biker1

Tonky removing your lid certainly makes a diffrence but only in the noise department, in the power dept you will loose power why? because you are putting hot air in to the system and not cold. The engine will produce more power on new fresh air, that is why you see and hear the threads on CAI (cold air induction) people trying to get some sort of system to bring cold fresh exterior air into the air box. By taking the lid off all you are getting is the hot stale air from under the engine bay, it may be getting a greater volume of air with the lid off (so you think its breathing better) but its the wrong sort of air.

volume hot stale =

volume cold fresh =

volume cold fresh ram effect =

Tonky

BIKER1:

Gracias

awinskill

There's a big thread on this over in the Petrol Head's forum. The general concensus is that taking the top cover off makes for a slower car due to the hot air intake. Also, there was an opinion that the ECU will adjust to compensate for the potentially increased air intake. Views were that the ECU is conservatively setup to protect the engine.

When I drove without the cover on I definately thought there was much better pickup in mid range. Felt like there was much more torque. (The weight transfer felt more pronounced). Top end didn't feel as strong.

The noise was incredible - I'll go for that on Sunday purely to intimidate the ITR drivers!

When I put the top cover back on I noticed that the intake was definately dirtier and there was a nice set of fly's in the grooves. I took the air box off my ITR; sounded great until went through a deep puddle. It gave a cough and a splutter and picked up again. Air box went back on like a shot.....

Andy

Tonky

Actually I've put my lid back on a few minutes ago. I noticed that on tickover with no revs at all there was a pronounced hum from the engine, very high pitched almost like the cooling fan was running(which it wasn't). Stopped as soon as I put the lid on

biker1

Tonky don't think theres somthing wrong just with yours making that humming sound, they all do it when you take the lid off or increase the air flow. Anybody know what note it is? b/flat?, C perhapse

awinskill

Yep, mine did it too. I just assumed it was the air in the intake vibrating.

Definately b/flat

Did you notice how it disappeared under an open throttle?