fuel mileage but at 80-100% 12.9 will get you near right. :thumbsup:That's awesome info Vince.... I didn't know that one about how they figured out the A/F for lambda. Maybe that's why Ivan likes runing CO2 readings instead of A/F, eh?
:crackup: I don´t have to tell you forget everything I said......how am I (or this guy) going to get 10 more MPH on a bike that already hits the limiter in 6th gear... by leaning out the last 800 rpm?
I mean really... let's think about this: an extra 10mph --in addition- to the 190 or so my 06 does at sea level on stock gearing with a big tire on it (and it's still pulling into the limiter...). Leaning out my mixture a full point and a half would give me a 200+mph on a stock bike IF I did have the gear to get there? How much HP do you think that is that you're picking up by going lean like that? And is it honestly worth the risk/complication for a street driven vehicle that sees the limiter in 6th maybe a handful of times per year? That's just plain bullshit. Show me a dyno graph, or anything that coincides. All my graphs and real world testing show otherwise. I HAVE run it back-to-back AND on the dyno: the bike likes it fatter. It picks up 1/4mph and still pulls all the way through 6th. It sure as hell didn't pick up enough hp "in the last 800rpm" to go 10mph faster @ 190ish mph when it was lean. It didn't lose a damn bit of hp when we took it from 14.2 to 13.0... and it went faster in the 1/4 by 1-2mph at 12.5:1 vs 13:1 (dyno #'s, all those).... though I still don't know exactly why.
"The 08/09 10R with full exhaust (no PC3/V) is running pretty close to stoichiometric at WOT close to the rev limiter, and are doing GPS197mph with +1front/-1rear every day."
----show me the same run(s) with the A/F cranked down to the low 13 range and show me that it actually goes slower. I'd like to see that.
...and we're not talking about speed trials here anyway... we're talking about a good, strong, SAFE street AUTOTUNE that the guy can set his bike to and forget about. Even IF (big if here) you're right, it's about usless to this guy anyway. We can all appreciate some pedantic input/bench racing here and there, but this guy wanted some real world info... and it's just responsible to give advice to strangers with a safety margin added in. I sure don't want to be the guy that gave him the aggressive advice and he ends up fragging the top of the piston @ 170+mph because he had a bad load of pump gas. Common sense man.
I cant chime in on what you said because I dont do that kind of racing and I have never tried to lean a motor out that much on top because as you said in drag racing the top end extra speed is not needed. also did you mean .96 and .95v lambda in this post? .76 is very rich not lean??? :thumbsup::crackup: I don´t have to tell you forget everything I said.
Perhaps if you read this comment of mine that seems ridiculous to you from another member, you will take it into account.
Just to extend a little bit more the topic, you can´t see the advantage of this A/F ratio on the dyno.
As a matter of fact you can probably see a very slight drop in power, but as the bike is accelerating on the dyno (as it does in the 1/4 mile) you´ll need a fatter ratio to show best power (and accelerate faster).
Once acceleration is not necessary (at 190mph) you can take advantage of the faster flame front inside the combustion chamber, of leaner ratios.
Fatter ratios achieve good power and best acceleration times, but not best top speed.
Then, if you´re hitting the limiter in 6th, continue to drop teeth at the rear until you don´t anymore.
Best 2nd gens here are doing are doing GPS 198mph without internal engine work. You may think that this is pure :bs:, but it´s not. (about the same the 3rd gen does without Pcommander)
08-09 GSXR1K are doing GPS 203mph without the hell of a work.
In every case lambda sensors showing around .76 / .75V close to rev. limiter.
That means something is being done right down here, and in no case, as I consider myself not to be any kind of moron, I will throw here some false info (not even "in doubt" info)
As Vince says, best power is get from a .86V lambda reading. Completely agree with that and the rest you said Vince. Really good post.:thumbsup:
Eh, if that's the way it is then. If you have something that works really well in what you do, by all means go for it. :thumbsup: It's apparently a highly-specialized area... the exception that proves the rule, as it is.:crackup: I don´t have to tell you forget everything I said.
Vince, I mean reading the lambda sensor with a digital voltmeter.I cant chime in on what you said because I dont do that kind of racing and I have never tried to lean a motor out that much on top because as you said in drag racing the top end extra speed is not needed. also did you mean .96 and .95v lambda in this post? .76 is very rich not lean??? :thumbsup:
:thumbsup: OK I was thinking lambda not actual voltage from the sensor. I have this chart it may help some others figure out what we are talking about: range is voltage at the sensor:Vince, I mean reading the lambda sensor with a digital voltmeter.
I´m sure you´re saying the lambda factor. At .8x the lambda factor aprox equals the same figure in output voltage (.8x volts)
Towards 0 volts is the lean side, and towards 1 volt to the rich one.
.75 volts is towards the stoich ratio.
I´ve search the internet for a conversion table (lambda output voltage vs A/F ratio) that I do not have right now in this computer and found this kinda poor graphics..
So tuning a bike in accordance with that chart would make for good street riding? Run 14.5-15:1 for say anything under 20% throttle, and I've always thought to tune to 12.6-13.1 for optimum power so would this work Vince?:thumbsup: OK I was thinking lambda not actual voltage from the sensor. I have this chart it may help some others figure out what we are talking about: range is voltage at the sensor: