I don't think there is a question as to the greater flow charateristics of K&N type filters over paper. But I have to wonder why they don't help HP on LS1s, maybe even hurting HP?

Obviously there is a difference that hurts HP with K&Ns on these engines, even thought K&Ns are proven HP producers in carb applications. I've tested that myself on different vehicles at the track over the years. Not to mention numerous dyno test I've read in mags, most recently in Car Craft.

Is it because of better quality, if reduced, flow with a paper filter vs K&N or no filter at all? Might it have to do with resonance characteristics of the intake tract in it's entirety, as in an engine making more HP with a little back pressure than with none? Does the restriction of the paper filter dampen pulses, allowing better control over engine trim by the PCM? i.e. something like flow averaging?

 

i am not sure to the exact reason,but i dont think k&n even makes one for the ls1. Its a filter from a jeep that comes with a rubber seal. But buying an air filter for power is just rediculous. I have a k&n because it never needs changing....i bought the cai for power.

 

the MAIN reason is they over oil them and then the MAF getts covered with oil and reports the wrong info to the PCM.

There is a service bulliten from GM on the subject

BTW A K&N has been proven to make power over and over again for the last 20 or so years

 

Fit or over oiling is not the issue. I have a K&N on my 98, and it just takes a spacer to fit in place of the stock paper filter; spacer doesn't restrict flow at all. Over oiling makes the engine run obviously wrong, so that isn't a power loss from oil in the MAF.

Effect is also seen with no filter installed. Does the LS1 somehow need the restriction of the paper filter, at least in stock form?

Using a K&N for power is proven on carbed engines. Why does the LS1 not seem to benefit similarly?

 

hey nobie on his site but i do have some imput
i have a turbo lt1, and i have wooked with force induction for a while
i have found that the reason that the ls1 would loose power is the same reason a lt1 would loose power with just headers muffler no cats etc, but a stock paper filter and the same reason a huge cam wont make power in a restricted stock motor. things have to be matched. the ls1 has a huge potential for air intake but the stock exhaust is restrictive.

 

My first guess is the cars are going lean. Seen it time and time again on LS1s, start with little mods like that and they go lean. I would bet money that if you tune for 12.8 AFR before the filter, and then again for 12.8 after, you would see a gain.

 

I thought it was a CFM thing. Certain filters will only flow so much air. Put a small K&N on a car that only flows say 600cfm. On a 600hp car, that going to hurt performance. Maybe I'm wrong here, but it makes sence to me.


Neal

 

K&N does have an LS-1 specific filter. No spacers or buying filters from another vehicle to fit. I bought mine at advanced auto and it said chevy LS-1 on the sticker on the box. Popped out the paper one and dropped this one in, no problem. Some try to do tests in a controled enviroment, but the thing is, the ECM changes, so there is no "real" controlled enviroment. The only way to do this is to get a locked PCM like they did in GM high tech, that reads from one program and only that program. It cannot adjust for this or that. This is the best way to test small items like filters, MAF's and lids. The biggest thing going around on LS1 tech is that the filters aren't showing much of a gain over a paper filter and they don't filter near as well. Hence most people save their $60 and have a better filtering element and 1 less hp.

 

they suck anyway after the 1st re-charing, they dont filter NEARLY as effectively as new and let in a lot of crap

 

All I can say is, My K&N is fairly dirty, and I ran it back to back with and without the filter at the track and it made zero difference on my times, so it's staying in.