Technical Understanding: Intakes: Stock vs. Drop In vs. Aftermarket

[McQueen77]

And no one is concerned about the possibility of reduced filtration from one of these filters?
aFe is quoting 99.2% filtration but you never see
1. what is the filtration of the OEM filter
2. what particle size are we talking about.

Performance is one thing but not at the expense of durability, particularly if the performance gain is minimal.

However, if this is safe, for $40 why not instal it.

Sorry if this has already been covered.

PS: the 31-10172 is an exact fit? On Audizine some Audi owners have had to fudge a cardboard or foam piece to raise the filter to fully cover the intake opening or else they are finding dust behind the filter.

the aFe I have fits like a glove. nicest drop-in i have seen. very well made.. fitment is excellent. drawback of the foam VWR one is its just harder to clean and flow isn't as good as synthetic gauze after it starts to get dirty.. oiled is well, oiled.. anyhow, aFe drop-in have been very popular with heavy duty truck guys for a long time. trucks that do heavy duty in extreme conditions... pretty sure the filtration is fine. that .00whatever % difference probably isn't going to toast your engine.. or at least, youd have to have the car for 200k miles to see if itd make a difference.

for me ill take my chances anyway. after having an intake and then trying to go back to the stock airbox with baffle and big old paper filter, i just couldn't do it. its whisper quiet and feels all choked. theres probably 30% truth to that and 70% butt dyno but driver feel/perception is important and i can't hang with that stock filter/airbox combo ever again. current set up feels like a good compromise.

 

[fredf]

Great. Thanks for the response.

If anyone has any numbers or further advice on filtration, I'd like to hear it.

 

[McQueen77]

Great. Thanks for the response.

If anyone has any numbers or further advice on filtration, I'd like to hear it.

theres a lot of articles on filtration online, comparisons with OEM paper and high flow drop-ins. Bob is the Oil guy sides with the OEM filters but the benefits of the drop-in are obvious to me and Grambles' runs/graphs etc. show the benefit over OEM. but if filtration is all you are concerned w/first and foremost, id stick with OEM paper which to me, feels like the equivalent of running 100 yard dash at 2500ft with a paper bag over my head..

 

[xd-data-ii]

notice anything? how is the aFe treating you? I am back to really loving this set up. just have a real boner over it. a real boner.

Further to my last message, without the snow grate I have noticed that I don't like the feel of how the car drives and especially the noise. Can really hear the hissing sound of the turbo etc. - don't like it. Reminds me of my old mk1 Leon Cupra and not the refined-ness of the mk6.
It's also feels kind of surgy under acceleration.
Put the grate back in tonight and its feels and sounds better to me. Probably all in me head but I did notice how I didn't like the sound the most.

Side note, drove to and from Vegas at the weekend and after 345 mile trip and in 102F heat the car felt completely dead on power. Very little response. Figure it was all down to the heat.

 

[McQueen77]

Further to my last message, without the snow grate I have noticed that I don't like the feel of how the car drives and especially the noise. Can really hear the hissing sound of the turbo etc. - don't like it. Reminds me of my old mk1 Leon Cupra and not the refined-ness of the mk6.
It's also feels kind of surgy under acceleration.
Put the grate back in tonight and its feels and sounds better to me. Probably all in me head but I did notice how I didn't like the sound the most.

Side note, drove to and from Vegas at the weekend and after 345 mile trip and in 102F heat the car felt completely dead on power. Very little response. Figure it was all down to the heat.

yeah, 102 degree weather will do that...

re: the grate, yes you are right and its subjective. I actually like hearing more of the turbo and a little blowoff whereas with the paper filter it is extremely muffled in comparison, so it all depends on what you like.

 

[fredf]

I switched out my OEM air filter for the aFe and I really do think I can feel a better throttle response.
I wouldn't have thought so, but there you are.
It was worth it for me.

BTW: I'm APR stage 1.

 

[McQueen77]

I switched out my OEM air filter for the aFe and I really do think I can feel a better throttle response.
I wouldn't have thought so, but there you are.
It was worth it for me.

BTW: I'm APR stage 1.

I had the aFe at first when i was stock and didnt notice much if anything but with stage 1, oem paper vs the aFe is, id go so far as to say night and day as far as louder turbo spool, slight blowoff and better throttle. Grambles graphs show that the dropin still beats oem paper so its a no brainer if youre on stock airbox.
Did you take the grate out of the airbox? Thats essential

 

[fredf]

No, I'm taking the grate out this weekend.

I was hesitant because I don't like any extra noise from the engine compartment. However, to be honest, I don't hear any more noise with the change in filter. Maybe I don't know what to listen for, but I can't hear turbo spooling.

 

[xd-data-ii]

Would be interested to know if you notice a difference with the snow grate in or out.
I recently removed it and put it back after a few days. Felt it changed the sound for the bad and made the car feel less smooth and surgy under acceleration. Wouldnt have thought it would but when i put it back in the car was immediately back to sounding and running smoother.

 

[fredf]

I will let you know my impressions.

Off topic but what I'm really interested in the APR update for Stage 1 that promises 'better driveability'. But, with APR, you never know when it's going to happen.

 

[xd-data-ii]

"the APR update for Stage 1"

Whats this now??? Eh?

 

[fredf]

1. Re: the grate removal: I know theory and practice sometimes don't coincide but there is no way I can imagine removing that crate causing surging. I'm not discounting your observations but how can improving air flow leading to that?

I can understand removing the grate having no effect if the obstruction caused by it is insignificant. But improved air flow irritating an engine?

2. Re: APR: there is a thread somewhere that began with Arin saying that APR was working on an update to the K04 file.
I asked him if it was only that file or whether there would be updates for Stage 1. He replied that several files would be improved, including the Stage 1 file.

He did say that there would be no increase in horsepower or torque but that it would improve driveability. Things like smoother power delivery.

He did not commit a time frame for delivery to customers and said that the Stage 1 file was number 3 or 4 on their priority list. But he confirmed that it is in the works and will be an update to current APR users.

 

[xd-data-ii]

1. Re: the grate removal: I know theory and practice sometimes don't coincide but there is no way I can imagine removing that crate causing surging. I'm not discounting your observations but how can improving air flow leading to that?

I can understand removing the grate having no effect if the obstruction caused by it is insignificant. But improved air flow irritating an engine?

I agree. Its just how it felt to me. Was definitely there and went when i put it back in. i'm not gonna get technical or care anymore than that about it. Driving cars comes down to how it feels rather than the whole science etc. It is a strange one. I have a DSG by the way.

2. Re: APR: there is a thread somewhere that began with Arin saying that APR was working on an update to the K04 file.
I asked him if it was only that file or whether there would be updates for Stage 1. He replied that several files would be improved, including the Stage 1 file.

He did say that there would be no increase in horsepower or torque but that it would improve driveability. Things like smoother power delivery.

He did not commit a time frame for delivery to customers and said that the Stage 1 file was number 3 or 4 on their priority list. But he confirmed that it is in the works and will be an update to current APR users.

Thats definitely interesting and the correct focus. Thanks for the info. Hopefully would help the DSG dbw lag. Best thing i added in recent months is the sprint booster (i know ... leave out the bashing) and it transforms how the car feels to drive seeming much more response and fun.

 

[McQueen77]

1. Re: the grate removal: I know theory and practice sometimes don't coincide but there is no way I can imagine removing that crate causing surging. I'm not discounting your observations but how can improving air flow leading to that?

I can understand removing the grate having no effect if the obstruction caused by it is insignificant. But improved air flow irritating an engine?

2. Re: APR: there is a thread somewhere that began with Arin saying that APR was working on an update to the K04 file.
I asked him if it was only that file or whether there would be updates for Stage 1. He replied that several files would be improved, including the Stage 1 file.

He did say that there would be no increase in horsepower or torque but that it would improve driveability. Things like smoother power delivery.

He did not commit a time frame for delivery to customers and said that the Stage 1 file was number 3 or 4 on their priority list. But he confirmed that it is in the works and will be an update to current APR users.

Damn, sign me up, that would be amazing. Stage 1 power with stock feel and delivery would rule!

 

[fredf]

I've been thinking about this xd-data-ii and the only way I can figure that you got surging when you removed that grate in the airbox is if your MAF was somehow not reading the air delivery correctly.

I don't know why that would happen since any airflow turbulence or distribution from that grate should be evened out when the air goes through the filter. But I can only think that it has something to do with your MAF or the way the air is being presented to it.

Since it seems fairly unique to your situation I would think you moved the MAF or something changed when you opened your airbox.

But, as I said previously, I'll let you know what happens when I take mine out this weekend.