Got this reply from a tuner about egts from tuning. Opinions needed.

[threedogs]

Fuel was changed about 2k ago and fresh air cleaner for that trip.
I'll have a fiddle and see what I can acheive

[Stropp]

But don't the ZD30's not like extra boost.
Boom. For instance.

yeh depends on how much boost is in it now but generally if its low boost and egt's are high if you add a bit more boost or back the fuel off a bit the egt's will drop, from my understanding a good tuner can get the balance just right and if a person is somewhat competent then fiddling with the fuel and boost yourself can be setup well too as you can see by the threads of members who have done it themselves with great results but i for one would not be cranking 20lb of boost into a 3ltr DI.

my experience is only with the 4.2 but plenty here have done the di.

[SG1]

Interesting differences in EGT's, I can only get max 14 psi atm but have something to try soon so hopefully can get the boost up a bit more, when we went from Yarrawonga to Echuca along the Murray Valley highway recently with outside temps around 32c with a very strong head and side wind with camping gear and a couple swags and chairs on the roof we were sitting around 415c EGT's @ 100k's and nearly touched 500c when overtaking, that road was a EGT killer, normally we can range from 350-360c @100K's and funnily enough when getting to 110K's the EGT's can go down to 325c pending weather temp but normally sit 15-20c lower at 110k than 100.

As soon as it cooled down a bit heading towards Melbourne (same day and about 30c around there instead of 32c) the EGT's dropped back to around 385c and then in the evening was back down to 365c as we headed towards the Valley(home).

Conclusion was ambient temperature can and does affect EGT's(in our vehicle), add other variables like head winds/side winds and affects it even more.

[Sir Roofy]

interesting differences in egt's, i can only get max 14 psi atm but have something to try soon so hopefully can get the boost up a bit more, when we went from yarrawonga to echuca along the murray valley highway recently with outside temps around 32c with a very strong head and side wind with camping gear and a couple swags and chairs on the roof we were sitting around 415c egt's @ 100k's and nearly touched 500c when overtaking, that road was a egt killer, normally we can range from 350-360c @100k's and funnily enough when getting to 110k's the egt's can go down to 325c pending weather temp but normally sit 15-20c lower at 110k than 100.

As soon as it cooled down a bit heading towards melbourne (same day and about 30c around there instead of 32c) the egt's dropped back to around 385c and then in the evening was back down to 365c as we headed towards the valley(home).

Conclusion was ambient temperature can and does affect egt's(in our vehicle), add other variables like head winds/side winds and affects it even more.

you hit the nail on the head mate

[threedogs]

One thing that just hit me driving around this morning, If I had a manual on the freeway
sitting on 100kph my revs are about 2500-2600 is that right?, no wonder the manuals get lower EGTs.
My auto sitting on 100kph sits on 2000 rpm if my EGTs go up I hit the dual ratio button to bring
the revs up thus allowing exhaust to escape quicker, therefore my EGTs will go down.
Can't see myself driving at 2500 rpm at 100ks not good on fuel I would think.
I future we need to ask is it a 5 speed manual or and Auto

[Hodge]

I don't think it's that high TD. I think mine sits about 2200RPM @ 100km/h. But I will confirm on my next drive.

[Sir Roofy]

one thing that just hit me driving around this morning, if i had a manual on the freeway
sitting on 100kph my revs are about 2500-2600 is that right?, no wonder the manuals get lower egts.
My auto sitting on 100kph sits on 2000 rpm if my egts go up i hit the dual ratio button to bring
the revs up thus allowing exhaust to escape quicker, therefore my egts will go down.
Can't see myself driving at 2500 rpm at 100ks not good on fuel i would think.
I future we need to ask is it a 5 speed manual or and auto

good thinking there 99

[paulyg]

My DI auto with 285/75/16 tyres sits on 2200 revs at 100kmh, but mine runs hot 400 to 450 at 110kmh with roof top tent.

[mudski]

But don't the ZD30's not like extra boost.
Boom. For instance.

I can't talk for the crd's Mick but the Di's are fine with extra boost. Mine runs 25psi and has done for well over 12 months. The only issue with running higher boost is premature wear on the turbo. How much and how fast the wear is? Dunno.I have been told of the impellers busting off at over 25psi. I just checked my turbo as a pre trip check and it spins free and there is zero play in the shaft.
The "boom" you talk of I personally believe that's from under boosting. Hence adding the NADs to control this issue. Too low boost pressure and your egts sky rocket...I have now seen two motors that have dropped the pin, both had done the exact same damage. Melted number 3 and 4 pistons, plus other damage to the motor. The cylinder colour, you could tell it got bloody hot. And both were just cruising too with no stress on the motor. That's my personal belief on this theory.

[MEGOMONSTER]

I can't talk for the crd's Mick but the Di's are fine with extra boost. Mine runs 25psi and has done for well over 12 months. The only issue with running higher boost is premature wear on the turbo. I have been told of the impellers busting off at over 25psi. I just checked my turbo as a pre trip check and it spins free and there is zero play in the shaft. The "boom" you talk of I personally believe that's from under boosting. Too low boost pressure and your egts sky rocket...I have now seen two motors that have dropped the pin, both had done the exact same damage. Melted number 3 and 4 pistons, plus other damage to the motor. The cylinder colour, you could tell it got bloody hot. And both were just cruising too with no stress on the motor. That's my personal belief on this theory.

So GoNADS might be the key to get my temps downs by giving her only a few more pounds of boost.
All this High EGT's alwAys scares me a little knowing my 600 and 650's are really hot.