Sheady

Hi All,

I want to upgrade my Air Filter on my Scooby Impreza 2000 AWD 1999, what is the best buy, I have look at Induction kits but there is no room with the rad, please can some give me some advise.

Thanks

Splitpin

There's plenty already written on this subject so Search is your friend.

Not sure what you mean about there not being enough room to fit an induction kit because of the "rad". You presumably know that you remove the airbox and regular induction tract, and fit the induction kit in the space its removal creates?

Short answer is that if your car is standard or modified below a level of around 350-360bhp, the best way forward with an induction kit is not to bother with one. If you want to upgrade, fit a replacement panel filter from the likes of K&N, Green or Cosworth.

r1c

iTrader: (9)

Got a green panel in mine pal. It's the way forward. I fitted a induction kit a year or two ago was on for 1 short trip! Sounded great car had no power!! I had a mate who had a hks mushroom appeared to have no Ill effects. It's really not worth spending the money to find out. Get a good panel filter!! As splitpin says green, k&n or cosworth.

Sheady

Thanks for the advise

initialD

iTrader: (2)

if u are gonna get an induction kit i strongly reccomend aem cold air ,had one on my type r sounded amazing and as far as induction kits go are the cream of tha crop hks and blitz seem overated to me considering the price . im confident u will notice tha difference mate

jura11

iTrader: (7)

I'm recently upgrade my Scoobie with FMIC and Cold Air Induction Kit due i fit new carbon bonnet from Vis Racing(big thanks to Neil- Slowboy Racing ),my recommendation its buy Aem cold air induction kit or any induction kit(its worth little hassle,on my Bugeye i never have problem with MAF or whatsoever),when i first turn car OMG this sound....

initialD

iTrader: (2)

did u have to fit fuel pressure regulator with your front mount ? ive got a bugeye too
would u reccomend fmic ? notice much difference ? im just sendin one back as got it from ebay £200 and quality is terrible even for that money
but i think a turbo motor aint complete til it has one lurkin behing tha bumper

jura11

iTrader: (7)

No,i dont have fitted fuel pressure regulator,but good idea
I recommend for everyone FMIC(difference i can feel and,but end of this month i go on remap),if you buy cheap FMIC you are sometimes pay twice(missing parts,missing fitting manual),but worth little hassle and money(i pay for fitting 250£).

initialD

iTrader: (2)

sounds a good price , i didnt get fitting guide or even a reciept ! ill get a huuuuge 1 one day til then might go for top mount and aem indution as only got pipercross panel at the mo ! cheers mate hope u get good results from ur mappin session

harvey

iTrader: (48)

Per the advice from Splitpin, if your car is lightly modified and below 340-350 bhp stay with the OE airbox. If you want a bit of induction roar more than you have just now fit a K+N panel. The only advantage is that the K+N panel can be cleaned and reoiled and has a quarter million or million mle warranty or something like that but it won't make any more power than your OE cardboard panel. 350 and beyond in my experience and you fit the largest cone you can fit in the space available.

alcazar

iTrader: (2)

You should see the one Harvey put on mine..............

It replaces one he said was "suitable for a lawnmower"

harvey

iTrader: (48)

What I said Jeff was it was not suitable for my lawnmower which has been modified
Always fit the biggest air filter you can get in the space available for any turbo charged engine.

joz8968

iTrader: (13)

FTR, the 'new' Do-Luck foam - yes a foam one!?! - OEM style panel filter was tested by a specialist for a magazine's air filter group test article, and it outperformed all contenders in BOTH torque and bhp gains. Other protagonists were K&N, Green, Cosworth, ITG, etc...

Being foam, it also filters great too.

topshot

iTrader: (4)

Stick with panel filter, Pipercross, Cosworth etc as above the do-luck from sumo power looks worth a punt

harvey

iTrader: (48)

Link to the test???
My experience of filtration ability of foam filters has not been good. HKS in particular.
When I tested four pannel filters the power spread was less than 2 bhp. The foam gave the "biggest" power figure but was clearly poor on stopping particles as large as grains of sand. The O/E filter and K+N were the same with the STi trailing but that had best filtration. !.7 bhp spread from "best" to "worst"

Splitpin

As if one thread wasn't enough...

That's a bit of a non-sequitur. It's a bit like saying that this pencil sharpener, being made of aluminium and steel, would make a fantastic engine block.

One could probably more accurately say that being synthetic foam, it's probably great at allowing its liquid filter medium to be sucked out into the induction tract. Daresay you could get a 12bhp power increase if your MAF sensor is covered in gunk.

joz8968

iTrader: (13)

That's not to say that others produce 0 bhp. The others, on average, were around 10-11bhp, so it's a moot point anyway. At least it looked like they were tested under like-for-like conditions. Now whether those gains are due to solely the filter itself, is highly debatable...

Also, I thought foam was supposed to be better than paper or cotton at dirt filtration - hence why usually it's bad for airflow through it... hence why most punters don't go for them...?


EDIT: Reading harvey's post above, I've got it **** about face. Foam traditionally good for airflow/power, bad for filtration?

Splitpin

So are you saying that in this test, all the aftermarket filters gave 10-11bhp more than a standard paper one, while the Do-Luck "won" with 12.9bhp "extra"?

It's not really appropriate to generalise in either direction, there would be too many exceptions to the "rule".

I don't think Harvey is saying that. What he was saying was that of the filters he tested, the one with the worst filtration performance was a foam unit. You seem to be interpreting this as a generalisation.

I'm sure it's possible to design a foam filter that filters as (if not more) effectively as a cotton gauze one. It's all a question of how thick a piece you use, and how small the cell structure is. Although if you design a filter so effective it could stop everything, no matter how small, it'll probably restrict power so everything is a compromise.

Unless, I wonder if you could fit a Dyson vortex unit under a Subaru bonnet...

joz8968

iTrader: (13)

Yes you got it. So the Do-Luck "won" by a margin of c.1 to 3 bhp more than the average of all the others.


I might fit one of those post-air filter/pre-MAF mini electric "supercharger" eBay special efforts LOL... Bound to give a gazillion extra bhp. And all completely safely too.

harvey

iTrader: (48)

From what I have done with air filters I have come to the conclusion that metal mesh and the foam I have tested offer very poor filtration properties. This includes filters from Blitz and HKS. The filtration offered by the OE Subaru panel filter is good as is that offered by the oiled K+N. The OE cardboard gets dirty and clogs up quite quickly in dusty atmosphere much the same as the K+N. The advantage of the OE cardboard is that it is cheap but if you are working in arduous conditions don't expect more than 5000 miles before its restriction is already increasing alarmingly. The advantage of the K+N is that you can reuse it with a relatively cheap cleaning kit.
Stories of MAF failures with K+N oiled filters are another Scooby myth unless of course someone has oiled their own filter and gone OTT with the oil and completely ignored the instructions.

Too many people change to cone filters way too early in the bhp stakes.

Far too many people run too small a filter.

They put on a relatively small filter which acts as a constriction on the inlet tract and there is a pressure depression or vacuum in the inlet tract when measured against outside ambient atmosphere. The turbo impellor has to work against this. To measure the depression I use a Magnahelix guage and it is with the use of Magnahelx guages that I have come to realise how large an air filter needs to be to support whatever power is required. There may well be an Apexi cone filter to support upwards of 400 bhp but I have not seen one yet although I hear people raving about Apexi cone air filters and as far as cold air kits are concerned, because you cannot get a big enough filter in the inner wing I think they start to become a constriction somewhere before 400 bhp and well before 400 bhp in many cases.

Now this is what I have found having put in a fair bit of effort and being as careful as possible in drawing my conclusions. I do wonder why people purchase filters based on glossy advertising. Find out if the company has a technical laboratory and if they can quote CFM for each filter at whatever depression and then you will be making informed choices but if they have no technical data published and don't support a technical department chances are the filter is not much use and has to be sold on the back of glossy advertising and flowery bumff.

joz8968

iTrader: (13)

Huge K&N with tuned trumpet every time.

harvey

iTrader: (48)

Jeff, can you put up photos of your set up.

Saint AAI

I can confirm that a Blitz SUS is very poor at filtration. I really need to get rid of mine, I'm changing MAFs far too frequent, and the last one that went was covered in a fine black sooty deposit.