I was looking at my 84 300D engine and realized that the air cleaner
really puts a lot of twists and turns in the flow path for the air
coming in. I was thinking about streamlining this flow with an
aftermarket air cleaner/intake piping.
Has anyone else done this, or can recommend this for increased fuel
mileage and/or power from their engine?
Additionally, the engine has 263k miles on it, does that make a
MB filter housing is the best... I would not change it for anything. Alot of
time, these aftermarket filters makes things worse... especially for gas
engine.... like those conical one that requires you to eliminate your
factory airbox... those are just dumb as it is sucking hot engine air
rather than colder denser air via air duct.
Thats my point though. The factory airbox has a lot of restrictions
and turns to get to the turbo intake. Additionally, the "cold" air
intake for the factory air duct is only about a 1"x6" slot mounted
above the passenger headlight with a 2" plastic hose leading to the
filter housing. Not nearly as large as an aftermarket pipe would be
pulling in air directly from below the car (i.e. away from the
engine). Whether it is 50F hotter air or not doesn't make a difference
if there is 4x the volume getting to the turbo (or 4x less depending
on your POV). Another concern is to get the housing off of the top of
the turbo and exhaust. That is the hottest part of the engine, and it
basically turns the housing into an oven.
My thought was to provide a K&N filter housing that would draw air
from a cooler part of the car (not the hood) lower in the engine
compartment, with a much larger pipe to get the most air into the
turbo, while also moving the filter from atop the turbo and exhaust
manifold. I should mention that since this car is my daily driver at
the moment, I won't actually be performing any of this work yet. I
just want to do a little research and thought that I would bounce some
ideas off of this newsgroup.
Secondly, has anyone noticed any adverse effects when removing the PCV
tube that goes to the air filter? I don't mind recycling those blow-by
gases, but it sure does get the air filter nasty.
With turbo, it doesn't matter... because the turbo takes care of the
restrictions like any compressor would. It is trivial... or othertwise MB
wouldn't design it that way.
Drawing cool air from bottom of engine compartment will lead to suction of
water in rainy day from splashes and will destroy the turbo and engine. You
can't compress water
On 95 E300D, MB actually made snorkel fins on the passenger side fender for
cold air intake. On your car, I think it is from behind headlight area.
Turbo will heat up the air... and it doesn't matter if you could get 4x more
air... turbo will only pushes as much as it can... 11 PSI... and drawing hot
air at that pressure will lead to even hotter air and less O2 than the
factory air duct routing.
On Aug 2, 7:58 pm, "-->> T.G. Lambach <<--" <"T.G. Lambach at
While that is true (about the turbo), it can only compress what gets
to it. The more air you can get into it, the more it can move (and the
more completely the fuel will burn). I basically just want to get it
to be the most efficient it can be. 11psi seems to be about the
average for the turbo boost, but the spec is closer to 15psi isn't it?
I know someone else was saying that 16psi is the mechanical limit due
to fuel deliver and safety valves, but you still have to get enough
air into the turbo/engine for it have something to compress and burn.
I assume you just mistyped my mileage. It was 263,000 miles, not
26,000 miles.Yes, over a quarter of a million.I'm shooting for 3 more
quarters on it.So I won't be hot-rodding it, just trying to increase
efficiency and gas mileage.
There is much easier way to get 5 extra MPG... just put in Marvel Mystery
Oil into your fuel... 4 to 6 oz per 10 gallons of fuel. It is cheap enough
and no messing with air filter.
Routine Diesel Purge will make sure you injectors are clean... this is much
more important than anything else.
The turbo boost specification is 10.2 - 11.6 psi at 4,000 engine rpm,
under load in L or S gear.
The safety switch on the intake manifold opens at 16 psi to prevent a
These engines were "efficient" in their time - about 40 HP / L. That's
what gas engine were making at that time too.
The way to have an efficient engine is to regularly change its oil and
filter, keep its valves adjusted, replace the injectors with Bosch
remanufactured ones (to improve the spray pattern) and keep the paper
air filter clean. Then leave it alone to do its job.
I've driven a '80 300SD since new and do those things and it runs like
it did when it was new.
On Aug 3, 9:38 pm, "-->> T.G. Lambach <<--" <"T.G. Lambach at
Thanks for the responses and the recommendations. I've definitely
decided that my money is better off somewhere else in my car (like
fixing the vacuum leak in the passenger door). I haven't used the
Marvel Mystery Oil in a while. I had been using the Lucas Upper
Cylinder Lubricant (I had a quart of it in my garage), and my uncle
recommended it (he's a farmer and a real diesel nut). I will probably
look at the Marvel and see how its price compares to the Lucas. I have
always changed oil and filters regularly in all my vehicles, and am
pretty good about keeping up on other routine maintenance.
This is totally off-topic to this thread, but I was wondering, what
kind of oil (weight, brand, synthetic, etc.) do you (i.e. anyone
reading this) put in your diesels when you change the oil? I bought
two gallons of Mobil Delvac 15W-40 when I changed the oil the other
day, how does this compare to the normal run of diesel oils?
Most popular is the Chevron Delo... followed by the Mobil Delvac followed by
Shell Rotella. All three are excellent oil and all can be bought at
Walmart... (I am not sure about Delvac)
15W40 is the standard oil for diesel engine.
5W40 is the standard for diesel synthetic oil.... Shell Rotella Synthetic
oil is the best deal at $4 a quart when bought in gallon size. Better oils
are Mobil 1 and Amsoil... but they are much pricier... 50% more.
If you have no leak or excessive oil lost, then it should be fine. I
switched to synthetic when engine are at like 205,000 miles or 196,000
miles... two different cars. Another one at like 115,000 miles. no problem
with any of them.
That's what I used.... the Shell Rotell Synthetic. It is great in winter.
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