there MUST be a thread on this, but i can't find it ( then the search feature went down ). anyway:

while cruising on the fwy i'm at 14.7-15.3 a/f.. but i've noticed, at times it may hit low 16s every once in a while. this is no the fwy at part throttle/70mph/plenty of vaccum.

is this okay or should i add a bit more fuel? also: when accelerating, in the slightest, it goes right back down to 12:1-13:1

 

Im guessing that this is on a wideband display right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tgreaves &raquo;</TD></TR><TR><TD CLASS="quote">Im guessing that this is on a wideband display right?</TD></TR></TABLE>

um. yes.

 

What engine? Some of the new Honda stuff will idle happily @18:1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LsVtec92Hatch &raquo;</TD></TR><TR><TD CLASS="quote">What engine? Some of the new Honda stuff will idle happily @18:1</TD></TR></TABLE>

idle a/f is a totally different story.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kaj &raquo;</TD></TR><TR><TD CLASS="quote">there MUST be a thread on this, but i can't find it ( then the search feature went down ). anyway:

while cruising on the fwy i'm at 14.7-15.3 a/f.. but i've noticed, at times it may hit low 16s every once in a while. this is no the fwy at part throttle/70mph/plenty of vaccum.

is this okay or should i add a bit more fuel? also: when accelerating, in the slightest, it goes right back down to 12:1-13:1</TD></TR></TABLE>

sounds fine. 15-16 will do you good on the highway, but only at a light load

 

Yeah, part throttle no worries. its just when you're gunning it, you dont want it to go lean.

 

I've noticed 15:1 and above gives me slight stuttering. Technically speaking, 14.7:1 gives the best fuel ecconomy. Slight blips of 16:1 isn't bad at all.

The reason it goes to 12:1 with added throttle is because your ecu registers a heavy load (high speed, high gear), and goes open loop - not correcting with the o2 sensor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kaj &raquo;</TD></TR><TR><TD CLASS="quote">

um. yes. </TD></TR></TABLE>

Sometimes people come in here and ask simular questions when using one of those autometer narrowband pos's..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">I've noticed 15:1 and above gives me slight stuttering. Technically speaking, 14.7:1 gives the best fuel ecconomy. Slight blips of 16:1 isn't bad at all.

The reason it goes to 12:1 with added throttle is because your ecu registers a heavy load (high speed, high gear), and goes open loop - not correcting with the o2 sensor.</TD></TR></TABLE>

wrong, 14.7 is stoich which is the best possible mixture for emissions gasses. best fuel economy is as less fuel as possible without risking detination

 

There is no ideal mpg fuel ratio for all loads. Lean is great for gas mileage when you're cruising or decelerating, but terrible for mileage when you're accelerating or going uphill.

16:1 on cruise sounds like normal for the stock ECU. Very bad at WOT.

 

14.7 at low loads allows for much more timing than 16:1 - it's the most effecient. 1 part of gasoline needs 14.7 parts atmosphere - any more air and there's unused air, any less and there's unused gasoline being spit out. 14.7:1 gives the most power production at the same amount of air pressure. I know for a fact that above 16:1 constant, you loose a lot of power. When tuning my car, it was very touchy above 15:1 for anything but idling.

I guess if nothing else, I'll test this in the future. One thing to note would be how much more throttle would be needed for 16:1 cruising vs. 14.7:1 cruising. You are using a leaner mixture, but if its reading from fuel cells that dump in more fuel due to more air pressure needed...


BTW - atm running uberdata, I can tell exactly when its at 21.5 in/hg of vacuum. It starts reading the lowest cell (almost 0 fuel), slightly sputters resuling in less motor suction, which then has normal power...and repeats. My point - obd1 honda ecu's correct as close to 14.7:1.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">14.7 at low loads allows for much more timing than 16:1 - it's the most effecient. 1 part of gasoline needs 14.7 parts atmosphere - any more air and there's unused air, any less and there's unused gasoline being spit out. 14.7:1 gives the most power production at the same amount of air pressure. I know for a fact that above 16:1 constant, you loose a lot of power. When tuning my car, it was very touchy above 15:1 for anything but idling.

I guess if nothing else, I'll test this in the future. One thing to note would be how much more throttle would be needed for 16:1 cruising vs. 14.7:1 cruising. You are using a leaner mixture, but if its reading from fuel cells that dump in more fuel due to more air pressure needed...


BTW - atm running uberdata, I can tell exactly when its at 21.5 in/hg of vacuum. It starts reading the lowest cell (almost 0 fuel), slightly sputters resuling in less motor suction, which then has normal power...and repeats. My point - obd1 honda ecu's correct as close to 14.7:1.</TD></TR></TABLE>

it only takes so much powerto maintain a consistant cruising speed, any more than needed is wasted, and therefore wasted fuel.

honda ecus keep the mixture as close to 14.7 along with every other stock ecu because of emissions

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tgreaves &raquo;</TD></TR><TR><TD CLASS="quote">

Sometimes people come in here and ask simular questions when using one of those autometer narrowband pos's..</TD></TR></TABLE>

i can't imagine. that is the lamest thing i've ever heard LOL. how can they pick a number out of that "knight rider" oscillation of lights???

anyway, this is a boosted B18c5 running S300, so i can make the a/f whatever i want. for SOME reason i'm only getting 24mpg so i wanted to lean it out a bit. i'm now cruising at high 14's - mid 15's, though it does, occasionally, hit 16s ( down hill.. tail wind, i dunno haha ). anyway, i assumed it would be okay.

and yes. i know the A/F drops when i'm accelerating and adding a load.

now, if i can only get the weird, cyclical leaning condition to go away while in closed loop, i'd be set

thanks for the help, guys. i feel better now. as for 18:1.. that scares me a bit. i'd LOVE to for fuel economy reasons.... but that is scary. can anyone else vouch that is okay? i would never run THAT lean, but if i could lean it out a bit more just for freeway cruising, maybe i could get a bit metter MPG.

i dunno. just thinking outloud.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">One thing to note would be how much more throttle would be needed for 16:1 cruising vs. 14.7:1 cruising. You are using a leaner mixture, but if its reading from fuel cells that dump in more fuel due to more air pressure needed...
.</TD></TR></TABLE>

all i know is that while cruising on the freeway, i'm in the same cells at 70mph whether i'm at 13:1 or 16:1. that's the point. to adjust a/f in THOSE cells. if i had to give me more gas, it would move to another section; same RPM, but different vacuum cells. at least that's how it is on my car. when we're tuning part throttle, i hold a constant rpm/speed and adjust a/f. i never noticed any change in how much throttle i needed to give it.

 

My high comp all motor car blips into the 16:s while cruising, no probs here. Ur fine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Used2beAb16 &raquo;</TD></TR><TR><TD CLASS="quote">My high comp all motor car blips into the 16:s while cruising, no probs here. Ur fine. </TD></TR></TABLE>

awesome. if YOU are save with the high comp, then i am

 

You can completely shut off the fuel when decelerating with the throttle closed. The stock ECU does. It's called DFCO.

You don't want power when cruising. Cruising is pretty much the only time that running lean will benefit you. Running lean at any other time (other than decel as I mentioned earlier) will actually hurt your gas mileage and could be dangerous for your motor. Not just any motor can safely run 16:1 at cruise. Each motor is a little different. The motor I referred to was an OBD2 HX motor with an AEM EMS tuned by Scott Fox. Do you think he ran lean at any other time than cruising? Hell no. WOT and other loads were dyno tuned purely for power. Sometimes quite rich.

Despite what people think they know, running lean does not save fuel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suspendedHatch &raquo;</TD></TR><TR><TD CLASS="quote">Do you think he ran lean at any other time than cruising? Hell no. WOT and other loads were dyno tuned purely for power. Sometimes quite rich.
</TD></TR></TABLE>

well, yeah. but thanks for the other info quite insightful!

 

air adds power, not fuel. running lean _does_ save quite a bit of fuel. anyone who's driven their car while it's running rich, and then while running lean would know that very well.

your car at 16:1 will be faster than it will at 14.7:1 with the same amount of fuel. with diminishing return, of course. by logrithmic graph, you can show what happens to power. more oxygen is able to be burned with said fuel, and fuel atomization is greater beyond 14.7. that's not to say that it'll be noticably faster. it'll be negligible, for the most part.

in other words air is power, not fuel. you need the fuel to allow the ignition of the mixture. 14.7 is stoich in perfect conditions with ~10:1 comp, perfect atomization, etc. we don't live in that world. leaner is faster, but winds up a much hotter compressed mixture (a la detonation risk etc) and burns more quickly.

once you open the throttle and let air in, you either better be adding fuel or not adding fuel. adding way to little (18:1++ at cruising, for ex) will promote the said problems.

in other words, the oscillation of a/f between 14 and 17:1 is fine cruising on the highway. there isn't enough air getting in at part throttle to be a damage threat to your motor. your knock sensor will add fuel with minimal knocking. don't worry about it.

and shutting off fuel as in DFCO, keep in mind, is the same as having a rev-limiting fuel cut. of course you can eliminate fuel. it's required to burn the mixture. however, in decel, your average lean-burning import motor can see up to 18:1 safely.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmb20a &raquo;</TD></TR><TR><TD CLASS="quote">your car at 16:1 will be faster than it will at 14.7:1 with the same amount of fuel. with diminishing return, of course. by logrithmic graph, you can show what happens to power. more oxygen is able to be burned with said fuel, and fuel atomization is greater beyond 14.7. that's not to say that it'll be noticably faster. it'll be negligible, for the most part.</TD></TR></TABLE>

You're not serious are you? Maximum power will always be achieved slightly rich of stoich. What you wrote doesn't even make sense. How would a 16:1 mixture and a 14.7:1 mixture have the same amount of fuel? It's not the oxygen that is being burned, it's the fuel that's being burned. How does running lean atomize the fuel better?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmb20a &raquo;</TD></TR><TR><TD CLASS="quote">in other words air is power, not fuel. you need the fuel to allow the ignition of the mixture. 14.7 is stoich in perfect conditions with ~10:1 comp, perfect atomization, etc. we don't live in that world. leaner is faster, but winds up a much hotter compressed mixture (a la detonation risk etc) and burns more quickly.</TD></TR></TABLE>

The energy is contained in the fuel, not the air. Lean mixtures burn slower.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmb20a &raquo;</TD></TR><TR><TD CLASS="quote">air adds power, not fuel. running lean _does_ save quite a bit of fuel. anyone who's driven their car while it's running rich, and then while running lean would know that very well.

your car at 16:1 will be faster than it will at 14.7:1 with the same amount of fuel. with diminishing return, of course. by logrithmic graph, you can show what happens to power. more oxygen is able to be burned with said fuel, and fuel atomization is greater beyond 14.7. that's not to say that it'll be noticably faster. it'll be negligible, for the most part.

in other words air is power, not fuel. you need the fuel to allow the ignition of the mixture. 14.7 is stoich in perfect conditions with ~10:1 comp, perfect atomization, etc. we don't live in that world. leaner is faster, but winds up a much hotter compressed mixture (a la detonation risk etc) and burns more quickly.

once you open the throttle and let air in, you either better be adding fuel or not adding fuel. adding way to little (18:1++ at cruising, for ex) will promote the said problems.

in other words, the oscillation of a/f between 14 and 17:1 is fine cruising on the highway. there isn't enough air getting in at part throttle to be a damage threat to your motor. your knock sensor will add fuel with minimal knocking. don't worry about it.

and shutting off fuel as in DFCO, keep in mind, is the same as having a rev-limiting fuel cut. of course you can eliminate fuel. it's required to burn the mixture. however, in decel, your average lean-burning import motor can see up to 18:1 safely.</TD></TR></TABLE>

If fuel doesn't add power, then hows come guys that switch over to methanol usually gain around 30% more hp????

I think you should go get really drunk to try to forget everything you just wrote/previously knew and relearn it all once you come to

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">

If fuel doesn't add power, then hows come guys that switch over to methanol usually gain around 30% more hp????

I think you should go get really drunk to try to forget everything you just wrote/previously knew and relearn it all once you come to</TD></TR></TABLE>

i'm gonna run water/alk injection so i can run more boost with less chance if detonation, due to the high air intake temps that go with high boost pressures.

meth cools down the temps in the combustion chamber, allowing you to add compression, boost, etc.

meth does not really add power. it allows you to add power.

at least that's the way i understand it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kaj &raquo;</TD></TR><TR><TD CLASS="quote">

i'm gonna run water/alk injection so i can run more boost with less chance if detonation, due to the high air intake temps that go with high boost pressures.

meth cools down the temps in the combustion chamber, allowing you to add compression, boost, etc.

meth does not really add power. it allows you to add power.

at least that's the way i understand it. </TD></TR></TABLE>

Methanol is a completely different fuel than gasoline. Its stoichiometrically correct mixture is way different than that of gasoline. Methanol actually contains less energy per lb. than gasoline so you are correct in saying that it is not the methanol in itself that is adding the power. It is the heat of vaporization of methanol that allows it to make such high amounts of power. It has the ability to draw heat out of the intake charge (as you mentioned), therefore making it less prone to detonation so you can run higher compression ratios, and therefore expansion ratios making the engine more efficient.

 

the point i was trying to get at is that its the properties of the fuel that effect the power the engine makes.ie you can't do the same things with a 93octane motor that you can with a meth car. I know what meth does, kinda cool, on a hot day it will make parts "sweat" like intake manis

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16hybridsol &raquo;</TD></TR><TR><TD CLASS="quote">the point i was trying to get at is that its the properties of the fuel that effect the power the engine makes.ie you can't do the same things with a 93octane motor that you can with a meth car. I know what meth does, kinda cool, on a hot day it will make parts "sweat" like intake manis</TD></TR></TABLE>

I'm not sure what you mean by 'making parts sweat' but I think I know what you are saying in general and agree with you.