Thread: very high egt

Well... First port of call is to find out what temperatures would be recommended for the TD5 (in other words... Is 900 Deg a problem). Unfortunately, I don't know...

Also, 900 deg is the temp around the sensor... What's the temp at the turbo?? IIRC, the other area of concern would be the head & valves.

In my mind, to reduce the temp, you've got 2x options:

• Bigger intercooler.
• Change chip.

M

the probe is just before the turbo about 100mm from the head

Another thing is back off on the loud pedal will reduce egt,s

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.
I'd first check the reliability of the gauge before proceeding investigating. And, as stated, keeping the foot of the throttle is a potent remedy .
Cheers

EGT is sort of misunderstood on this site ( and by most)

We spend time and money freeing up our pipes to improve flow, then we stick a turbo on it to restrict flow.

I would say that your problem is really to much presser in the manifold or just before the turbine. The turbine in this case working a bit like valve in say a fridge or aircon. as soon at the gasses pass though this restriction it expands, increasing velocity and cooling ( up to 40%) . The pressure point or bottleneck is usually just before the blade tips.

As for the temperature at 900c this will encourage grain growth visible my the blade becoming rusty ( a bit like brake disks) if that’s the case you may have weakened the tips but I would suspect that the bearings would fail first.

Anyway I think that even though you have a reading of 900c I doubt that you will have that temp at the blade tips. But with out inlet temp & pressure as well as outlet temp & pressure I cant do the maths.

Originally Posted by clean32

EGT is sort of misunderstood on this site ( and by most)

We spend time and money freeing up our pipes to improve flow, then we stick a turbo on it to restrict flow.

I would say that your problem is really to much presser in the manifold or just before the turbine. The turbine in this case working a bit like valve in say a fridge or aircon. as soon at the gasses pass though this restriction it expands, increasing velocity and cooling ( up to 40%) . The pressure point or bottleneck is usually just before the blade tips.

As for the temperature at 900c this will encourage grain growth visible my the blade becoming rusty ( a bit like brake disks) if thats the case you may have weakened the tips but I would suspect that the bearings would fail first.

Anyway I think that even though you have a reading of 900c I doubt that you will have that temp at the blade tips. But with out inlet temp & pressure as well as outlet temp & pressure I cant do the maths.

Thanks. I guess there is not a way to remove this restriction short of a new turbo. Which funds will not allow. Guess will have to practice welly self control.

thats another feature of the BD chip...way to much fuel up top.
on 2 occasions now ive towed 3ton back from dorrigo, one via glouster, very hilly. on the freway at 110 with the cruise controll on and flat road i sit on 600-650deg. hills will see it raise to 750deg but i just back off slightly and drive to suit the temps not the speed. around town im lucky to see 400deg@60kph.

my probe is in the exhaust manifold crossing #1&2 ports. i have the tombie2 chip/IC bla bla bla...

cheers phil

Originally Posted by paul-defender

Thanks. I guess there is not a way to remove this restriction short of a new turbo. Which funds will not allow. Guess will have to practice welly self control.

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.