Recently I have noticed that full boost has gone further up the rev range than where it used to be, maybe it's my imagination but I don't know. I'm pretty sure full boost was lower than it is now. I now get full boost at around 4+ to 4.5k is this right or is something amiss or about to go on me :confused:

Also, now this may also be my imagination, but my stock recirc valves seem to be louder than they used to be. Are these two ralated or am I getting paranoid ?

Where in the rev range do you get full boost ?

 

CheerZ

Paul

deffo something wrong there mate - you should be achieving full boost around 2.5k rpm. start by checking the hoses under the bonnet to make sure youve not got a leak somewhere. you shouldnt be able to hear the recircs at all (unless one is honking but that'll only happen when you throttle off) - can you hear a whistling noise?

deffo something wrong there mate - you should be achieving full boost around 2.5k rpm. start by checking the hoses under the bonnet to make sure youve not got a leak somewhere. you shouldnt be able to hear the recircs at all (unless one is honking but that'll only happen when you throttle off) - can you hear a whistling noise?

 

 

Checked all the 'easiest to get to' hoses, i.e. the TB and inlet hoses in the engine bay and they seem tight. Recircs arn't honking, just a subtle ppsssst on throttle off and yes I do get a bit of turbo whistle on boost.

2.5k for full boost, in the 2 years I've owned it I'm sure it's never been as low down as that !

One thing I have just found, oops :slap: . I fitted an apexi filter some time ago and I hadn't tightened the two jubilee clips either side of the AFM up, doh ! They were completely loose. That was probably why I was getting bad dett with 1mm boost jets in as it would have been running lean but I can't see that causing the full boost to come in at 4 odd k rpm would it ?

Where do I need to start looking for leaks and what should I remove to gain access to the piping ?

 

CheerZ

surprised a techie hasnt come on here yet

possible other cause may be a wastegate partially stuck open

i know youve mentioned jets but you dont have an electronic boost controller installed do you?

are the jets installed the right way around? [clucthing at straws here]

there's a small pipe coming from the driver's side of the balance bar - only about 5/10cm long - is that secure at both ends?

surprised a techie hasnt come on here yet

possible other cause may be a wastegate partially stuck open

i know youve mentioned jets but you dont have an electronic boost controller installed do you?

are the jets installed the right way around? [clucthing at straws here]

there's a small pipe coming from the driver's side of the balance bar - only about 5/10cm long - is that secure at both ends?

 

 

Hmm, wastegate stuck open, now thats worrying.

No, no boost controlled just 1.2mm mig welding tips and think they are the right way around but don't think that will effect it will it ? Will check the pipe you mentiond. I bet theres loads of small pipes that need to be looked at, could be any one of them really I suppose.

put it this way - a waste gate stuck open is better than a wastegate stuck closed!!

other than piping im a bit stuck for ideas - if you did have a boost leak that caused your tubbies to be so slow at building up the car would whistle like a bitch im sure!

It does whistle but not really load like a bitch lol, but thinking about it it has got louder than it used to be it's just got steadly louder and so subtle that I didn't really notice it. I'm stuck on where to look rally now :(

come on somebody!!

 

bugger - tried to send a pm but it wont let me, youre not a subscribed user!

 

have you thought about dropping it off at a Z specialist?

Oh sh!te, forgot to resubscribe. Will do it on payday (Monday) Taking it to a specialist is my last resort really, would like to sort is myself, with a little help from my friends (you lot) of course.

Obviously first port of call is boost leaks but to be honest if you did have a leak you wouldnt be getting full boost so check your boost jets and possible change them or IMHO get a boost controller ;)

 

Take the recircs off and see if theres any water in them as they tend to gather water, see if you can borrow a boost leak detector to check all the pipework. If you have a compressor try plumbing it into the wastegate pipe and see if the wastegate is moving freely.

 

If your still having no joy then it could be something worse so next call will be to get a leak down test done which will tell you if you have a valve/ring/piston/head gasket etc leak which will also affect your boost threshold

 

Mike

Obviously first port of call is boost leaks but to be honest if you did have a leak you wouldnt be getting full boost so check your boost jets and possible change them or IMHO get a boost controller ;)

 

Take the recircs off and see if theres any water in them as they tend to gather water, see if you can borrow a boost leak detector to check all the pipework. If you have a compressor try plumbing it into the wastegate pipe and see if the wastegate is moving freely.

 

If your still having no joy then it could be something worse so next call will be to get a leak down test done which will tell you if you have a valve/ring/piston/head gasket etc leak which will also affect your boost threshold

 

Mike

 

Cheers Mike

 

Hmmm, sounds like it could be bad. If I pump air in to wastegate pipe from a compressor would it be easy to see the wastgate move. Is it easy, probably not, to het the recircs off ?

Cheers Mike

 

Hmmm, sounds like it could be bad. If I pump air in to wastegate pipe from a compressor would it be easy to see the wastgate move. Is it easy, probably not, to het the recircs off ?

 

you should be able to see the wastegate arm moving freely, not that easy.

 

if you need to borrow a leak down tester let me know as i have one, great peice of kit and pointed straight away to my problems :)

 

Mike

Cheerz Mike, I'll let you know

you should be able to see the wastegate arm moving freely, not that easy.

 

if you need to borrow a leak down tester let me know as i have one, great peice of kit and pointed straight away to my problems :)

 

Mike

 

How do you perform a leak down test and what does it do Mike ?

How do you perform a leak down test and what does it do Mike ?

 

you plug it into each spark plug at a time and then plug it into a compressor at a set pressure and it has a dial on the tester which goes down if your losing pressure and if you are you listen to where its coming out from ie oil cap means its the piston or rings, the throttle body and its an inlet valve, exhaust its an exhaust valve and if its the head gasket then you will hear it from the side of the engine

 

its pretty easy ;)

 

Mike

May have discovered something this afternoon :-

Thought I'd take a look under the bonet after coming home from work with the engine still running, if I blip the throttle I can hear maybe some sort of vacuum leak. Sounds as if it's coming from directly underneath the throttle cable cover, right in the middle or thereabouts. Would this have anything to do with it.

 

If I gradually increase the throttle I can't hear it, only when I blip it.

 

CheerZ

Paul

does it sound like someone sucking through a straw? if so i had the same problem. it was a leak at the exhaust fannymould.

when you try and boot it, can you hear a kind of growl/splutter coming from behind the driver's side dashboard?

does it sound like someone sucking through a straw? if so i had the same problem. it was a leak at the exhaust fannymould.

when you try and boot it, can you hear a kind of growl/splutter coming from behind the driver's side dashboard?

 

 

Yeah, the sucking through the straw kinda sound but not the growl/splutter you describe

Anyone ?

bump

 

sounds as if its coming from around the plenum area, took the cover off and can hear it a bit better but can't pin point it.

i see youre only in Nottingham bud - im off work this Saturday if you fancy meeting half-way. im not very mechanically-minded by i might be able to shed more light on the problem.

Cheers Dave, I'm gonna start with a boost leak detector, gonna put up another thread to see if anyone will lend me one and take it from there

 

CheerZ