Hastings units Class 201 to 207 : 500hp to 600hp ?

[Justin Smith]

Apologies if this has been asked on here before, Google didn't bring it up if it has !

Various sources from Wiki to my old Ian Allan spotter books quote 500hp for the Class 201 to 203s, and 600hp for the 204 to 207s. But the same engine is quoted (an EE 4SRKT MkII, i.e. they all had 4 valve heads) and the power is quoted at the same rpm, i.e. 850rpm. One source on the net said the increase in power was just down to a change in turbochargers, is that really right ?
Can anyone explain exactly how just changing the turbo type could give such a big increase in power, and at the same rpm ?

 

[hexagon789]

Apologies if this has been asked on here before, Google didn't bring it up if it has !

Various sources from Wiki to my old Ian Allan spotter books quote 500hp for the Class 201 to 203s, and 600hp for the 204 to 207s. But the same engine is quoted (an EE 4SRKT MkII, i.e. they all had 4 valve heads) and the power is quoted at the same rpm, i.e. 850rpm. One source on the net said the increase in power was just down to a change in turbochargers, is that really right ?
Can anyone explain exactly how just changing the turbo type could give such a big increase in power, and at the same rpm ?

The driving instructions describe it as a 'larger pressure charger'.

 

[30907]

I don't know the technicalities, but the Hampshire units were provided with 500hp engines when built, but then extended from 2 to 3 cars, at which point AIUI engines were swapped with the 600hp version in the Hastings units.

 

[Gloster]

According to Southern DEMUs by Michael Welch (Capital, 2005), although this is from the preamble by John Atkinson, the original Napier MS100 turbocharger was exchanged for an MS200 and the fuel delivery system was modified. Some of original engines from the Hampshire units were swapped with ones from late-build Hastings sets to speed up the process.

 

[30907]

According to Southern DEMUs by Michael Welch (Capital, 2005), although this is from the preamble by John Atkinson, the original Napier MS100 turbocharger was exchanged for an MS200 and the fuel delivery system was modified. Some of original engines from the Hampshire units were swapped with ones from late-build Hastings sets to speed up the process.

Thanks. That sounds a plausible technical explanation of the garbled version I'd read many years ago.

 

[Magdalia]

I am not an engineer, and my understanding of this is numerical and chemical.

Internal combustion is hydrocarbon fuel and oxygen combusting in the cylinders.

The turbocharger forces oxygen into the cylinder under pressure. A more efficient turbocharger forces in more oxygen. This means that more fuel can also be injected into the cylinder to match the increased amount of oxygen. More fuel and more oxygen gives a bigger bang in the cylinders which is transmitted to more horse power at the crankshaft, even tough the rpm has not changed.

 

[Cowley]

I am not an engineer, and my understanding of this is numerical and chemical.

Internal combustion is hydrocarbon fuel and oxygen combusting in the cylinders.

The turbocharger forces oxygen into the cylinder under pressure. A more efficient turbocharger forces in more oxygen. This means that more fuel can also be injected into the cylinder to match the increased amount of oxygen. More fuel and more oxygen gives a bigger bang in the cylinders which is transmitted to more horse power at the crankshaft, even tough the rpm has not changed.

I think that’s a very well written and coherent summary @Magdalia.

 

[Justin Smith]

I am not an engineer, and my understanding of this is numerical and chemical.

Internal combustion is hydrocarbon fuel and oxygen combusting in the cylinders.

The turbocharger forces oxygen into the cylinder under pressure. A more efficient turbocharger forces in more oxygen. This means that more fuel can also be injected into the cylinder to match the increased amount of oxygen. More fuel and more oxygen gives a bigger bang in the cylinders which is transmitted to more horse power at the crankshaft, even tough the rpm has not changed.

Well yes, but to go from 500hp to 600hp (at the same revs) just by changing the turbo (remember the 500hp version has a turbo as well) seems a very big jump ! It would be interesting to know if the torque went up by the same amount and at the same revs, plus if the bigger blower meant more turbo lag (or some other negative) ?
Are either intercooled ?

 

[Cowley]

Well yes, but to go from 500hp to 600hp (at the same revs) just by changing the turbo (remember the 500hp version has a turbo as well) seems a very big jump ! It would be interesting to know if the torque went up by the same amount and at the same revs, plus if the bigger blower meant more turbo lag (or some other negative) ?
Are either intercooled ?

Pretty sure none of those engines are intercooled. They’d have a ‘C’ for Charge cooled in the engine name if they did. I think the 37 was the first UK EE loco with an intercooler and they came along a couple of years later.

 

[ac6000cw]

Well yes, but to go from 500hp to 600hp (at the same revs) just by changing the turbo (remember the 500hp version has a turbo as well) seems a very big jump ! It would be interesting to know if the torque went up by the same amount and at the same revs, plus if the bigger blower meant more turbo lag (or some other negative) ?
Are either intercooled ?

It's a 20% increase in power, which doesn't sound unreasonable for presumably a significant increase in turbo pressure/airflow. The torque must increase if the power increases at the same RPM - it's basic physics: work = force x distance, power = work/time. At the same RPM, the distance per unit time is unchanged, so the force (torque) must increase to increase the power.

(As a comparison, in the 1970s/80s, EMD sold basically the same loco using a V16 645-series engine - the GP38-2 had the blown (supercharged) version rated at 2000hp, the GP40-2 had the turbo version rated at 3000hp. Over its roughly 15 year development life the turbo version went from 3000hp @ 900rpm to 3600hp @ 950rpm, a 20% increase).

 

[Gloster]

British Rail Fleet Survey:9 (Haresnape, Ian Allan, 1986) does say that the new turbocharger was larger than the original one.

 

[Justin Smith]

It's a 20% increase in power, which doesn't sound unreasonable for presumably a significant increase in turbo pressure/airflow. The torque must increase if the power increases at the same RPM - it's basic physics: work = force x distance, power = work/time. At the same RPM, the distance per unit time is unchanged, so the force (torque) must increase to increase the power.

(As a comparison, in the 1970s/80s, EMD sold basically the same loco using a V16 645-series engine - the GP38-2 had the blown (supercharged) version rated at 2000hp, the GP40-2 had the turbo version rated at 3000hp. Over its roughly 15 year development life the turbo version went from 3000hp @ 900rpm to 3600hp @ 950rpm, a 20% increase).

20% higher power at the same rpm seems like a lot to me if they really did just put a bigger turbo on it !

 

[matchmaker]

Any turbocharged internal combustion engine will produce more power with a larger turbo and altered fuelling. I'm more au fait with petrol engines in cars, but (for example) the 2 litre petrol Audi/VW/Skoda EA888 engine can have power boosted by well over 20% just by altering the amount of boost pressure from the turbo and altering the amount of fuel injected. This is simply done by "remapping" the engine ECU via a computer link. No mechanical changes needed. There are plenty of similar examples including plenty of diesel engines, even "old school" ones like the venerable VW PD130 unit which was as basic a diesel engine as you got nearly 25 years ago.

 

[43096]

It's a 20% increase in power, which doesn't sound unreasonable for presumably a significant increase in turbo pressure/airflow. The torque must increase if the power increases at the same RPM - it's basic physics: work = force x distance, power = work/time. At the same RPM, the distance per unit time is unchanged, so the force (torque) must increase to increase the power.

(As a comparison, in the 1970s/80s, EMD sold basically the same loco using a V16 645-series engine - the GP38-2 had the blown (supercharged) version rated at 2000hp, the GP40-2 had the turbo version rated at 3000hp. Over its roughly 15 year development life the turbo version went from 3000hp @ 900rpm to 3600hp @ 950rpm, a 20% increase).

British Rail Fleet Survey:9 (Haresnape, Ian Allan, 1986) does say that the new turbocharger was larger than the original one.

The Hastings Diesels website has photos of both the turbo for the 500hp engine (Napier MS100) and the 600hp version (Napier MS200). Further down there is more information mon the two turbo types.

Turbocharger:	Napier MS100 (5psi) (Napier MS200 (8psi) on Hampshire/Oxted units)
Engine rating at 850rpm:	500 horsepower (600 horsepower with Napier MS200 turbocharger)

From: https://www.hastingsdiesels.co.uk/1001/#technical

 

[Magdalia]

I'm more au fait with petrol engines in cars, but (for example) the 2 litre petrol Audi/VW/Skoda EA888 engine can have power boosted by well over 20% just by altering the amount of boost pressure from the turbo and altering the amount of fuel injected.

Isn't that what boy racers did to their Ford Capris half a century ago?

 

[matchmaker]

Isn't that what boy racers did to their Ford Capris half a century ago?

Not really. Forced induction (turbocharged) engines are far easier to extract more power from than naturally aspirated (non turboed) engines. To get more power 50 years ago needed a lot of modifications for a relatively small increase in power. Very few turbocharged car engines back then!

 

[Nicholas Lewis]

Any turbocharged internal combustion engine will produce more power with a larger turbo and altered fuelling. I'm more au fait with petrol engines in cars, but (for example) the 2 litre petrol Audi/VW/Skoda EA888 engine can have power boosted by well over 20% just by altering the amount of boost pressure from the turbo and altering the amount of fuel injected. This is simply done by "remapping" the engine ECU via a computer link. No mechanical changes needed. There are plenty of similar examples including plenty of diesel engines, even "old school" ones like the venerable VW PD130 unit which was as basic a diesel engine as you got nearly 25 years ago.

Apart from you put a lot more thermal energy into the engine and overstress it if you don't beef up the cooling system by probably adding separate oil cooler.

 

[Harpo]

Back to EE vee engines - Their V16 made fairly huge strides in output over a couple of decades.

 

[Magdalia]

Back to EE vee engines - Their V16 made fairly huge strides in output over a couple of decades.

mainly by adding turbochargers and then intercoolers?

 

[Bikeman78]

I had never really thought about the turbochargers on the Thumpers before. Is it the whistling sound that can be heard on the engine room video below around 1m 50 and 2m 30? I take it the whining sound is the generator? That is the main sound that can be heard from the passenger saloon.

 

[Justin Smith]

Not really. Forced induction (turbocharged) engines are far easier to extract more power from than naturally aspirated (non turboed) engines. To get more power 50 years ago needed a lot of modifications for a relatively small increase in power. Very few turbocharged car engines back then!

It's all a compromise though isn't it ? It's very rare you get something for nothing, other than possibly by using a free flow exhaust (in the days when exhaust systems were restrictive) and/or gas flowing the head. Pretty much everything else will have a downside, e.g. making the engine more "peaky" or increasing the turbo lag, and that's before you get to lowering its reliability / longevity.

The Hastings Diesels website has photos of both the turbo for the 500hp engine (Napier MS100) and the 600hp version (Napier MS200). Further down there is more information mon the two turbo types.

Turbocharger:	Napier MS100 (5psi) (Napier MS200 (8psi) on Hampshire/Oxted units)
Engine rating at 850rpm:	500 horsepower (600 horsepower with Napier MS200 turbocharger)

From: https://www.hastingsdiesels.co.uk/1001/#technical

Excellent info.

 

[Snow1964]

20% higher power at the same rpm seems like a lot to me if they really did just put a bigger turbo on it !

The mark 1 variants in 1940s weren't turbocharged, adding the turbocharger added around 60% to power. Increasing the pressure makes gases hotter, so if they are then cooled (by using intercooler) get even more power.

In a high pressure intercooled version can get something like 2.5 times the power of non turbo version of same size at same engine revs.

Modern injectors can create better fuel mist so output goes even higher. By modern standards they would be deemed big slow engines.

 

[ac6000cw]

It's all a compromise though isn't it ? It's very rare you get something for nothing, other than possibly by using a free flow exhaust (in the days when exhaust systems were restrictive) and/or gas flowing the head. Pretty much everything else will have a downside, e.g. making the engine more "peaky" or increasing the turbo lag, and that's before you get to lowering its reliability / longevity.

Of course - engineering design almost always is (having been doing it for over 40 years).

But the modern turbo-charged engines in cars can be really nice to drive (having owned a Saab 93 1.8t for a long time and currently two cars with Suzuki 'BoosterJet' engines). The Suzuki engines in particular are lovely - very drivable at low/medium revs and powerful at high revs, with good fuel economy.

The Hastings Diesels website has photos of both the turbo for the 500hp engine (Napier MS100) and the 600hp version (Napier MS200). Further down there is more information mon the two turbo types.

Turbocharger:	Napier MS100 (5psi) (Napier MS200 (8psi) on Hampshire/Oxted units)
Engine rating at 850rpm:	500 horsepower (600 horsepower with Napier MS200 turbocharger)

Thanks for the info - so 60% more boost pressure with the larger turbo.

I had never really thought about the turbochargers on the Thumpers before. Is it the whistling sound that can be heard on the engine room video below around 1m 50 and 2m 30? I take it the whining sound is the generator? That is the main sound that can be heard from the passenger saloon.

Yes, almost certainly - the build up and decay of the whistling noise lagging behind the change in engine revs is a bit of a giveaway - that's the 'turbo lag' that people talk about. That also contributes to the amount of exhaust 'clag' that old diesel locos produce when opened up - until the turbo speeds up and pumps enough air (oxygen) in, more fuel is being injected than the oxygen in the cylinders can fully combust, producing sooty particles and partly burnt/unburnt fuel in the exhaust. Modern diesel engines control the fuel injection much more precisely to minimise the issue and keep within emissions rules. Old US Alco diesel locos were notorious for the amount of black 'clag' they could produce in that situation...

 

[Strathclyder]

Yes, almost certainly - the build up and decay of the whistling noise lagging behind the change in engine revs is a bit of a giveaway - that's the 'turbo lag' that people talk about. That also contributes to the amount of exhaust 'clag' that old diesel locos produce when opened up - until the turbo speeds up and pumps enough air (oxygen) in, more fuel is being injected than the oxygen in the cylinders can fully combust, producing sooty particles and partly burnt/unburnt fuel in the exhaust. Modern diesel engines control the fuel injection much more precisely to minimise the issue and keep within emissions rules. Old US Alco diesel locos were notorious for the amount of black 'clag' they could produce in that situation...

And when the turbo packs up or isn't functioning as it should, the same black 'clag'/smoke is emitted more or less continuously under power with an array of rather ghastly noises as the backing track. See this vid of 47368 at Leyland from October 1990 (from the Hughesy YT channel) as an example, complete with spitting flames.

Or this one of 56067 at Burton Salmon from June 1993 (from the same channel). The turbo in this one definitely seems to be on the way out or otherwise broken in some way (the classes' distinctive turbo scream is still audible when it passes the camera tho), as I've never heard any other 56 make that kind of 'chirping' noise - or see one continuously throw out those bursts of black clag - under power; clearly a major component was broken, breaking or about to break.

 

[Bikeman78]

Modern injectors can create better fuel mist so output goes even higher. By modern standards they would be deemed big slow engines.

They are undeniably big slow engines. The Thumpers never felt like they were in a rush. The engine sounded the same slogging up a bank at 20 mph or whizzing along at 75 mph.

Yes, almost certainly - the build up and decay of the whistling noise lagging behind the change in engine revs is a bit of a giveaway - that's the 'turbo lag' that people talk about. That also contributes to the amount of exhaust 'clag' that old diesel locos produce when opened up - until the turbo speeds up and pumps enough air (oxygen) in, more fuel is being injected than the oxygen in the cylinders can fully combust, producing sooty particles and partly burnt/unburnt fuel in the exhaust. Modern diesel engines control the fuel injection much more precisely to minimise the issue and keep within emissions rules. Old US Alco diesel locos were notorious for the amount of black 'clag' they could produce in that

Thanks. To be fair, my recollection is that the exhaust was usually pretty clear.

 

[43096]

Modern diesel engines control the fuel injection much more precisely to minimise the issue and keep within emissions rules.

I assume that also applies to older engines retro-fitted with modern fuel injection kit - I’m thinking of things like GE’s “Advantage” mods for the 7FDL engine.

Old US Alco diesel locos were notorious for the amount of black 'clag' they could produce in that situation...

Nothing wrong with a bit of clag!

 

[Cowley]

And when the turbo packs up or isn't functioning as it should, the same black 'clag'/smoke is emitted more or less continuously under power with an array of rather ghastly noises as the backing track. See this vid of 47368 at Leyland from October 1990 (from the Hughesy YT channel) as an example, complete with spitting flames.

Or this one of 56067 at Burton Salmon from June 1993 (from the same channel). The turbo in this one definitely seems to be on the way out or otherwise broken in some way (the classes' distinctive turbo scream is still audible when it passes the camera tho), as I've never heard any other 56 make that kind of 'chirping' noise - or see one continuously throw out those bursts of black clag - under power; clearly a major component was broken, breaking or about to break.

Those are very interesting clips. On a modern turbo, if they fail they can start blowing the engine oil out, I wonder if that’s about to happen with those two?

 

[Justin Smith]

They are undeniably big slow engines. The Thumpers never felt like they were in a rush. The engine sounded the same slogging up a bank at 20 mph or whizzing along at 75 mph.

Which is why they'll still be running decades after these modern "efficient" engines have all gone to the scrapyard in the sky !

The mark 1 variants in 1940s weren't turbocharged, adding the turbocharger added around 60% to power. Increasing the pressure makes gases hotter, so if they are then cooled (by using intercooler) get even more power.

In a high pressure intercooled version can get something like 2.5 times the power of non turbo version of same size at same engine revs.

Modern injectors can create better fuel mist so output goes even higher. By modern standards they would be deemed big slow engines.

I could understand the power increase much more easily had the 600hp version been intercooled, 500hp to 600hp is plus 20% power !
As far as I can remember the Sulzer 264 litre 12cyl double bank engine went like this :

12LDA28-A (non intercooled) (Class 44) = 2300hp at 750rpm
12LDA28-B (intercooled) (Class 45) = 2500hp at 750rpm (plus 9% power)
12LDA28-C (intercooled) (Class 47 original spec) = 2750hp at 800rpm (plus 10% power)

12LDA28-A to 12LDA28-C (i.e. intercooled and higher revs) is plus 20% more power

 

[Strathclyder]

Nothing wrong with a bit of clag!

A 'bit of clag' is Alco code for 'turning day into night and letting slip the gods of war every time you notch her up'. Not a bad thing obviously lol

Those are very interesting clips. On a modern turbo, if they fail they can start blowing the engine oil out, I wonder if that’s about to happen with those two?

It wouldn't surprise me if it was about to happen when they were caught on camera there, or had already happened. The 47 in particular sounds really unhealthy, easily the worst-sounding one I've ever heard.

And no, all you Duff detractors out there, they didn't all sound like that lol

A healthy one for the sake of comparison:

 

[matchmaker]

Which is why they'll still be running decades after these modern "efficient" engines have all gone to the scrapyard in the sky !


I could understand the power increase much more easily had the 600hp version been intercooled, 500hp to 600hp is plus 20% power !
As far as I can remember the Sulzer 264 litre 12cyl double bank engine went like this :

12LDA28-A (non intercooled) (Class 44) = 2300hp at 750rpm
12LDA28-B (intercooled) (Class 45) = 2500hp at 750rpm (plus 9% power)
12LDA28-C (intercooled) (Class 47 original spec) = 2750hp at 800rpm (plus 10% power)

12LDA28-A to 12LDA28-C (i.e. intercooled and higher revs) is plus 20% more power

Anothere good example is the EE V12. The 12SVT (1470bhp) in the 31s isn't intercooled. The 12CSVT (1750bhp) in the 37s is. I think I read that the 12CSVT could produce 2000bhp but was kept at 1750bhp for economy/reliability/longevity reasons.