Probably the best idea - you get the sound, better throttle response than stock, and its not too expensive.

 

Original post said it was a mid 60's evening, so probably no noticable power loss as heat soak would be minimal at best. Glad you got to hear the S without that restriction. If get were to get an aftermarket intake, it would sound great all the time .

Keep the lid on when it's hot out, but otherwise, no real issue other than having fun.

 

I used to do this every once in a while too. I got a PRM intake and I love it. Better sound plus gains in power and some weight loss.

 

I've had my S2000 for almost six years now, and have almost always left the airbox lid on. Once it finally got consistently cooler (highs in 60s and 70s, lows in 40s and 50s) and less humid down here in the Florida swamp last year, I removed my lid and secured the clips with black tape. The cooler air doesn't seem to bog it down, the loss in horspower is hardly noticeable, and the sound is terrific! As soon as it warmed up again though, the lid went back on. Plan to do the same thing this year.

 

K&N intake is so cheap, "common do it, bacardi and cola, do it"

 

So many cool things about this car.

 

I too went without the airbox cover for a few days. But in Wisconsin, heat soak usually isn't an issue.

PRM intake is one of the best for intake sound.

 

why dont you be safe and get power out of it and just put a intake on it, i have a cold air and not only did i get power but its safe to the extent i dont drive it in the rain but i never did even when i had the air box.. and if you like the noise without the air box see how it is with a cold air intake.. (K&N cold air intake if anyone was wondering)

 

Fwiw, there's nothing unsafe about having the lid off, it just makes the intake system less efficient. The only unsafe thing people do regarding intakes is put on a low-placement like an AEM and then you run the risk of hydrolock via rain and puddles.

 

i did that for a couple months coz it sounded so cool
then for some odd reason i put the lid on one day and never took it back off again

if you try it out for a couple months and put the lid back on, im sure you'll feel the power gain back!
but nonetheless i agree with most ppl here, get an intake for the best of both world, sound and.power