I'm speculating, but if the ahu/1z 90-hp engine is calculated with intercooler, and the aaz 75-hp engine is calculated without intercooler, what would be the horsepower of the ahu/1z engine without intercooler and with a manual ve injection pump?
I would think that the direct injection itself would increase the efficiency of the tdi vs the idi, so perhaps a reasonable horsepower estimate of the tdi without intercooler and with a manual ve injection pump, would be between 75 and 90-hp - maybe 80 to 82.5-hp?
foxfour
With a proper DI mechanical pump you can easily make the same or more power than an electronic TDI.
On its own an intercooler doesn't make any power, it just allows more air in to the engine. You could get 90hp out of a mechanical TDI without it for sure, though you are probably getting a fair bit of smoke with that.
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Thank you for the reply.
With regard to the following statement: "On its own an intercooler doesn't make any power, it just allows more air in to the engine." I agree that the intercooler allows more air into the engine, because the cooled air is denser, more compressed, than the hot air exiting the turbo. To my way of thinking, delivering more oxygen to the engine would increase combustion efficiency and result in higher horsepower. Without a turbo though, an intercooler would not be worth the cost of installation.
I would be interested to know what amount of horsepower, if any, is derived strictly from direct injection vs indirect injection. I'm unable to find this information on the web and I'm not versed in the volumetric efficiency of the two different methods of getting fuel into the combustion chamber. Still, "direct" always sounds better than "indirect."
I have a low mileage (61k) 1z engine on a stand equipped for installation into my 1986 Westfalia. I also have a very nice LR300tdi pump with machined hub, alh shaved sprocket, and enlarged ahu/1z bracket. I've located an aaz, also low mileage, that's ready to go as is for $1950 shipped. I'm trying to decide which way to go, hence the discussion on horsepower of the ahu/1z vis a vis the aaz.
I realize this is my decision, but I am wrestling with it because I've no experience with turbo charged diesels, only the na models.
foxfour
Without a turbo though, an intercooler would not be worth the cost of installation.
think your looking at this in the wrong direction, you wouldnt use an intercooler with out a turbo. any motor you want to breath fresh cool air.
i wonder though, in theory an na motor with (a useless) intercooler, it may well be like a restriction on an na motor having to pull its own intake thru piping and a cooler(and again more piping). the air for one (as i said) should already be cool, however if it does get cooled by a intercooler wouldnt it be more drag for the motor to pull that -now cool(er) air back thru piping. it would also be hard to find a place to put an intercooler where youd have -very- short piping. not to say cool fresh air being cooled a little more wont gain much for an na motor.
Diesels are fuel limited rather than air throttled like a gasser. The engine runs on the lean side already. More air adds capability for more fuel but doesn't add it on its own.
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An air to air intercooler will do absolutely nothing on a non-turbo engine. The air being sucked into the engine is ambient temperature. The air is not compressed, so it is not heated. If anything, it will be under a very slight vacuum causing it to be slightly COOLER than ambient. The 'cooling' air passing through the fins of the intercooler would also be ambient temperature so no heat would move either direction. It would just be a waste of space.
AAZ vs. 1Z with similar ancillary components will make similar overall power. The AAZ will rev higher, the 1Z will have better torque and so will have better low-rpm performance. AAZ will consume 10-15% more fuel than the 1Z for a similar power output. The AAZ will occasionally drop a pre-chamber insert.
Thanks for the specifics between the aaz and 1z. It's what I was looking for.
As for my statement, "Without a turbo though, an intercooler would not be worth the cost of installation." I'm saying that an intercooler on a naturally aspirated engine would be useless, a waste of money. There must be something in the wording that made this unclear. I do understand the function of an intercooler and apologize for any confusion on that topic.
foxfour
the b3 passat was available with an intercooled 1.6td which made 80hp, i think it would be easy to believe that an aaz with an intercooler could make 90hp... of course its very subjective to the tune of pump.