RADRick said:
Yesterday you were speaking of forum fairness, today you can't wait to try and catch me in something.
You took a shot at Motometal accusing him of not understanding the basis of a statement he made and I'm just following in the same line of discussion, hopefully with the same condescending tone you used.;)
RADRick said:
I didn't need Google to know what stoichemetry (not stoichiometry) is. Some won't notice the subtle difference in spelling and think you rightly caught me with my pants down. Nice try.
RADRick said:
As used, stoichemetry refers to the ratio of fuel to air for proper combustion in an ICE.
The correct term in combustion chemistry, is
stoichiometry, most often referred to as the stoichiometric ratio, or the chemically correct ratio between air and a specific fuel. Obviously the chemically correct ratio will vary based on the fuel's make up.
Honestly I've never seen the word
stoichemetry used in any automotive engineering paper or text, I've never seen it in thermal fluid engineering texts, or thermochemical enginering texts. That said, I'm sure there are tons of words I've never heard of given my lack of formal education. Common usage in engineering circles is
stoichiometry. ;)
Spelling and usage differences aside I think we can agree on the point you were trying to make with the word:
the exact amount of fuel for the available air to achieve complete combustion.
I also don't appreciate the obvious reference to my Cuban heritage. Was that supposed to be a slur?
I didn't know you were Cuban, and never gave it a minutes thought.
I think Ricky Riccardo is funny when he says that and I say it to people all the time when they same something that I think is silly or misguided. If it offended you I can say with all sincerity that it was unintentional. Anyone who knows me or has read my posts over the years can verify that kind of crap just isn't my style.
The main point is that with a race bike so finely tuned to achieve perfect stoichemetry, hard hot restarts are a lot more likely, particularly when changes in ambient air temp or barometric pressure occur during the race.
DING DING DING, that's where you are completely full of #@*% . (that WAS intended to offend ;) )
Four-stroke race engines make best power in the .82 -.87 Lambda range, or something in the neighborhood of 12-13:1 air fuel ratio. Even at part throttle and light loads (low manifold pressure) you rarely see the air fuel ratios above 13.6 or so with a carb and 13.9 is a common lean upper limit with EFI on a street/race type engine. So even plunking through the pits you are running well to the rich side of chemically correct.
Chemically correct ratios in the 14.2 -14.7 air fuel ratio range (depending on fuel makeup) , make nice numbers on an exhaust gas analyzer, and show good thermal efficiency numbers which translate into good gas mileage but you are unlikely to ever encounter
stoichiometry in a properly tuned race engine. Even in your computer controlled street car you will usually only see part of the time. Usually at light loads like in highway cruising or steady state partial throttle running. The air/fuel numbers at WOT are often times as rich as 10-11:1.
I don't expect you to take my word for it, so if you'd like to see real world lambda numbers I've pulled from my race engines using data acquisition systems and O2 sensors I'll be happy to share.
Hard starting during the course of a RACE has far more to do with anxiety, bad technique due to anxiety (throttle pumping, short stabbing the kickstarter, not using the hot start lever etc), and after a crash fuel puddling in the port takes time to clear. It's not really specific to the specific output of the engine or the tuning.
Race fuels designed for high rpm four-strokes tend to have narrow range low temp distillation curves. While this is great for throttle response and power at 13,000 rpm, it makes an engine intolerant of raw fuel puddling in the intake tract from a crash, or a rider accidently pumping the throttle during a hot restart.
This is true on stock CRF250s as well as 65 horsepower big bores. All my highly tuned race engines are 1-2 kick starters hot or cold in the pits or anywhere else when you take your time and don't rush. The problem is most never take the time (and I include myself even though I certainly know better) , and they hurry to not lose a position on the track and just end up prolonging the agony.
Riders on two-strokes do the same stupid things, the difference is most 2-T engines are just more tolerant of our doofus behavior due to their basic design and lack of an accelerator pump in the carb.
Four-stroke engines even when highly modified aren't so sensitive as to be influenced by small changes in air density or temperature. If an engine DOES get the bends everytime the air temp changes 5 degrees, it's a sure bet someone screwed up the cam timing in some horrific way at TDC and totally compromised the scavening.
There is a name for engines like this
S L O W . Front runners in pro races aren't likely to be saddled with half-assed designs like this. Density altitude (DA) numbers have to change fairly significantly before starting is affected, and thats ONLY if the tuning isn't changed to compensate for it. No tuner worth the name gets surprised by huge DA swings to the point that his bike won't start.
The secondary point is that TV announcers make more of an issue about it than what is experienced by the average rider.
On that point we agree, generic TV commentators tend to be pretty clueless.
Did I pass your test? :whoa:
It's not a test and I really couldn't care less if you know the difference between a fuel's stoichiometric ratio and best power lambda ratios that are actually present in race engines.
The point is you want fair treatment and yet you go and take a shot at a member, essentially calling him a TV parrot, and then hack the guts out of a concept you clearly have little understanding of to try and prop up your wobbly point.
Make your point without the BS and no one will chime in. Float up that weak ass pseudo science BS and someone will call you out everytime. There are lots of DRN members way smarter than me, so you should be glad none of them decided to rip you a new one. :p