AEM vs. Cobb intake system questions

[mattsmith87]

@SD_GR,

Here's a dyno run sheet from the K&N typhoon intake for an '09 STI. You can see the horsepower and torque gains across the rpm range. The vehicle mileage and which gear the pull was done in were posted but for some reason the temperature, humidity, and pressure readings weren't put on this chart. Below the STI dyno sheet is the sheet for the MkV GTI which has the atmospheric conditions listed for that kit. I don't know why they weren't listed for the STI kit, but they were recorded. I'll bring it up so we can get the info displayed online.

http://www.knfilters.com/dynocharts/69-8005_dyno.pdf
http://www.knfilters.com/dynocharts/69-9503_dyno.pdf

You can read about the horsepower gains testing procedures here. We do three runs with the stock intake, 3 runs with the K&N intake, and the gains posted on the website are an average. AEM follows a fairly similar testing procedure, as far as I know from talking with their guys.

K&N Power and Torque Testing Information

Here's AEMs dyno pull for their 09 STI kit which has all the atmospheric conditions listed.

http://www.aemintakes.com/dynocharts...1-478_dyno.pdf

And links to some independent reviews of AEM intakes.

Independent Product Reviews of AEM Cold Air Intakes

@anub1s,

Yes, intake systems aren't the most horsepower/dollar investment; however, they do help.

Hope this helps guys.

[Anub1s]

Very interesting, and good to see. Thanks. I'd like to see something along the lines of airflow numbers if they're available, as opposed to dyno graphs. Dynos tell a part of the story, but not all of it.

Would you happen to have graphs available for earlier model WRX/STIs? I don't recall ever seeing any graphs like that pertaining to any earlier models, I'm sure they're out there somewhere though. I wonder if the changes in the intake were drastic enough with this last generation to make it that much better to have an intake installed.

Cobb's dyno numbers with regards to AEM intakes are a bit different. Granted, they only show max percentages gained though. 93 Octane for 2011 WRX Stage 1 with AEM: 16.6% HP and 21.2% tq gains, and stock intake: 13.5% HP and 17.3% gains.

Now, I haven't gone in and looked at the details of the mapping, these can differ quite greatly where things count, so there's no real knowing of what is the intake and what is tuning, but there is an obvious showing of improved gains with an intake at least with newer models. Cobb has only recently began supporting tuning for differing intakes, so older models will most definitely vary with regards to gains.

[SD_GR]

OK good thanks for the links, the dyno graph of the Subaru is interesting for us here I think.

Do you have a feeling for what deviation is to be expected from the dyno used? (Unless I misunderstood, one car is used for all tests?) Taken at face value the numbers are impressive but is the implication that six dyno runs are the basis for product development? I would not find that impressive -- but then again the stuff sells so everything else is moot.

I take these as advertising claims. The leading indicator that they are advertising claims is that the company labels them as such. Three runs for each part are stated as meeting advertising claim requirements. I can't dispute that.

Do you know if the firm's claims are based solely on the runs summarized in the figure? Or are there other data not presented?

[zax]

If you drive through a puddle deep enough to hydrolock your motor, you're a moron and deserve it.

:looks at Drews:


SD, there were some independent dyno graphs posted over at NASIOC regarding high-flow conical filters (before and after intake installation IIRC) on the 2009+ WRX. As I recall, the conclusion pointed towards the idea that the LGT-style intake was indeed restrictive even at stock air consumption. I'll see if I can find the graphs...

[Donkey]

The most important info missing from both of those tests is the Openloop/WOT AFR and the boost pressure. If the AFR changed/leaned out then the intake made power purely to the fact that it leaned out the airfuel mixture. That tells you two things. The MAF calibration is off due to either to a change in the inner diameter of the MAF housing or due to turbulence. If the boost pressure goes up,then that explains for some gains but more importantly shows the stock intake was restricing flow. Now change the boost pressure to match stock and does the intake still make power? If the power was made by either leaning out the car or raising boost pressure,I can do that without buying a $200 intake. Testing intakes on forced induction cars is a different animal than N/A cars.

[SD_GR]

As I recall, the conclusion pointed towards the idea that the LGT-style intake was indeed restrictive even at stock air consumption. I'll see if I can find the graphs...

I think we're thinking of the same thread, I think I've seen it. Again the sample size was very low.

So far the info given has proven to me that K&N can sell intakes. I firmly believe that. What I am still skeptical of is whether their intake will benefit my car in terms of output, and whether the intake will filter better than the correct intake. To be fair I can't think of a way for them to prove the latter either despite or because I'm relatively familiar with some analytical methods. Also to be fair for them to prove the former would require a lot more effort than is needed to simply build and sell intakes, so from their point of view it could/would/should be pointless, but from mine, the data are not there.

[MainFrame]

I feel like if it doesn't need a tune then any differences in flow, good or bad, are negligible. The tune is where power is made.. if a mod allows you to be more aggressive with the tune then there is a performance to be had.

[EJ257]

The most important info missing from both of those tests is the Openloop/WOT AFR and the boost pressure. If the AFR changed/leaned out then the intake made power purely to the fact that it leaned out the airfuel mixture. That tells you two things. The MAF calibration is off due to either to a change in the inner diameter of the MAF housing or due to turbulence. If the boost pressure goes up,then that explains for some gains but more importantly shows the stock intake was restricing flow. Now change the boost pressure to match stock and does the intake still make power? If the power was made by either leaning out the car or raising boost pressure,I can do that without buying a $200 intake. Testing intakes on forced induction cars is a different animal than N/A cars.

Bingo.

:looks at Drews:

[SD_GR]

Mainframe makes a good point too IMO (and I hope I don't mangle it): If something does not require calibration then how significant are its effects on air flow?

[BigDaddyRex]

A less technical thought, but for me I'm not planning on an intake "upgrade" simply because I have a feeling that when a warranty issue arises having one in the engine bay raises the likelihood that the dealer could have "claim denial" thoughts. I'll be Stage I shortly and figure that if I can keep the engine bay looking stock they will be less likely to call me on the tune (or look for it, as I intend to install/unistall for dealer visits). I also hardly feel compelled due to the minimal gains that are realized on this car.

That said, there are plenty of people who install them because they like having the modded look in the engine bay to show off and they like to modded sound that it adds. HPs are not their primary motivation.

BTW - I had a K&N intake on my Grand Cherokee 5.9, and that really did add some serious power. Of course, that was with a NA motor desperate for all the air it could get.

[T0rque]

If you drive through a puddle deep enough to hydrolock your motor, you're a moron and deserve it.

*cough* James *cough* lol

[mattsmith87]

Would you happen to have graphs available for earlier model WRX/STIs? I don't recall ever seeing any graphs like that pertaining to any earlier models, I'm sure they're out there somewhere though. I wonder if the changes in the intake were drastic enough with this last generation to make it that much better to have an intake installed.

All of these dynos are available on knfilters.com and aemintakes.com but I'll centrailze them here.

Dyno for K&N's CAI for the 2000-2007 WRX and STI
http://www.knfilters.com/dynocharts/69-8001_dyno.pdf

Dyno for K&N's CAI for the 2008-2011 WRX
http://www.knfilters.com/dynocharts/69-8004_dyno.pdf

And the dyno for K&N's CAI for the 2008-2011 STI is already posted.

Dyno for AEM's SRI for the 2002-2007 WRX and STI
http://www.aemintakes.com/dynocharts...2-474_dyno.pdf

And the dyno for AEM's CAI for the 2008-2011 WRX and STI is already posted.

I'd like to see something along the lines of airflow numbers if they're available,

I don't have numbers specifically on how the K&N or AEM intakes flow vs. the factory system but you can see on this link below how K&N filters outflow their paper cousins in drop-in OE applications in the factory box. If you replace the filter with a high flow filter, then replace the factory intake system on top of that, you're going to get even more airflow and less restriction.

http://www.knfilters.com/Images/AFCcharts.gif

Do you have a feeling for what deviation is to be expected from the dyno used? (Unless I misunderstood, one car is used for all tests?) Taken at face value the numbers are impressive but is the implication that six dyno runs are the basis for product development?

We do 3 dyno runs on at least 3 different vehicles, typically 5 different vehicles. This produces between 9 and 15 dyno runs. Even two cars that roll off the production line at the exact same time will produce different power, especially when they're driven by different people under different conditions. As such, we toss the highest and lowest power gains and the number shown on the dynos is an average and realistic horsepower gain from the kit. These dyno runs for horsepower gains are once the kit is dialed in and as it will be constructed and sold in its final version.

What I am still skeptical of is whether their intake will benefit my car in terms of output, and whether the intake will filter better than the correct intake.

Every person's car is going to be slightly different so we can't and don't have a guarantee on a specific number for a kit, but we do guarantee a gain in power. We don't post the highest number just for better advertising, only to have our customers disappointed. We're realistic, and we offer 100% satisfaction. We're not going to stick you with a kit you don't like so you can always return it.

All of our air filters are 96-99% efficient at removing dust from the incoming air. You can (and please do) read about our air filter testing procedures and horsepower testing procedures here on our website. Please don't just skim them. There's lots of good info there.

K&N Product Testing

The most important info missing from both of those tests is the Openloop/WOT AFR and the boost pressure. If the AFR changed/leaned out then the intake made power purely to the fact that it leaned out the airfuel mixture.

I talked to our R&D kit manager and we do have that info but as I already mentioned, every person's car is different and every dyno run is going to be different which is why we don't publish that data. What we guarantee is that the kit will safely produce horsepower on a stock tune and your engine and car are protected by K&N's Engine Protection Limited Warranty K&N Product Warranties.

I'm not planning on an intake "upgrade" simply because I have a feeling that when a warranty issue arises having one in the engine bay raises the likelihood that the dealer could have "claim denial" thoughts.

We have you covered under our Consumer Protection Pledge
K&N Consumer Protection Pledge

Under the Magnuson Moss Act of 1975, a dealership has to prove that an aftermarket part caused damage to your vehicle in order to deny warranty claims relating to the damage. If a dealership ever gives you hassle, contact us immediately at 1-800-858-3333. We have an entire department dedicated to dealer relations and we will step in and fight for you.

I'm not trying to hi-jack the thread to pitch K&N, and AEM has many similar policies. At least with these two companies, you have nothing to worry about.

[jd92677]

The most important info missing from both of those tests is the Openloop/WOT AFR and the boost pressure. If the AFR changed/leaned out then the intake made power purely to the fact that it leaned out the airfuel mixture. That tells you two things. The MAF calibration is off due to either to a change in the inner diameter of the MAF housing or due to turbulence. If the boost pressure goes up,then that explains for some gains but more importantly shows the stock intake was restricing flow. Now change the boost pressure to match stock and does the intake still make power? If the power was made by either leaning out the car or raising boost pressure,I can do that without buying a $200 intake. Testing intakes on forced induction cars is a different animal than N/A cars.

I talked to our R&D kit manager and we do have that info but as I already mentioned, every person's car is different and every dyno run is going to be different which is why we don't publish that data. What we guarantee is that the kit will safely produce horsepower on a stock tune and your engine and car are protected by K&N's Engine Protection Limited Warranty K&N Product Warranties.

I'm not meaning to be offensive, please don't take this as an insult, but all the other stuff in the post sounded like sales. This info would really interest me and I'm sure others as well. This is the data that we would like to know in order to determine if it is something to purchase. Yes every car is different and may yield different results, but how the product produces those results would be consistent therefore this is the info that would be the constant across the board, if that makes sense.

[mudferret]

Is knock and knock correction measured during the tests? Even on the stock tune, stock intake many WRX's and STI's are knock prone at the CL/OL transition and it's not uncommon to see very, very lean AFR's and a bunch of timing pulled. It's not unheard of to see AFR's in the 14.X area at WOT, ~4000 rpm. Subaru made a move to awful tunes around 06/07.

APU there are many more knowledgeable people than me in regards to anything tune related.

[mattsmith87]

I'm not meaning to be offensive, please don't take this as an insult, but all the other stuff in the post sounded like sales. This info would really interest me and I'm sure others as well. This is the data that we would like to know in order to determine if it is something to purchase. Yes every car is different and may yield different results, but how the product produces those results would be consistent therefore this is the info that would be the constant across the board, if that makes sense.

Oh no I don't take offense to it at all, and I understand. I'd like to know that information too so as to better understand the kits. Unfortunately it's not gonna happen :/ Personally I find confidence in knowing that a company develops their product to that extent (detailed in the horsepower testing and airflow testing) and that the company protects my motor and would fight for and with me against a money hungry dealership. It may sound like sales to you, but as I said I don't care what kit you guys decide to run. I'm not paid to be on this forum.

Is knock and knock correction measured during the tests?

Yes, that's measured and accounted for during the R&D of an intake. And it's good to know that Subaru started using crappy tunes around 06/07 as I was thinking about picking up an 06/07 in the not-too-distant future. Makes me think about getting an 05 Rex now.