Mikey way to go dude - love the way you turned your table lamp into scientific testing equipment. Very simple and to the point.

 

Just did 4 back to back dyno runs under identical conditions. My first run was with the stock filters in, followed by a quick change to Airhogs and another run. The stock filters gave more power, so I thought maybe the first set was a fluke, maybe I had knock on the second run, the computer needed to get used to it, etc. so I ran the Airhogs one more time and then went back to stock and ran the final run. The order was (1) Stock, (2) Airhogs, (3) Airhogs, (4) Stock. The two Airhog runs just about overlapped as did the two stock runs. Both times, the stock filters beat the Airhogs.

To smooth out little localized "bumps" in the graphs, I averaged the two Airhog runs and the two stock runs and that's what you see in the graphs above: the two Airhogs runs averaged versus the two stock runs averaged.

I was a bit surprised but I think I might be able to explain it. While the stock filter is much more dense and lets very little light through, it has a huge number of folds, equating to a larger filter surface area. As a comparison, the stock filter has 53 folds to the Airhogs 22. That means the stock filter while physically close to the same size has a lot more filter media (more than double). Maybe that accounts for the difference. I guess this was a lesson learned in that you can't tell how a filter flows by how much light passes through it!

Also, I found it interesting that the low-mid range torque was less with the Airhogs but the Airhogs seemed to "catch up" at the high RPM and actually slightly passed the stock filter at maybe 6300-6500 RPM. This would seem to indicate that the Airhogs flow well at high volume but not at low volume. I wouldn't expect a change in filter to affect low-mid range power, only the high end, so I'm not sure what is going on, whether we are looking at some strange effect of airflow and the difference between how air flows through the hogs versus stock due to the direction or number of the folds, or some other issue(s).

In any case, this was convincing enough to me to take them back to Wal Mart. Wish me luck that they'll refund my money even though they are no longer sealed in plastic.

Mike

 

Back from Wal Mart. They took them back for a refund and I got my $84 back.

Based on my tests with the Airhogs and the latest post regarding a gain of 9-10 RWHP with no filters at all (and loss of power with a K&N bolted directly on), it looks like beating the stock setup is going to be quite difficult in the C6 and will require more effort and thought than just bolting on a big air filter!

Mike

 

are these runs done with the "extra" filter cover removed. that extra piece of plastic that hides the filters. the first thing you need to remove when you change the filters, you even ask yourself while your holding it in your hand, "what did they put this on for ?"

there must be some other factors at play. why wouldn't more air in be able to produce more power, unless it's corked at the rear, and mufflers need to be swapped out. just the mufflers not the whole exhaust.

-zig

 

Yes. I actually removed that piece when I first got the car, so these runs (all of them) were done without that long snap-on piece. I think that outer snap on piece was probably put there for sound deadening.

That's just it. I don't think the AirHog is actually letting more air in. There are many factors that could lead to the AirHog actually letting less air in which is what I believe is happening. Here are a couple.

- First and foremost, the stock filter has a lot more filter surface area! The stock filter has 53 folds of paper at 1.5 inches tall in an 8x6 opening. That equates to 1272 square inches of filter media per filter. The Airhog has 22 folds at about the same 1.5 inches in a slightly smaller opening size of 7.75 x 6 inches for a total filter media of 396 square inches of media in the AirHog. That means if you unfolded the stock filter media and the AirHog media and placed them side by side, the stock filter actually has more than 3 times the amount of filter media. I know the stocker looks restrictive and the media itself probably is a lot more dense, but looks can be deceiving and do I really think the AirHog media itself flows 3 times better than stock? I kinda doubt it. Plus the fact that the stocker has denser media but a lot more of it probably means it will filter a lot better too!

- Next, the folds on the stocker are parallel to the flow of air so that air flows along the folds evenly and enters the filter. With the folds going perpendicular to airflow, air is forced through those little openings at the edges of the filter across the folds of the filter, so the leading edge of each fold is going to see a lot more "action" than the trailing edges, possibly causing a lot more turbulence. The edges of the AirHog are also boxed in so that air cannot flow through the sides of the filter and must go into the "slots" on the sides where air comes in, change direction while being buffetted by the folds in the wrong direction, and then enter the airway. With the edges/folds being open on the sides of the stocker and the folds going the same direction as flow, you might get a lot more "laminar" flow with the stocker.

I think it is highly possible that the AirHog actually flows much worse than stock, maybe partly because this filter was not designed for our cars.

Mike

 

Great analysis!!! Maybe after the C-5's (later versions) and the abundance of "after market" toys & mods, we all got used to the fact that STOCK = CRAP.
This isn't to say that given a little bit of time, the mod wars won't begin in full, but remember... the C-5 had an eight year run. That's a lot of time to come up with ways to get our money.
C-6 has only been in true circulation for a couple of months, AND it started out at the head of it's class.
Let's give Chev a little credit (maybe).
They set the mark pretty high, and it's good to know that they were serious.
Your report makes me glad that the car came with a little bit of performance, regardless of HOW muck I like to add.
Good job!

 

Much thanks from all of us to Mikey for taking the time, effort and $$$ to evaluate this project.

 

Airhog's returned to Kragen..dyno graph proved not worth the money..they were 49.95 each

 

Though perhaps the wrong point. We're interested in how much air the filter will flow, and how much dirt it won't flow, not how much light it lets through. Mike's dyno testing shows us the difference in flow, and it doesn't favor the Airhog.

No one here has as yet tested filtering effectiveness, which is really important for long engine life. But I suspect that the stock filters win there too. Modders are just going to have to accept that Chevy did the air box and filters right from the factory on the C6.

There doesn't seem to be much, if any, power left on the table in the catbacks either. The only external bolt on that does seem to produce significant power gains is long tube headers, but installing them impairs the operation of the quick light cats, and can cause emissions problems (read, can't get your tag renewed).

While I've got the floor, I'd also note that it takes a power increase of about 10% to produce a real seat of the pants improvement. Sure, more noise, or the amount of money spent, can give you a false sense of a SOTP improvement, but that's just placebo effect. If a mod doesn't give you at least 30-40 hp on this car, you can't really feel it.

The best bang for the buck remains a shot of N2O. A 75 hp wet shot on this car (a $500 NX system) should be easy and safe with no need to get into the computer to tune it, and you will really feel it. Dropping $1200 on a louder catback, or $500 on a trick air box, or $90 on a set of filters, won't do it. If you want SOTP then spend your money where it can make a difference.

 

Amen to that! Greatly appeciated.

 

yes, thanks for the eval. it's nice when something can be proven instead of just guessing. i suspect the airflow problem with the hos is the direction of the fins or folds. less filter media should permit more air in but like you pointed out the fins are pointing the wrong direction and thus most likely the reason it's not flowing any better. thanks again.. gotta love this forum.

-zig