Just wondering what you all prefered, a pattern performance filter or an induction kit of some kind.I have been looking at both types for a while and in trying to keep the car as standard as possible i went for the Green cotton pattern filter. Not expecting any power gains though just clean air.Thanks to Pete at waxacar nice guy and very helpful. Check out his website at waxacar.co.uk

 

i take it you mean panel filter ?? as an airbox direct replacement ??

 

i think thats what he must mean

 

i think thats what he must mean

 

yep just a direct replacement but a better quality item..

 

im a she

 

i should of noticed that sorry opppppsys
green one is good. i went for the K&N :-)

 

yep i had a k+n in my beem and it seemed fine i supose just knowing you have a quality make is peace of mind and any kind of performance gain no matter how small is just an added extra

 

The difference in power between panel filters is so small it is hardly worth bothering about. What is noticable is the difference in filtration ability. The disposable OE panel filter is a pretty good item as it is.

 

I bet that falls on deaf ears Harvey.

 

daft question, but how long do panel filters last for if not used

ie can I buy one now, and just keep it in the garage till I need one, or are they coated / impregnated and will dry up if not being used ?

Only reason I ask, is that my Scoob is currently off the road for a while, but needs new bits like panel filter, oil filter etc, but I was thinking of buying the bits as and when, then putting them all on when I come to put the car back on the road

 

One of the "New Age Impreza Modifications" articles off the main forum menu looks into this in some depth, worth having a look at. My impression though is:

Without any other mods, there'd only be a slight gain from any change to the filter, but if you're doing other mods the better breating would probably be necessary. Powerstation's performance upgrade, for example, uses the K&N replacement filter, which lasts for life with an occassional clean. Seems to be an integral part of the upgrade. The article I mentioned earlier describe how they fitted an induction kit and it took in too much air, leading to surge and a drop in performance. The message would seem to be, if you're planning other mods make sure that any filter modification is done to balance the flow of air in to the engine against the flow out. If you fit a 3" exhaust you need to ensure the engine can draw in enough air to take advantage of the better expulsion; on the other hand if you change the induction system you need to make sure the engine can get rid of the extra air.

There's an interesting DIY mod (a "resonator-ectomy"!) described on ScoobyTuner that sounds promising, but I haven't had the guts to try it...
http://www.scoobytuner.com/tuning/?tSfID1=19&tuningID=9

Hope this helps

Dai

 

I had a green panel filter fitted for a while, but was concerned about the filtration. I replaced it with the genuine subaru fitment filter £11 in your local dealers, and to be honest the performance was the same.
So in my opinion there is no point in getting a 'performance' panel filter if you are running 300hp.

 

Ive had a HKS cone induction kit on a classic for 6 years...Dont know if they still make them like this but its very fine mesh stainless steel. When the service is due I scrub it with soapy water....PS I dont think it was meant for a scoob i had to miss out some bits to keep the MAF standard. I know the price of parts is comming down but this part was priceless....no solvent or messing. The scoob geeks i know call it the wash and go.

 

Having invested in rolling road time to investigate the performance of various panel filters and separately, the effect of running without the resonator box, I completely disagree with the article linked above and that view is re-enforced as there is no data to support the claims of more power.
The resonator does NOT restrict air flow.
Something like 8 or 9 bhp was lost on a 335 bhp car when removing the resonator. This was restored when the resonator was refitted.
Four well known panel filters were tried. The total performance differences, best to worst, was 2 bhp.
The best power was obtained from the filter we now know had the least filtration ability. It could pass surprisingly large amounts of dust particles and some grit.
As the results from the various filters and the deletion of the snorkle were contrary to what was expected, the experiments were repeated with the same results.
The actual figures were published on S/Net sometime ago for all to see. Someone might be able to dig them up and post a link on here.
The car in question was running an O/E Subaru ECU. With a mappable ECU it may have been possible to reduce the power loss.
I concluded that the O/E panel filter was good for filtration and performance. If a reusable panel filter was required, I would choose a K+N but that would be for recycling reasons and not performance gains.

I believe that in removing the snorkle, the air flow presented to the MAF sensor is very disturbed whereas air flow through the snorkle to the MAF sensor is smoothed out.

 

They also call it the MAF sensor killer, due to its vastly inferior filtration properties. Probabaly one of the top ranking filters that can be the trigger factor associated with causing melted pistons and shock loaded big end bearings, especially on a MY98-00 car.

Simon, this is the aftermarket "performance" part industry we're talking about. It HAS to be better by default, just look at all those wild claims on the box

 

6 years!
most of what they tell you your car needs to be filtered from is pants....most of the finer or organic crap will burn in the combustion process....As for MAF killing the MAF switch is just a pot actuated by a padle in the air flow....Give it a clean with some swith lubricant if its towing.

 

I had one of those stainless "fine" mess jobs on my motor for a short period, never again....within a couple of days of running I could see small particles inside the inlet (and that's the ones that stuck to the walls!! ). Changed it for a Hyperflow cold air induction kit and then massive K&N filter and then enlarged MAF tube (of course the process of upgrading here follows alot of other mods including stages of exhaust, turbos and bigger engine). K&N is very good bit of kit...not seen any rubbish on the inside ever, even after a couple of cleans.

 

The Mass AirFlow Sesnor (MAF). Is not a flap type sensor, I haven't seen one of them on a car since the end of the 1980's. Unless your car is a 1980's VW golf or 80's Range Rover, it won't be a vane type sensor.

The sensor fitted to the Impreza is a hot-wire type sensor, there is no flap, there is no potentiometer. There are several thin resistive wires placed across the intake tubing that are heated, where the cooling effect of passing airflow affects its temperture and thus its resistance.

When the wire is coated in crud, it does not cool correctly and will result in inaccurate fueling. And how often does the average car owner check the cleanliness of the sensor?

Then there is the added factor of how delicate and susceptible to failure the sensor is on MY98-00 cars. Especially when vibration is added caused by some kits being bolted to the engine or coolant tank by the cone filter's fitting kit where some don't use any rubberised fittings.

It well documented on this site. I should not need to express this any futher

 

im sure your right i will remove my MAF tommorow......just to have a look. But after 6 years you cant call the HKS cone a MAF killer.


ill even hook it up to power...you have a repair manual for a classic you wanna sell?


would you mind checking my post on money saving since you have such knowledege of the electrical system of the scoob?

 

Harvey

When the resonator was disconected was the cold feed reconnected using the link pipe mentioned in the scooby tuner article or was it left disconnected. Just curious to see if its worth removing the resonator and using link pipe to reconnect minus the resonator box.

 

Harvey

When the resonator was disconected was the cold feed reconnected using the link pipe mentioned in the scooby tuner article or was it left disconnected. Just curious to see if its worth removing the resonator and using link pipe to reconnect minus the resonator box.

 

When changing any of the induction track components it will have an influence on the airflow signal past the MAF, this in turn will change the fueling and ignition timing.
In order to properly assess the effects of any mods you MUST remap to optimise the tuning. Simply swapping bits on a std ECU only confirms that the airflow pattern changes, it doesn't tell you if it is better or worse.

An example of this is on my own Spec C, I just fitted an APS 70mm cold air kit and lost approx 10bhp. Having fitted this kit to a considerable number of similar cars, I know for a fact that once mapped to suit the revised airflow pattern I will end up with more power.

Andy

 

been there done that - does bugger all to remove the resonator performance wise.

it does mean that you can hear the std dump valve better and more turbo whine though. whether that is good or bad is up to you

 

Agree on this.

This is my set up:



89mm ducting goes straight to the input of the standard airbox with green air filter.

When mapped to suit this, the additional air flow was quite noticeable. Now flowing at around 294 grams/sec.

Water ingress is negligible too - even on very wet days there is no water going up to the airbox.

 

There was no link pipe. The feed to the air box was sealed to the inner wing and the duct above the headlight was still in place.

 

So Lisa wat will we be doing next? I hear my till ringing lol :-)

 

Apexi flat panel filter, no oil no maf problems - or stick with paper and change more often. K&N = oil