280Z gets new lungs – K&N Filter Intake

 

 

The Datsun 280z gets a new cold air intake!

I’ve had this part for a little while rolling around in the back, thought I’d take a few minutes to see how it works.

Among all the intakes on eBay, I figured it’d be just as easy to make my own. Here’s what you’ll need:

– K&N Air Filter – various models can be used. I decided on the K&N RC-4690
– Spectre cold air intake – model #94990, 3″ 90 degree aluminum elbow
– some Windex
– Philips and flathead screwdrivers

Just a few notes before we begin, the Spectre 94990 is a 3″ diameter tube which is just larger than the original intake opening, so getting the original intake boot on the elbow is a bit tough. Hence, the Windex.

1) Use the philips screwdriver to remove the original intake from the car frame, also removing the plastic intake extension, and loosing the intake-to-AFM boot

2) Attach the K&N filter to the elbow, tighten

3) Fit the elbow to the intake-to-AFM boot (you can use some Windex here to help it slide on). It’ll be a pretty tight fit, but it’ll go on. You can also use the flathead screw driver to help get that last bit of lip over the intake tube.

Estimated completion time: 30min – 1hr

 

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All the parts laid out…

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Dry fitting the K&N intake to the Spectre elbow – a 3″ ID (inner diameter) filter SHOULD fit on a 3″ OD (outer diameter) intake.. right?

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And installed!

Now to tune this beast…huh, kinda runs ok without doing anything.
okok, so now to strap this down so it doesn’t wiggle off…

Smog-xperiment

Oy.

280z still didn’t pass. But got some useful data.

From the previous post, I installed a new catalytic converter, popped in new spark plugs, and re-filled an empty tank with 87 octane. Here are the old / new numbers:

CO% Levels   1st Try   2nd Try  
Speed MAX AVE MEAS MEAS
15 MPH 1.36 0.17 2.03 1.73
25 MPH 1.16 0.15 2.66  n/a

1st Try: Catalytic converter was supposedly original, but no numbers when inspected. Bosch Platinum Plus spark plugs had heavy carbon buildup. Ran 91 octane gas.

2nd Try: New Magnaflow catalytic converter, NGK spark plugs and 87 octane gas.

Thankfully Nguyen from Smog Tech did a quick CO% test just to see where we’re at. It ran steadily at 1.73% CO, just 0.37% more than MAX. Okay, time to adjust the 280z’s AFM (Air Flow Meter) to run a bit more lean air/fuel mixture.

3rd times a charm, right?… right?