Smooth Airbox

pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
How many have you have done this simple mod.

(There is an article on the main site that goes into detail on this mod: Smoothing an airbox)

basically you remove the airbox and cut back all the ribs in the airbox to get a better airflow.

i had a go at this this afternoon, only got the bottom cut down though still halve to do the harder top part.

done some recording before and after.

throughout the whole rev range i was recording around 4-6 grams more air over the MAF.

both runs were done on an ambient temp of 18 degrees. revved from 2500rpm to 6500rpm at wide open throttle in 3rd gear
 
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pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
turbo seemed a little less lagged but this might have just been me.
turbos usually on full boost by 3000 rpm. Never noticed the huge jump around 4000 rpm

Rpm MAF Normal MAF bottom smoothed
3040 --74.56 --81.78
3440 --82.81 --87.08
3800 --91.97 --96.92
4160 --98.14 --107.89
4520 --110.22 --118.56
4880 --120.08 --126.81
5280 --129.83 --134.83

rpms were off by around 40 revs on the second run. torque readings were near enough the same

going to get the snorkel off the airbox and replace it with a 3inch cold air feed from further down
 
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obi_waynne

Administrator
Staff member
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1,157
Location
Deal, Kent UK
Car
A3 1.4 TFSI 150 COD
Drill some holes in the bottom ;) Try it without the bottom and see what you get then fit a cold air feed to the bottom I bet you'll be surprised at the result. (Tie your air filter to the top to try this!)

Take the air filter off altogether and you will experience flat spots all over the place. :(
 

pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
did look at drilling holes. but decided that taking the small restrictive snorkel off, which sits behind the near sides headlight and putting a 3" tube that i got a while ago in its place lifting the air from behind the bumper. i checked it today while i had the airbox off and it fits. if it works might look at getting one mad out od stainless rather than a duct pipe.

did look at trying to fit a cone filter into the airbox as found some nice findings from this

dont want to go down the route of drilling as it will increase the noise
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
dont want to go down the route of drilling as it will increase the noise

Not just me then who likes serenity on the move. Those MAF numbers do indicate that there's some true merit in smoothing out the airflow path. I suppose this is the reason that people port and polish cylinder heads.
 

pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
ok so i took a trip to bradfords vw last week and ordered up some new parts

first up this is my standard air snorkel to the air box

2555430647_c3a1fda085.jpg


And my nice new one

2556256706_91f299fd37.jpg


full system, Snorkel and headlight cover, missing the duct to the front grill as this didnt need changed.
2555431233_2dec9d3aa6.jpg


and just to show the difference between the old and new snorkels. left ones the old one

2556258558_cf8008ec55.jpg


And fitted

2571174048_1f5e90f56f.jpg


still to finish off smoothing the airbox got around half of the top smoothed off once its finished am hoping to get more figures taken
 
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pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
yeah just a little bit. had to cut out around a inch off the bottom of the airbox where the old snorkel was to get the new 1 to fit.
if i get time the morro im going to try and finish off the airbox and put some vinyl or something similar in so it proper smooth. next up a green panel filter.

looking at taking readings from this once its finished then refitting my old universal cone and seeing what gives the bet flow results.
it better be worth it :confused:. if it is itll hopefully help a lot of members here, rather than spending £150-200 on a induction kit. £40 for a panel filter and a couple of hours with a chisel and sandpaper for similar results. the larger snorkel can be replicated using some 3" hose. Halords do it for around £10 in aluminum for a meter length.
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
Do the drop in panel filters make much difference in reality? I can get OEM paper ones (they also have a gauze stuff on the intake side) for about five quid so I don't mind changing then every couple of months.

If I have to splash out on a filter (£40), oil (£10-12), cleaning detergent (£10-12) am I going to see really stunning airflow?

The filter box in the Pug is a big thing but inside it's as you say ie. no-one on the design team paid any attention to airflow
 

obi_waynne

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Points
1,157
Location
Deal, Kent UK
Car
A3 1.4 TFSI 150 COD
I just wash mine with washing up liquid. Oil is not vital - in fact if you use too much you can ruin your AFM. Over time a washable filter has to be better value than a replacement one each service. You will notice it - especially at the top end. Everything breathes a bit more freely - at least it did on mine.

Don't forget our sponsors shop (top link) they do a pretty full range of panel filters.
 

pgarner

TC ModFather
Points
417
Location
Lockerbie, SW Scotland
Car
Octy smoke machine
most people seem to have seen a gain with them. and they, the manufactures, claim gains of 30% more airflow. dont think itll be that much tho.

yeah the outside of the airbox is all nice and smooth but like you say the inside isnt. i suppose its because more people see the outside rather than the inside of them.

that was the idea of going with the green filter (yes http://torquecars.potn.com do them so will prob be in the shop ) . i dont think they need the oil like pipercross and k&n.

did toy with the idea of a full cold air intake but although the noise is suppressed a little ,over a normal induction kit, its still a bit loud.

but is there any need for a cold air intake on a turboed car ? i would have thought the cold air rushing into the turbo would still come out just as hot at the other side.
 
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bobkingfish

New member
Points
16
Location
N.J.
Car
2019 Elantra se 2.0
Sounds and looks very good, sounds and looks like you are using your head and not your wallet. I completely gutted and insulated my stock air intake housing system, from the entrance to the throttle body and ported the throttle body stock 2019 2.0 Elantra, the bottom end is much more responsive. Next get throttle body bored, good luck.
 

TCJBOLDIE

Moderator
Staff member
Points
697
Location
Brisbane
Car
2011 Honda FN2
but is there any need for a cold air intake on a turboed car ? i would have thought the cold air rushing into the turbo would still come out just as hot at the other side.

I disagree totally with the last "thought" as the colder the inlet air is when entering the turbo the lower the hot temperature will be exiting the compressor housing and that means a higher power output.
 

thexav

Pro Tuner
Staff member
Points
387
Car
2002 Clio 172
I disagree totally with the last "thought" as the colder the inlet air is when entering the turbo the lower the hot temperature will be exiting the compressor housing and that means a higher power output.
Yup me too, the turbo will compress more lovely oxygen if the intake air is colder.

In reality when you are running a turbo I doubt the difference between hot and cool intake make much power difference, compared to say the difference you get in summer/winter.
 

bobkingfish

New member
Points
16
Location
N.J.
Car
2019 Elantra se 2.0
did look at drilling holes. but decided that taking the small restrictive snorkel off, which sits behind the near sides headlight and putting a 3" tube that i got a while ago in its place lifting the air from behind the bumper. i checked it today while i had the airbox off and it fits. if it works might look at getting one mad out od stainless rather than a duct pipe.

did look at trying to fit a cone filter into the airbox as found some nice findings from this

dont want to go down the route of drilling as it will increase the noise
did look at drilling holes. but decided that taking the small restrictive snorkel off, which sits behind the near sides headlight and putting a 3" tube that i got a while ago in its place lifting the air from behind the bumper. i checked it today while i had the airbox off and it fits. if it works might look at getting one mad out od stainless rather than a duct pipe.

did look at trying to fit a cone filter into the airbox as found some nice findings from this

dont want to go down the route of drilling as it will increase the noise
And i think you might pick up a little under hood hot air, keep it sealed if you can from engine heat
 

bobkingfish

New member
Points
16
Location
N.J.
Car
2019 Elantra se 2.0
I disagree totally with the last "thought" as the colder the inlet air is when entering the turbo the lower the hot temperature will be exiting the compressor housing and that means a higher power output.
100% correct, cooler in, cooler out.
 

bobkingfish

New member
Points
16
Location
N.J.
Car
2019 Elantra se 2.0
ok so i took a trip to bradfords vw last week and ordered up some new parts

ull system, Snorkel and headlight cover, missing the duct to the front grill as this didnt need changed.
2555431233_2dec9d3aa6.jpg


and just to show the difference between the old and new snorkels. left ones the old one

2556258558_cf8008ec55.jpg


And fitted

2571174048_1f5e90f56f.jpg


still to finish off smoothing the airbox got around half of the top smoothed off once its finished am hoping to get more figures taken
Looks much nicer, bigg.
 
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goldmariee9

Newbie
Points
3
Location
texas
Car
AEFESF
I just wash mine with washing up liquid. Oil is not vital - in fact if you use too much you can ruin your AFM. Over time a washable filter has to be better value than a replacement one each service. You will notice it - especially at the top end. Everything breathes a bit more freely - at least it did on mine.
 
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