Is the 280Z stock air box filter less restrictive than an aftermarket cone intake?

If you compare both filter styles, the stock filter seems to have as much surface area.

Stock:

Aftermarket cone:

If you were to unroll the cone filter, it would seem to be the same size as the stock filter.

The stock air box doesn't look that restrictive either:

I was just wondering. I have the aftermarket cone intake, but was considering putting in a stock air box if there was no actual gains from having aftermarket.

I don't know, I had both on my 78 at one time or another. It looked and sounded cool , but I couldn't really tell any difference performance wise.

The cone filter is made of oiled cloth and can be cleaned, reoiled, and reused. The stock filter is paper and cannot be reused. K&N is the main (original?) company making the cone type of filter. There are copies, of course. K&N claims thier filter does not restric air flow as much as the paper types when they get full of dirt.

The cone filter is made of oiled cloth and can be cleaned, reoiled, and reused. The stock filter is paper and cannot be reused. K&N is the main (original?) company making the cone type of filter. There are copies, of course. K&N claims thier filter does not restric air flow as much as the paper types when they get full of dirt.

I used a K&N drop in filter in the original housing as well as a K&N cone filter on the CAI, so they both could be cleaned, re oiled, and reused.

A friend dynoed his car when he built the engine in it. The difference between using a paper filter and a K&N was something in the single digits (3 or 4) nothing noticeable.

A friend dynoed his car when he built the engine in it. The difference between using a paper filter and a K&N was something in the single digits (3 or 4) nothing noticeable.

I think we've got a couple of differnent directions going. His question was about a stock air box vs. an aftermarket intake rather than a paper filter vs. a K&N filter. I only added that a K&N filter could be used in either.

FWIW (no hands on experience with a 280--i drive a 240), stock airboxes typically go to a resonator. As well, they are limited to drawing air from any openings which the airbox may have. With a cone filter, you are no longer utilizing the box and are drawing air from all its surroundings (albiet hot air). From experience, I've noticed better throttle response without the airbox on my other cars.

FWIW (no hands on experience with a 280--i drive a 240), stock airboxes typically go to a resonator. As well, they are limited to drawing air from any openings which the airbox may have. With a cone filter, you are no longer utilizing the box and are drawing air from all its surroundings (albiet hot air). From experience, I've noticed better throttle response without the airbox on my other cars.

There is no "resonator" and how did you quantify "better throttle response"?

There is no "resonator" and how did you quantify "better throttle response"?

A quicker response to any pedal input.

This is especially noted on rev matches and heal toe.

My results were from 2 cars which had very restrictive airboxes (despite K&N dropins), however.

Lastly, since it seems that the 280 doesnt have a resonator, the difference may be negligeable or simply non existent.

A quicker response to any pedal input.

This is especially noted on rev matches and heal toe.

My results were from 2 cars which had very restrictive airboxes (despite K&N dropins), however.

Lastly, since it seems that the 280 doesnt have a resonator, the difference may be negligeable or simply non existent.

Again, how did you quantify better response? Something may feel different but not necessarily be different. The airbox lies upstream of the throttle plate. If the airboxes were truly very restrictive, as you say, then you would see a power increase over the entire powerband because of decreased pumping losses. Throttle response, which people seem to love to talk about, is a seemingly subjective subject which is ultimately dictated by the volume between the throttle plate and intake valve, and definitely not before the throttle.

But this is getting to be a didactic digression. I seem to be all about alliterations today.

FWIW (no hands on experience with a 280--i drive a 240), stock airboxes typically go to a resonator. As well, they are limited to drawing air from any openings which the airbox may have. With a cone filter, you are no longer utilizing the box and are drawing air from all its surroundings (albiet hot air). From experience, I've noticed better throttle response without the airbox on my other cars.

Note the picture in post *1. The stock 280Z air box draws air from in front of the radiator, just behind the center-right side of the grille. Pretty much the same area that the aftermarket one does (post #2). As 'cool' and area as it could draw air from. I drove the car for 12 years, alternating between the two systems, using the stock setup for emissions testing. The air still has to make a sharp right turn and then a sharp left turn in either case. I didn't notice any difference in throttle response.

Edited October 26, 201113 yr by sblake01