Anyone?

 

Interesting,

So, I'm also running a TD61 on my FD. Same 1.0 AR. T4 divided with wastegates dumped near my EGT thermocouples. TCs are plumbed in about 4 inches post exhaust port. So, last week cruising to Sevenstock and back from Phoenix to LA (5 hr trip each way), I'm noticing that the EGT readings in my rear rotor housing were getting getting close to 900C during light load cruise conditions with 14.7 to 15 AFRs. This was at 80 mph (3100 rpm). Since I was sensitive to the 900C reading, I found that if I would "lift from the throttle temporarily or "mash" the throttle my EGTs would go down. Just the cruise light load setting seemed to make my EGTs climb. Also noticed about a 30C difference between my front and rear housings (I'm running the Ground X LIM). Is that delta temp between front and rear housings fairly "normal"? My coolant temps stayed between 83 and 85C with no knock noted on my Power FC the entire trip. So, at what what point temp-wise do I need to start being concerned. I think the Garrett web site states that their turbine wheels are good to about 1050C. How much heat will the manifold take before the temps start affecting integrity? I pulled close to 25 mpg on several tanks during the trip. Just wanting to know what the general consensus is on op temps.

Thx

P.S. This is on 91 octane with Aquamist water injection (straight water).

 

Do you know what your spark timing was at those speeds?

When you tip in, you have acceleration enrichment fuel which should cool temperatures. When you tip out, the engine will go into fuel cut. Without combustion the exhaust temperatures will naturally go down.

It's hard to say what the thermal limit is for your manifold. As a sustained temperature 900C is getting up there for most turbos, but even if you exceed some threshold--will it cause an immediate catastrophic failure? I doubt it. It's more likely to cause some degradation that could be hard to quantify.

 

You should check your rear trailing plug wire and coil. I had a bad rear training plug wire and had almost identical symptoms. It was hard to diagnose because the car drove great otherwise.