Change to Turbo `dump` noise?

Can you help?

I have a 93 MK1V TT (auto) that I have had now for about 3 yrs. Very recently I have noticed that when the first turbo spools up and you back off the gas the waste air noise has changed?

Instead of the single `tssssssssh` noise I am now getting a staggard air release that has the a series of smaller `tssssh tsssh tssh tsh` sounds after the main air release?

Note. Theres no fancy stuff under the hood, just an HKS air filter, the rest is standard.

Untechnical as I am does anyone know what might be the cause of this?

Welcome

What BOV do you have fitted? Also, does it still do the single "tsssssh" sound when backing off from full throttle?

The HKS dump valves normally only make the fluttery "tssssh tsssh tssh tsh" sound when backing out of part throttle at lower boost. Its caused by the wastegate, but this is normal.

BTW, are you the guy that owns the silver one with the number plate **** VIL ?

Stock BOV sticking?

Thanks for the response.

Its a standard BOV. If it is sticking should I be worried?

Homer. Yes I do have a silver TT with the number plate `VIL ****`, have you seen me around?

Its almost certainly a sticky valve, you'll need to replace it as it won't be releasing the pressure correctly (Maybe a reasoin to go for an aftermarket one if you like that sort of thing!)

Yes, seen you around a few times, as have other local club members.

Its almost certainly a sticky valve, you'll need to replace it as it won't be releasing the pressure correctly (Maybe a reasoin to go for an aftermarket one if you like that sort of thing!)

 

Yes, seen you around a few times, as have other local club members.

ive got a spare std bov if ya need one matey

Burt: Thanks for your posting. It looks like i`m gonna have to do something so would be interested in the BOV. What would you be looking for it?

Homer: Thanks again. I`ve seen a few guys round Reading, two cars spring to mind, one similar to mine in silver with muti-spoke alloys and another `well tricked up` Supra, I actually spoke to the guy for about 20 seconds at some traffic lights ages ago, I think he may be a member, from memory I think he said his name was `DASH`? Out of interest where do you guys go to get service work etc done on your cars locally?

Dash - thats Darren (or known as 'Dash Rendar' on here). There's a LOT of Supra's in the area and but most of us know each other.

A few of us use Thames Valley MOT (http://www.tvmot.com) for basic servicing stuff, they charge sensible prices and do good work. For more complex problems and modifications I use Phoenix in Watford.

Burt: Thanks for your posting. It looks like i`m gonna have to do something so would be interested in the BOV. What would you be looking for it?

 

Homer: Thanks again. I`ve seen a few guys round Reading, two cars spring to mind, one similar to mine in silver with muti-spoke alloys and another `well tricked up` Supra, I actually spoke to the guy for about 20 seconds at some traffic lights ages ago, I think he may be a member, from memory I think he said his name was `DASH`? Out of interest where do you guys go to get service work etc done on your cars locally?

DON'T KNOW WHAT ITS WORTH REALLY, MAKE AN OFFER MATEY AND ILL SEND IT TO YA

Still no change !!!

I have fitted another standard BOV (thanks Burt for the supply of this, really appreciated). However, no change, its still giving out a `fluttered` air dump. :thumbdown

Does anyone have any other ideas what might be going on?

are you *sure* your second turbo is coming online?

I think the second turbo is coming in, although since this problem has started I have tried to drive it carefully as I dont know if I will be making it worse.

If I just drive it up to the point that the first turbo spools up and back off you get the `flutter` (no where near the point where the second turbo would come in).

i may be saying something really stupid, it wouldn't be the first time, but the flutter you are describing could be the wastegate no? A friend of mine had to remove his leaking dump valve until he got a new one (on a nissan 200sx) and when he backed off that fluttered like crazy. (actually sounded rather nice - bit like a rally car maybe).

Could the wastegate be a little baggy maybe? just a thought.

MMmmmm... The symptoms fit.

It does sound a bit like a ralley car backing off (the noise I dont mind, the cause of it I do!!) ;0)

How could I go about checking for this? Any ideas?

sorry to hear that it hasn't solved the prob matey, i'll have a chat to my mate who works on these beasts for a living and i'll let ya know what i manage to find out matey.

I don't know of a technical method, but I think you can feel if the actuator is knackered. Now I'm not suggesting you should do this for one second, but if you were to take it off you may be able to compare it to another one for resistance. Please someone correct me if I'm talking crap

Referring to my earlier post, does it make the single "Tssssh" sound when letting off from higher boost (4krpm and above).

The 'fluttery' noise is normal when letting off from low boost or part throttle, though as this has started only recently it could indicate another problem. Could be a wastegate or actuator problem.

Might be worth you getting in touch with Max-GT, they're the most local Supra specialist and shouldn't have any difficulty finding the problem. They're based near Micheldever.

Alternatively, if you're in the Whitley/ M4 J11 area tomorrow I can take a quick look at it, if only to eliminate the obvious causes...

Sounds like we are wandering into the realms of Mr Mechanic and his `random number generating` calculator !!!!

As my technical understanding of this part of the system is limited to say the least. Could the symptoms I am experiencing come from a leak somewhere in one of the pipes or joins? All looks OK, but its hard to be sure there is no air leak.

Homer.... I would be really grateful for that!

I only live just up the road from Whitley. I would be back from work around 6:00, is sometime in the evening good for you?

Homer.... I would be really grateful for that!

 

I only live just up the road from Whitley. I would be back from work around 6:00, is sometime in the evening good for you?

No problem mate, I’ll be finished around 6 so could meet sometime after that. I’ll PM my mobile

BTW: Some easy night time reading on the turbo system http://www.mkivsupra.net/vbb/showthread.php?t=35926

Yes, look for a split or loose hose between turbo outlet and throttle body.

Nice to meet you today mate! Thats a lovely car you have there, just can't beleive you've had it for 3 years and never been tempted by the modding bug

On to the problem at hand, technical guys, need your input here as I'm not 100% sure what the cause of this problem is:

There is one small boost leak in the BOV pipe, this seems does cause a bit of a 'whooshing' noise under medium boost. However this was only done recently while swapping the BOV so does not seem to be the cause of the 'fluttery' noise.

The 'fluttery' noise is the wastegate, it can be heard the air filter when letting off power at any boost or rpm (even when parked up and blipping the throttle). It is VERY loud (almost HKS dump valve level of noise), I've never heard a Jap car make that much wastegate noise.

There does not "appear" to be any further boost leaks, though the IC pipes are very brittle so it is not ruled out by any means.

The only thing that did seem odd was that while blipping the throttle to positive boost, while parked up, the EGCV arm doesn't move at all - is that normal?

Any ideas guys?

Homer.... Thanks once again for meeting me to take a look at the car, its refreshing to talk to another Supra owner. Most of my friends have joined the `Mondeo` club ZZZZzzzz

Really appreciate your time and effort!

To add to your comments (if it helps, and is relevant) there is also occasionally a `wooooo` noise. As Homer pointed out to my relief, not the `Death Whine` but a sound almost like your humming softly through a cazoo! I guess this points to an air leak again and/or could be where I put a split in the brittle pipes to the BOV, as to be honest I did not hear this noise up until I changed the BOV. (NB new pipes on order with Toyota).

The only thing that did seem odd was that while blipping the throttle to positive boost, while parked up, the EGCV arm doesn't move at all - is that normal?

As far as I know the turbos don't spool on an auto in neutral or park so I'd think that was normal.... unless someone with some actual knowledge cares to correct me!

This may be a totally stupid question, but could the fluttery noise just be turbo stall? As in the wastegate / actuator etc is blocked, and on lift off all the air is going straight back through turbo no1?

I've heard somewhere that the sound of the turbo blades being stopped suddenly by backpressure can cause that fluttery noise..... but again that may be complete rubbish