Exige S compressor. How to test it?

[simpo555]

With the weather being very nice I've been able to blast around in my car. One thing slightly mystifies me. I was under the impression that the compressor made quite a significant noise. I don't notice much difference which makes me wonder if it is actually working. The car 'zips along' yet I find myself wondering if it should perhaps accelerate more. I feel my 'R' was perhaps more dramatic when the second cam dropped in whereas the acceleration on my Exige comes in from lower down without the significant boost. Not being technically minded, I find myself wondering if I would know if it was working or not. Could it be possible that the compressor is not working, which would still leave me with the feeling that the car is fast, without that bit extra. Is there a moment that the compressor kicks in or does it work throughout the rev range. I'm perhaps imagining things but knowing that I got a very good price for the car makes me nevertheless very wary. I've checked the history and its complete, but find no specific mention of servicing carried out on the compressor. I understand that there are belts to be changed. As stated, the car seems quick but the nagging doubt remains.

[bencollins]

A compressor is mechancially driven so it will be working unless:
belt slipping
belt is snapped

also you could have:
air leakage.
air filter dirty - maybe there's a fast flow oiled one which get dirtier quicker.
air flow or lambda sensor not reading correctly / fuel metering off.

The last one is the most likely, as dirty sensors / failing readings will upset the fuel air ratio.
Of course there is a hundred other things, dirty spark plugs or blocked injector so one cylinder is missing.
Other people will be able to add to this list.
Or press the pedal harder

[Exige77]

Get a boost gauge.

[schrodinger]

this is on an s2? if so, then the noise is unmistakeable. It's a high pitched whine, something like a jet fighter when wound up to the top of the rev range.

[Exige77]

schrodinger said:

this is on an s2? if so, then the noise is unmistakeable. It's a high pitched whine, something like a jet fighter when wound up to the top of the rev range.

You can still get the whine but if there is a leak somewhere or the internals of the SC are damaged you can lose some or all of your boost.

VOE

[Captain Muppet]

Exige77 said:

schrodinger said:

this is on an s2? if so, then the noise is unmistakeable. It's a high pitched whine, something like a jet fighter when wound up to the top of the rev range.

You can still get the whine but if there is a leak somewhere or the internals of the SC are damaged you can lose some or all of your boost.

VOE

From the OP it seems he isn't getting a whine at all, which is very odd. It's not like you can run the engine without the superchrger belt, because it's the same belt as the alternator and water pump (and AC if fitted).

[simpo555]

I confirm that I don't seem to be getting a whine which is what prompted my initial question. What I would like to know is at what moment does the whine become apparent. Its faesible as has been said that I'm simply not hitting the pedal hard enough, although I would have expected at 7000 to hear the compressor. Sorry for my ignorance but does the 243 perf pack alter anything related to the compressor. Car is completely standard with no upgrades on air filters or exhaust. Had originally thought that it might be a belt issue, but don't have any problems with the alternator or air con, both of which work fine.

Normally I'm seeing a Lotus specialist in the next coulple of weeks, albeit a French one (Dizier-Paris). For the moment at least I've no feedback positive or negative concerning the specialist. Despite living over here for more than 18 years, I'd still have a preference for a UK specialist but won't be across for some time.

[jock mcsporran]

The whine on mine isn't so noticeable over the noise of the exhaust and I didn't really notice it when I first got the car. One day I did notice a noise and it sounded like something was going to take off and explode in the back of the car so I guess that was the charger.

[The Bandit]

Get a TRD(OEM - buy from Lotus)airbox and filter for about £70, you'll hear the supercharger then alright