If K&N's are so good........

[Fanum]

Ok. this may be a really stupid question but I've been wondering....

On a turbo diesel car, a K&N air filter is supposed to add up to 15BHP.....on a GS, it's less but still allegedly significant.

So they do this by allowing more air to flow???

In that case, why don't you get an even bigger increase in power if you just take the air filter out?????

My Saab TDi air filter got clogged one day so I took it out...no difference.
It makes no difference in the Zantia...and after a fording day, the filter in my Adv got soggy so I took it out to dry.....no difference....nada, zip.

So what's that all about then huh???

 

[Schtum]

On a turbo diesel car, a K&N air filter is supposed to add up to 15BHP.....

Hmmm.....pinch of salt with that please.

Apart from that, K&N having been getting a fair bit of bad press recently. Some tests suggest that their increased airflow is achieved at the expense of filtration.....

 

[Fanum]

Hmmm.....pinch of salt with that please.

Apart from that, K&N having been getting a fair bit of bad press recently. Some tests suggest that their increased airflow is achieved at the expense of filtration.....

I don't doubt that at all.....how can you increase the flow without losing filtration (unless you get a fancy cyclonic filter like wot me old man designs and makes for nuclear power stations ) ......but why doesn't the power increase (by 'seat of the pants dyno anyway) when you remove the filter altogether???

 

[2 wheel humvee]

up to 15BHP.....

"Up" and "to" are the words you're not paying enough attention to
Clever but subtle wording,as with all forms of good advertising.
The horsepower at the expense of filtration may be a valid one,and has been done to death elsewhere and maybe even here

My take on the "up to 15bhp power gain" is that you Might see it if you carry out other mods to improve the engine's breathing via exhaust and fuelling etc.But 15bhp from an air filter alone? I don't think so
If I were you I'd be looking at "pre filters" and a snorkel kit for where you're planning to go, and carrying a spare filter or 2 at all times given your lust for water crossings
Good Luck with the venture Bill

 

[Steptoe]

Removed my K&N , went back to standard air filter. No fecking about cleaning, oiling and worrying if it's letting to much shite into the engine.

Standard so much simpler - Just chuck the old filter, put in the new one .

 

[Fanum]

Hold on a sec, rewind......read the original post again.


I'm not after a power increase....really.

I don't want to fit K&N's, or understand that they don't filter as well...that's just logical and common sense......

My question is very simple......

If a 'sports' or 'power' filter like a K&N is supposed to increase BHP by improving the breathing (and the figures were just top of the head figueres..again, I'm not interested in those, they're just numbers...)...then why doesn't the engine get even more power by breathing freely WITHOUT a filter???

It's not big, it ain't clever fitting one, but where does the logic break down??


I honestly don't want to fit anything, I just want to know

 

[Steptoe]

It's not big, it ain't clever fitting one, but where does the logic break down??


I honestly don't want to fit anything, I just want to know

People pay their money, and like to think it really is that simple to gain a few BHP.
So they convince themselves it's made a Huuuuuge difference to their bike.

Like most of the other stuff that you just add/plug in and will increase BHP - it mostly doesn't, it just alters the engine characteristic, so the punters that have paid out the money think it's improved .

 

[Fanum]

People pay their money, and like to think it really is that simple to gain a few BHP.
So they convince themselves it's made a Huuuuuge difference to their bike.

Like most of the other stuff that you just add/plug in and will increase BHP - it mostly doesn't, it just alters the engine characteristic, so the punters that have paid out the money think it's improved .

That's what the implication is when there's no improvement with no filter...but shirley the ad standards people would shag them over for the claims??? there must be something in it.....we've had dyno prints showing improvements in power curves with K&N's in......so why doesn't the no filter thing follow on and if it doesn't, where's the line and why????


Surely someone must know???

 

[Schtum]

That's what the implication is when there's no improvement with no filter...?

Maybe there is an improvement with no filter. 2 or 3 bhp is quite difficult to detect via the seat of your pants. If you really want to know the answer, book some time on a rolling road, armed with OE and K&N filters and also do a run with no filter in the airbox.

 

[(RIP) Kaister]

I hate K&N's for road use - too much pissing about - as steptoe says.

I'm sure we've been over this before - but most std air filters show NO appreciable pressure drop across them at air flows in excess of the max volumetric flow of the engine.

In the 70's - 80's - maybe ? Not anymore.

Trucks use cyclonic oil bath filters - no elements and 500.000 k's between services

and yes - bill - no filter is the same or better than a K&N - but the only thing that a filter MAY do is stop induction turbulence and pressure wave fluctuation.

 

[Fanum]

most std air filters show NO appreciable pressure drop across them at air flows in excess of the max volumetric flow of the engine.

Cheers...that makes sense.

Have you seen those cyclonic inserts???

SS jobbies like jet engine blades..supposed to induce air spin in the induction to mix fuel/air better....

 

[harry]

Will the engine not run too lean without the air filter?

 

[(RIP) Kaister]

Have you seen those cyclonic inserts???

SS jobbies like jet engine blades..supposed to induce air spin in the induction to mix fuel/air better....

drop some pepper into a glass of water - then give it a stir.

all the pepper re-combines in the centre.

if the fuel droplets did this in an air stream - then its a bad thing.

however - centrifugal forces and specific densities may cause different actions depending on the vortex speed

 

[IainMac]

More air flow usually needs more fuel to obtain extra power, unless your already running on the rich side of optimum when more air flow will liberate a couple of extra horses (if your lucky). Usually what happens is you'll end up running leaner and might end up with the same or less hp so unless you have a means of balancing the air/fuel ratio your not getting much benifit. And as stated above that doesnt even consider what the negatives are (less filtration!)

 

[motobiker]

It's simple... you want a faster bike?


paint it Black !!!

 

[turbine_2]

Got to say, I can tell the difference between and old filter and a new own in my discovery, though I haven't run it without one to see if that makes a difference.