little Chris

I've found that when I remove the lid off the air box the fan is on almost 100% of the time. Is this normal? It can even kick in as soon as I start the engine and the engine is cold. I'm getting worried about this now, but at the same time, whilst I dont have an aftermarket Air filter I love the noise the stock filter makes with the lid off.

Now, wheres the nearest tunnel????

xviper

The airbox lid has nothing to do with the fan coming on or not coming on. Is your air conditioning turned ON by any chance? If not, then it may just be coincidence that something is amiss with the fan thermoswitch.

koala

I think you're just hearing that vacuum-cleaner sound that you'll get by removing the airbox lid, or by going to an aftermarket intake.

xviper

hehe, Now there's a thought. Have you visually confirmed that the fans are running?

little Chris

Thats exactly what it sounds like!

Thanks for your help chaps

Xviper: I should of visually confirmed before posting I suppose, but with the lid off, I dont want to stop and take a look, just head for the twisty roads and give it some serious .

Thanks once again.

Chris

xviper

No harm done. In fact this was different enough to be entertaining. Just glad it wasn't anything wrong.
A bit of a departure from "What color of S2000 should I buy?"

Lurker1222

And what intake gives the best hp increase.

SheDrivesIt

Oh, you think those topics irritate you. Take a look at the 100 Octane thread. I swear, you'll want to blow your top!
Most of the posts (not all) are really over the top.
"I ran higher octane and picked up xxx horsepower" Hmm -- think maybe you should have been running that octane all along? Or maybe you're just full of sh!t.
or --
"I ran racing fuel and it ran great but it fried my catalytic" Hmm -- think maybe it had lead in it?

SouthDakotaS2K

I thought that the whistling noise upon startup was the secondary air pump cycling? I also lost 3 hp and 2 ft/lb of torque by removing the lid on the dyno, but in defence I love the sound.

xviper

True. On start up the air pump comes on for a 1/2 minute to several minutes depending upon the temp. But he indicated that it was on 100% of the time, so this would indicate some confusion as to exactly what is making the noise. If it were the rad fan, this can be easily confirmed visually. I'm still going with the likelihood that it's just the intake noise being much louder when the lid is off.