Thread: Where to mount EGT probe ??

I have mine in the main part or the manifold where all 4 ports combine as your arrow suggests. The boost is determined by the waste gate if fitted, or by a certain sized turbo to give x boost at x speed. Pls correct me if I am wrong Dougal, JC, and the rest

Justin

On heavy trucks the pyrometer thermocouple is always fitted post turbo. A threaded boss is welded into the engine pipe.

Murray,
Increasing the fuel wont increase the boost (this is influenced by the compressor vanes and wastgate setting). But it will give you more power if set up properly.
I would insert the pyro probe just after the turbo in the exhaust pipe which is the easiest. Just weld a boss or nut into the pipe. Regards...Brian

Originally Posted by Bearman

Murray,
Increasing the fuel wont increase the boost (this is influenced by the compressor vanes and wastgate setting). But it will give you more power if set up properly.
I would insert the pyro probe just after the turbo in the exhaust pipe which is the easiest. Just weld a boss or nut into the pipe. Regards...Brian

Mounting the probe in the exhaust pipe would certainly be the easiest option, but I still need to know the maximum safe temp to run to. I believe the temp from pre to post turbo can drop significantly.

Given it's the original turbo and should be capable of the 13 psi, to alter the boost, do I need to change the waste gate vac canister or can it be controlled by making the pull/push rod adjustable in length.
When I fitted the intercooler I span the turbo compressor housing around and remounted the vac canister. The rod ended up on a slight angle to what it was before. I'm guessing this might be a possible cause of the boost difference.

Extra fuelling WILL increase the boost, up till the waste gate, starts to actuated, then it does as suggested, "wastes" the excess exhaust gas, you can't make boost, without exhaust, you can't make exhaust without fuel

Mines post turbo, so null and void on where

The max temp specified by Isuzu for the IHI RHB6A (factory 4BD1T) is 750 degrees C. This is measured at the Turbo intake. So slightly lower temperatures would be experienced at the turbo outlet. I have had mine to 650 on a long uphill pull, running 10psi boost and increased fuel. The boost can be adjusted by the wastegate pushrod so I guess that is why yours has changed a little

Originally Posted by Bearman

The max temp specified by Isuzu for the IHI RHB6A (factory 4BD1T) is 750 degrees C. This is measured at the Turbo intake. So slightly lower temperatures would be experienced at the turbo outlet. I have had mine to 650 on a long uphill pull, running 10psi boost and increased fuel. The boost can be adjusted by the wastegate pushrod so I guess that is why yours has changed a little

Increaing you boost will actually cool the temps down, allowing more fuel, which is required to achieve more boost....phew, make sense?

But when playing, it gets prefereable to fit an intercooler of sorts

Hi Murray,

I have mine drilled into the manifold where your second arrow is, just as all the cylinders enter the mounting flange. Fuelling increase WILL increase the speed in which your engine reaches the wastegate opening setting, which is adjustable for more boost by shortening the rod. I'm using a fairly restrictive exhaust housing for no lag, and I have dialled in the max boost of 15psi AT the manifold using fuel adjustments only. I have disconnected my wastegate and I use the pyrometer to drive by. I have fuel settings that allow a max of around 600 deg(I have a front mount air to air IC) which allows for excellent fuel economy and power, and even at these settings I have clutch slipping issues if in a too high gear, and like Dougal, serious traction problems in the wet with 33" Mudders on

Upstream of the turbo is definately the most accurate and sensible place to fit a probe, with the excellent metallurgy these days it is very unlikely that any bits of it are going to melt and enter the turbine etc.

I'd say that you will find 550 to 600 deg PLENTY, That Dougal is just a revhead of the highest order

JC