mustangfan123

I've seen those allegations before, but he is highly acclaimed to be a good guy on s197forum w/ 100% itrader feedback so he sounds ok to me. Btw he verified that the graph above was provided by C&L.

PTRocks

Does anyone find it dubious that there is such a huge difference between stock and "no tune", then only a small difference to the "tune required" version?

Also, someone please correct me if I'm wrong, but I think this graph should be turned sideways. The really important number is the pressure loss for a given flow rate. For example, let's say that at 7000 RPM the engine could ideally be pumping 600cfm at 100% volumetric efficiency. (The actual number is 611 for the 5.0) 100% volumetric essentially means that as the intake valve closes the cylinder is filled with air at the same density as the ambient (outside) air. But because the 2011 intake isn't perfect, there is a 20in H20 pressure drop. That drop would be approximately 5% of the ambient pressure, so the density of air in the cylinder would also be down by 5%, and the engine would be pumping 600*.95 = 570cfm. (The actual number would be slightly higher).

By extrapolating the graphed data to the left, we could see that Company X's super cool "1100cfm" intake which "Flows 50% more!" has a pressure drop of only 6.2n H20 at 600cfm. Seemingly a very impressive number, it's 31% of the drop the stock intake needs. (5%*.31 = 1.5%). However, this means that the actual potential power gain is 5%-1.5% = 3.5%. With Company X's intake the engine can now pump 600*.985 = 591cfm.

For an engine producing 412 hp, the net gain is on the order of 3.5%, or about 15 hp.

This is close to what was said earlier (Intake 4%, Exhaust 20%)

I don't believe that an intake alone is able to release the potential of this engine.

mustangfan123

Impressive math, I'm smart but I can't calculate things involving pressure as you did above. That sure helps paint a big picture about this engine's potential from a CAI.

mjbarnet

The dependent variable (variable of interest) should be on the Y axis, so I think having CFM on the Y axis is correct. The slope of the line tells you how much of a change in X (depression in inches of water) causes a change in Y (CFM). The difference between the sloped lines tells you how much of a change (improvement or decrease) you get from one set of conditions (2010 stock) to another set of conditions (2010 CAI with tune).

PTRocks

There is another factor which I intentionally neglected in my previous post. There is an additional potential gain if an intake can pull in colder (and thus denser) air than the stock unit. Since the 2010/2011 OEM intakes already pull cold air, there is very little to be gained for the Mustang.

However, in a case where a CAI can pull air in that is ~25C colder than the OEM intake, an additional gain of about 8-9% can be realized. This is the real benefit of installing a CAI.

PTRocks

My take on it is that since the engine dictates the base CFM, in a car the pressure drop is the dependent variable.

This is the opposite of how the bench tests are run. The way the graph is presented is logical for bench tests, but in my view it's harder to derive useful information when applying the data to a vehicle.

mjbarnet

Another way to think of it is the X variable is the variable that you have control over and the Y variable is the variable that you observe after making changes in X, so if the CFM is the variable that is manipulated then you are correct, it should be ploted on the X axis.

JJ@WMS

As much as I like the majority of C&L products over the last few years the claims coming from them and companies associated with them are getting ridiculous and are being challenged/disproved every once in awhile. The C&L intake manifold for the 4.6 3V was supposed to give 37hp and never came anywhere near that number, most likely 7-9hp on most applications and at a 30+lb weight gain for the unit it was a wash. I did the testing/tuning on one of the first units released to the general public and then its subsequent upgraded/improved unit with the same results.

I'm sure the 5.0's performance will be greatly enhanced by a CAI and a tune and I'm sure C&L will bring a quality product to market but I will be leary of any "advertised gains" and will test as many units on our WMS test 5.0 as possible in an attempt to give you guys some real results that might not sit well with dyno sheet racers but will sit well with those who spend their money wisely. We will also be producing our own niche line of CAI's in house as we do for the Ford Lightning. It will be low volume hand built unit but one of very high quality and it will perform as advertised.

JJ