HEEEEEEEEEEEEEELP - its making a funny noise

[grinder]

right then - on the run back from RS we all got a little carried away and i think i was up to about 130 when i backed off

from 80-128 the car was shaking itself apart but settled down at 130 ish

anyways thats not the problem

right then ... 3rd gear doing say 40 mph , foot to the floor it sounds like something is blowing behind the dash ?? - and its really loud - and stops as soon as the turbo starts pulling the car

both boost gauges working fine

so i assume there isnt a pipe off

stop the car ... nail it in first , second , third etc...

there is no noise

its like when the turbo is spooling ( i take it that this is know as lag ?? ) - its like there is someone behind the dash blowing ? ( yeah i know - sounds silly )

checked under the hood , all pipes seem ok , it boosts fine , boost gauges work ok

any ideas , anyone ??

thanks

Stu

[Grizzly]

Check the gromit in the bulkhead has\'nt come out.

What you mean is 130 on the Track right

[grinder]

cunning plan matey

will check that - would it make that sort of noise though ??

[Grizzly]

Just makes the engine bay noises louder.

[grinder]

had a look under the bonnet tonight

all the pipes seem to be on OK - and the only grommet i can see is on the passenger side - and that looks fine

anyother ideas ??

Ta

Stu
( suddenly dreading the worst )

[Archbish]

y\'know, on most RX-7\'s most people would consider BRRRRM - BRRRRRRM a funny noise... *LMAO*

[Grizzly]

I take it the engine idles ok? That would be a sign of a leak if it wont idle.

But having said that if it is just a small vac pipe off it may idle diffrently (maybe a bit higher revs or iratic).

[grinder]

idles just fine ( well as it always has )

like i say - put foot down - and you can hear the turbo spool - just before it kicks in

bit hard to test on the drive with the bonnet up though

just another peice in the puzzle though eh !!

just hope i havent damaged anything ( or damaging it when drivign it )

Stu

[Brett]

What air filter do you have in atm?  If its suddenly got a big hole inot you would hear the turbo more, itsd also possible you have a hole in the exhaust somewhere...

[grinder]

back to the standard filter - and it only started after the 130 episode

and a hole in the exhaust - hummm interesting thoery - why would it do it before the turbo pulls - and stops when the turbo is fully running ??

to me - if there was a hole in the exhaust you would hear it all the time ??

when the car is ticking over and the bonnet up - there is no noise

when you are driving normally - there is no noise

when you put your foot down - you get the noise - then the turbo spools right up to xx psi and noise stops - change gear and floor it - you get the noise - turbo spools to full speed and noise goes

only thing i think of - is at full boost - you cant hear it for the turbo whine - you dont think ive knackered the turbo do you

it really wierd - cause im still getting .5 or .6 bar on the boost gauge at full boost

bloody car - really starting to annoy me now

this and the not going in a straight line

will try to investigate more tomorrow - i just need someone to sit in the engine bay whilst i drive along - any volunteers

Stu

[Grizzly]

You say it is doing it on boost, is that on Peak (when the wast gate opens) or when it goes into the possative boost?

Chris

[grinder]

chris , i have to admit - that just confused me

it seems to do it from vacum to .3 bar on the boost gauge

when the turbo is pushing the car along - it seems to stop

arkward to exaplain with my limited terminology !!

right - see if this explains better

drive along at say 30 mph in 3rd gear

floor it

you get the noise then

when the turbo kicks in ( say at 45 ) the noise stops

does this explain better ??

its like the prespool of the tubo ( if that actually happens or make sense )

its like just before the turbo breaks into life - thats when it happens - so not sure if its a wastegate problem ( i think that lives in the turbo ?? )

but then i have NO idea how to fix it - or where to even begin

i suppose if it is turbo related - then when i get round to fitting the decat - i could have a look

chris - if you heard the car or saw it - would you have a better idea ?? - and what are you like at fitting from decat pipes

ta

stu

[Grizzly]

So it does it when its in Vacume? or starts at 0 and stops at .3?

How does it drive? Does it feel responcive (Turbo spools up quickly)

Do you have a Blow off valve (Dump valve)?

Do you think the Vibration you where getting has anything to do with it?

Are you getting any extra Road noise etc?

What i don\'t understand is you say "it seems to do it from vacum to .3 bar on the boost gauge" Does this mean it stops when you get over .3? This would be confusing? because if it was any sort of boost leak (maybe a small pipe or something) you would expect it to get progressively worse (Louder).

Chris

[Grizzly]

chris - if you heard the car or saw it - would you have a better idea ?? - and what are you like at fitting from decat pipes
[/B]

Proberly..  and Decats are easy, just don\'t try and struggle round stuff. your better off removing the Upper inlet to get good access to the Back of the turbo.

HEALTH WARNING!!!!! if you take the upper inlet of push some rag into the runners (making sure you can still get it out) so if you drop a nut or somthing you don\'t have to pull the engine to get it out.

[Grizzly]

Originally posted by grinder

its like just before the turbo breaks into life - thats when it happens - so not sure if its a wastegate problem ( i think that lives in the turbo ?? )

i suppose if it is turbo related - then when i get round to fitting the decat - i could have a look

If you are seeing your Target Boost and the boost responce in the gears is good then i\'d say it wasn\'t your wastegate becouse its two jobs are working Properly.

The wastegate on a S5 T2 is atualy two wastegates they are about the size of a pound coin (You may have to open your walet to find out what one looks like :eek) they live in the Hot side of the Turbo (the back bit where the Exhaust bolts up to) they open and close when the Boost presure pushes the Actuator Open (the Round thing on the side of the Turbo with a long arm sticking out)  this governs the Boost presure the car is running. Now if you imagen when you are WOT and change gear the Waste gate will be open and the BOV will have let all the boost go, so the wategate will snap shut so the presure can be built back up.

Now if for example the face that wategate mates up to is Damaged or cracked it will take an age for the presure to build up causing poor boost responce in the gears and more than likly will not hit Target Boost.

If the Actuator its self is damaged or leaking you will see excessive boost presures or very low boost presure.

So the moral of the story is if your boost is doing odd things or won\'t hit target boost then you should be looking at the Vac pipes that feed the Actuator,Tha Actuator its self or the waste gate, But from what your saying it sounds like a good old leak.

Does it get better or worse with heat? that is a sign of Exhaust problems (blown gasket etc)