Thread: very high egt

Originally Posted by catch-22

Regarding mixtures and EGT's, many race cars richen their mixture to lower EGT's.

True, but diesels run on the other side of the hump that is mixture vs temperature.
We're running very lean so richer (more fuel) gives higher temps.

I've always found it amusing that a 13B can be either a mazda rotary or a toyota diesel.

Originally Posted by Tusker

I thought 750 degrees was the magic mark becuase that's the temperature aluminium melts..

Aluminium melts at 660 degrees C.

Originally Posted by nice1guv

Aluminium melts at 660 degrees C.

Pure aluminium does, but there are hundreds, maybe thousands of different aluminium alloys. All have a different solidus-liquidus temperature range.
The one I'm looking at right now is 590-640C.

and then theres alli or was that alloy............

cheers phil

Originally Posted by Jojo

A bigger intercooler won't do much as only the air on the intake side is cooled somewhat and not -as discussed here- on the exhaust port.

The cooler air on the intake does have a relationship to the temp on the zorst...

M

Any chance that the temp sensor is not the correct one for the gauge?

Cheers
Simon

Don't confuse race engines with road engines.We are not out to win so we don't wind up the wick,on our road vehicles there is a balance between performance and engine life,more towards the latter and if the probe is pre turbo it is on the limit for any engine and if it post turbo you should start saving your penny's.Overfueling a diesel engine is the second quickest way to kill it after boiling so I would ''drive it by the pyro'' as truckers say. Pat

Originally Posted by Dougal

That's not the right way to look at it.
Restrictions in your exhaust cause only minor increases in EGT (in line with predictions made using the ideal gas laws), it's lack of boost or too much fuel that causes major EGT problems.
Your inital cause was too much fuel, now the question is "have these temps caused any other damage?"

Some turbos can only handle exhaust temps up to 750C, some can handle 900C and last I heard garrett had some built for 1050C. Since the TD5 turbo is a modern GT2052 it may be perfectly fine with temps that high.
But your pistons will be having a very hard time.

First thing to do, back off on the pedal to keep the EGT's down to semi-sane limits.
Second thing to do, check boost levels. A drop in boost will cause a massive increase in EGT.

Regarding turbo backpressure, the higher your exhaust temps get, the more efficiently your turbo runs and the less drive pressure it requires. My current setup runs 2:1 drive pressure to boost when the exhaust manifold and turbo are accelerating and cold (20psi boost, 40psi drive pressure).
As the EGT's increase, the drive pressure drops. Above 600C EGT's I have more boost than drive pressure (provided I keep the revs down).

Hope that clears things up.

The boost is 17 to 19 measured at the turbo and this has not changed over time. Perhaps i should be looking at what is happening at the inlet manifold. Not sure what pressures i should see there. Could the intercooler need a clean. Car has 140k on it. It may have always had high egt since chip i have only been able to see it recently