Cold air intake? - Page 2 - PeachParts Mercedes-Benz Forum

Matt L · #16 10-17-2007, 10:24 AM

I'd like to see some evidence either way, Forced.

Old300D · #17 10-17-2007, 11:35 AM

Quote:

Originally Posted by Number_Cruncher

Although this flies in the face of conventional wisdom on this and many other mortoring web sites, taking intake air from behind the radiator is not IMO an entirely stupid thing to do.

When you are sludging around town, the air behind the radiator will be quite a bit hotter than in front. The engine isn't being used to make a lot of power, and the hot air improves the engine's efficiency.

When you are motoring on the open road, the air blasting through the radiator doesn't actually become that much hotter, and so, the power loss is minimal.

No, ok, just partially stupid, since the factory air cleaner does an entirely adequate job. If you are making the claim hot air improves "efficiency" maybe you need to state what you mean by "efficiency" as there are many types -- air flow efficiency, engine volumetric efficiency, thermal efficiency, get my drift?

So basically to justify installing a "cold air" intake which is really a "hot air" intake, you'd need some reason to do it. Oh, it looks cool? Fine, just say so.

winmutt · #18 10-17-2007, 11:58 AM

Quote:

Originally Posted by Matt L

I'd like to see some evidence either way, Forced.

It is not really needed. Drive your car in winter and drive it in summer..... Mine practically sings in the winter.

Number_Cruncher · #19 10-17-2007, 03:34 PM

A little further up, I mentioned that the warmer air can increase efficiency. Please allow me to clarify - or to write what I should have written!

Most people talk about colder air being denser, and hence being more efficient. However, our engines are power limited by the fuel pump settings - they are still running with a large excess of air when they begin to smoke.

The meaningful efficiency gain that is open to us is the reduction in pumping losses which the warmer air gives.

Number_Cruncher · #20 10-17-2007, 03:43 PM

A little more on the subject - although from a petrol engine and Jaguar perspective can be read here;

http://www.jagweb.com/aj6eng/technics.php

It's quite a long page - the section on intake temperature is about half way down the page, just after a nice sectioned view of the Jaguar V12 intake tract.

-------

In response to the statement above that the current air filter set-up is perfectly adequate, I agree entirely, and would not propose any modification or butchery. My herecy is just that I don't buy into the worship of so-called cold air intakes to the exclusion of all other.

Hatterasguy · #21 10-17-2007, 05:36 PM

Its a ricer Mercedes!

Someone needs to buy a Civic.

This is what an aftermarket intake on a properly tuned Mercedes looks like.

I need to look up the specs on that engine, but its probably damn near 700hp. Notice the air intake runners, I don't beleive they are stock. I think Brabus made them. Notice the clean factory looking finish, which if you consider what that costs is demanded.

Now if thats the setup that Brabus one of the most respected tunners of Mercedes uses, which is very similer to stock BTW. Why in the world would you put some lame K&N stuck at the end of a pipe on a Mercedes? These are not Chevy's, save that crap for your small block. If their was a better setup cost is no object Brabus would use it.

MTI · #22 10-17-2007, 05:52 PM

The seller "Wade Performance" aka "steelwindow" will be the first to tell you that he has never put any car on a dyno to do a "before & after" test. You'd think that even if such a test produced consistent BHP gains he would sell a lot more intakes, no?

Mister Byrnzoil · #23 10-17-2007, 06:26 PM

I did precisely the same thing on my coupe and I could not be happier...

It cleans up the engine bay quite nicely... it makes certain types of maintainence MUCH easier, it looks extremely cool and you can really hear the turbo spool. It also makes other engine mods... propane, intercooler etc an easier undertaking.

As for the whole cold air/hot air thing, consider the following... the stock air cleaner is black so it absorbs heat more readily than my shiny intake pipe.... it is in extremely close proximity to the turbo/exhaust manifold/exhaust pipe so it gets damn hot on the bottom... It has a large volume, so the air must travel slower thru this volume allowing more heat to be transferred to the intake charge.

And finally, thanks to what amounts to BS under-engineering from our friends in stuttgart, there is a good possibility that you will waste a saturday changing your broken air cleaner mounts.

#24 10-17-2007, 07:28 PM

Quote:

Originally Posted by Number_Cruncher

Most people talk about colder air being denser, and hence being more efficient. However, our engines are power limited by the fuel pump settings - they are still running with a large excess of air when they begin to smoke.

OK, let me try. The reason colder inlet air is more efficient has nothing to do with the amount of O2 available for combustion. You have to think of an internal combustion engine as a thermodynamic air cycle, all the fuel does is provide the energy to heat (and expand) the air. The maximum efficiency is obtained by having the maximum density difference between the cold inlet air (that must be compressed) and the heated air that provides the pressure during the power stroke. The net energy generated by the engine is really just the difference between the energy obtained by the power stroke and the energy required to compress the air. That is why inter-coolers provide higher efficiency on turbo-charged engines. End of Thermodynamics 101 class.

Cervan · #25 10-17-2007, 11:52 PM

Quote:

Originally Posted by Craig

OK, let me try. The reason colder inlet air is more efficient has nothing to do with the amount of O2 available for combustion. You have to think of an internal combustion engine as a thermodynamic air cycle, all the fuel does is provide the energy to heat (and expand) the air. The maximum efficiency is obtained by having the maximum density difference between the cold inlet air (that must be compressed) and the heated air that provides the pressure during the power stroke. The net energy generated by the engine is really just the difference between the energy obtained by the power stroke and the energy required to compress the air. That is why inter-coolers provide higher efficiency on turbo-charged engines. End of Thermodynamics 101 class.

.. when a diesel spews black smoke.. that means there is no oxygen left to burn and fuel is being dumped out the tailpipe unburnt. and for one, the color of the plastic does not matter under the hood. a white pipe and a black pipe will generate the same ammount of heat Covered. it is only Light waves that cause more heat because black absorbs all the spectrum. where as white reflects all. Secondly. look where your turbo is. its right infront of the raidiator... and where does all that hot air go? it doesnt dissapear after it goes through the raidiator. it goes right past the turbo. and thats not to mention the reduced air filtering capabilitys of this crap ass filter. Third. the factory intake is a cold air intake, i dont know why anybody would put something like this on there car if they allready have one.

Mister Byrnzoil · #26 10-18-2007, 12:56 AM

Quote:

Originally Posted by Cervan

.. when a diesel spews black smoke.. that means there is no oxygen left to burn and fuel is being dumped out the tailpipe unburnt. and for one, the color of the plastic does not matter under the hood. a white pipe and a black pipe will generate the same ammount of heat Covered. it is only Light waves that cause more heat because black absorbs all the spectrum. where as white reflects all. Secondly. look where your turbo is. its right infront of the raidiator... and where does all that hot air go? it doesnt dissapear after it goes through the raidiator. it goes right past the turbo. and thats not to mention the reduced air filtering capabilitys of this crap ass filter. Third. the factory intake is a cold air intake, i dont know why anybody would put something like this on there car if they allready have one.

Ignorance truely is bliss.

I don't know where to begin to deal w/ that mess I just had the displeasure of reading, but perhaps you'd like to take a lesson from the silver portion of my stock hood pad??

Congrats... you just made the ignore list, along w/ ineon and that guy who never changed his oil... you're in good company.

Hatterasguy · #27 10-18-2007, 01:08 AM

Quote:

Originally Posted by Craig

OK, let me try. The reason colder inlet air is more efficient has nothing to do with the amount of O2 available for combustion. You have to think of an internal combustion engine as a thermodynamic air cycle, all the fuel does is provide the energy to heat (and expand) the air. The maximum efficiency is obtained by having the maximum density difference between the cold inlet air (that must be compressed) and the heated air that provides the pressure during the power stroke. The net energy generated by the engine is really just the difference between the energy obtained by the power stroke and the energy required to compress the air. That is why inter-coolers provide higher efficiency on turbo-charged engines. End of Thermodynamics 101 class.

Correct. Not to mention the fact that turbo charging, or super charging increases the temp of the air on its own because its being compressed. The cooler the air the better. Thats why cars will run slower 0-60 times on 100 degree days vs 40 degree.

Mister Byrnzoil · #28 10-18-2007, 01:13 AM

Theres no such thing as 'cold air' in a uniflow head situation...

I'll quote FI...

The exhaust proximity isn't much of a problem. It's a uniflow head, the intake ports share the same walls with the exhaust ports, the intake manifold is attached to a 180*f cylinder head and the air is 200*f+ at 13psi.

from this link...

Butchering the intake - part deux

Post #43 of that link shows the temps of the intake manifold... draw your own conclusions.

Hatterasguy · #29 10-18-2007, 01:18 AM

We can argue theory all we want. I want to see dyno sheets. Intake air temp readings would be nice as well.

Any mod that doesn't show on the dyno is a waste and rice.

Are intake temps changed? If so by how much in what conditions and RPMs?

Is power increased, or the same? Torque? If so where in the power band?

I suspect gains are zip because the turbo would force enough air through just about anything. You may gain slightly faster turbo spool up; you will gain a lot more noise!

Hatterasguy · #30 10-18-2007, 01:24 AM

http://www.youtube.com/watch?v=VEqQbdf5RMI

Dyno's don't lie excuses walk.