Wow I never ever heard a car sounding like that 300ZX. To my ears UUgghh! This is nothing like the sound I have referred to. In my case the sound was an extremely high pitched whistle. I could well believe that it might be related to the alternator from what you have said. Strangely though it seemed in contradiction to what you expect, if I read you correctly, ie in my case it was perceived to be when constantly maintaining the desired speed, which was in the region of 50-60mph.

Liam - yes that is the speed - in my original post I stated 55mph upwards, Rothbard says 90+kph (56+mph). Also if you just hover with the accelerator you should be able to find the position between charging and regenerative braking charging when the sound is momentarily inaudible. The workshop controller also achieved this point when he was driving my car.

Straight cut gears are very efficient and also take some considerable abuse, that's why they are used in racing and rally cars. For the best example of how horrendous the sound can be view the video below of a racing BMW 320 STW in the Dutch Supercar Challenge:

You will probably need to turn your speakers down because at high revs it's like someone scratching a chalk board with their fingernails!!

Mind you, the driver (one Rolf Van Os) is quite incredible - in the early stages he drives like he is in a video game!

Edit: To amend incorrect kph/mph conversion.

Edited 10 November, 201213 yr by CortinaGT

Quite a driver. If it's like F1 he must have had a penalty to have started so far back the grid. The noise...well I guess ear defenders are mandatory. As regards 'abuse' I felt like I wouldn't have been surprised if the gearbox ended up being a bunch of cogs hoping down the track after the car!

Funny I noticed this noise and just turned up my music a bit louder bit late to post I know

Yep, I have this too, probably a gear whine, I'm not worried about it

I had a Suzuki Swift that did this too, except that it whined when you were sitting at a constant speed at a particular rpm in 5th gear. The speed that matched this rpm almost perfectly was 60mph

Hello Mike

Yes there are some transmission noises with the Citigo, but they are generally well subdued. If you read my post 21 above and the following couple of replies, what we are talking about is a more unusual sound, which some of us believe is the regenerative alternator. The straight cut gear things I posted were to help explain to those who have not heard straight cuts, how they sound.

So I am convinced the sound many hear is the alternator. Just part of the new technology we have to get used to and more apparent in the Citigo with its lack of sound insulation. :-)