Does size matter?
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but a 40 vs 80 that's not fair ..
I think David means you have to run the hz out (higher shift point) to get the same "go" vs. the hd-t.
I'm going to jump on the "show me 2 real motors" band wagon... I imagine that a brand new, fancy common rail with twin turbos and a 3" exhaust might be able to outperform an old, bad compression 2H that is twice the size. Maybe.
But 3x size with similar power at similar rpms? I'm dubious. Unless the large motor is de-tuned to the point of being absurd and the smaller motor is running 30 or 40 psi through god-knows what sort of forced induction with fancy propane injection and magic unicorns galavanting in the exhaust, helping reduce unwanted power-robbing vortices while a team of small, imaginary smurf-like gnomes fart HOH gas into your intake.
If that latter is, in fact, the case... then I guess all bets are off.
I'm going to jump on the "show me 2 real motors" band wagon... I imagine that a brand new, fancy common rail with twin turbos and a 3" exhaust might be able to outperform an old, bad compression 2H that is twice the size. Maybe.
But 3x size with similar power at similar rpms? I'm dubious. Unless the large motor is de-tuned to the point of being absurd and the smaller motor is running 30 or 40 psi through god-knows what sort of forced induction with fancy propane injection and magic unicorns galavanting in the exhaust, helping reduce unwanted power-robbing vortices while a team of small, imaginary smurf-like gnomes fart HOH gas into your intake.
If that latter is, in fact, the case... then I guess all bets are off.
A 2l vs 6l comparison is rather ludicrous.
If you were to compare say 3 litre to 4 litre it would be a lot more meaningful.
To get the same torque from a 2 litre as a 6 requires three times the air density. That's a lot of boost.
How about 3.9 litre cummins to 6.2 litre chev?
If you were to compare say 3 litre to 4 litre it would be a lot more meaningful.
To get the same torque from a 2 litre as a 6 requires three times the air density. That's a lot of boost.
How about 3.9 litre cummins to 6.2 litre chev?
Ok, trying to keep the spirit of the OP's question. I decided to try and find two different motors with displacements around 2.0L and 6.0L that produced similar power. I used as my benchmark of power, the 2003 6.0L Powerstroke TurboDiesel V8 offered in the Ford Super Duty F-series trucks, E-series Vans, and Excursion SUVs. Next I took a look at another Ford engine for the sake of comparison. The Ford Duratorq 2.0L I4 Turbo Diesel from a 2003 Ford C-Max. This engine is based on the Peugeot DW10 Diesel. Anyway, I do not have at what RPM these engines produce their power/torque figures at and the actual power/torque curves of the engines, so I'll just post up some basic info for you.
Ford Powerstroke 6.0L (~365 cu. in.) V8 Turbo Diesel
Power: 325 HP (242 kW)
Torque: 570 lb. ft. (773 Nm)
Bore: 3.74 in. (95mm)
Stroke: 4.13 in. (104.9mm)
Ford/Peugeot Duratorq/DW10 2.0L (~120 cu. in.) I4 Turbo Diesel
Power: 134 HP (100 kW)
Torque: 251 lb. ft. (340 Nm)
Bore: 3.3 in. (85mm)
Stroke: 3.5 in. (88mm)
So, once somebody can find me an engine that is 2.0L in displacement and can produce 325 HP and 570 lb. ft. of torque from the factory, I'll continue to think that the argument has no point until then.
Side Note: There's some guys in my unit that own Mitsubishi Eclipses that have tiny 4 pot (gasser) engines with whopping big turbos on them that produce 400 HP and about 350 lb. ft. of torque, but they have to thrash them and get them to produce that kind of power and torque.
EDIT: Alternatively, we could use an older set of engines for comparison, such as a 6.2 non-turbo GM V8 Diesel and something else, don't know what, maybe compare it to modern small diesels to see if there can be some discussion of some sort in this.
EDIT #2: Ok, here's some more info for thought on this subject. 1982 GM 6.2L V8 Non-turbo Diesel as from the factory in 1982.
GM/Detroit Diesel 6.2L (~379 cu. in.) V8
Power: 130 hp (97 kW) @ 3,600 rpm
Torque: 240 lb·ft (325 N·m) @ 2,000 rpm
Bore: 3.98 in. (101mm)
Stroke: 3.80 in. (97mm)
All info regarding engine power, torque, and displacement was copied from Wikipedia at the following URLs.
http://en.wikipedia.org/wiki/Powerstroke_Diesel#6.0
http://en.wikipedia.org/wiki/PSA_EW/DW_engine#DW10
http://en.wikipedia.org/wiki/Detroit_Diesel_V8_engine#Specifications
Ford Powerstroke 6.0L (~365 cu. in.) V8 Turbo Diesel
Power: 325 HP (242 kW)
Torque: 570 lb. ft. (773 Nm)
Bore: 3.74 in. (95mm)
Stroke: 4.13 in. (104.9mm)
Ford/Peugeot Duratorq/DW10 2.0L (~120 cu. in.) I4 Turbo Diesel
Power: 134 HP (100 kW)
Torque: 251 lb. ft. (340 Nm)
Bore: 3.3 in. (85mm)
Stroke: 3.5 in. (88mm)
So, once somebody can find me an engine that is 2.0L in displacement and can produce 325 HP and 570 lb. ft. of torque from the factory, I'll continue to think that the argument has no point until then.
Side Note: There's some guys in my unit that own Mitsubishi Eclipses that have tiny 4 pot (gasser) engines with whopping big turbos on them that produce 400 HP and about 350 lb. ft. of torque, but they have to thrash them and get them to produce that kind of power and torque.
EDIT: Alternatively, we could use an older set of engines for comparison, such as a 6.2 non-turbo GM V8 Diesel and something else, don't know what, maybe compare it to modern small diesels to see if there can be some discussion of some sort in this.
EDIT #2: Ok, here's some more info for thought on this subject. 1982 GM 6.2L V8 Non-turbo Diesel as from the factory in 1982.
GM/Detroit Diesel 6.2L (~379 cu. in.) V8
Power: 130 hp (97 kW) @ 3,600 rpm
Torque: 240 lb·ft (325 N·m) @ 2,000 rpm
Bore: 3.98 in. (101mm)
Stroke: 3.80 in. (97mm)
All info regarding engine power, torque, and displacement was copied from Wikipedia at the following URLs.
http://en.wikipedia.org/wiki/Powerstroke_Diesel#6.0
http://en.wikipedia.org/wiki/PSA_EW/DW_engine#DW10
http://en.wikipedia.org/wiki/Detroit_Diesel_V8_engine#Specifications
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2L-TE from Toyota. EFI, Turbo, SOHC.
2.4L (2446cc)
97HP (72.3kW) at 3800 RPM
torque 24.54 kg.m (240.3 Nm) at 2400 RPM
bore 92 mm
stroke 92 mm.
Redline 4800 RPM.
Compression ratio is 21.0 : 1
Or
the Toyota 2AD-FTV (brand new Common rail, turbo, intercooled)
2.2 liters
134 HP (100kW) @ 3600rpm
310Nm @ 2000rpm
That second motor is pretty close to the 1982 GM 6.2l listed above. In fact, the only difference appears to be just a hair lower torque (15 NM) but 4 extra ponies.
So.... I guess that we do have a 2.2 liter that can put out numbers that are almost the exact same as a 6.2l, at the same RPM even. Which boggles my mind and shows an impressive lack of efficiency in the 6.2l motor.
The more I read it, the more surprised I get.
Toyota L engine - Wikipedia, the free encyclopedia
Toyota diesels finally NZ-bound | Stuff.co.nz
2.4L (2446cc)
97HP (72.3kW) at 3800 RPM
torque 24.54 kg.m (240.3 Nm) at 2400 RPM
bore 92 mm
stroke 92 mm.
Redline 4800 RPM.
Compression ratio is 21.0 : 1
Or
the Toyota 2AD-FTV (brand new Common rail, turbo, intercooled)
2.2 liters
134 HP (100kW) @ 3600rpm
310Nm @ 2000rpm
That second motor is pretty close to the 1982 GM 6.2l listed above. In fact, the only difference appears to be just a hair lower torque (15 NM) but 4 extra ponies.
So.... I guess that we do have a 2.2 liter that can put out numbers that are almost the exact same as a 6.2l, at the same RPM even. Which boggles my mind and shows an impressive lack of efficiency in the 6.2l motor.
The more I read it, the more surprised I get.
Toyota L engine - Wikipedia, the free encyclopedia
Toyota diesels finally NZ-bound | Stuff.co.nz
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Well done. It only took you guys a few days to shoot holes in my emphatic statement that there's no way a 2.0L and 6.0L could make the same numbers at the same rpms.
That'll teach me to make emphatic assertions....
Ok, so now that you have found some excellent examples for comparison, it's time to discuss the OP's questions regarding the effects of the engine weight and rotating mass on drive-ability.
Don't have any facts, but that won't stop me from guessing there's a 400lb difference in weight between the motors. The differences in a low compression NA motor and a turboed motor will have a accelleration effect that's bound to create a different driving feel, and the rotating mass would probably have an effect, tho' hard to measure.
I'm amazed at what is possible through forced air induction and engine design/tuning, but technological advancements are not what I'm seeking when I sit in the drivers seat. What puts me in the seat is the torque down low and the short shifting through the gears. That tractor feel is what makes it easy to off road.
Rick
It only takes a Formula One 2.4L V8/10/12 19,000 RPMS to make 750 horsepower 
and yes I know they are naturally aspirated...
and yes I know they are naturally aspirated...
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OK, For the sake of argument consider the BMW 123d engine. It's probably the most high performance small displacement diesel available from the factory. It is a common rail direct injection, computer controlled, sequential turbo engine that produces about 200 horses and almost 300 foot pounds of torque by 2200 RPM. It's not a monster but it highlights the argument well.
The efficiency of the smaller, modern engine will be a whole lot better, but then again the older bigger engine has a "nominal" max. power which could be used for thousands of hours whereas the smaller has a "peak" max. hp which will melt after a couple of hours.
The torque curve from below idle up to the max. torque speed will be a lot fatter on the big engine as well, which will give the nice truckish feel.
It only takes a Formula One 2.4L V8/10/12 19,000 RPMS to make 750 horsepower
Yes and it only takes one race for it to need a complete overhaul.
A top drag engine is done in under a minute.
And even then they quite regularly blow up before that. They only put enough metal into them to last the race, or, in the case of a drag car, squeeze the most amount of power out of it, an inch away from its life.
That's one thing you guys should be looking at when thinking that smaller and lighter is better.
Big, heavy lumbering diesels are designed to last and to be reliable, and they are.
It's not that one or the other is better, the question is "better for what?".
well,
i would have to disagree here with the old 3B moving the BJ60 down the road and returning better fuel milage than a HJ61 with direct injection.
a small diesel in a small vehicle MIGHT return better fuel milage than a big engine. but stick a small engine into a big vehicle and it will be hard to accomplish. usually the small engine requires lower gearing to move the bigger vehicle ... which makes the small engine rev higher which reduces fuel milage.
usually.
i would have to disagree here with the old 3B moving the BJ60 down the road and returning better fuel milage than a HJ61 with direct injection.
a small diesel in a small vehicle MIGHT return better fuel milage than a big engine. but stick a small engine into a big vehicle and it will be hard to accomplish. usually the small engine requires lower gearing to move the bigger vehicle ... which makes the small engine rev higher which reduces fuel milage.
usually.
I'm still reeling from the 2.2=6.2 information
WAG: the larger, lumbering beast is going to outlast the little guy. It just seems like it must, right? As for efficiency, I'm inclined to believe that the smaller motor is more efficient because it is super-tuned to get the numbers it gets, and there is simply less mass moving round to waste energy through friction.
but in a 3rd world environment, there is no question in my mind that I'd rather have a de-tuned vehicle with longevity.
Besides, the 6.2 is a poor example in that it would be trivial to add a turbo, adjust fueling, ad an IC, and probably gain a lot without major engineering.
As for drivability: the rotating mass of the motor itself is probably mirrored by a much larger flywheel, which is going to perform better at slow n low. I've driven a prado around here several times that should have numbers that are higher than my 2H on both torque and HP. but the 2H lumbers through stuff and in the prado you've got to downshift and rev it up to prevent stalling.
Man, I sure would like to drive 2 different 60 series: 1 w/ the little 2.2 and one with the 6.2 to see just how they are different in the real world. I want *everything* identical except the motor (but imagine that isn't possible).
fun to imagine
OP: great post. I thought it was stupid at first blush, but you've got at least 6 brains engaged, which is better than most posts (unless they involve boobs or tires)
WAG: the larger, lumbering beast is going to outlast the little guy. It just seems like it must, right? As for efficiency, I'm inclined to believe that the smaller motor is more efficient because it is super-tuned to get the numbers it gets, and there is simply less mass moving round to waste energy through friction.
but in a 3rd world environment, there is no question in my mind that I'd rather have a de-tuned vehicle with longevity.
Besides, the 6.2 is a poor example in that it would be trivial to add a turbo, adjust fueling, ad an IC, and probably gain a lot without major engineering.
As for drivability: the rotating mass of the motor itself is probably mirrored by a much larger flywheel, which is going to perform better at slow n low. I've driven a prado around here several times that should have numbers that are higher than my 2H on both torque and HP. but the 2H lumbers through stuff and in the prado you've got to downshift and rev it up to prevent stalling.
Man, I sure would like to drive 2 different 60 series: 1 w/ the little 2.2 and one with the 6.2 to see just how they are different in the real world. I want *everything* identical except the motor (but imagine that isn't possible).
fun to imagine
OP: great post. I thought it was stupid at first blush, but you've got at least 6 brains engaged, which is better than most posts (unless they involve boobs or tires)
Swap that ford/PSA diesel for a VW 2.0 TDI. They come in two tunes, the lower output one has 105kw around 4200rpm and have a flat 320Nm from 1750-2500rpm.
These engines with the variable vane turbos pull better than anything else at low rpm. The couple I drove last month would pull strongly from 1200rpm.
It's also the most efficient small diesel on the planet, at 196 g/kwh it's over 20% more efficient than a 12HT.
Given that a 12HT probably has a similar gain on the old chev 6.2 it's pretty clear which one is going to suck the planet dry.
VW sell these engines as industrial powerplants (albeit detuned), so longevity/reliability is beyond question. Where the chev 6.2 has a terrible reputation. Keep the oil, change the motor.
Volkswagen Industriemotoren: TDI 2.0 - 474 ND
http://www.vw-industrial-engines.co...nload/public/en/Datasheets/en_TDI_2-0_4XX.pdf
Having worked on said Chev 6.2 diesels, I can attest to them having reliability problems as from the factory in early models, but later models are just as reliable as anything else on the road as you can get. I just pulled the 6.2 numbers out because I realized how little power and torque they produced compared to other diesels and even power/displacement ratio was pretty low and could compare power and torque wise to modern diesels. Reliability of initial models wasn't part of the OP's hypothetical question.
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Ok, now we can use the 2.2L 4 cylinder TD Toyota and the 6.2L NA GM diesel motor to test the OP's hypothesis.
First item:
Probably not 750lbs in weight difference. Anyone with this info? Significant weight changes in either direction will require a revisit of the brakes, suspension (and headlight aim). While lighter is probably easier to work with, this is a consideration that impacts the scope and budget of a conversion. More on this next.
Second item:
Not so fast! Physical size and characteristics matters and clearance around the firewall, front axle and radiator often dictates which motor gets the nod.
The acquisition/fabrication/conversion work and expense for adaption to the tranny or drivetrain/chassis dictates (for me) the choice of which motor is used in the conversion. Do you want a $12,000 conversion, or a $2000 conversion?
Third item:
With identical gearing and tires, we are now in position to ponder the effects of the differences in the curves and breadth of the power band (torque curve), and the rotating mass effects.
I'm not of the opinion they would be similar, and I cannot ignore the effects of cost, availability and ease of installation when it comes to making a choice.
My conclusion is that yes, size does matter.
Rick
no doubt that the brand new Toyota wundermotor is going to cost a large amount more than an 82 chevy!
I don't have any direct experience with them, but reading others experiences makes me want to run the other way:
6.2/.5 chevy. what are they really like ? - Cummins 4BT & Diesel Conversions Forums