Yeah, I don't track my car, so I don't think a scangauge is necessary for me. That would be overkill.

I do agree that an experiment is in order! Though, I'm confident that the results from Alta's dyno testing are correct. And, actually, Adam and I had a recent discussion about their testing methods. They're very sound, experimentally.

 

Thanks you, I agree with you. The starting point is that hot air is less dense than cold air.

FYI, the DDM website have some intake temp charts for the DDM RIS. Just wish they identified the different intakes but I know why they did not.

 

In god we trust but when it comes to my money, I prefer an independent tester to help me in my decision.

There are very few of these independent test so for example only, R53 intercoolers were reputed to gain 10-15 hp in vendor tests but an independent shop only managed 3-5 hp. Look at Matt's article here http://www.fes-auto.com/upload/artic...valuations.pdf

I use scangauge for many things including reseting my CELs (when I get them), knowing when I can apply power safely (coolant temp above 180 degrees) and measuring boost.

 

Doesn't surprise me one bit. Conditions can always be manipulated. And tests can always be just plain bad.

Coincidentally, I happen to be reading a chapter out of my Psychometrics book right now.

 

The Alta team have tested their products and backed it with graphs and told us what we need to know. Their site says the gain will be in the negatives if you have a closed scoop, and an actual gain in power with an opened scoop. The Alta intake also utilizes the cold air source tube.

For those concerned about having a "True Cold Air Intake", I would suggest putting the stock intake box and putting a K&N filter in it. The stock airbox only grabs air through the cold source opening located on the right side of the grill. The tubes that run the cold source keeps most of the heat out. BMW clearly thought of how to build the intake the way it is.

 

Ok back to my explanation. Take a bottle fill it with 100 degree air to 2000 psi. fill the same bottle with 60 degree air to 2000 psi. the air inside to bottle is going to be the same because the psi is the same. the only way to change that would be to cool the outlet temp. so if its hard to understand think of it like this turbo it compressing air to 10psi pre intercooler then it gets released through the intercooler which cools it down ( stock intercooler to like 280 or close to it, according to altas graph) so it does not matter how cold the air going in to the turbo it cuz its going to come out at the same temp. and anyone who has ever filled an air-pack bottle will know when you fill it up its hotter then it was even if it is 60 ambient temp.

 

That actually makes good sense.

 

That makes sense also.

 

Sorry but your explanation is not very connected even though I read it a few times. The only thing I will say is that 60 degree air at 2000 psi is more dense than 100 degree air at 2000 psi in the same bottle. More dense air = more air in bottle = more oxygen = more power . I think this is Boyles law, not even thermodynamics first or second law. When you say come back out the same temp is it the hot or cold end of the turbo or the exhaust?

Maybe someone else can help you with this because you are a little too confusing in your explanation.

 

it may not be in the law but it is how it works

 

My question at this point is... If the Alta CAI is so "bad," then why are there so many other CAI's on the market like it? Even DDM and M7 make one, and the DDM is almost the exact same thing! And straying from that (like we've been doing) is getting away from the intention of the OP. He wants to know which is better... the DDM street or the Alta. Not the stuff that's $500+ (and is overkill, IMO).

 

Hey Guys,

I understand all of the "theory" being thrown around. But the dyno simply doesn't lie (and neither do we.)

The ALTA intake still gets cold air from the back lower side from the fresh air tube that comes from behind the left side headlamp. Plus fresh air is drawn over and across the engine from and through the front hood scoop. Finally air is also drawn up and down from the rear of the motor.

The cars are tested with hood closed on the dyno. Stock box, 5 runs, stop test, open hood, install ALTA intake, close hood, 5 runs, stop and report results. (this is WAY abbreviated for brevity sake here.) No funny business.

Those results are shown below for an 2007 MCS:



Results for the 2009 Cooper JCW:



If block the filter was necessary, we would do it! But why add more expense and complexity needlessly?

I hope this helps some. Fully understanding that armchair dyno'ing and racing has been going on for years and I doubt the evidence above will change everyone's opinion, I would put my reputation on the results!

Thanks again to NAM for allowing this type of dialogue!

 

Nice writing there, I was trying to explain that. The intake argument is the same as the exhaust argument, its all opinions and desires.

 

He is basically making use of the gas law: PV/T=PV/T, except he is doing it wrong. If you actually run the numbers on the example he gave using say, 20psi for the starting pressure, 2000psi for the final pressure, and you keep the volume at 1 liter you get the following setup by using 60 degrees kelvin and 100 degrees kelvin. Yes I realize the numbers are little crazy, but you could use "real numbers" and reach the same conclusion.

60 degrees

(20*1)/60=(2000*1)/x
(1/3)x=2000
x=6000


100 degrees

(20*1)/100=(2000*1)/x
(1/5)x=2000
x=10000


So... same pressure does note equal same temp given different starting temperatures and an equal increase in pressure. No thermodynamics involved, it all just gas laws, we are talking high school level here.

 

Thanks, Adam!

 

one more fact i forgot to add. you turbo is going to heat the air up enough that 20 degree change wont matter. in my opinion the alta one is better. easy instal, makes your car sound great, looks good. all a + for me

 

interesting math. ask an engineer he will agree with me

 

There are many solutions to the same problem. You start with a hypothesis and test it. Then you compare many different tests which is the basis of the scientific method. Open CAI's is one solution. Closed CAIs is another. There are many variants to each. All we ask is to understand the differences and why that is so. I, for one, am not interested in one vendor consistently saying that he is the best, believe only me. Many may choose to believe one set of test for one CAI and that is your right. No, we are not arm chair dynos but willing to ask and evaluate as we want to understand. Maybe the HP and torque could be even better. Maybe the NM engineering solution is better? Maybe Forge is better? It is really difficult to weed out the crap, the stuff that is suboptimal. I think this information is useful to the op.

I do not advocate a single brand or product but want to get all the information out there to make a proper decision. I have only continually ask why? And I have nothing to sell you or make you part with your money?

I would like to see some comparisons, especially one that is tested by an independent evaulator so everyones CAI is tested using the same procedure so we can understand better what we are buying.

 

im going to go to the hardware store tomorrow get a hi temp thermometer zip tie it to my alta intake and i will tell you how hot it is.

 

No. The gauge pressure alone isn't an accurate measure of how much air's in the bottle - you have to include temperature in the calculation.

If you have two identical bottles with gauge readings of 2000 psig, but one's at 60 °F and the other is at 100 °F, the 60 °F bottle will have a greater mass of air (more air molecules) in it.

In fact, if you warm the 60 °F bottle up to 100 °F, the gauge reading will go from 2000 psig to about 2150 psig. Now that both bottles are at the same temperature, you can accurately use the gauge readings as an indication that one bottle has more air in it than the other bottle.

Likewise, if you've got a 10 psig airflow coming out of a turbocharger at 200 °F, there's a greater mass of air in the flow than if the same turbocharger were putting out 10 psig at 300 °F.

 

this is basicly true, if you fill the bottles up and then heat them the one that was filled with hotter air if cooled would loose psi. but all of this is erelivent for the air intake due to the turbo heating it up. yes the air will be more dense but the amnount of air will be the same. and the turbo in our car will heat up the air enough that the intake temp will almost be erelivent. besides that this is not what the op wanted.
so for the op
i like the alta intake
it is easy to instal you can here the bov and it is load. you can here your turbo spool up and suck in air. it is easy to clean. and it looks good. i would go with alta over ddm

 

No, the amount of air will not be the same. Hotter air going into the turbo means hotter air coming out of the turbo, and unless you increase the boost to compensate, the mass airflow (the actual number of air molecules leaving the turbo in a given amount of time) will be lower.

If you can lower the intake temperature from 100 °F to 80 °F, then the intake air going into the turbocharger will be about 4% denser. That means that the mass airflow coming out of the turbocharger will be 4% greater as a result of the cooler intake air, no matter how much the turbo heats up the air while compressing it. (This is assuming a fixed amount of boost from the turbo, say 10 psi). Granted, 4% isn't a lot, but no one expects 20-30% gains from an aftermarket intake, either.

 

Here's (hopefully) a simple explanation.

1) Oxygen is what we really want to get into the engine, since that's what we burn with the fuel to make power.

2) Turbochargers don't create, destroy or store oxygen, so the amount of oxygen flowing into the turbo in a given period of time is the same as the amount of oxygen flowing out of the turbo in the same period of time.

3) The pressure at the inlet side of the turbocharger is the same whether the intake air is hot or cold, so the turbo will flow the same *volume* of air regardless of intake temperature.

4) If you can cool the air at the intake by 20 °F, you'll increase the amount of oxygen per unit volume of air by about 4%.

5) The *volume* airflow through the turbo is the same in either case (hot or cold intake air), but the *mass* of air (and therefore, oxygen) flowing through the turbo into the engine will be about 4% greater as a result of the cooler intake air. This is true regardless of how much the turbo heats the air. (remember, the turbo doesn't create, destroy or store oxygen).

This means that the cooler intake air allows more oxygen to reach the engine, so the ECU can inject more fuel, resulting in more power.


In short, it's incorrect to say that the extremely-high turbo outlet temperature means that the intake temperature is almost irrelevant. It's the intake temperature that directly determines how much *oxygen* the turbo can suck in and pass onto the engine, and that's what really matters when it comes to making power.

 

i 100% agree with that. the colder the air the more dense it is with o2. should of added that to my explnation. the mass will be the same but the colder inlet temp will contain more 02. but anyway lest get back on topic.

 

haha yeah this got kinda off topic. but the majority opinion seems to be alta?