Diesel Power Increase

[Jim@sea]

I have a 72hp Iveco Inboard Diesel. I want to increase the power. I cant fit a Turbo. In the good old days when I messed about tuning cars to provide more BHP I would fit a "sports Camshaft" Double the carbs from one to two, balance the crank, fit racing valve springs, swap the head to a bigger valve one with polished ports. Balance the flywheel, etc.
There must be some improvement I can do. Somebody suggested a slightly bigger propeller as the one fitted might be a compromise propeller as what the boat manufactures dont want is a too large propeller so that on tick over the boat is doing 4 knots.

 

[RAI]

What is the maximum rpm you get on full power? My guess is that if it is over 3000 a different propeller might be able to absorb some more power. If not the prop is probably taking it all.

 

[rafiki_]

With some attention, you might be able to increase fuel pump pressures, and injector volumes, but this is only relatively simple if Iveco have a spec in place.

The best option is to fit a turbo, but again this will need a different pump and injectors.

Neither of these are easy options.

 

[Bassplayer]

Talk to Lancing Marine, they are usually very helpfull and are about the best for Ford engines. Simply increasing fueling won't help power - you'll just make it smoke. You will probably do better looking at the prop sizes.

 

[PaulGooch]

To get any worthwhile increase in horsepower and retain reliability you're probably best changing the engine for one with a turbo.

 

[ulyden]

You can turbocharge any engine! Even a fiat. But if you dont have the space or other things you can tune a diesel in the same way like a petrol.

Its all about air! If you can increase the amout of air flowing thru your engine the power will increase! The best way is to increase the fillig ratio at high speed.

If you can ceep the ratio the same at 4500rpm as at 4000rpm you gain 9hp.
To get that you might need to improve the air intake and the exhaust back pressure! Increase the max speed setting to 5000rpm and increase the amount of fuel untill you get black smoke. Keep the fuel and air as cold as possible!

Running like this will decrease the engine life time but its the only way without turbo! Highest ratio on a 2.5litre natural aspirated diesel in series production is the 2.5litre 20V prechamber mercedes engine! At 5000revs it gave 113hp!

Its easy to se how much power you get! You divide the new (speed/old max spedd)^2.5. Multiply this number with the old power.

Exsample old speed 4000rpm New speed 4150rpm. New power (4150/4000)^2.5 = 1.09*72hp = 79hp!

To be able to know the highest power you need to make a full load curve for your engine! It is possible you get higher output with a smaller propeller!

Its realy easy to turbocharge these engines. Why not?

 

[Andrew_Fanner]

I had always had it as an article of faith that turbo and non turbocharged versions of the same base engine had differently specced conn rods and crankshafts at the very least, even possibly differing between 3 and 5 bearings on the crankshaft, in order to handle the significant power increase. Heads and head bolt settings may be different as well as the compression ratio goes up. Injectors and pump will need different settings to deliver more fuel. You can't just bolt a turbocharger on.

Having said that, I have known many young lads who have replumbed their cars electric blower fan to the engine air intake to blow cold air into the engine and there is a noticeable change when the switch is thrown.

 

[ianj99]

Having said that, I have known many young lads who have replumbed their cars electric blower fan to the engine air intake to blow cold air into the engine and there is a noticeable change when the switch is thrown.

This is exactly what I intend to try once I have refitted the overhauled pump and injectors. I suspect the boat is overpropped and won't pull 3000rpm (max continuous rpm) without smoking.

So using a large surplus bilge blower I will find out quickly whether the 'electric supercharger' principle does work when the rpm increases and smoke decreases, or not as the case may be.

The engine is a Perkins 4108. I suspect there will be some effect on this relatively small, low revving, non turbo engine. We shall see..

I

 

[ulyden]

Tell me were to buy? Approx 2KW of eletrical power vill give aprox 0.1bar boost.

0.1bar (1.5psi) boost give 10% power increase or 3% higher engine speed!

This is requiring a good compressor!

 

[ianj99]

Tell me were to buy? Approx 2KW of eletrical power vill give aprox 0.1bar boost.

0.1bar (1.5psi) boost give 10% power increase or 3% higher engine speed!

This is requiring a good compressor!

Rubbish.

You cannot say 2Kw will give 0.1bar boost without knowing anything about the blower. My paint sprayer's compressor is 2hp (1.5kw) and generates upto
6bar and 6cu ft /min but the cpu cooling fan on my pc flows more air with generating any pressure.

The turbo on a diesel does not rquire 2Kw (almost 3hp) to generate .1bar or this would mean a modern diesel that runs 1.2bar would need 24kw or 70hp just to drive the turbo. Ditto a supercharger.

So the pressure isn't as important as mass airflow. The pressure increases because all of the air is not sucked in and hence the surplus pressurises the intake system. Its still possible to 'assist' the engine breathing and cause more air to be inducted. How much effect this has on a 1.6L nasp diesel I will find out in a few weeks. I'm not expecting much but if there is surplus fuel (as evidenced by black smoke from the exhaust) I may see a slight change.

In fact I measured the air flow of the blower using a 150bhp turbo diesel air mass meter attached (in its original housing) to it and was surprised to get a reading of about 80% of maximum. I will look up the figures for the sensor and blower later.

I

 

[ulyden]

Well you can try it! I calculate it! 1500W vill give 0.1bar boost at 4000rpm!

Compressor efficancy 0.73!

On a large engine the shaft power of the turbo is above 30% of the engine power! So if you have a 3000kw engine and 3bar boost you need 1000KW shaft power to run the compressor! Its the same power if you take it from a eletrical motor ,exhaust turbine or a belt drive!

24kw is 32hp! Pressure is important! Its the mass of air trapped in the cylinder at BDS that is limiting your fuel and power!

Higher density is more air mass!

Try your experiment and see the flow with 0.2bar backpressure!


http://www.grc.nasa.gov/WWW/K-12/airplane/compth.html

 

[ianj99]

Well you can try it! I calculate it! 1500W vill give 0.1bar boost at 4000rpm!

Show us your calculations then!

 

[ulyden]

Compressor power is W

K Air kappa 1.4

M air mass flow 4000rpm 1,2bara press 0.95 vol eff! 0,086 kg/s

Cp Air spes heat 1.05kJ/KG/K

T1 start temp kelvin 300

P2 end pressure

P1 start pressure

e = Compressor efficancy! 0.73

Formula : W= mCpT1/e(P2/P1^(K-1/K))-1)

W= (1/0.73)0,086kg/s*1.05KJ/KgK*300K(1.2bara/1.0bara)^(1.4-1/1.4)-1)= 2.0KW

Remember that when VW introdused the G charger the power consumption was 7 KW.

It had 0.6bar boost on a 1.4litre engine! Polo!

 

[ianj99]

Compressor power is W

K Air kappa 1.4

M air mass flow 4000rpm 1,2bara press 0.95 vol eff! 0,086 kg/s

Cp Air spes heat 1.05kJ/KG/K

T1 start temp kelvin 300

P2 end pressure

P1 start pressure

e = Compressor efficancy! 0.73

Formula : W= mCpT1/e(P2/P1^(K-1/K))-1)

W= (1/0.73)0,086kg/s*1.05KJ/KgK*300K(1.2bara/1.0bara)^(1.4-1/1.4)-1)= 2.0KW

Remember that when VW introdused the G charger the power consumption was 7 KW.

It had 0.6bar boost on a 1.4litre engine! Polo!

It always puzzles me how the companies selling electric superchargers which consume a few amps can provide dyno charts claiming a 10% torque increase.

I did find this company with some interesting products:

http://www.cpowert.com/

Theirs requires 1.8kw for a 1.45 pressure ratio so I won't be expecting too much from a 180w blower.

Now where's my petrol powered 2hp leaf blower... That'll work...

 

[ulyden]

Thanks! I have been locking for a eletric turbocharger for a long time.
I have a to small engine in one of my cars! I have a 2kw generator so i can use 2kw for short periods! The curves on the internet pages is the same as i were calculating. Improoved torque on low speed and a little bit higher max power!

I was tired of all the hits on 180W blowers when i was searching for an el turbo!

 

[grafozz]

interesting thread , now from one of the class , am I to deduce ,then, that cooler , therefore denser air, brought from outside the engine room and boat , via an el. fan will produce more power ?? I,ll sit down now ......

 

[volvopaul]

In order to turbo a standard engine thats not been designed for that purpose, to make it work properly and reliably then the list of mods is endless, so dont bother unless you want say another 20hp from the 75hp engine.

The pistons will hav ethe wrong compression ratio, the crowns will be the wrong shape and piston material.

The camshaft will be the wrong profile, the valves will be the wrong material, especially the exhaust as they run nearly cherry red when boost is applied.

The pistons will overheat unless they have oil piston cooling jets.

The oil cooler, if fitted will need uprating, as you increse the power you also increase the kw output so the heat exchanger may not keep up, the sea water pump may not deliver the right amount of flow.

The crankshaft is usually nitrided after its machining process, so the extra load may knock the big end shells out.......................... shall I go on??

In a word dont bother, just buy an engine thats already done.

 

[ianj99]

In order to turbo a standard engine thats not been designed for that purpose, to make it work properly and reliably then the list of mods is endless, so dont bother unless you want say another 20hp from the 75hp engine.

The pistons will hav ethe wrong compression ratio, the crowns will be the wrong shape and piston material.

The camshaft will be the wrong profile, the valves will be the wrong material, especially the exhaust as they run nearly cherry red when boost is applied.

The pistons will overheat unless they have oil piston cooling jets.

The oil cooler, if fitted will need uprating, as you increse the power you also increase the kw output so the heat exchanger may not keep up, the sea water pump may not deliver the right amount of flow.

The crankshaft is usually nitrided after its machining process, so the extra load may knock the big end shells out.......................... shall I go on??

In a word dont bother, just buy an engine thats already done.

Don't entirely agree if you are willing to accept a modest increase especially since engines tend to be over engineered in the first place.

In fact there was a very successful company in Lancs (TB Turbo) that specialised in turbo charging and intercooling non turbo diesel cars, motorhomes, tractors and commercial vehicles some years ago. They did my 2.5 Fiat engine motorhome in 1995 with no side effects and it certainly made a difference. I was no longer reduced to a hgv driver maddening 30mph on motorway inclines!

4 years ago I fitted a turbo and intercooler to a Citroen Relay 1.9 D camper. Again I had no reliability issues possibly because I never tried to match the factory turbo diesels torque and bhp and also by driving sensibly - ie not flat out.

I'd do the same again to a marine engine (assuming it was in good condition) but again, I'd not try to match the factory turbo version's performance.

I

 

[ulyden]

In order to turbo a standard engine thats not been designed for that purpose, to make it work properly and reliably then the list of mods is endless, so dont bother unless you want say another 20hp from the 75hp engine.

The pistons will hav ethe wrong compression ratio, the crowns will be the wrong shape and piston material.

The camshaft will be the wrong profile, the valves will be the wrong material, especially the exhaust as they run nearly cherry red when boost is applied.

The pistons will overheat unless they have oil piston cooling jets.

The oil cooler, if fitted will need uprating, as you increse the power you also increase the kw output so the heat exchanger may not keep up, the sea water pump may not deliver the right amount of flow.

The crankshaft is usually nitrided after its machining process, so the extra load may knock the big end shells out.......................... shall I go on??

In a word dont bother, just buy an engine thats already done.

Just some comments!

Of course you are right! in principle you don’t know what the engine can take!

Only the guys in charge of calculations can do that!

But the reason why i said this was that in the late 70 IVECO claimed that all their engines could take turbo charging! The 2.5litre have had turbo since early 80. In production lines it’s an good to have most possible common parts!

But anyway! What is the risk? A used automotive engine like this have a cost similar to one common rail nozzle. If you run it with a low boost pressure 0.4bar and increase the amount of fuel 15% the risk is very low!

I have done this my selves! 4 seasons with a boost of 0.7bar on a NA ford 2.5litre! No problem at all!

The only care I take is to run it some minutes at maximum when I’m close to home and in good whether condition. If the engine don’t take it am not in distress. Just needs to by a new block! 500p?

On my current engine i took a original turbo engine 85hp! I increased the nozzles and mounted a turbo similar to VP 31P (130hp) Bowmann intercooler!

No problem. I have a 140hp TDI engine to a cost lower than a couple of nozzles to a D3 engine! (D3 nozzles 850euro each)

http://www.marinepartseurope.com/sv/volvo-penta-sprangskiss-7744550-23-6350.aspx

 

[ulyden]

Denser air

interesting thread , now from one of the class , am I to deduce ,then, that cooler , therefore denser air, brought from outside the engine room and boat , via an el. fan will produce more power ?? I,ll sit down now ......

If you have a diesel engine that is out of air at maximum power and are smoking black the power will increase with denser air!

Normal air has a density like 1.18kg/M^3 at 25deg and 1.013bar pressure!
(Sorry for my SI units)

If you run your engine in a low pressure zone the density is lower!

A bad low pressure is 960mBar. At 25 degree the density is 1.12kg/m^3

This means you loose 5% air! That means 5% less power!

On a good day you have 1040mbar Then the density is 1.215kg/m^3

Then you have 8-9% higher power than on the low pressure day!

If you are out on a cold day and the intake to the engine is 0deg you have a density of 1.29kg/m^3 so now we are talking! 10% increase!

But back to life. Your engine is sucking air from the engine rom. The air is heated form the radiation of the engine! If you don’t have any ventilation you easily get 25deg increase in temperature! Then our density are down to 1.09kg/m^3. Then you loose 9%.

So that means! If you can suck the air to the engine without heating it you gain horsepover! How much depends on how bad it is today!

The ambient pressure is more difficult to control. But it makes a difference!

Just remember tat all old diesels are adjusted to worse case so you don’t se any difference! Some diesels have a compensator for ambient pressure and some newer engines can compensate for everything!