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Stock Intake VS K&N FIPK Data

2047 Views 9 Replies 4 Participants Last post by  Twitch
So i just received my K&N intake and I decide to do a couple of test and datalogs.

Temperature today was 55.4F and the two test were done without one hour of each other. The car used is a 2001 Mustang GT. The stock intake used had the silencer removed.

I did a idle log just to see what the intake temperatures are like. Engine coolant temperatures were the same.


IAT AV : 89.42722266F

ECT MAX : 202F
ECT MIN : 190F
ECT AV : 195.1125098F

MAF AV : 468.1471282GM/S

IAT MAX : 112F
IAT AV : 102.4705F

ECT MAX : 202F
ECT MIN : 190F
ECT AV : 195.8300551F

MAF AV : 489.9677419GM/S

As you can see, the IAT for the K&N is higher than the stock one for obvious reasons. The K&N is fully exposed to the engine compartement as oppsed to the stock one which has a casing around the whole filter. So when the car is not moving, K&N will have a higher IAT.

Also, MAF reading for the K&N are a more than stock(better hope so:p ).

Here's a graph of both runs at idle for 120 seconds

The next run is a 1 mile higway run from one exit to another. I tried to keep the same speed and driving habits so the data can be relevant.


IAT MAX : 110F
IAT AV : 91.99381F

ECT MAX : 196F
ECT MIN : 190F
ECT AV : 191.8602F

MAF MAX : 19 910GM/S
MAF AV : 2376.385GM/S

IAT MAX : 104F
IAT AV : 73.77699F

ECT MAX : 202F
ECT MIN : 188F
ECT AV : 191.5991F

MAF MAX : 20 707M/S
MAF AV : 2511.444GM/S

Right away you see a differene of 18F in average IATs. Since the K&N filter is more exposed, air flowing through the engine bay can be sucked in by the K&N filter. The stock filter being enclosed in a plastic shell, can only suck air from a small area, close to the fender. With K&N you can get IAT as low as 68F. So, once the car is moving, K&N IAT will dramatically drop and will ahve cooler charge than stock even though it's not a cold air intake kit, jsut the fact it can be in contact with the air outside flowing through the engine bay can reduce IAT.

Here's a graph of both runs. You can see those two fine curves, those are the VSS of both runs, in MPH, so you can see the speed are very close to each other in both runs.

I've got more data but Í'm just too tired to look at it. I hope you guys frind thios useful.
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BlueStreak03 said:
Heck yeah this is useful. Hard, empirical data is always useful. Now if I could find all the pieces to my stock air box, I could do a comparison between the MAC and stock, with all the mods in my sig still in place. BTW, what did you use to do your datalogging?
I used Diablosport Predator
Here's a 3rd gear pull on the highway atabout the same speeds. I've also calculated the RPM curve equation and VSS curve equation.

As you can see, the acceleration with K&N is slightly higher than the stock one. K&N is increasing at a rate of 30.602 RPM/Unit time as opposed to the stock which is increasing at 30.132 RPM/Unit Time.

VSS for K&N is increasing at a rate of 0.5296 MPH/Unit Time compared to the stock's rate at 0.4906 RPM/Unit Time.

The fine red and green curves are the IAT during the run.
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Jakes said:
This is soooo cool! A couple of questions....

What was the ambient air temp?

Since the stock unit can only draw air from outside, do you have any ideas as to why the stocker is higher than th KN?

Based on what you wrote I'm guessing air temp was some where around 70*, and since stock only draws from outside, any ideas how stock IAT get higher than ambient air?
If you read carefully, I posted that the outside temperature that day was 55.4 F.

The stock intake has the silencer removed, so there only and opening of like 6X3 inch for the filter element, the rest of it is covered by the plastic cover. The K&N FIPK has no cover, the whole filte element is exposed.

There's a reason why I logged IDLE intake temperature to see the difference. Like you said, the stock draws air from that little hole in the fender and is protected from the engine heat because of the plastic cover, that's why it has a cooler IAT at IDLE compared to K&N.

But once you start moving, air from outside passes through the engine bay (engine bay is not sealed, it's made to let outside air flow through), remeber that air is at 55.4F. So, like I said, the stock intake has only a small 6X3 inch opening to try to suck in all that air as opposed to the K&N which has a fully exposed filter element taking advantage of that 55.4F air.
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