In reply to A 401 CJ :
The USMC's Light Armored Vehicles are powered by Detroit 6v53Ts . The sound they make is Glorious...
In reply to A 401 CJ :
The USMC's Light Armored Vehicles are powered by Detroit 6v53Ts . The sound they make is Glorious...
In reply to RossD :
They had 3 and 4 cyl. Detroits too. My grandfather had a 4 swapped into a small GMC dump truck, I wish I'd been able to hold onto it.
In reply to Wally :
I believe the Detroit-equipped GMC dump trucks are the ones that spawned the nickname "Screaming Jimmy".
Well, the thing about 2 strokes is you get twice as many power "pulses" per revolution. But everybody knows that. And likely the torque number 485? is high compared to the hp number 285? because they just aren't spinning it very fast. So yeah, with 2X the power pulses it's got some twist.
I rode in an old International Fleetstar with a Detroit 2-stroke up through Boonville Gorge with a loaded flatbed trailer. God, what a soundtrack, that thing howling out the stacks.
Recon1342 said:In reply to Wally :
I believe the Detroit-equipped GMC dump trucks are the ones that spawned the nickname "Screaming Jimmy".
I've passed some old GMC car carriers that would peel your ears back.
In reply to A 401 CJ :
Diesels have always had skewed HP to Torque numbers... Even the 4 strokes. A Cummins 4bt can make a whopping 190 HP and put out 450 lbft of torque.
I love two strokes because they sound cooler...
NickD said:I rode in an old International Fleetstar with a Detroit 2-stroke up through Boonville Gorge with a loaded flatbed trailer. God, what a soundtrack, that thing howling out the stacks.
Howling is an apt description. I helped pull and test a Detroit 6v53t out of an LAV, and the sound was unearthly. It was unmuffled and on a test stand. Sounded like the meanest weed-eater in the history of ever...
STM317 said:I doubt the 2.7 could be laid down really easily and still fit between shock towers. They've got 2 crankshafts instead of just one in the center like a Subie engine. It's pretty tall in the current layout The reason it's leaned over is because of the height when the cylinders were perfectly vertical. They had to lean it over to fit into normal truck engine bays.
But there is some precedent for the tech in a flat layout. Their big engine is laid flat, and has a central bell housing. Perhaps scaling something like this down:
Couldn't help but notice at 2:34 he mentions that Achates (those making OP's 2.7) were the ones who tested a single cylinder (twin piston?) version of the Advanced Combat Engine. Maybe one is licensing the tech from the other?
Recon1342 said:In reply to A 401 CJ :
Diesels have always had skewed HP to Torque numbers... Even the 4 strokes. A Cummins 4bt can make a whopping 190 HP and put out 450 lbft of torque.
I love two strokes because they sound cooler...
But the Achates is gasoline and makes diesel numbers as well, (270hp/480lb-ft) largely due to the 2-stroke factor, I'm guessing.
In reply to NickD :
Not quite as extreme, but my 2.7L gas f150 makes 325hp and 400ft-lbs... And that's just a regular old 4 stroke gas engine (with DI and turbos)
Seems like an interesting concept, but what's the advantage of having more pistons instead of just running a higher static compression ratio? Mazda's HCCI engine comes to mind.
Recon1342 said:In reply to A 401 CJ :
Diesels have always had skewed HP to Torque numbers... Even the 4 strokes. A Cummins 4bt can make a whopping 190 HP and put out 450 lbft of torque.
I love two strokes because they sound cooler...
Sorry but it's not "skewed". It's just maths. It makes 190 hp at a relatively low rpm. That translates to a high torque number.
Once upon a time, when I was a skull full of mush beginning engineer, they took me onto the floor at USSteel Gary Works. There was a GE motor there built in 1918. 300 hp. So what? 300 hp at 18 (eighteen) rpm. That's hideous torque. It was a 3 story tall machine. That got me thinking...how much torque would 1 hp at 1 rpm be? I once did the calculation and don't feel like doing it again but it's a LOT! Sorry for the rant. I don't know much really but the relationship between hp and torque is one I never get tired of babbling on about :-)
morello159 said:In reply to NickD :
Not quite as extreme, but my 2.7L gas f150 makes 325hp and 400ft-lbs... And that's just a regular old 4 stroke gas engine (with DI and turbos)
Seems like an interesting concept, but what's the advantage of having more pistons instead of just running a higher static compression ratio? Mazda's HCCI engine comes to mind.
The advantage is less moving parts. Because it's two-stroke with an opposing-piston design, you can toss the entire valvetrain out. No timing chains, cam actuators, rocker arms, valves, valve springs, etc. The other advantage, and I have no clue how true this bit is, this is just what they are claiming, is that it supposedly will get 47mpg.
A 401 CJ said:Recon1342 said:In reply to A 401 CJ :
Diesels have always had skewed HP to Torque numbers... Even the 4 strokes. A Cummins 4bt can make a whopping 190 HP and put out 450 lbft of torque.
I love two strokes because they sound cooler...
Sorry but it's not "skewed". It's just maths. It makes 190 hp at a relatively low rpm. That translates to a high torque number.
Once upon a time, when I was a skull full of mush beginning engineer, they took me onto the floor at USSteel Gary Works. There was a GE motor there built in 1918. 300 hp. So what? 300 hp at 18 (eighteen) rpm. That's hideous torque. It was a 3 story tall machine. That got me thinking...how much torque would 1 hp at 1 rpm be? I once did the calculation and don't feel like doing it again but it's a LOT! Sorry for the rant. I don't know much really but the relationship between hp and torque is one I never get tired of babbling on about :-)
300hp at 18rpm is 87,533ft-lbs of torque!
300hp at 1,575,600ft-lbs!!
That's why you have those old "10hp" steam tractors that can pull a huge plow setup. That's because that 10hp cames at a ridiculously low rpm, meaning tons of torque.
RossD said:In reply to A 401 CJ :
There is a 2-71 for sale locally. I didnt know there were less than 6 cylinders.
Inline models included one, two, three, four and six cylinders, and the V-types six, eight, 12, 16 and 24 cylinders. And they sound sooo good!
Sk1dmark said:Couldn't help but notice at 2:34 he mentions that Achates (those making OP's 2.7) were the ones who tested a single cylinder (twin piston?) version of the Advanced Combat Engine. Maybe one is licensing the tech from the other?
Yes, that's why I posted that link. The ACE engine is a joint effort between Cummins and Achates. Compared to a small startup like Achates, Cummins has the funding, engineering prowess, manufacturing scale, and existing ties with the Military to actually bring the thing to fruition.
There's also a lot of familiarity among the VIPs of the two companies as well. Achates CEO is a former Cummins exec. And so is their Chairman of the Board. So if the claims are true, and the tech has merit, perhaps something like this 2.7, or another opposed piston engine, would wear Cummins badging if it made it to market?
In reply to NickD :
yes. You gots it.
And a gearbox will "make" all the torque you want. Which is why 10 spd > 8 spd >> 3 spd.
Back when I only had 3 speeds plus an overdrive I NEEDED a 7.3 Stroke or a Cummins. Nowdays not so much. 10 spds and a 3.5 twin turbo gasser (or 5.0 NA) will do the same work.
In reply to A 401 CJ :
It can also work the other way too. Make the same torque at higher rpm and you get a boatload of horsepower. Make 500lb-ft at 5000rpm and you have 475hp. Bump that same 500lb-ft up to 7500rpm and suddenly you have 714hp
NickD said:morello159 said:In reply to NickD :
Not quite as extreme, but my 2.7L gas f150 makes 325hp and 400ft-lbs... And that's just a regular old 4 stroke gas engine (with DI and turbos)
Seems like an interesting concept, but what's the advantage of having more pistons instead of just running a higher static compression ratio? Mazda's HCCI engine comes to mind.
The advantage is less moving parts. Because it's two-stroke with an opposing-piston design, you can toss the entire valvetrain out. No timing chains, cam actuators, rocker arms, valves, valve springs, etc. The other advantage, and I have no clue how true this bit is, this is just what they are claiming, is that it supposedly will get 47mpg.
I think the most interesting thing about it, will be finding out if they can meet their power and fuel efficiency claims after somehow cleaning up a two stroke enough to meet modern emissions standards.
STM317 said:NickD said:morello159 said:In reply to NickD :
Not quite as extreme, but my 2.7L gas f150 makes 325hp and 400ft-lbs... And that's just a regular old 4 stroke gas engine (with DI and turbos)
Seems like an interesting concept, but what's the advantage of having more pistons instead of just running a higher static compression ratio? Mazda's HCCI engine comes to mind.
The advantage is less moving parts. Because it's two-stroke with an opposing-piston design, you can toss the entire valvetrain out. No timing chains, cam actuators, rocker arms, valves, valve springs, etc. The other advantage, and I have no clue how true this bit is, this is just what they are claiming, is that it supposedly will get 47mpg.
I think the most interesting thing about it, will be finding out if they can meet their power and fuel efficiency claims after somehow cleaning up a two stroke enough to meet modern emissions standards.
That, and I feel like NVH might be a bit of a struggle for them too. The prototypes they have running are pretty rowdy sounding. That'll be okay in fleet sales, where all they care about is power and fuel mileage, or for truck guys who think it sounds awesome, but plop one in an Explorer or Tahoe and sell it to the average person and they'll gripe up a storm.
Also, I wonder how they are managing oil. Oil-metering pump, like a rotary or a snowmobile? Will you be able to hammer into John Q Public that they have to frequently check the oil?
I really hope they pull it off, because the numbers and overall logic are pretty darn compelling. I'd buy one just for the novelty factor, let alone the power and promised mileage.
There's been talk of the Detroit Sound but no examples, so here's some guys having fun turning fuel into noise with a 16V71 warning it is kind of long https://m.youtube.com/watch?v=JxLb3Yqqds4
STM317 said:NickD said:morello159 said:In reply to NickD :
Not quite as extreme, but my 2.7L gas f150 makes 325hp and 400ft-lbs... And that's just a regular old 4 stroke gas engine (with DI and turbos)
Seems like an interesting concept, but what's the advantage of having more pistons instead of just running a higher static compression ratio? Mazda's HCCI engine comes to mind.
The advantage is less moving parts. Because it's two-stroke with an opposing-piston design, you can toss the entire valvetrain out. No timing chains, cam actuators, rocker arms, valves, valve springs, etc. The other advantage, and I have no clue how true this bit is, this is just what they are claiming, is that it supposedly will get 47mpg.
I think the most interesting thing about it, will be finding out if they can meet their power and fuel efficiency claims after somehow cleaning up a two stroke enough to meet modern emissions standards.
I'm just spitballing- i've never played with 2-strokes before- BUT...
Tossing out all the valvetrain means we only have rotational losses from driving the two cranks and the supercharger, and being twincharged it's constantly under boost for scavenging. Since each drop of fuel goes to pushing two pistons and the supercharger likely shuts off when the turbo comes on, I think the whole "50% more efficient" is totally believable.
With it constantly under boost you feasibly have constant air being pushed into the exhaust while it's still hot, which would allow any hydrocarbons to burn to CO2 similar to old EGR air pumps. The REAL question tho, is how the heck the drivetrain is being lubricated without putting oil into the gas unless A. it's a 2-stroke diesel or B. It's using E85 only, which CAN be a lubricant. I wonder if that EGR it points to is really some kind thermal reactor like on an old Mazda.
We had a pair of 12 cylinder inline FM's vertically opposed in our ship. Neat stuff- turbo and supercharged, inter and aftercooled. Very interested to work on/with.
The CG is just finally getting rid of those ships now, but the dudes in the Phillipine Navy will have fun trying to keep them running!
So I'm going to be real honest and say I had no idea that vertically opposed engines existed until this thread started. I've just spent the better part of the last two days researching the Detroit 6v53t and, holy e36m3, I want that engine in everything. I don't care how heavy or unwieldy it is. It sounds magical.
penultimeta said:I've just spent the better part of the last two days researching the Detroit 6v53t and, holy e36m3, I want that engine in everything. I don't care how heavy or unwieldy it is. It sounds magical.
There was a rat rod/T-bucket running around on the internet with a 6V53T for a while. As I recall, I think it might have had a twin-stick transmission too. Watching those guys drive the old rigs with a Detroit and a twin-stick and 2-speed rearend is mighty impressive. There is always something going on.
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