W210 e300td driving w/o intercooler - Page 2 - PeachParts Mercedes-Benz Forum

nhdoc · #16 09-04-2009, 08:56 AM

Quote:

Originally Posted by KarTek

It's on the front of the up-pipe into the EGR "mixing" chamber. You can see it when you look down past the anti-lock brake unit toward the bottom of the intake.

Thanks! Learn something new every day!

Olivier · #17 09-04-2009, 09:30 AM

Quote:

Originally Posted by nhdoc

The intercooler's function is to cool the compressed "boost" air before it enters the intake. All fluids (air is a fluid) heat-up when compressed and cooler air is denser (more oxygen per unit of volume) than warmer air so the theory is if you can lower the temperature of the pressurized air, back to near ambient temps it will produce more power when mixed with the fuel. Cooling the intake air probably also help lower exhaust gas temps too.

As others have said, if you disconnect the intercooler (and don't connect the boost pipe directly to the intake) then you will get no boost and be able to draw unfiltered air into the intake...both bad things.

If, however, you were able to bypass the intercooler and connect the turbo's boost pipe directly to the intake all you would have is a car with boost that wasn't cooled and would not be as powerful and efficient as it is with the intercooler. You might also cause it to run hotter than it was designed to but since most of us don't have a way to monitor EGT I don't know how we would know if we did any damage or not.

Here is an article that explains it with numbers:

http://autospeed.com/cms/A_109789/printArticle.html

Hello,
This is the question I had, is the intercooler really effective on cooling litres and litres of air/ second in a kind of static area ( city center) and then on starting. going to high speed while reving very high, I wonder the effeciency of it as the ratio of "hot" air going through it seems to me way behond the ability of the intercooler to cool any?
Cheers.
Olivier

nhdoc · #18 09-04-2009, 09:52 AM

Quote:

Originally Posted by Olivier

Hello,
This is the question I had, is the intercooler really effective on cooling litres and litres of air/ second in a kind of static area ( city center) and then on starting. going to high speed while reving very high, I wonder the effeciency of it as the ratio of "hot" air going through it seems to me way behond the ability of the intercooler to cool any?
Cheers.
Olivier

I'm sure it is more efficient when there's a good deal of airflow and so when you are stuck in traffic it probably isn't doing too much but, on the other hand, you really aren't using the turbo that much going in bumper to bumper traffic. My guess is with some decent speed of ram air that it has some effect. It probably isn't very efficient because of its small size and where it is located but probably better than nothing and probably has the most effectiveness when cruising on the highway, and then you punch the pedal.

To me it always seemed like an afterthought because of where they put it. It probably was as much a marketing ploy (sound good in the sales brochures to say "turbocharged, intercooled engine), and not terribly effective, would be my guess.

Olivier · #19 09-04-2009, 10:09 AM

I saw long ago a picture of a one especially made, and the chap was saying he made it on order as mercedes intercooler were not really performant.
I love to isolate my air box too, its getting so hot, this would be a little help.
On another forum someone wrapped the manifold in insulating thingy, to prevent it from heating from the engine.
Olivier

nhdoc · #20 09-04-2009, 09:38 PM

I drove my car down to Boston today and monitored the intake air temps. Once the car warmed up the IAT was steady at about 10-15F above ambient until you started to induce some boost, and depending on how aggressive your pedal was it would rise up about another 50F at its peak at max boost (it was just about 150F at its peak here with 80-85F ambient air). It's amazing how fast the IAT climbs and how much it climbs just from the pressurized air.

The temp differential I observed was the same (more or less) regardless of how fast or slow I was going. The only unknown is how much differently it would behave with the intercooler blocked from ram airflow to see how much more the temperature rises without the cooling effect of the intercooler.

I'd guess that some of its effect is just because the intercooler itself is always going to be cooler than the boosted air and you don't use boost all the time so it cools off between uses but it would be very interesting to see how much higher the IAT climbs over ambient without the intercooler functioning.

mdisav · #21 10-19-2009, 07:34 PM

Hey Marty,
Since you have gone this far, do you feel like blocking off the intercooler with some carboard or plastic and taking another run? I would be very interested to see the results.

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