Fireman Sam

My recently fitted VF22 is quiet under all circumstances if my boost is kept at say 1.0 bar, but if i set my boost to 1.2 bar, if i put my foot down it will "squeal" or "screech" as the revs rise.
I have to point out that fuelling / ignition etc is fine (datalogs) and no oil / water etc is used or seen but the noise is just disconcerting at times.
Is it the turbo do you think? or is it maybe something else?

Scooby-Duke

First and foremost, you should go back to the supplier who fitted it. If the unit is faulty they should replace it, no quibble.
Consumer's do have rights you know.

One vane on the impellor either side could cause the noise if either bent or fractured.

Dont attempt to rectify any fault yourself!

Good luck

Dukey.

R19KET

The noise could be due to several things. Hopefully it's just turbulence through the intake system, caused by the extra air flow. My hybrid does this, sounds like a high pitch whistle.

Does the turbo have VF22 on the compressor cover, or is it blank.

Were you there when it was fitted. Did the mechanic do an oil/filter change. Did he check the secondary oil filter, in the main oil feed banjo. Did he prime the turbo before starting the engine......

If you're happy with the above.....

What ecu do you have, and who re-mapped it. Do they have the flow map for the turbo, so that the ecu boost controls are set up not to over speed the turbo.

If there is a fault with the turbo, and for some reason the bearings, shaft, or compressor has gone, this can normally be heard by listening to the turbo, via a metal rod, or long screwdriver. If you blip the throttle (via the throttle body) this will spin the turbo up enough to hear anything dodgy.

If the compressor cover ID plate (cast) doesn't have VF22 on it, it has almost certainly been made up from a "core assembley", exhaust, and compressor covers. If this has been done by an "expert", this is fine, but unlike an "off the shelf" VF22, would need to be balanced, and put together very carefully.

Lastly, there was a "suspect" batch of VF22 turbo's about 6 months ago, but I'm pretty certain they'll be long gone by now, as only a few came in at the time.

If it does turn out to be damaged, a good turbo rebuilder/hybrid'er, will be able to identify the probable cause. Turbo Dynamics have helped me out when my VF22 lasted 3 weeks !!!!!

Mark.

Fireman Sam

Hi Mark, thanks for the advice.
Excuse the short sentence replies but here goes:
It has VF22 stamped on the boss at the front of the compressor.
I fitted the unit myself, had an oil change and filter but didn`t check the secondary filter.
When fitted, I turned the engine over without starting the car to prime the unit.

I use a Link ECU, it has only been re-mapped by myself in the last 3 rows to accomodate the greater flow from the VF22.

The only time I can hear the turbo is when i switch off and you can hear it slowing down to a stop.
Wouldn`t have thought it was overspeeding since the car achieves the boost targets okay with only a slight overboost to 1.3bar as it spools up, but does not stay here, returns to 1.2 bar right away.

How can I tell if it is part of a "suspect" batch?

FS

Bob Rawle

You are probably just pulling the boost in too quickly and crossing the surge line causing some overspeeding and the noise you hear would then be caused by the velocity of air through the throttle body, its a common mistake to make. Taylor the boost profile differently to stay away from the surge line and it will reduce but not disapear.

VF series wheels make a different sound to the Garret wheel mark has in his hybrid.

It will only be overspeeding at certain points in the profile.

Fireman Sam

Thanks Bob for the advice, I`ll alter the boost profile and see what happens.
So, do you think I am doing any damage with this going on?

FS

Fireman Sam

I re-checked to see when the squeal was happening again today and it seems to happen just as i lift my foot from full throttle but still on boost and only from about 5000rpm upwards.It only makes a short squeal if i lift my foot completely off the throttle.
I can keep the squeal going if i lift my foot off the throttle and maintain throttle position when it occurs. This usually happens with both 5000rpm upwards on the rev counter and 0.5-1 bar on the boost gauge.
I haven`t altered my targets yet Bob `cause i`m on shifts but on my way to work, I altered sensitivity from 3 to 1 to see if this reduced the squeal but it didn`t .

Bob Rawle

overspeeding can cause wheel stretch which, if the blade tips touch, will chip/bend the blade causing unbalance and ultimately bearing failure.

Fireman Sam

Hi all
I`ve now altered my boost targets which has helped reduce but not eliminate the noise as Bob has said.
The thing is I now have max boost of 1.2 bar for only about 1500rpm as I have had to reduce the top end (circa 6000rpm+) to help minimise the noise.
Is there anything else I can do?

Mark or anyone else,
Does anyone know how to tell if the VF22 has came from a suspect batch?

FS

R19KET

Sam,

We never got a specific list of serial no.s, but your latest description leads me to think the problems are unrelated. Like your turbo still works.

The other problem involved the blades simply letting go.

Can you hear any noise with a rod/screwdriver.

Mark.

Fireman Sam

Hi Mark
Just finished my shift and have checked for noise at the turbo but can`t hear anything untoward. When you rev the engine you can hear the beat of the engine through the screwdriver and when you stop the engine, the bearings sound okay as it winds down.
FS

Going off track slightly, is there any suggestion on how i can better my torque off boost? as I feel it could be better. I know there is greater lag on the VF22 than others but wondered what to try with the Link to help improve matters if it`s possible.

Cheers for your help guys, much appreciated.

FS