Delica Canada | Mitsubishi Van Club

Alright, I found my old text books, and here is the text book answer to the argument made by myself and psilosin, contradicting the arguments made by tonydca and the green1 in the thread "losing power black smoke. Help". I apoligize that I could not figure out how to scan this for you, but my skills are as a mechanic. This quote is taken from the text book titled "Diesel Technology Fundamentals, Service, Repair. It was written by Andrew Norman, John "Drew" Corinchock and Robert Scharff. It was published by The Goodheart-Willcox Company, Inc. It is under the chapter titled "Exhaust Systems" and the quote is subtitled "turbocharger advantages". It reads as follows:
The turbocharger offers a distinct advantage to a diesel engine operating at high altitudes. The turbocharger automatically compensates for the normal loss of air density and power as altitude increases. With a naturally aspirated engine, horsepower drops off 3% per 1000 feet because of the 3% decrease in air density per 1000 feet. If fuel delivery is not reduced, smoke level and fuel dilution will increase with altitude.
With a turbocharged engine, an increase in altitude also increases the pressure drop across the turbine. Inlet turbine pressure remains the same, but the outlet pressure decreases as the altitude increases. Turbine speed also increases as the pressure differential increases. The compressor wheel turns faster, providing the same inlet pressureas at sea level, even though the incoming air is less dense. However, there are limitations to the amount of altitude compensation a turbocharged engine can produce. This is primarily determined by the amount of turbocharger boost and the turbo to engine match. Thank you Jason

FalcoColumbarius wrote:I can see how the argument started, based on diesels with turbos and diesels without turbos. Easy to confuse. This is a good post Manitoba, is this book still in print? I would love to get a copy of this one.

Falco.

x2

And THIS quote sums it all up.

However, there are limitations to the amount of altitude compensation a turbocharged engine can produce. This is primarily determined by the amount of turbocharger boost and the turbo to engine match.

Basically it counts on the turbo charger being overkill at sea level, and therefore still adequate at altitude.

I have never heard a Delica's turbo described as overkill. (if so, why do we have so many posts on how to raise the boost pressure?)

Turbos have a HUGE advantage over non-turbos at altitude, but they are NOT immune to it's affects.

Without altitude compensation the engine WILL loose power, and it WILL smoke, this is proven fact, known by, and adjusted for, by the best and most reputable delica mechanics on this site.

Delicas do not have altitude compensation, but other turbo diesels do, see mercedes and their ALDA system for example, installed on all their turbo diesel vehicles to compensate for this exact problem. Are you telling me that mercedes doesn't know how a turbocharged diesel engine works?

No, this is refering to the fact that this book covers land and sea based engines. If you are talking about aircraft, then there are differences. If you still feel you need to pay some one for a "high altitude" adjustment, go ahead, but let me sell you a pail of steam to go with it.

Jason

You fail to answer why other turbo diesels bother with altitude compensation then if they aren't affected by altitude?

face it, even the source you quote states that they can only compensate for so much, and that the amount depends on the amount of boost the turbo gives, small turbo, small amount of altitude, large turbo, large amount of altitude. Delicas don't have big turbos

If you take the time to check the delica sites in other countries, you will find some have adjusted their wastegates to get over 20psi of boost with a stock turbo. This is overkill from a stock turbo. The altitude compensators on turbo diesel engines only function at 0 psi boost (idle) to prevent smoking when idling. Did you want 1 or 2 pails of steam?

Jason

Sorry for not answering your question Falco, I don't know if the book is still in print, it was one of the required text books for diesel mechanics in 1989. A book store from a community college or trade school would probably have it, or you may find one somewhere on the internet, sure glad I saved mine, always wanted to hit two birds with one stone, not kill them, just hit them.

Jason

Manitoba deli wrote:If you take the time to check the delica sites in other countries, you will find some have adjusted their wastegates to get over 20psi of boost with a stock turbo. This is overkill from a stock turbo. The altitude compensators on turbo diesel engines only function at 0 psi boost (idle) to prevent smoking when idling.

So in other words, you know just as little about other turbo diesels as you do about Delicas. Funny how people drive from other provinces to BC to get work done on their diesels, but nobody drives to Manitoba for Delica service.... why is that?

The ALDA system I referred to earlier works when the turbo IS generating boost, and adjusts fuel delivery, less fuel at higher altitude, more at lower altitudes. in fact ALL altitude compensation works when the turbo is generating boost.

If you are so sure that the altitude they talk about in your book is irrelevant, tell me at exactly what altitude did they mean?
What altitude does this magic turbo you think we have stop making up for 100% of the pressure loss due to altitude? is it 1m? 10? 100? 1000? 10000? 100000? keep in mind that we're talking altitudes a kilometre higher than sea level here, this is significantly higher than these vehicles are designed for, and an altitude at which altitude compensation starts to make some real sense

FalcoColumbarius wrote:The Miss Lil' Bitchi's turbo boost is set at between 8 & 9 PSI, and that is at 100 metres above sea level. When I drove to Cowtown via Roger's pass I didn't notice a great deal of difference in performance. Going though the pass, east of Golden there were a few hills that I lost a "little" power on, but that was it. Cruising into Calgary was 105KPH@2,600RPM no smoking issues. The only real issues I had were about cooling but they weren't that big and that was resolved with a new radiator.

Pardon me if I take Mardy, Butch, Edwin, and several thousand diesel engineers working at mercedes and other diesel engine manufacturers over the past century as more reliable sources than one anecdotal description on a single trip.

I have posted written proof with documentation as to where I got it. If anyone cannot find this book, PM me and I'd be happy to send you a photocopy of any section. Until you (Green1) can provide documented proof otherwise, I am politely saying put some pie in your piehole and start reading. Let me know when you have something more to contribute than just the opinion of a ....? What the heck do you do anyway?

Jason

Manitoba deli wrote:I have posted written proof with documentation as to where I got it.

except that your written proof CONTRADICTS YOU! it states that they do better than non-turbo (which I have never once debated) however it also states that there is a limit to their compensation, something you refuse to admit.

People who know these engines know they need compensation. that's why the most reputable mechanics on this site do that modification for people living at altitude.
Manufacturers of turbo diesels know they need that compensation, that's why many turbo diesels come with altitude compensators.

As for telling me to start reading, I have been, that's why I know that engines require air to work, something that isn't as prevalent at high altitudes as it is at low altitudes.
I have already given you more than my opinion, I've given you how to adjust the vehicle, who adjusts the vehicle, why they do it, and keywords to search for to learn more about it.

Just because you've managed to work on diesels, doesn't mean you know more about them than the engineers who design turbo diesels, nor does it mean people are likely to take your word for something over the word of the most reputable mechanics on this site. And the simple fact that you can't answer why turbo diesels frequently have altitude compensation, nor can you answer at what altitude it becomes necessary, proves that you don't actually understand the whole system well enough to give an educated opinion.

Please reread my last post, and ensure your brain is in gear before you pop the clutch for your typing fingers.
Jason