This is why todays four cylinders have those high 11-12:1 compressions. It is so they can run that alcohol gas. When they used to build Alky outboards in the old days from regular engines, they would build it so that the piston would be barely shy of hitting the head for compression. They would then use big fuel lines and large size jets to flow the more viscous alcohol/castor-oil mix. And they used a lot of fuel in one heat!! The alcohol burns cooler and burns cleaner and more completely. That is why they make that amazing Pro class power. The downside is that they guzzle the heck out of it. A pure alcohol engine car would be a dream to the corn industry because drivers would have to use a lot of it. We couldn't afford to go anywhere much then at all except to work and the store. Now lower compression car motors don't run that good off of it. My Mercury Mark 20 outboard actually likes ethanol gas!! But I have a few antique outboards of lesser compression I just collected that don't run well on ethanol as they do pure gas actually.
New souped up cars that look like toasters on four wheels, big Tonka Toy looking trucks with 390-405hp, and ethanol gas!!!! YIKES!!!!! SOMEBODY IS AFTER SOMBODIES MONEY!!!!!!
..."This is why todays four cylinders have those high 11-12:1 compressions. It is so they can run that alcohol gas"
Direct fuel injection into the cylinder is why modern engines can run such high compression ratios (like my Focus with its 12:1). The octant rating of 87 octane fuel--with or without ethanol--is the same.
As my late and sorely missed buddy explained, the advantage of direct injection is charge cooling. Port injection wastes the cooling effect of the vaporized gas by cooling the metal parts; direct injection cools the gas/ air charge itself, dramatically lowering pre-ignition tendencies. And the low end torque these motors make is truly impressive!
Jeff
direct injection is all about controlled combustion and keeping fuel away from any surface.
HC and NoX emissions
I cant see any relationship to increased CR?
It has only been useful since they have massive injection pressure, did anyone ever use it on unlimited race engines?
( ok dirt track alcohol)
..."...keeping fuel away from any surface."
That's why it cools the charge so well, reducing pre-ignition, and allowing such high CRs on 87 octane fuel. (By the way, I wisely paid for the full warrantee on my Focus with its 2,000psi injector system!) RACE engines on RACE fuel were limited to about 11:1 ratios a few decades ago.
The dirt track cars (like Outlaws) now use direct injection, possibly to allow even higher CRs.
Jeff
I agree with Jeff on the extra cooling effects of the charge, but more so the fuel is only injected at the perfect time not allowing the charge to over-compress and pre-ignite, there's a reason these systems run such high PSI ratings. Fuel management has advanced more in the last 10-15 years than it had in the prior 100 years. And yes whether it's reg unld or oxygenated 87octane is 87 octane both fuels will support the same engines.
And to Ron the mileage drop on the sticker would have been going from Reg 87 Octane fuel whether it's oxygenated or not (doesn't matter) to running E-85, as E-85 is about 20% less efficient.
From my understanding why alky's evolved to methanol in the early days and upped compression ratios and different timing is because a couple of properties allowed increased horsepower with that fuel over gasoline without damaging the engines. The two factors are that methanol itself cools the engine allowing for increased compression without the tendency to stick pistons. The main thing I think though is that methanol burns much slower. Compared to methanol, gasoline is a flash in the pan. Methanol burns much slower than gasoline so methanol is still burning and expanding while the piston is moving forward and continues to do so while driving the piston back on the downstroke. Compared to that, gasoline is "poof" and gone. And because of the cooling effect and slow burn, you run a bigger carbueretor, more fuel, and more air and get lots of cooling fuel into the combustion chamber. Nitro burns even slower than methanol, hence even more power, but it has a corrosive effect on motor parts. You have to do a lot of experimentation with altered heads and timing to run a methanol nitro mix, and even the experts blow a lot of engines while leading a race.
Yes those are two of the big reasons as to why Alcohol can make more power among other are oxygen is a byproduct of burning alcohol so it get a better burn, and it's also a lot easier to compress an alcohol charge than a gasoline charge, so it robs less hp to keep running.
And even though in a standard motor setup pure Ethanol would be about 30% less efficient, but if burned at it's preferred AFR it creates almost 20% more energy and Methanol more than that.
What I don't get is that it doesn't matter what form of motorsport it is all these guys that are forever tinkering or working on there stuff, complain so much about having to do a little more maintenance (and I mean a little) to not have problems with fuel. It's kinda like the fuel injection war all over again, all the ols school guys bitched and complained about it non stop knowing damn well it was better than carbs. All the while the new generation of gearheads ended up leaps and bounds ahead. It's the same as computer controlled management systems guys hated it, and again the new generation was leaps and bounds ahead.
I am by no way stating this is the best fuel out there, but it's what we have and soon it will be the only fuel out there. So instead of bitching about so much learn/figure out how to make it work for you.
Gotta 'fess up and admit that I--repeat I--was one of those stick-in-the-mud geezers who resented EFI and injection. Long as I don't have to mess with it, I think it's grand!
Jeff
PS: If some terrorist (or that fool Putin) detonates an electromagnetic pulse bomb over our country, only engines with (gasp!) breaker points will still run! And I don't have a single one of them!
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