| Author | Message | ||
     Rick_A |
Typically: 30-35% of combustion heat leaves through the exhaust 30-35% of the heat imparts a working force on the piston 30-35% is radiated through the engine surfaces So, under most conditions, temps should change proportionately, shouldn't they? | ||
| Rick_A |
I know from tuning miniature nitro 2-stroke engines leaner was always hotter and more power...to an extent. That was always obvious with those engines...however, keeping the mixture at peak power levels kills one pretty quick. The trick was leaning it to max power and richening just enough for a safety factor and better longevity. Leaning too much meant it ran too hot and just wouldn't run right...missing, coughing, sputtering...and keeping it in that state meant a very premature death...richening too much just made 'em run too cool, sluggishly, and increased combustion deposits. Much like most engines, really...just SO much simpler | ||
| Aesquire |
Modern lightplane with EGT practice is tune for peak EGT then richen up a bit (to keep from melting pistons) at a FIXED throttle position. Since altitude is a function of power output (modified by trim, which sets the speed the plane flys level at) Pilots typically set a throttle as a % of redline say 70% then tune mixture & retrim. This is for best economy. For best power you run rich as heck (that melting thing) takeoffs, acrobatics etc. Not far past peak EGT the engine quits, and may not restart, (that melting thing again) easily. 2 stroke ultralight aircraft engines seize up & melt pistons FAST with lean mixtures. Lean burn engines take careful engineering. | ||
| Blake |
What Rick says is fairly accurate. Though an engine exhibiting 35% total efficiency would be quite exceptional. Some clarifications... Heat cannot "impart a working force on the piston." Correctly stated we would say that 30-35% of combustion heat energy is converted into mechanical energy. It is also inaccurate to say that "30-35% (of combustion heat energy) is radiated through the engine surfaces." After being conducted through the engine to exposed surfaces, some is radiated; most is shed through convection. | ||
| Aesquire |
Rick_A Happy motor is (like you said) just rich of lean. WWII planes typically ran fairly rich for cooling on takeoff, climb & combat. Crappy for emissions to run that rich, but you can get more power out of a typically supercharged engine with the additional cooling of a rich mixture. I'll bet most fuel is wasted in a top fuel drag engine. | ||
| Rick_A |
Hey...what can I say...I know how 'tis but I never quite know exactly how to word it.  | ||
| Blake |
Aesquire, They didn't run rich for cooling, they ran rich to make maximum power. Rick, Me neither. I once told my wife... never mind, better to never go there again.  | ||
| Featheredfiend |
"WWII planes typically ran fairly rich for cooling on takeoff" They employed water(water/alcohol) injection taking off under full load and during "war emergency". Most engines showed a ten percent boost during injection. Feathered | ||
| Rick_A |
I've spoken to a few race tuners that adamantly believe a stoichiometric mixture makes the most power...it seems like how well a particular motor can support normal combustion on a particular fuel is what makes the difference. So, I think that's probably how a richer mixture can make more power. | ||
| Sarodude |
Blake / Aesquire- The aircraft richness is not for peak power. It sacrifices power to allow for an otherwise overly simplistic carburetor to be able to handle abrupt power changes. Under marginal conditions, an abrupt throttle change can cause a major stumble in those engine / carb combos - major enough to lead to a dead stick situation - not something fun in critical stages of flight (takeoff, approach, aerobatics). Clearly, it's wise to sacrifice some minimal percentage of power to achieve a less stumble prone engine. Full rich to an airplane is simply "full safe" and gives no consideration to power outpur other than full rich isn't TOO much less powerful than a more ideal (not stoichio) mix. Like I said above, a CLEAR AND OBVIOUS observation of leaning out the fuel mix is that, for a given throttle setting and altitude, peak EGT would COINCIDE with peak RPM. I'm not making this up. I've BEEN THERE and DONE THAT. How does that NOT equal max power? Blake-
Once again, I never said anything about max economy or anything. Max economy would come from tuning LEANER than peak EGT - whatever the engine could stand. That would likely cause some overheating issues though - and THAT power loss is not a result of a lean condition but a result of an overheated condition.
I don't mean at all to be splitting hairs but do you mean exhaust gas or exhaust system? Ya know what I'm getting at? If the whole engine starts to get hot (regardless of EGT) how much could that contribute to the exhaust pipe temps? I don't imagine a significant amount - but I don't know that. Once again, the thing I MUST reiterate is this aircraft observation: In an airplane with an EGT gauge, peak EGT always coincided with peak RPM, all other thing being equal. Would peak RPM not indicate peak power in that scenario? Seems the only way to prove this out is with a load dyno and an EGT! Other than that, I'm not so sure there's much point to this ping pong tournament!  I'm actually not so sure that we're both seeing the complete picture. Here's one final question... Would peak combusion temps yield peak combustion pressures? -Saro | ||
| Benm2 |
I didn’t say they were better. I offered that they weren’t as bad as was being said about them. Of course closed-loop is better, but the feedback is good for ADJUSTMENTS.
What conditions? Show me the areas where the O2 sensor offers better instant adaptability. It provides good feedback for control around steady-state conditions, and can help keep an engine at stoich as it degrades, by offsetting the base curve.
I doubt it. The XB has satisfactory emissions numbers, just like everyone else. Is the XB certified as a Low Emissions Vehicle? Or an Ultra-Low Emissions Vehicle? Perhaps you know, I don’t. I’m sure you’ll tell me if you do.
You mean like that crappy system on the Ducati’s? Also, what does being a v-twin have to do with emissions? Good for Buell to get the system to pass emissions without a catalytic converter. However, do you know what you gain by fitting one? Be careful here when you get ready to tell me how much they weigh or hurt performance.
Yes, I know, I am an evil Toyota owner. Bad me. Shame on me. Look how bad I am for the economy. I’m probably some tree-hugging SOB, and my momma dresses me funny too. Hell, I’m probably for gun control, and drink coffee from one of those fancy-pants places with my pinky in the air. Thanks for the information on the origination of the ECU, but I had asked a QUESTION. Thanks for the answer, and I’m glad that it was sourced within the US. | ||
| Sarodude |
One quick note... I wonder if my aircraft observations are a bit out of context. Think about it - those things are considered SCREAMING at 3500 rpm! Like I said, everyone can't be seeing the complete picture. -Saro PS - I feel really bad going so off topic for so long... | ||
| Mikej |
 (just passing thru) | ||
| Blake |
Saro, I agree, if higher EGT coincides with higher rpm it is indicating higher power. What you are failing to recognize however is that we need to be comparing EGT for equal power outputs to ascertain the effects of mixture on EGT. If you continue to lean the mixture without further opening of the throttle, power drops. If you were to open the throttle to maintain the same airspeed, (same power output) the EGT would rise further. Do you agree? I don't think your aircraft observations are out of context at all. Interesting stuff really. | ||
| Sarodude |
Blake- Now I'm a bit lost. it was only a matter of time! I'm not sure I understand what you're saying. Lemme try rephrasing... I don't remember the numbers so these are just examples. Say I just leveled off my "getting to know your unstructor really well" rent-a-can and the engine is spinning at 1800 RPM with an EGT of like 1200F. I go to lean the mix and wind up with a max of maybe 1875 RPM and 1350F. Now I start FURTHER leaning the mix until the RPM drops back down to 1800 (assuming the engine will support the lean burn). I'm saying that, since peak EGT coincides with peak power / RPM, yes, the EGT will DROP for the given amount of power regardless of the overly lean mix. Now, I haven't tested that scenrio in an airplane before which is an easy, controlled test. I don't fly anymore so I can't go out and try it. Am I now about your scenario of identical power output? -Saro | ||
| Sarodude |
Blake- I take back my statement I realized WAY after the fact. I was somewhere between the computer room and the bathroom when the above scenrio properly drew itself out in my head. I was THINKING that the EGT will drop from the max RPM achieved with the peak EGT. Wasn't thinking about what I was saying. Like you say, I suspect EGT, given identical power output in the above scenario, will be higher with the leaner than ideal (not stoichio) mix rather than the richer than ideal mix. I still hold to the issue of peak EGT generally gets you peak power. -Saro | ||
| Court |
>>>I take back my statement Saro: No can do, the "law of the internet". You are allowed to make misstatements and, more commonly the case, make afool of oneself, but we observe the doctrine of retroactive essoppel...once you said it, we hereby claim license to beat you up in perpetuity.  | ||
| Anonymous |
BenM2, A situation where the O2 sensor offers better adaptation? There is one described in the story from Imonabuss...actually a pretty good one. If you can't understand it, then you need to learn more about both types of systems. Nope, the XB does not meet ULEV numbers. I meant fantastic in its ranking among motorcycles. How do I know? It's my business to know. What does being a v-twin have to do with emissions numbers? If you were in the business you would know. Let me start you on the path of one of several reasons. Piston diameter. No advantage in emissions over a Ducati, is that what you are asking? Well, we'll see if the '04 Ducatis pass California without catalyst. I doubt it. And ask anyone, including journalists, which system runs more flawlessly. Regarding catalysts, no, I don't like them. Why use one when you don't need one? Why? 1) Extra parts and welds in the muffler - complexity and weight; 2) Serious issue if you run anything other than unleaded, MUCH more of an issue than just replacing an O2 sensor; 3)Poor function on short trips until warm, which is exactly the oppoite of the advantage that air-cooled motors have over water-cooled...basically poor results in bag 1 of emissions tests; 4) Putting the use of nasty heavy metals into industry, and then into the dumps...I know, it'll only be a problem for our grandkids...why worry?; 5) Heat issues with catalysts. So, are catalysts the end of the world? No. Are they examples of wonderful flawless technology? No. Is a vehicle that makes the same emissions numbers without a catalyst a better piece of engineering than one that has a catalyst? IMHO, absolutely. | ||
| Davegess |
Good point anon, with catalysts we are mining heavy metals, a pretty nasty business at best and often a seriously dirty business to improve air quality. We certainly see better air in LA but is it at the cost of serious ground water pollution in South Africa? Don't think that answer is well known or even much asked. Second, what happens to all those heavy metal in the landfills in 100 years? We have never done it so we don't know. I do know that the best landfill practices 50 years ago resulted in all sorts of nasty chemicals making it into our water. We have fixed that but are today.s best practices good for long range storage of the crap in used up catalysts? Will we find in 50 years that platinum is migrating into the air from old landfills? We don't know. Plus less parts is better than more parts on general principle. | ||
| Featheredfiend |
To the original question: Will an XB owner have to remove the DDFI system in his or her quest to attain 100rwh? Feathered | ||
| Bud |
Yea, lets stick to the tread  Why are we looking for > 100 rwp on the XB ?? -Is it to go faster ??? Eeeeh, i shout have bought a hayabusa or a vfr SP2 Faster then 210 km/h it would not go, you have to gear it first & put a streamline on the XB, -Is it for the mind friking ¼ mile numbers ??? Eeeeh, i shout have bought a V-max ( 165 hp one ) or a boss hoss V8 or a W3 ( only I wish ) The wheel base of the XB is’t mend fore dragracing , you can always put a nice 100 lb front wheel on , ore put some lead in the exhaust. Why are we always looking to make things bigger & faster ???? Psychology 101, I can’t even drive my bike ( racekit only ) at his limits yet!! This will come very soon , I’m learning every day ! I didn’t had any super bike or racing type off bike or even a bike that corners well before I bought the XB. Hell, no one told me a new rear tyre made so much difference But don’t get me wrong, I’m eager to join the HP ratrace But , first I would like to see a clean cut solution for the DDFI on a 1200 Xb and leaving it a DDFI ! Remember, no race solution that you have to tinker before every ride Other wise ill stick to a nice poorting/head job and maybe some higher compression piston’s Just my 2 eurocent’s Fore now , let’s ride Gr, martin | ||
| Rick_A |
You guys want tips look at what the racers have been doing with DDFI...bigger injectors, dual injectors, ported throttle bodies, flowed manifolds, add on programmable modules (or unobtanum "factory" modules), etc. It probably sounds easy 'till you get down to doin' it, though. | ||
| Benm2 |
That situation is a leaky intake valve. How bad is it leaking? Let's say it's not leaking badly enough to cause a rough-running condition or back-firing (through the throttle body). That would mean its a minor leak, on one cylinder. Combustion pressure's approach 2000psi, so even a small leak during the combustion cycle would blow a significant charge back into the airbox. Lets say, that at that time the mixture left in the intake port is not ready to ingite. (good thing) Then, why wouldn't the feed-forward devices (MAP or MAF) be able to detect the change in average intake pressure or intake flow? Also, on a closed-loop system, the O2 sensor is usually after the exhausts are manifolded together, where the impact of a single cylinder having a valve problem would be diluted. I think on the Buell's, its by the head, but there's still only one? In that case, if the leaky inlet valve were on the cylinder without the o2 sensor, what would find the condition then?
Are you going to post your resume? Neither am I.
Perhaps I was unclear. I wasn't saying that the Ducati offered an emissions advantage, just that ducati's have been praised by journalists for having good fuel injection systems. As have various Japanese manufacturers. I haven't seen written text that says the Buell has better injection that a 999, or an R1. If you have, tell me where, I'd be interested to read it. If you have inside knowledge from personal conversations, then I've got to take your word. Also, the ducati's DO have a catalyst.
Like a fish to bait. The new R6 has a catalyst in its muffler, and it weighs less than last years. There's a cutaway of it in RRW, possibly one extra weld. In a typical chambered muffler, there are connector pipes between the chambers. One of those pipes could be filled with a small foil-type catalyst without any additional welding. Or, the discs of a supertrapp muffler could be coated with catalytic material. (Imagine that, an aftermarket performance accessory that REDUCES emissions) And, if you want to run leaded race fuel (if you don't give a crap about heavy metals and their impact on the environment ) on a closed-loop machine, how does the system perform once you cripple its feedback device? On a catalyst equipped vehicle, you run a race pipe. Also, how long does it take for exhaust to warm up the catalyst? Is it any longer than the use of the cold-start enrichment circuit takes to cut out? What are the hazardous heavy metals? Mercury, Arsenic, Lead. Know anyone with a lead wedding ring? Also, how nasty are the refining processes for copper? Or aluminum? Lastly heat. Exhaust is already hot, a catalyst won't get that much hotter unless there's something wrong with the engine (like a bad O2 sensor). Yes, then they can get very hot. Typically, though exhausts systems are already designed to accomodate exhaust gas temperatures.
A catalyst equipped vehicle can meet the same emissions numbers with a more generous fuel curve, and less compromises in engine dynamics to get there. Also, during acceleration & cold running conditions, there will be better emissions performance from the catalyst equipped vehicle. | ||
| Featheredfiend |
To the original question: Will an XB owner have to remove the DDFI system in his or her quest to attain 100rwh? I know I'm repeating myself. It's not all old age. Is everyone satisfied with just a fast microprocessor? Feathered | ||
| Blake |
Feathered, Remove the DDFI system? From what I understand, no. But you may need to add and map an augmentation module like a PCIII. Bummer that. Ben, Race fuel is leaded?! I had no idea. Whether the R6's muffler is lighter than last year's or not, catalytic converters are pretty darn heavy, at least the ones I've held in my hand. I suspect that last year's R6 also included a converter in its muffler. As to the quality of the Buell EFI, I've not seen any other bike's fuel injection lauded as much as the Buell XB's. To quote Cycle World in their evaluation of the new Ducati 749... A friend of mine mounted an aftermarket slip-on on his ZX12R. The bike would not hold a steady idle. Other examples of quirky and finicky current model moto EFI systems abound. You do make a valid point about the O2 sensor only monitoring the one cylinder. | ||
| Benm2 |
Was that sarcasm, Blake? Might need an emoticon to know for sure. Some race fuels with lead in them: http://www.kemcooil.com/racing_fuel.php http://www.nutecdivision.com http://www.vpracingfuels.com/vp_01_fuels.html?mgiToken=D031D8023CF6B191FD#leaded It is also available as an additive. The standard company lines about the evils of catalytic converters are well rehearsed. Automotive manufacturers have been practicing for years. However, they have led to great reductions in emissions from cars, starting before fuel injection systems were in widespread use. They do NOT have to be terrible things, they serve a purpose just as fuel injection does. Your friend with the zx12, that was after the slip on? Does the XB handle a slip on (without ECM) better? Topic? Oh yeah. I wondered if a downdraft carb (like Keihein's, or mikuni's, or a Holley 2-bbl) might work. They'd need a new manifold, though. If such a carb could be made to work, would it represent a cheaper upgrade than a new ecm? | ||
| Blake |
heheh, No not being sarcastic. I had no idea that race gas contained lead. That's frightening, speaking as a corner worker who spent last Sunday inhaling copious amounts of racebike fumes. WTF! Yes, my friend's ZX12R would not idle smoothly immediately after installation of the slip-on. Upon swapping mufflers, it would fluctuate rapidly between 800 and 1500 rpm. The reason Dynojet sells so many Power Commander EFI augmentation modules is due to the inability of the open loop EFI systems to properly adapt to the freer flowing exhaust systems so often installed. The Buell XB9's work fine with the addition of a slip-on as far as I've heard. Of course most XB'rs probably install a race ECM too, so it might be difficult to know for sure. |
