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Old 22-10-2015, 19:44   #16
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Re: YAnmar 3GM30F forced air induction mod

[QUOTE=julius222;1942812]OPINIONS WANTED

Using round/close enough good enough numbers so I can use mental arithmetic for my estimates

Engine is 1 litre (0.954)
RPM 4000 (3600)
therefore need a blower that moves more than 4000 litres per minute. Is this right?

Before you think of modifying your Yanmar, you should realize that it's a 4 stroke engine. Each stroke is the travel of the piston up or down. This means that the intake stroke on each cylinder is every second revolution. That is it's only drawing in air every second revolution or 4 strokes of a single piston / cylinder. So to begin; it's not 4 litres / a minute using your assumption. It's 2 litres / minute.
I certainly wouldn't run my Yanmar at 4000 rpm.
Learn how a diesel works first.
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Old 22-10-2015, 19:44   #17
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Re: YAnmar 3GM30F forced air induction mod

Ok....I have read opinions, leaned and less than learned and will only use the blower to cool the engine area.

I am convinced that adding more air will increase the output therefore reducing fuel consumption. That is basic physics. That is why we buy turbo charged engines.

I am also convinced that taking an engine past its design parameters can only lead to reduced reliability
.
Reliability is far more important than fuel savings.

Thank you to all who took the time to respond seriously to a serious enquiry.

BTW to those who made sarcastic comments for a genuine enquiry...your inferiority complex is showing.
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Old 22-10-2015, 20:03   #18
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Re: YAnmar 3GM30F forced air induction mod

[QUOTE=GrahamHO;1944131]
Quote:
Originally Posted by julius222 View Post
OPINIONS WANTED

Using round/close enough good enough numbers so I can use mental arithmetic for my estimates

Engine is 1 litre (0.954)
RPM 4000 (3600)
therefore need a blower that moves more than 4000 litres per minute. Is this right?

Before you think of modifying your Yanmar, you should realize that it's a 4 stroke engine. Each stroke is the travel of the piston up or down. This means that the intake stroke on each cylinder is every second revolution. That is it's only drawing in air every second revolution or 4 strokes of a single piston / cylinder. So to begin; it's not 4 litres / a minute using your assumption. It's 2 litres / minute.


I certainly wouldn't run my Yanmar at 4000 rpm.
Learn how a diesel works first.
Neither would I and I do know how a diesel works. You mistake that 2 litres per minute is all that is needed. Forced air induction is under discussion. therefore you need more than 2 litres to provide an over pressure, just like the commercial turbos.
But as a theoretical discussion 4000 is as good a number as 5000 or 1000

BTW why the sarcastic and unwaranted agro?? "Learn how a diesel works first" ...No wonder we have "Going Postal" added to the idiom.


Thanks again to all who have responded seriously...

I'm out of this discussion now

Just carry on without me
cheers
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Old 22-10-2015, 20:40   #19
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Re: YAnmar 3GM30F forced air induction mod

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Originally Posted by julius222 View Post
OPINIONS WANTED……...
Quote:
Originally Posted by julius222 View Post

Neither would I and I do know how a diesel works. You mistake that 2 litres per minute is all that is needed. Forced air induction is under discussion. therefore you need more than 2 litres to provide an over pressure, just like the commercial turbos.
But as a theoretical discussion 4000 is as good a number as 5000 or 1000

BTW why the sarcastic and unwaranted agro?? "Learn how a diesel works first" ...No wonder we have "Going Postal" added to the idiom.


Thanks again to all who have responded seriously...

I'm out of this discussion now

Just carry on without me
cheers
Whoa there Julius…
You did ask for opinions and some kind folk have provided them!

Let's revisit your proposal to increase the rated output of your 3GM30F by way of increasing the amount of air induced and lowering it's temperature.

So you get more cold air in than Yanamr designed - what does that do?
It increases compression and the density of the air and as you suggest, more oxygen. But that is all it does!

You can't easily alter the amount of diesel injected as that is set by the injector pump and governor. The "throttle" lever only selects the RPM the governor will attempt to maintain.

So without any extra fuel, no extra power - as others have explained.

As for water injection, don't laugh (although I admit that bilge water was not a serious option). Nevertheless, adding a fine spray of water into the inlet manifold does increase compression and cools the induced air at the same time. So this is a technical and feasible way to increase compression and cool the induced air.

Unfortunately as with your first idea, it won't add power or efficiency unless you wish to modify the injector pump / governor to dump more fuel in to combust with the extra oxygen.
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Old 22-10-2015, 22:50   #20
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Re: YAnmar 3GM30F forced air induction mod

Indeed there are turbo versions of the same basic engines however, there are some crucial internal differences; Remember, your engine will be operating at a heavier sustained load than say, a highway vehicle. Cruising, at highway speeds, is actually a very light load. Your boat has much more drag, thus higher loads for longer periods.
Unlike gas engines, diesels are "compression ignition" engines, very efficient.
The injectors and pumps may well be the same, externally, but they are set up to deliver fuel to the engine quite differently; in some cases they are also equipped with devices to match the fuel delivery to the amount of air being pumped in by the turbo, under varying load conditions, not necessarily commensurate with RPM.
The increased combustion chamber temperatures, generated by turbo engines, often demands additional cooling oil be directed up under the combustion chamber, in the piston crown.
Higher output versions may also employ intake air coolers to control the combustion air temperature.
It is quite common to add a small degree of turbo boost, to diesel engines operating in higher altitudes, without the addition of a lot of these items but, really all they are doing is to compensate for the reduced air density. Essentially, in your case, this is what you'd be doing. It is highly unlikely that your gain would exceed the pain, so to speak. Hope that helps?
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Old 23-10-2015, 00:11   #21
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Re: YAnmar 3GM30F forced air induction mod

We are on the same page! It's difficult to know how technical to get.

It would be interesting to develop a new class race. My suggestion is canal boat racing because of their long waterline length and narrow beam. They could be quite fast.

You know those long canal boats they have in England. They could all be fitted with Yanmar 30 HP motors and any modifications you want allowed.

Nitrous oxide injection is what I'll work on. It contains 36% oxygen while the air we breath is only 20% oxygen. I should be able to get 40 HP out of a 30 HP Yanmar @ 4,500 rpm simply fitting the intake with a N2O nozzle as well as squirting in more fuel. I'll bore the diesel injector pump out oversize and fit double valve springs to limit valve bounce.

I'll also have a N2O nozzle going up to the helm station so I can take a sniff and burst out laughing as I squeeze past the opposition.
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Old 23-10-2015, 00:17   #22
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Re: YAnmar 3GM30F forced air induction mod

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We are on the same page! It's difficult to know how technical to get.

It would be interesting to develop a new class race. My suggestion is canal boat racing because of their long waterline length and narrow beam. They could be quite fast.

You know those long canal boats they have in England. They could all be fitted with Yanmar 30 HP motors and any modifications you want allowed.

Nitrous oxide injection is what I'll work on. It contains 36% oxygen while the air we breath is only 20% oxygen. I should be able to get 40 HP out of a 30 HP Yanmar @ 4,500 rpm simply fitting the intake with a N2O nozzle as well as squirting in more fuel. I'll bore the diesel injector pump out oversize and fit double valve springs to limit valve bounce.

I'll also have a N2O nozzle going up to the helm station so I can take a sniff and burst out laughing as I squeeze past the opposition.
with diesel I prefer propane injection. might not be as much fun at the helm though...lol
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Old 23-10-2015, 01:36   #23
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Re: YAnmar 3GM30F forced air induction mod

[QUOTE=julius222;1944145]
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Originally Posted by GrahamHO View Post

Neither would I and I do know how a diesel works. You mistake that 2 litres per minute is all that is needed. Forced air induction is under discussion. therefore you need more than 2 litres to provide an over pressure, just like the commercial turbos.
But as a theoretical discussion 4000 is as good a number as 5000 or 1000

BTW why the sarcastic and unwaranted agro?? "Learn how a diesel works first" ...No wonder we have "Going Postal" added to the idiom.


Thanks again to all who have responded seriously...

I'm out of this discussion now

Just carry on without me
cheers
Sorry to offend you. A 2 stroke 1 litre engine could suck in (displaces) 4000 litres of air per minute at 4,000 rpm, ie 1 litre every revolution. A 4 stroke 1 litre engine could suck in 2000 litres of air per minute at 4,000 rpm, ie 1 litre every 2 revolutions.( 4,000 /2 ) Both cases ignoring volumetric inefficiencies.

2 litre a minute over pressure, as you state above (or boost), is 1/1000 of what the 4,000 rpm 1 litre 4 stroke engine draws in every minute under atmospheric pressure. Your 2 litre / min "boost" may probably cause a restriction.
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Old 23-10-2015, 02:31   #24
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Re: YAnmar 3GM30F forced air induction mod

Being a bit of an empiricist myself I'd say give it a go.

I recall one of the items in hotting an auto engine was to "port and polish" the head to allow freer flow of intake of the air and fuel mix to allow greater power.

The engine sucks in air and this takes power so reducing the amount of suck required by increasing the ambient air pressure should increase power. Whether it is significant or not who knows without a trial.

On the practical side if you could get hold of a plot of elevation above sea level V power output you should be able to ascertain roughly the effect of boosting ambient air pressure.
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Old 23-10-2015, 02:47   #25
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Re: YAnmar 3GM30F forced air induction mod

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with diesel I prefer propane injection. might not be as much fun at the helm though...lol
Yeah I did read once about someone's cooking gas pipe line leaking into the diesel intake. I can't remember the other details except the engine ran overspeed.

And another case in NZ a few years ago in the news, when a motor launch engine ran over speed out of control for whatever reason and exploded sinking the vessel. It could simply be a fuel pipe leaking near the air intake.

So practically any combustible you care to squirt into a diesel air intake should increase the power. If you don't mind blowing up your motor.

I've occasionally considered that the Yanmar air intake could easily be blocked off with one of those tapered wooden plugs if it ran over speed. I've even thought of hanging one near the intake but that's being pessimistic.....
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Old 23-10-2015, 04:17   #26
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Re: YAnmar 3GM30F forced air induction mod

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Yeah I did read once about someone's cooking gas pipe line leaking into the diesel intake. I can't remember the other details except the engine ran overspeed.

And another case in NZ a few years ago in the news, when a motor launch engine ran over speed out of control for whatever reason and exploded sinking the vessel. It could simply be a fuel pipe leaking near the air intake.
The engines on oil and gas land drilling rigs have air operated valves on the air intakes of the diesel engines which allow the drillers to shut off runaway engines before they come apart from over speed in the presence of gas contaminates atmospheres.
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Old 23-10-2015, 13:04   #27
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Re: YAnmar 3GM30F forced air induction mod

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The engines on oil and gas land drilling rigs have air operated valves on the air intakes of the diesel engines which allow the drillers to shut off runaway engines before they come apart from over speed in the presence of gas contaminates atmospheres.
Thanks. I didn't know that. You wouldn't want to get close to a runway engine especially on an oil rig.
We have all sorts of other safety equipment on our boats that we hope we'll never need so why not a cable operated panic handle?
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Old 23-10-2015, 14:27   #28
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Re: YAnmar 3GM30F forced air induction mod

Pretty serious outcome if an engine runs away and comes apart in the presence of an explosive atmosphere. The anti spark water deluges on the engine exhaust systems are rendered ineffective allowing ignition of the gas cloud resulting in a fairly massive explosion and possible death of the drillers. I believe it was the explosion of an ignited gaseous atmosphere which was responsible for the deaths aboard the "Deepwater Horizon" in the Gulf of Mexico a few years ago.

Could happen in a boat if enough cooking gas was present in the bilges so maybe drawing in cool air from outside the boat and slightly pressurizing the engine enclosure could provide a safer vessel even if it does not result in more power from the engine.
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Old 23-10-2015, 16:04   #29
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Re: YAnmar 3GM30F forced air induction mod

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Pretty serious outcome if an engine runs away and comes apart in the presence of an explosive atmosphere. The anti spark water deluges on the engine exhaust systems are rendered ineffective allowing ignition of the gas cloud resulting in a fairly massive explosion and possible death of the drillers. I believe it was the explosion of an ignited gaseous atmosphere which was responsible for the deaths aboard the "Deepwater Horizon" in the Gulf of Mexico a few years ago.

Could happen in a boat if enough cooking gas was present in the bilges so maybe drawing in cool air from outside the boat and slightly pressurizing the engine enclosure could provide a safer vessel even if it does not result in more power from the engine.
Yes I believe in plenty of ventilation. I have a hatch / locker slightly raised and under my tiller. It's lid is fitted with a hurricane vent with a float inside. The locker is vented to under the cockpit, and to my motor with a usually open screw in port inside the locker and a couple of vents in the quarter berths. Fresh air is good for keeping the engine compartment and accessories such as the alternator cool and as you suggest for safety. No doubt our engine power changes with the weather, though we would be hard put to notice that.

Somebody I know was out doing trials in a much larger boat and couldn't open the engine room doors when the large motor was running. So presumably leaving the doors open in that case might increase its power.

We don't usually need more engine power in our displacement yachts. I don't anyway as I usually cruise around 2900 rpm if I'm motoring. If I want to get out of the way of a container ship I go at 3400 rpm and then we are going as fast as the boat can motor and my adjustable pitch prop is preset accordingly. Any more power would just stir up the water. A yacht engine is virtually a constant speed motor.

It's different for a car engine where we need the power for acceleration in traffic or maintaining speed up a hill. A car engine can be reving up and down anywhere between say 900 rpm and 6000 rpm within seconds or minutes. We want it to have ample power anywhere in that range.

Sorry, I'm drifting off topic.
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Old 23-10-2015, 16:59   #30
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Re: YAnmar 3GM30F forced air induction mod

Why not just try it and see what happens. Take data points before and after so it's not anecdotal.

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