Port injection is superior to direct injection because it can start dumping fuel before the intake valves open, Prove me wrong.
Carburetors are superior to fuel injection because the atomized fuel in the intake tract has an evaporative cooling effect, which lowers intake charge temperatures and lets you make more power.
>>28746329whats stopping direct injection from spraying before the valve opens?
>>28746329Horses are better than cars because you can refuel at the side of the road whenever you want
>>28746337horses have to graze basically all day to keep their energy up, if you want to use them for anything you have to feed them something more nutritious than grass
>>28746336was about to ask this myself
>>28746334*Citation needed.
>>28746350https://en.wikipedia.org/wiki/Carburetor_icingPressure drop in the venturi + fuel evaporating using the heat of the surrounding air = colder intake charge. This is why carbs make more power than EFI for the same CFM, colder air = denser air so more air/fuel mixture can get crammed into the cylinders.It's also why draw-through carbs work so well with a Roots blower, the evaporative cooling means you don't need a big bulky intercooler brick on your intake.
>>28746349>>28746336it would mostly get sucked out the exhaust, as there is a period called overlap when both intake and exhaust valves are open when you would want the injectors to be spraying fuel.
>>28746361*and, not as
>>28746361Depends on cam profile, some have high lift but short duration and lobe separation angle, they tend to make a tonne of power down low but don't make for a revvy engine.t. boomer
>>28746365that has nothing to do with what we're talking about.
>>28746329>bolting train turbo on carI wish I had the excess cash to fuck around like this.
>>28746369It defines how much valve overlap there is if any.
>>28746329DI makes more power though.It raises dynamic compression since fuel is added to the chamber while the compression stroke is happening.
>>28746371yeah i guess i worded that poorly. the main issue is that it will just get all thrown out the exhaust due to the exhaust valve being open at the very least right up to the point of the intake valve opening, and usually several degrees after. you will waste a lot of fuel spraying before the exhaust valve closes so DI engines generally have to wait until it's fully closed before they start spraying which is further delayed by overlap.
>>28746380Makes sense, I think DI would give less time and turbulence for air fuel mix too. But somehow they are squeezing more power out of smaller enginers.
>>28746329Thats a fake pic.I can tell because the turbonetics lettering is distorted.
>>28746390could be compression ratios, leaded petrol saw engines with very high compression ratios, once that got banned they dropped down to around 9 or so. we seem to have figured things out with unleaded because now we see engines floating around 10, sometimes much higher. but they usually call for midgrade fuel at a minimum
>>28746334>>28746359Lmao you could just put a venturi in the intake of a fuel injected car and spray the fuel there.Nobody does this because it doesn't actually increase power.
>>28746359>This is why carbs make more power than EFI for the same CFMThis has never in the entirety of automotive history happened
>>28746408People designing engines for f1 or other performance applications could run over 18 to one ratios or more if rules didn't stop them, using stratified charges, pre-ignition chambers, spark controlled compression ignition, and other methods of operation. Mazda uses some of these techniques under the 'skyactiv' label in their engines, which can run around 14-16 to 1 ratios (or ~10 to 1 with ~20 pounds of boost - dependent on the total cylinder pressures/enthalpy gain), which in turns allows the use of very lean air fuel ratios (conventional wisdom is that 'lean' means 'hot' because fuel can act as a coolant due to lower static temperature and heat loss from the phase change of liquid to gas; but if you *keep* going even leaner, the curve turns to cool again, because the total heat released by combustion will continue getting lower to the point where that becomes the dominant factor).
>>28746506I think normally you get lean missfires if you try to run too lean, but maybe that's negated by the massive cylinder pressures you're talking about.
>>28746449Anon......Thats called "throttle bidy injection" (TBI).
>>28746820(TBI doesn't make more power)(they don't add a magical venturi to it to magically make more power because that doesn't actually make more power)
>>28746839Correct.
>>28746334>the atomized fuel in the intake tract has an evaporative cooling effectWhat the fuck do you think injectors do, retard?
>>28747102the effect is not instant
>>28746359Horseshit. What you propose (sucking the heat out of the intake pipe) means you're increasing the heat of your fuel-air charge (which you want cold) even more. You're heat-soaking the fuel, which increases the risk of detonation, meaning you can't run as much compression ratio and you have to use much more conservative timing.Don't take it from my mouth, look at what automakers actually put on the road - we didn't push past 10:1 ratios until port injection, and turbo engines didn't break 10:1 until direct injection.>draw-through carbs>Roots blower>the evaporative cooling means you don't need a big bulky intercooler brick on your intake.Boomer tech which no one apart from boomer drag racers actually uses. >colder air = denser airBoomer lore. You can always cram more air with more boost and high-flow intakes; you need to drop the air temps to delay knock. Due to the compression ratio, every extra degree of starting temperature of the fuel-air charge gets multiplied / amplified into a much more severe increase in temperature at top dead center.To begin with, the problem which you linked exists in general aviation aircraft, which use severely outdated Lyco/Continental engines, and they continue to use them because general aviation is a dead market serviced by 40-year-old airframes flown by "8 BALLS OF BROWNING TWO WORLD WARS!!!" boomers.The issue was entirely eliminated already in WW2 aircraft, which flew with MECHANICAL INJECTION.Carburetors are toys for geriatric manchildren who feel existentially threatened by the existence of semiconductors, and discussing old-ass float-types has no place in the quest for power.
>>28746613Part of it is greater heat from higher levels of boost/compression making leaner ignition easier, another part is that these really high compression engines use basically a quasi-diesel cycle style of operation (don't remember the technical term off the top of my head) by having a sub-critical amount of fuel vaporised in the main charge, and at a moment just prior to the downstroke a second charge of fuel is injected near the spark plug or in a special pre-chamber, creating a localized fuel rich zone which ignites, which in turn releases enough energy to ignite the rest of the charge too.https://www.youtube.com/watch?v=mUq-K9jcaB8
>>28747278hcci, homogenous-charge compression ignitionmix of both petrol and diesel engines
>>28746329Fake but it has Dragon Fire vibes
>>28747442that's in the ballpark yes, but none of these are running 'pure' hcci, hence i was thinking of a different term
>>28747278Wow ok so they DO have to put a lot of effort into getting it to fire right
>>28747233And you think the effect from a carburetor a few inches further away, when the air is moving thousands of inches per second, is meaningfully greater?
>>28747650think in terms of percentages not raw figures. if a few inches is double the distance then it'll be twice as effective which would be very meaningful.
>>28746359Carbs work well with a Roots style blower because it isn't compressing and heating the air.
>>28747656> if a few inches is double the distance then it'll be twice as effective which would be very meaningfulThat means fuckall if it's barely doing anything in the first place. 200% of next-to-nothing is next-to-nothing.
>>28747674actually anon it's twice as far away from nothing.
>>28747693
