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"Flat" spots after installing RS Lid + K&N Filter

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flyaway-boat

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Discussion starter · #1 ·
Hey guys,

I recently swapped my stock intake lid and filter for a K&N and put the RS lid on (not the bottom part yet). I noticed that the car has an awesome throaty sound from 1k-2k rpms and 3k up. However, there is a "flat" spot from 2k-3k rpms where the growl goes away and the car seems to have less power. Has this happened to anyone else? I am planning on doing the snorkel delete soon; I will report back if that made any changes.
 
#2 ·
flyaway-boat said:
Hey guys,

I recently swapped my stock intake lid and filter for a K&N and put the RS lid on (not the bottom part yet). I noticed that the car has an awesome throaty sound from 1k-2k rpms and 3k up. However, there is a "flat" spot from 2k-3k rpms where the growl goes away and the car seems to have less power. Has this happened to anyone else? I am planning on doing the snorkel delete soon; I will report back if that made any changes.
Click to expand...
What year is your car? The bottom of the box is the same for 16-18 RS 13-18 ST and all of the most current generation s, se, sel, and titanium up to 20'
Both the RS airbox and roush airbox are open under the hood. They have a little sealer strip but it doesn't do much TBH. You're possibly pulling hot air from under the hood into your motor. Could be the reason your butt dyno is telling you something is up. Lol

How old are your spark plugs? That'll do it too.
 
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Discussion starter · #3 ·
Skikri said:
What year is your car? The bottom of the box is the same for 16-18 RS 13-18 ST and all of the most current generation s, se, sel, and titanium up to 20'
Both the RS airbox and roush airbox are open under the hood. They have a little sealer strip but it doesn't do much TBH. You're possibly pulling hot air from under the hood into your motor. Could be the reason your butt dyno is telling you something is up. Lol

How old are your spark plugs? That'll do it too.
Click to expand...
It is a 2013 SE. Spark plugs have 63,000 miles on them. It seems to me that the RS bottom as the same as the current bottom, it just doesn't have the resonator.

So you believe that the lid will have this effect on its power due to its design, and there is no way to mitigate that effect?
 
#4 · (Edited)
flyaway-boat said:
It is a 2013 SE. Spark plugs have 63,000 miles on them. It seems to me that the RS bottom as the same as the current bottom, it just doesn't have the resonator.

So you believe that the lid will have this effect on its power due to its design, and there is no way to mitigate that effect?
Click to expand...
I mean, 63k miles is a lot on those plugs. Have you pulled them out to see their condition and gap them correctly?
I replace mine every 15k miles although my motor does like to eat plugs.
 
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Discussion starter · #5 ·
It is entirely possible that they have been replaced. I am the second owner so I am not sure if they were replaced or checked earlier. However, if the car didn't feel like this before the lid and filter, I would assume the spark plugs are not at fault.
 
#8 ·
'....it just doesn't have the resonator.'

Look hard at that, I have seen the effects you report on more than one car type doing that. The resonator often builds low end or middle response as well as silencing the intake.

That effect can be much worse than simple hot underhood air which I have done as well and no bad effect until summer and they just dog out a bit more doing that. If anything at all.

The resonator though can kill you on certain designs.
 
#10 ·
There will be no stored codes if resonator and a second driver may not be able to tell the loss of power unless it stumbles good and that requires no second driver.

Make sure the filter wasn't overshot with oil, if so the engine will pull some off filter to then coat MAF or whatever, the plugs won't like it either.
 
#12 ·
amc49 said:
Look hard at that, I have seen the effects you report on more than one car type doing that. The resonator often builds low end or middle response as well as silencing the intake.
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I think he meant the lower portion of the airbox from the RS doesn't have it. That half isn't currently installed so shouldn't be causing an issue.
The only thing installed is the lid, and a filter.

amc49 said:
Make sure the filter wasn't overshot with oil, if so the engine will pull some off filter
Click to expand...
100% yes on this. Good catch.
I've seen this happen before to local guys.

@flyaway-boat
I 2nd putting the stock intake back on.
Let us know what the results are.
 
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#14 ·
Skikri said:
I mean, 63k miles is a lot on those plugs. Have you pulled them out to see their condition and gap them correctly?
I replace mine every 15k miles although my motor does like to eat plugs.
Click to expand...
63K is nothing for factory plugs on an SE. They're good for 100K. Why does your engine eat them?
 
#15 ·
saintsfins said:
63K is nothing for factory plugs on an SE. They're good for 100K. Why does your engine eat them?
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2.0L ecoboost nomnoms plugs at 300ish WHP. 350ish wtq
Aftermarket NGK iridiums.
 
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Discussion starter · #16 ·
Hi, my replies keep on "waiting for moderator approval", which is why I haven't gotten back you guys.


amc49 said:
Make sure the filter wasn't overshot with oil, if so the engine will pull some off filter to then coat MAF or whatever, the plugs won't like it either.
Click to expand...
I will check that, thanks. I did buy this filter used and the previous owner just cleaned and oiled it. It did not seem to be overoiled, but I will check it again.

1turbofocus said:
Put the stock intake back on and see if the issue goes away , if it does you will have your answer and none of this guessing

Tom
Click to expand...
Skikri said:
@flyaway-boat
I 2nd putting the stock intake back on.
Let us know what the results are.
Click to expand...
I will do that soon as well.

I want to emphasize that what I experienced wasn't a drastic difference - the car still drives fine and most people wouldn't be able to tell. I just wanted to see if others have noticed this and/or avoided it.

I also yanked the snorkel out, so I will go for a drive with the K&N, RS lid, and snorkel delete first and report back if that made any difference. Thanks for all the replies! This site rocks.
 
#17 ·
The filters can commonly not seem overoiled unless you do what I do and set the fresh oiled one in a paper plate for a day or so, then gravity pulls off the excess oil and you may easily have a pool of oil in the plate.
 
#19 ·
Well, if you mean that there is no actual stumble, but just a reduction in growl sound, then that could be due to a normal change in pitch at those rpms (somewhere between 2K-3K). There are areas of constructive and destructive interference all along the torque curve of any engine that cause changes in sound, and you will notice it more when you make any change that allows you to hear the engine better... exhaust or intake. That is not to say there may not be an actual loss of some torque, but if you really don't notice a "stumble" but just notice a quieter sound, then that's all it is... just a flat spot in the sound of the motor, due to 'destructive interference'.
 
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Discussion starter · #20 ·
Pb-foot said:
Well, if you mean that there is no actual stumble, but just a reduction in growl sound, then that could be due to a normal change in pitch at those rpms (somewhere between 2K-3K). There are areas of constructive and destructive interference all along the torque curve of any engine that cause changes in sound, and you will notice it more when you make any change that allows you to hear the engine better... exhaust or intake. That is not to say there may not be an actual loss of some torque, but if you really don't notice a "stumble" but just notice a quieter sound, then that's all it is... just a flat spot in the sound of the motor, due to 'destructive interference'.
Click to expand...
Interesting. It does seem like there is a small loss or torque as well, but maybe it's perceived because of the noise changes. I'll recruit another butt dyno to get a second opinion.

Also, a small update on my research for everyone that is on the edge of their seats: the filter wasn't over-oiled; or at least it isn't now. I pulled it out and let it sit for a few days and no oil dripped out. Thanks for the advice @amc49
 
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