Turbo dead on 3200

[timkee330ci]

I have found on the workshop manual that the ECU is feed signal from a absolute pressure sensor upstream the throttle body, downstream the turbo.
There is no way the engine wont throw a code if one of the turbo is not working.


The sensor is part 29 on the diagram.

 

[Almichie]

But boost will be produced and as the turbos are in parallel it will meet the target pressure just not the flow rate. In series they wouldn't acheive pressure but would acheive flow...

 

[timkee330ci]

I am not sure about reaching the target pressure with only one turbo operational. The mass of air reaching the throttle must be reduced if one turbo is shot, given the piping are fixed in volume, the pressure would be reduced.

I have also checked with turbodynamic, their "hybrid" turbo are not mechanical combined with a electric motor, but in fact just with some modified components. I think i will just go for the original one if really need changing.

But boost will be produced and as the turbos are in parallel it will meet the target pressure just not the flow rate. In series they wouldn't acheive pressure but would acheive flow...

 

[Almichie]

I think you are looking up the wrong tree! A hybrid turbo is not combined with anything electric (unless you buy it off eBay), in fact it is a turbo Moddified and therefor a hybrid of the original. I could be a larger exhaust turbine, larger compressor turbine, different aspect ratio or a combination. They typically reduce lag of an older designed turbo (reducing inertia) and operate in far more efficient way (better operating envelope).

You are correct; mass flow will be reduced but pressure will not. Think of electricity (DC is best) you have two 10VDC batteries and wire them up in parallel you'll still have 10V but twice the current (flow), now wire them in parallel and you have 20V (pressure) but half the current (flow) than when in parallel.

You'll need to trust me on the pressures/flows - I can assure you that it is correct. A parallel operating centrifugal compressor will deliver twice as much flow as if they operate in series but at a reduced pressure than those in series.

Sequential turbos are there to reduce lag not increase flow.

 

[BennyD]

IMO, Almichie is absolutely correct.

 

[davy83]

Just replaced both, with 38k on the clock and one looked as if it had been changed before, so they do fail. maybe not common i would agree.

Turbos never go wrong...they last....not heard of failing turbos...

Bmw turbo goes a lot

 

[BennyD]

One thing that will kn4cker a turbo is a poor oil supply. IIRC, your car has oil pressure problems and that could be a reason one has been replaced previously. I would sort it out ASAP or this could be an expensive merry-go-round for you.

 

[timkee330ci]

Thanks for explaining Almichie.
I have talked to turbo dynamic, they do not have a hybrid turbo for the 3200gt, because of the complex CHRA bearing installed (exact wordings).
I am searching for a cheaper source of new Turbo. Please PM me if you know of any source. Thanks!

 

[timkee330ci]

Benny, as i know the oil pump of the 3200 engine is very robust, what would cause inadequate oil supply to the turbo? Could it be the connecting tubes? Blockage somewhere in the lubrication circuit? How could this be checked?
In fact the turbo is not certified yet, I was only told that it's shot by the not quite reliable dealer. Yet to take it to a reputable indy for further diagnosis. Are there anything I can do myself to check the condition of the turbo?
Thanks in advance!

One thing that will kn4cker a turbo is a poor oil supply. IIRC, your car has oil pressure problems and that could be a reason one has been replaced previously. I would sort it out ASAP or this could be an expensive merry-go-round for you.

 

[BennyD]

In the bad old days when turbos were air cooled, people used to switch them off without letting them cool properly. When this happened, oil in contact with the hot parts of the turbo and the end of the oil feed pipe would carbon up and reduce flow into the turbo. I appreciate that oil has got much better and turbos are water cooled and this doesn't happen as often as it once did, it might be worth checking the turbo ends of the feed pipes. To check the turbos condition, take the air inlet pipe off the turbo and spin it with your finger; it should spin freely. Best to do both so you can see that they are not noticably different.