Air intake problem.... So lost.

[V8WRXSTI]

Ok so I am having very weird problems ill upload a before and now picutre so you know what Ive changed.

This is Before:

This is Now:

Ok so it ran fine with the old HKS setup(Top Picture). Now since I have put this new pipe on, and changed the mushroom filter to a K&N it runs like s*** idles all wrong and sounds like a 2 stroke. BUT as soon as i take the K&N filter off and put the HKS mushroom filter on the new pipe, it runs fine no problems at all!!! Now if i run it with no filter it runs like crap, run it with no filter and slide the K&N on it runs like crap, run it with no filter and slide the HKS Mushroom filter on.... it runs fine!!!!!

Any ideas?!

[Wiretap]

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

[Drunkenmonkey]

 Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

its weird that it runs fine with the mushroom but crap without any filter, i did think firstly that it was the oil filter but im stumped..

[Wiretap]

 Drunkenmonkey']

[quote name='Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

/quote]

its weird that it runs fine with the mushroom but crap without any filter, i did think firstly that it was the oil filter but im stumped..

Late model MAFs don't have any mesh across them to linearise the flow, so it's not _that_ weird.

[V8WRXSTI]

 Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

Custom tube, Should be fine tho. its all set up right from what I believe. If it was the MAF tho surely I would be having the same problem with the HKS mushroom filter on it?

[Wiretap]

 V8WRXSTI']

[quote name='Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

/quote]

Custom tube, Should be fine tho. its all set up right from what I believe. If it was the MAF tho surely I would be having the same problem with the HKS mushroom filter on it?

Not neccessarily. Messing with the MAF tube is never a good idea though, as it can cause mis-measurement of the air leading to your car running either too rich or too lean

[V8WRXSTI]

 Wiretap']

[quote name='Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

/quote]

Custom tube, Should be fine tho. its all set up right from what I believe. If it was the MAF tho surely I would be having the same problem with the HKS mushroom filter on it?

Not neccessarily. Messing with the MAF tube is never a good idea though, as it can cause mis-measurement of the air leading to your car running either too rich or too lean

So in Theory.... If i was to cut off the MAF setup on this tube, and take the MAF section out of the HKS one and hose joint it to my new tube it should run fine?

[Wiretap]

 V8WRXSTI']

[quote name='Wiretap said:

Are you still using an appropriate MAF tube? Or is it a custom one? MAF sensor tubes are calibrated and don't like being messed with.

Also, some air filters can cause turbulence which causes the MAF sensor to misread...

/quote]

Custom tube, Should be fine tho. its all set up right from what I believe. If it was the MAF tho surely I would be having the same problem with the HKS mushroom filter on it?

Not neccessarily. Messing with the MAF tube is never a good idea though, as it can cause mis-measurement of the air leading to your car running either too rich or too lean

So in Theory.... If i was to cut off the MAF setup on this tube, and take the MAF section out of the HKS one and hose joint it to my new tube it should run fine?

In theory, yep. You have a better chance of it running fine using the HKS MAF tube that's for sure. I haven't extensively tested the newer MAFs, but older ones had some spectacular error if the filter was wrong or missing at higher power levels.

[V8WRXSTI]

mmmmm I think ill get the pipe back I copied and fit that one up and see what happens. I copied a pipe my mate had done for his verison 7 STI. The only difference between his pipe and mine is that mine is made out of stainless(his is aluminum) and my MAF sits 2mm lower then his. If its not the MAF what else you reckon it could be?

[Wiretap]

 V8WRXSTI said:

mmmmm I think ill get the pipe back I copied and fit that one up and see what happens. I copied a pipe my mate had done for his verison 7 STI. The only difference between his pipe and mine is that mine is made out of stainless(his is aluminum) and my MAF sits 2mm lower then his. If its not the MAF what else you reckon it could be?

Worth noting that you should leave about 4 inches between the MAF and any big bends. Most of those intake relocation systems have the MAF in the centre of the straight section between the guard and under-manifold pipe. The pipe you copied may have had baffles and/or vanes in the curves to stop the flow distorting.

[WRXONP]

is your maf inside the guard?

i would move it back to the engine bay

then it wuldnt matter about filter at all as changing turbulence into the pipe wouldnt effect the maf

plus you wouldnt want the maf geting wet and getting bungggg

[johnny5]

yup was gonna say the same thing. Its the one difference that I can see in the second pic unless I'm blind and its in there

[V8WRXSTI]

 WRXONP said:

is your maf inside the guard?

i would move it back to the engine bay

then it wuldnt matter about filter at all as changing turbulence into the pipe wouldnt effect the maf

plus you wouldnt want the maf geting wet and getting bungggg

Yeah MAF is about 2 inch's to the left of the blue hose joint you can see the wires going into it in the pic.

[RA_Jay]

yeah id definatly put the MAF back into the engine bay. seen what kind of trouble can be caused by getting water into 1 . if i was you id take a section outta your stainless pipe, just enough for MAF and a rubber connector either side. and then just put the stainless steel piece you cut out where you MAF is in pic 2 to keep filter in same position.

but it definatly does seem wierd how it works fine with hks? i would guess it would have something to do with the turbulence though.

[V8WRXSTI]

 RA_Jay said:

yeah id definatly put the MAF back into the engine bay. seen what kind of trouble can be caused by getting water into 1 . if i was you id take a section outta your stainless pipe, just enough for MAF and a rubber connector either side. and then just put the stainless steel piece you cut out where you MAF is in pic 2 to keep filter in same position.

but it definatly does seem wierd how it works fine with hks? i would guess it would have something to do with the turbulence though.

The MAF is in the engine bay, its in pretty much the same place as the old one its just been rotated 90 degrees so it going in the side of the pipe rather then the top. Turbulence seems to be the only answer I can find at the moment. Really would rather use the K&N filter over the mushroom one but the mushrooms the only filter it seems to work with.

[Wiretap]

 V8WRXSTI']

[quote name='RA_Jay said:

yeah id definatly put the MAF back into the engine bay. seen what kind of trouble can be caused by getting water into 1 . if i was you id take a section outta your stainless pipe, just enough for MAF and a rubber connector either side. and then just put the stainless steel piece you cut out where you MAF is in pic 2 to keep filter in same position.

but it definatly does seem wierd how it works fine with hks? i would guess it would have something to do with the turbulence though.

/quote]

The MAF is in the engine bay, its in pretty much the same place as the old one its just been rotated 90 degrees so it going in the side of the pipe rather then the top. Turbulence seems to be the only answer I can find at the moment. Really would rather use the K&N filter over the mushroom one but the mushrooms the only filter it seems to work with.

Even doing that check that the air/fuel ratios are healthy. Doesn't take much to mess with the MAF calibration to the point of danger, even when it 'feels ok'

[Stoffa]

is the inside diameter EXACTLY the same size?

a reflash may fix it, but using your original setup would be cheaper

[V8WRXSTI]

 Stoffa said:

is the inside diameter EXACTLY the same size?

a reflash may fix it, but using your original setup would be cheaper

Yeah the hole thing is 3"(76mm) Back to the HKS setup you reckon? Thinking about just running the new pipe with the HKS filter as it seemed to run alright.

[WRXONP]

is the stock maf tube 3 inch ?

if the tube is same as stock - then the tune wouldnt need touching - if its different - either make the maf tubing the stock size - or you need a tune as a larger than stock tube WILL be running lean

i dont see how turbulence which is down a straight pipe - around a bend and down even further can effect the maf signal

K&N filers are crap anyway they coat the MAF wire with their oil

[Wiretap]

 WRXONP said:

is the stock maf tube 3 inch ?

if the tube is same as stock - then the tune wouldnt need touching - if its different - either make the maf tubing the stock size - or you need a tune as a larger than stock tube WILL be running lean

i dont see how turbulence which is down a straight pipe - around a bend and down even further can effect the maf signal

K&N filers are crap anyway they coat the MAF wire with their oil

The stock tube has a conical turbulator baffle which the HKS one also emulates, most custom piping won't have that. (MAF can be recalibrated with a good tune though)

Another point: Late model MAF sensors are Kármán Vortex type, no hot wire/plate. So technically they should be K&N safe.

[WRXONP]

 Wiretap']

[quote name='WRXONP said:

is the stock maf tube 3 inch ?

if the tube is same as stock - then the tune wouldnt need touching - if its different - either make the maf tubing the stock size - or you need a tune as a larger than stock tube WILL be running lean

i dont see how turbulence which is down a straight pipe - around a bend and down even further can effect the maf signal

K&N filers are crap anyway they coat the MAF wire with their oil

/quote]

The stock tube has a conical turbulator baffle which the HKS one also emulates, most custom piping won't have that. (MAF can be recalibrated with a good tune though)

Another point: Late model MAF sensors are Kármán Vortex type, no hot wire/plate. So technically they should be K&N safe.

seriously ? carbon vortex? like the older mitsi ones?

if this conical turbulator is as important as it seems - i would be changing that over pretty asap !

[Wiretap]

 WRXONP']

[quote name='WRXONP said:

is the stock maf tube 3 inch ?

if the tube is same as stock - then the tune wouldnt need touching - if its different - either make the maf tubing the stock size - or you need a tune as a larger than stock tube WILL be running lean

i dont see how turbulence which is down a straight pipe - around a bend and down even further can effect the maf signal

K&N filers are crap anyway they coat the MAF wire with their oil

/quote]

The stock tube has a conical turbulator baffle which the HKS one also emulates, most custom piping won't have that. (MAF can be recalibrated with a good tune though)

Another point: Late model MAF sensors are Kármán Vortex type, no hot wire/plate. So technically they should be K&N safe.

seriously ? carbon vortex? like the older mitsi ones?

if this conical turbulator is as important as it seems - i would be changing that over pretty asap !

Similar however they output a voltage still not a frequency like the mitsi ones.

One can have the MAF re-scaled to work without adapting the baffle but it requires a tuner who knows about more than just Air/Fuel calculations and timing as calibrating the MAF is a fairly involved process.

[Guest]

Isnt it easy to reflash and delete maf in these?

[Wiretap]

 evowrx said:

Isnt it easy to reflash and delete maf in these?

As easy as tuning the car essentially from scratch, sure. But free, absolutely. Only problem with a MAF delete is that any modification is going to require further tuning.

[Guest]

 Wiretap']

[quote name='evowrx said:

Isnt it easy to reflash and delete maf in these?

/quote]

As easy as tuning the car essentially from scratch, sure. But free, absolutely. Only problem with a MAF delete is that any modification is going to require further tuning.

which is best to do to get the most out of mods anyway...i have no idea on difficulty though im a numpty with this sort of stuff. leave tuning to people i can trust.