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The mkiv Supra Owners Club

Confused on Turbo Operation


Guest Jason1
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Guest Jason1

Hi

 

I am slightly confused with the turbo setup on my car, after reading other posts has made it worse.

 

I have a GZ TT Auto and it appears my turbo's do not work correctly.

 

Driving the car, I get no turbo response till around 3k were I am at 0 bar but I can here them (hopefully) by 4k I am at 0.8 bar and holding steady.

No drop off and no spiking.

 

I do not get one at 1800 and a kick in the pants at 4k and there is no drop off.

I originally thought that the car has had the TCC mod and so both turbos are working together. However I get no kick from the turbos as described in other threads.

So after some investigation I have found a grub screw holding open the Exhaust flap. It cannot move at all. I am presuming this isn't correct.

image

 

image

 

As you can see this nut with a grub screw in it is holding the valve open.

Why would this be done? Is this some crude TCC which I originally thought it was.

Would someone do this as there is a problem with the turbo setup.

I think I am only using one turbo hence no seat of the pants moments

 

Any help would be appreciated as driving me nuts

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That is your exhaust gas control valve, its what operates no.2. It looks like its in its closed position, it would be opened up by the actuator that controls it. You can pull the rod away from the actuator to see if it moves, but even on a bench its quite a strong spring. That should open around 3,500-3,800rpm to fully bring on no.2.

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Guest Jason1

It does indeed

 

I have tested this and the wastegate with a mitty vac and they both appear to work correctly

On my drive home I noticed that I had boost at around 3.5k and then a little blip at 4k but still look to be .8bar

Maybe I am overlooking this and there is no problem.

Thanks for your help

I will trace all the vac pipes and make sure they are all fitted correctly next I think.

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Nah, it sounds like you aint getting anything from one turbo, Im just trying to work out if its no.2 or no.1. You say you get no boost until around 3.5, which is when no.2 in brought online, prior to that no.1 should be making .8bar up until 3.5'ish. Sounds like to me you have no no.1

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Guest Jason1

Thanks for the help

Very interesting read.

 

I too think the car isn't right as it just feels like a normal turbo setup

I will trace all the vac lines and see if anything is amiss

Also looking at different photos of the exhaust valve actuator none of them show the setup

that mine is as per the photos

If this isn't fully shutting because of the stop would this cause a problem.

also I have noticed the boost gauge is teed to the fuel pressure reg would this cause a problem?

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