K&N Dissappointment

GT300 · Apr 25, 2005

Hey Everyone, I recently bought a K&N drop in airfilter (No $ for CAI & tune) and for the past 2 weeks I actually felt a loss of power and noticed a loss of mileage too....definitely not what I expected!!!

I didn't get the engine light on YET, but I'm not expecting to either due to the vapor trap still intact. Additionally, I checked to make sure the air box was securly fastened. I'm considering putting back the stock filter, but before I do I want to see how it reacts to the SLP axleback getting installed today.

Anyone having any similiar issues and or experience with the K&N's drop in airfilter? It feels as though too much air is coming in for the engine to respond to. I don't even feel the shifts anymore it takes a awhile to get up and go. Anyhow, any comments would be appreciated!!!

NVERL8 · Apr 25, 2005

Dropped a K&N in over the weekend and havent noticed a good reaction or bad. Car still feels the same. I certainly wouldn't expect a check engine light because of an air filter change? What did you mean by vapor trap still intact?

fivepointohgt · Apr 25, 2005

Supposedly, if you change anything to do with the air intake, you MUST retune the computer.

'01SilverBullet · Apr 25, 2005

I've had the K & N in for 3 weeks now, and frankly I don't notice anything either way. On my '01 GT when I did it, I definitely got an increase in mileage, but haven't noticed that really yet in the '05. But again I've only had it in 3 weeks and had the car 6 so I need more time to evaluate.

slytherin · Apr 25, 2005

Vapor trap,Saw it in MMFF it looks like a rolled up chunk of cardboard(from what MMFF showed) in the intake piping.

Dean Gamburd · Apr 25, 2005

GT 300 there have been several threads about this. If you change anything to increase the air flow, including a K&N, your car COULD react negatively just as you described without a re-tune via an external tuner or Jet module. ;(

I'd just put the old filter back in it or pop in a Jet Module for $200.00. Either action should rid your car of it's ill's.

ExCon · Apr 25, 2005

What the hell do people expect from a stinkin air filter? C'mon!!

WSD42 · Apr 25, 2005

Remember that even with more air flow with a drop in K&N filter or other brand, you are still drawing through the OEM filter box inlet. The K&N may help a very small amount, but a good CAI will do a lot more since it is designed to be much much less restrictive. But you will need to re-tune the computer. The new '05 engine and engine management SW can be improved upon with a tune, fuel/air ratios adjusted, timing, spark advance, etc....but you can only do so much with intake and exhaust improvements without digging into the engine and/or adding a supercharger. You can improve your performance (many of us have so far), with not too much investment, so research here and other forums on making the most of your Mustang.

tomabram · Apr 25, 2005

You guys are unbelievable. Retune your computer? A K&N air filter will flow LESS air than a stock paper unit. The company makes claims but read the fine print. They only flow more air than a stock paper filter when the are both clogged with dirt. Both new, stocker is better. I have seen several cars dynoed before and after the K&N. ALWAYS less HP.

bleedingvayneAD · Apr 25, 2005

By what? 1 hp?

jt14894 · Apr 25, 2005

GT300 said:
Hey Everyone, I recently bought a K&N drop in airfilter (No $ for CAI & tune) and for the past 2 weeks I actually felt a loss of power and noticed a loss of mileage too....definitely not what I expected!!!

I didn't get the engine light on YET, but I'm not expecting to either due to the vapor trap still intact. Additionally, I checked to make sure the air box was securly fastened. I'm considering putting back the stock filter, but before I do I want to see how it reacts to the SLP axleback getting installed today.

Anyone having any similiar issues and or experience with the K&N's drop in airfilter? It feels as though too much air is coming in for the engine to respond to. I don't even feel the shifts anymore it takes a awhile to get up and go. Anyhow, any comments would be appreciated!!!

I've put K&N filters in every vehicle I've owned and noticed performance increases every time, especially with MPG.
I remember reading somewhere that K&N recommends that you do not to install it on a brand new vehicle because, I believe, it does not have a lot of miles yet and that the engine/CPU has not yet fully conditioned itself to the stock filter. If you put in a K&N as soon as you get your new car then the engine will condition the K&N as a stock filter and therefor no gain at all.
With my latest car (2003 Nissan 350Z), I waited until it had about 10,000 miles on it and then I added the K&N. The factory Nissan specs stated 20 MPG City and 26 MPG Hwy. Before the K&N, it was averaging about 21 MPG City/Hwy, but after I added the K&N the MPG improved approximately 1.5 to 2 MPG to average about 23 MPG City/Hwy. The car now has 26,000+ miles and it still gets excellent MPG. On my last road trip, the car averaged 27.5 MPG, on one fillup, while crusing between 75 - 80 MPH.
With my new Mustang, I'll be doing the same thing.

Another thing to note is that if you don't break in your car properly the car will perform poorly and the K&N isn't going to help.
Also, I've seen and ridden with people who constantly pump the gas pedal while cruising on the highway or intersate. That type of driving completely wastes gas.
Whenever someone like that comes around me on the highway, I see them slowdown and speed up slowdown and speed up so what I have to do is speed up and get the hell away from them. AAAH!! Its so annoying. I HATE THAT!
I just want to scream at them and tell them to control their foot or use their Cruise Control.

300bhp/ton · Apr 26, 2005

GT300 said:
Hey Everyone, I recently bought a K&N drop in airfilter (No $ for CAI & tune) and for the past 2 weeks I actually felt a loss of power and noticed a loss of mileage too....definitely not what I expected!!!

I didn't get the engine light on YET, but I'm not expecting to either due to the vapor trap still intact. Additionally, I checked to make sure the air box was securly fastened. I'm considering putting back the stock filter, but before I do I want to see how it reacts to the SLP axleback getting installed today.

Anyone having any similiar issues and or experience with the K&N's drop in airfilter? It feels as though too much air is coming in for the engine to respond to. I don't even feel the shifts anymore it takes a awhile to get up and go. Anyhow, any comments would be appreciated!!!

all it needs is a tune as the AF ratio will be out, and the 05's seem more suseptable to sbtle changes than the previous models. Think about it if you changed a standard setup to a high flow filter on an old carb engine it would probably need tuning maybe even re-jetting, so it shouldn't be any different on a new EFI car.

Older EFI cars where not as precisly tuned and didn't have to conform to the same mpg & emissions standards so a change may have been more effective, I have a 1982 v12 EFI Jag, with two of the 4 silencers removed and an air filter mod, it may be a little quicker (not much) but it certainly has affected it as it nows stays on the cold start cycle for about 5 mins longer than it used to.

get a tune, but don't expect too much, its only a filter at the end of the day, at best it should make a bit of noise and improve throttle response, NOT INCREASE BHP! At worst it should make no difference at all.

If your going for a more highly modded motor (cams, heads, exhaust, etc.) than a better air intake system will imporve performance, but the stock setup is more than capable of handling an axel back exhaust.

GOLDENPONY · Apr 26, 2005

ExCon said:
What the hell do people expect from a stinkin air filter? C'mon!!

I usually don't agree with anything this PITA says BUT THIS TIME HE'S DEAD ON.

NVERL8 · Apr 26, 2005

There is no way you have to retune for an air filter!!! If this were true every time the stock one got dirty and you replaced it you would have to retune?

300bhp/ton · Apr 26, 2005

NVERL8 said:
There is no way you have to retune for an air filter!!! If this were true every time the stock one got dirty and you replaced it you would have to retune?

no no no no no NO NO NO

You have it the wrong way round, see a dirty/clogged filter will reduce air flow, ie it may starve the car a little so it may reduce performance. But the car needs x amount of air to operate at designed tolorances. You could retune the car to except a lower air flow and still run ok, it would of course have a lower bhp output. This is exactly what 'air restrictors' are for on race cars. Hence a 5.7 litre GT Vette only produces the same bhp as a 3.6 litre Ferrari F360 GT racer, they are limited to the amount of air they are allowed to flow.

And of course you don't need to retune when you replace a dirty stock filter with a new stock filter as the car will already be tuned for the amount of air flow. If the old filter was really dirty and staving the engine it may waken the motor up.

On the flip side, a better flowing fliter, will have a greater air flow capability allowing the possibility of more power (although only minor with a drop in filter), but many new cars are tuned so strictly to meet emmissions standards that this little change causes the ECU to get it wrong without a re-tune. So a car may well run poorly until such a time. Of course due to manufacuring tolorancies in mass production not every Mustang will produce the exact same symtoms.

DukeOfValencia · Apr 26, 2005

...real K&N test... I took my 65 Nova, 383 stroker, 420+ hp and ran 12.95 and 12.96 in the 1/4 mile with a almost new K&N filter. Then I dropped in a very dirty Fram paper filter (same size) and ran 12.92 and 12.93. The K&N filter actually slowed me down. I'll never buy one again...
Rick

Wsmatau · Apr 26, 2005

RetiredGeneral said:
...real K&N test... I took my 65 Nova, 383 stroker, 420+ hp and ran 12.95 and 12.96 in the 1/4 mile with a almost new K&N filter. Then I dropped in a very dirty Fram paper filter (same size) and ran 12.92 and 12.93. The K&N filter actually slowed me down. I'll never buy one again...
Rick

With all due respect "Rick the retired General" That is the most ridiculous, unscientific comparison posted. Thanks for wasting my time.

'01SilverBullet · Apr 26, 2005

LOL, how is that a real test?

whiteboyslo · Apr 26, 2005

the only real gains to a drop-in cloth filter is the $$$ savings. in the long run, it's cheaper. look at how much new paper filter cost for some cars. it's easily between $12-$25 for a LOT of newer vehicles! $50-$60 once for a cloth filter is just cheaper. yeah, you have to clean it, but a cleaning kit costs $10-$12 and usually gets you 3-4 cleanings easy, plus it's my experience that a cloth filter has to be cleaned less often than a paper filter needs replaced.

Mike

jt14894 · Apr 26, 2005

RetiredGeneral said:
...real K&N test... I took my 65 Nova, 383 stroker, 420+ hp and ran 12.95 and 12.96 in the 1/4 mile with a almost new K&N filter. Then I dropped in a very dirty Fram paper filter (same size) and ran 12.92 and 12.93. The K&N filter actually slowed me down. I'll never buy one again...
Rick

This is the real info from K&N.
http://www.knfilters.com/facts.htm

K&N Dissappointment

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