Some intake questions

[Pomorza]

Hey guys.

Last night I did a basic run down on my engine. I do it every week to make sure that all the fluids are where they should be and there isn't anything interesting happening that I'm not aware of. Well I come to find that my air filter is rather filthy. I was thinking of switching over to a K&N filter (the one that goes in the stock box). I came across this earlier this morning. Anyone have any issue using the K&N filters? Any drawbacks to using them?

Secondly. Can someone explain to me what a BCCD does? For what I remember from reading my FSM (which I can't find now) is that it helps keep idle up when you release the accelerator. Is this true? My Z's idle will randomly drop to 600 sometimes when I let off the gas when I come to a stop. Does it more at night then in the day.

Thanks

Jan

[hogie]

Perhaps they cleaned and then over oiled their filter in that pic. I can't say about a z, but I have run a K&N filter on my 2 dakotas and an S10 without any ill effects.

[sblake01]

I've never had a problem with K & N drop ins in any vehicle I've used them in. Had them in my Z, my 810, my 320 Pickup, several other prior owned vehicles and presently have them in the vehicles we own now. The BCDD is an emissions control device that reduces HC emissions during off throttle coasting. It's triggered by intake manifold vacuum and allows an additional source of air and fuel to enter the intake manifold during deceleration to compenstate for the change in mixture. A problem in that circuit could have an effect on idle.

[mlc240z]

From what I've read, if you're looking for more 'performance' because of a 'better' air flow, you'll be disappointed.

K&N might flow a 'little' better but the tradeoff is usually the same or worse filtering of dirt than OEM/aftermarket stock filters.

The only benefit I would consider is the fact you can reuse them by cleaning and re-oiling (properly) the filters.

If it will last sort of indefinitely ($50 vs $15) due to the better construction/quality/nature of the filtering material, then it's worth it.

[Pomorza]

From what I've read, if you're looking for more 'performance' because of a 'better' air flow, you'll be disappointed.

K&N might flow a 'little' better but the tradeoff is usually the same or worse filtering of dirt than OEM/aftermarket stock filters.

The only benefit I would consider is the fact you can reuse them by cleaning and re-oiling (properly) the filters.

If it will last sort of indefinitely ($50 vs $15) due to the better construction/quality/nature of the filtering material, then it's worth it.

I'm not looking for "performance" as much as something that'll last a bit longer than normal paper filters. I have one in my brothers jeep that has been there for nearly six years now with no issues. Do k&n filters filter the air as well as say normal ones would?

[Z train]

When the truck was dyno'd recently,there was a ONE HP difference between a paper element & no element.

[Gary in NJ]

I use K&N filters on everything but my Z. I just don't put enough mileage on it to justify the expense. The paper filter does a better job of filtering, but I make that trade off on my other cars and motorcycles (my airplane too).

The job of the idle solenoid is to increase the idle and to keep the engine from stalling. At night there is more load on the engine due got the lights

[ozconnection]

"A plane that never lands, and a boat that never comes to shore" was a quote from David Vizard about the only times not to run an air cleaner of some sort. I think we all know what happens to our engines internals without some form of filtration. We wouldnt run a fuel line without a filter. Same logic here.

I use K&N filters in my car. I did a lot of dyno testing myself to dispel the BS on these things. When I replaced the paper element with a K&N, there was no power increase. Changed the filter box and power rose. It was the filter box that was restrictive, irrespective of the filter I used. I still believe that the K&N is a good product and the variety of styles they have for custom applications is impressive.

The dirty throat on that image you posted Pomorza is from the phenomenon called "intake reversion" and not from the K&N. I have seen this many times on carbed engines, especially on those where the owner likes to 'tune' their carbs themselves. They often set them up a little rich to smooth out any flat spots from lean mixtures and because of reversion, fuel residue is left staining the throat of the carb like in your picture. Another term for this phenomenon is 'standoff'. Its created by the firing order of the engine and the type of intake manifold used ie dual plane. I saw a cloud of air/fuel mix sit 6 inches above the throat of my Holley using an Arizona manifold once and thought "WTF is that?" I did some investigating and that is what I learned. Adjusted the jets to take into consideration this event and my power and torque rose substancially.

Leave it stock to play safe.

But to modify is to investigate and learn. That's the part I love.

Cheers.