ok here goes...

when i accelerate "hard" and hit between 3000 and 3500 rpm i hear a noise. i can only describe it as 'a grinding metal' kinda sound from underneath the car. not knowing where from i would say it sounds like a wheel region (but i often think the sound moves - the b*****d)

it lasts for a second or so and i only hear it in the lower gears at exactly the same point on the rev counter.

Any ideas?? its irrating me know, making me paranoid although i first heard it back i september so i dont think its serious, just seems to be a lot more frequent

cheers all

Mine does this as well...Havn't really bothered about it... it doesn't sound like the engine... its more a heatshield in the front of the car or maybe the exhaust

few people mentioned the exhaust

Yeah, there are heat shields that come away causing rattling and buzzin, just get em chopped off

Chopped off??

Im sure they actual shield heat from something... wouldn't it cause damage or melt something lol

Nah, they're pretty flimsy really, i had mine remeoved over 2 years ago, and no ill effects, in fact, since the de-cat, all the heat shields round that have gone too, still no problem

Don't forget, these cars are designed to perform faultlessly in all the coutries they're intended to sold in - Britain isn't the hottest

Mark

im guessing it will pass the mot with them chopped of??

if im looking for them, where should i look?

any pics anyone?

[quote="Dai"]im guessing it will pass the mot with them chopped of??

if im looking for them, where should i look?

any pics anyone?[/quote]

if you go to the drivers side door, and look under neath, u'll se a loose piece of metal touching the exhaust, unless ur cars lowered you shoud be able to get a grip on it to undo the clip holding it on or choose my method, rip the fu**er off. ggggrrrrrrrr!!!!!!!!

nice one Rich - cars lowered, but my nans garage has the hole in the floor to access under the car - i guess i will be paying her a visit to see how she is

LOL Great excuse Dai

:lol::lol:

I had the same problem - a tinny sound coming from underneath.
Took it down KwikFit and he got it up on the ramp, said its your heatshield and rippedit off!
Problem solved!
And he didnt charge me!
Just passed MOT too, so dont worry about that.

cheers!!! as the noise gets on my tits so much - any one know why it only occurs at a certain rev??

It happens to be the resonant frequency of it.


[url=http://hyperphysics.phy-astr.gsu.edu/hbase/sound/reson.html]Explanation of resonant frequency.[/url]



Mark

should know about resonance!!! must wake up at lectures

thanks Mark

lol every time i search the net for help with uni work i end up a that site!!

sorted now dai??

lol the time it takes me to do things you'll be lucky if ive stopped wingeing by JAE

i will get round to it

You'll probably see and hear my 323f rattling around Swansea. Will have to rip my heatsheild off, if I have time might do it later.

-------------------------

You think the universe is infinite? You should see how much course work I have to do!

yeah seems a few people ar having this problem !!!

I had a look under my car for a heatsheild touching the exhaust, but there was nothing. Worryingly the noise seems to come from somewhere in the very near vicinity of the cat. Had a MOT yesterday and it passed the emissions and everything. Could it be the cat even though the emmissions are fine?

the noise is between 3500 and 4000 RPM and also occurs around the 2000 rpm mark somewhere occasionally.

I may decide to get the cat bypassed until I can find anotherone for the next MOT. Do you think this would be ok on a 1.5?

I don't think there is any moving parts in the catalyst... I really doubt that is the noise... There might be another heatshield somewhere under your car..

No, I know there are not moving parts inside that cat, but maybe the internals have broken up and started to rattle around inside it.

Quite possible - mine has!

U can de-cat too, apparently a nice little diff in performance and prob sound too!
Que Andym323!

Have fun....

With the de-cat on a 1.5, what's it like come MOT time? Anyone tried an emmisions test de-cated in the UK?

Yep I have - two independent MOT test stations and it failed twice!

Mine's a 1.8 - full custom stainless system inc de-cat.... or was should I say... CAT's back on now!

Only just failed mind.... and the guy at the test station genuinely thought it was gonna!

Ecotek and FSE fitted too.... so maybe with more time and effort ..... tweeking it may have helped.... but I was well close to MOT day and just wanted it sorted in the end.

Phil.

Come MOT time, ideally pop the CAT back in!

i thought the de-cat on the 1.5 wasnt very beneficial??

Dunno where you got that idea chap, easiest way to an extra 10hp i've ever seen :D

just thought it wasnt to be on the 1.5, ah well congrats to you and your extra 10hp :P

Yay, got it up on a ramp finaly, so I could look underneath properly, it was a heatshield, that we couldn't see.

Only problem now is, I have no excuse to de-cat.