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Case Studies : Clocking a Turbo

After my diagnosis on the CT26 turbocharger, I’ve determined that the best path would be to service and sell the turbo, rather than put it on the 2JZ as a starter kit.

To do this and get the maximum return however, I’ve decided to just sell as a replacement MKIII Supra turbo. Problem is, the CT26 I have now is not clocked correctly for a 7MGTE motor, and the compressor housing just isn’t the correct outlet or shape.

While this CT26 is being sold, this method can be used to rotate any turbo or service any center cartridge when the need arises. While the need may not arise, there may come a time when a new intercooler, different feed and return lines or other details may dictate a new turbo orientation.

First we must remove the old compressor housing, install the new one and clock the center cartridge so that the oil lines match up and charge piping mates to the turbo.

Using a needle nose and a small flathead, you must first loosen the tension in the circlip holding the compressor housing to the CHRA.

Now, undoing the compressor housing will give you a full view of the compressor wheel, make sure to not damage the outer ring when installing the replacement compressor housing.

Now last but not least, you must rotate and loosen the bolts / circlip holding the exhaust housing to the hot side of the turbo. Installing the new compressor housing and moving the internal wastegate mounts and arm over are the final steps.

Make sure to line up and adjust the wastegate actuator, so that there is no excess slack or tension in the rod before installing into your car.

Happy boosting!

Project 240SX : And the hits just keep on coming…… CT26 turbo failure

I’ve begun to tear into the 2jz and start cleaning, prepping and stripping for the swap into my s14. It’s been slow going for Project 240SX, but I’ve had more than enough on my plate lately.

The saga of the 2JZ just refuses to die down, because after inspecting the CT26 turbos, I’ve been setback yet again.

Using a turbo bench, it appears as though the CT26 will not build more boost than 4 psi.

This CT26 from a 7MGTE was a cheap starter turbo to get my swap in and running before cams and headswap and a bigger single.

At a the cheap price I had found it at ( thanks to Frank @ TTA ) it was a no brainer but now it won’t build any boost which makes it about as useful as a doorjam.

Troubleshooting a CT26 Turbo

Recommended tools : Air compressor, 14mm open wrench, 8mm socket

First we check the shaft play of the turbo, which seems to be fine. There are no excessive oil leaks or signs of blown seals on our CT26, and the CHRA seems to be in decent shape all things considered.

The turbo spins freely and nothing looks like it’s hitting one another, so we turn to the wastegate.

Using a air hose nozzle to gently blow into the internal wastegate inlet, the arm of the internal wastegate appears to be moving.

That means either the flapper is done or the arm may be bent out of shape, holding the flapper open.

Removing the 4 14mm nuts that hold the 02 housing to the exhaust housing. This will allow access to the internal wastegate flapper and troubleshooting the lack of turbo pressure.

Upon opening the unit back up we find that the internal passage that leads to the flapper have completely cracked open. Since the flapper can no longer close the opening sufficiently to build boost due to the stress and cracking, it means that I’ll need a new housing.

This brings me to a crossroads because if this turbo cost anymore than it already did ( nothing ) I had to decide whether or not the investment would be worth it in the CT26.

Next up : Looking at possible turbo replacements