Anyone know the typical differences in exhaust gas temperatures in naturally aspirated versus turbocharged diesels? I'm figuring there must be a higher average temperature in turbocharged engines, why else would piston oil cooling squirters be installed. But, I can't find any info on the web about the temperature differentials. Anyone have a pyro in an NA and a turbo that can provide some insight?
I've read in a number of places that EGT's above 1300 degrees for sustained periods in a turbocharged engine are bad for the engine, but that's with oil cooled pistons. What's a safe operating EGT temperature for an NA without oil cooled pistons?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

It's also going to depend on piston material for safe EGT (steel, aluminum, etc). I've heard that anything under 1100 degrees is safe and the 1300 is only safe for short times. Like you, I've never seen info on NA engines, I wonder if you can even get the EGT too high?

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

I'm thinking about it because I'm considering purchasing a motorhome with a CAT 3208 naturally aspirated with an aftermarket turbo added to it. I'm trying to figure out if it is running at an acceptable EGT temperature since it has a pyrometer on it. It does not have the oil cooled pistons.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

A Cat engine may be totally different than a Mercedes engine. It might not use oil cooled pistons in the turbo model. You might have better luck asking this question on a Cat forum or a motorhome forum if they exist. I know that some ricer kids add an oil spray bar to their engines to squirt oil on the pistons to help keep them a little cooler. Something might exist for a Cat engine or Something might be adaptable to it.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

http://ecomodder.com/forum/fe-graphs/sig692a.png

The CAT does have oil cooled pistons on the turbo but not on the NA. I've talked to CAT about the differences.
It seems to me, at least in theory, that there should be an answer that applies in general to NA's and Turbo's regardless of the mfg.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

The melting point of aluminium is 933.47 °K [or 660.32 °C (1220.58 °F)

and once the point is reached, results look like this:
http://www.pbase.com/camerafin/image/55390266/original

Might ask the guys here about that engine http://www.thedieselgarage.com/forums/index.php

Also might want to read this http://forums.thedieselstop.com/ubbthreads/showflat.php?Cat=&Number=2799246&page=0&view=collapsed&sb=5&o=31&fpart=1#Post2801966

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Owning a 93 GM pickup with a turbocharged 6.5liter diesel I have learned quite a bit about them and the variants of this particular engine.

The generally accepted max EGT is 1100*F on any turbodiesel engine, if you are unsure about things like piston material, piston cooling, etc.

The GM 6.5 is a bored out 6.2 liter and they started off as NA engines. In the 80's Banks developed a turbo kit for the 6.2 in pickup trucks and this was limited to 1100*F (pre turbo) Interestingly the Banks kit was non-wastegated and availble as a dealer installed option through GMC dealers.

With the introduction of the 6.5 turbodiesel in 1992 the pistons were "hardened" or modified in some way to allow for a max EGT of 1250*F

I believe the 1997+ 6.5 turbodiesels were modified with a better cooling system and oil sprayers for the pistons, supposedly for durability reasons. Max EGT remained at 1250*F.

Suprisingly when a "performance" 6.5 is built most chose to use the older style block without the oil sprayers. Provided the EGT's are closely watched the non-cooled pistons do just fine. The oil spray just lends a measure of safety.

Lastly, I have read two instruction manuals for aftermarket turbo systems for the VW 1.6liter NA diesel. Both of them call for a max EGT of 1100*F.

I would say that keeping the EGT under 1100*F amd monitoring your oil and coolant temps should keep the Cat happy. Sure it won't make as much power as the factory turbo motor but it will be better than a NA.

RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

From the reading I've done (see my above post for some of it) the 3208 is a fairly solid engine as long as it's not rated too high. Definately get it checked out at a good shop before you decide that you're going to buy it, compression, oil leaks, etc. Might also take an oil sample and see if there are any unusual readings like coolant, fuel, high wear metals. You just want to make sure you aren't getting a time bomb because anything painted yellow is expensive to work on.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

It's a Cat remanufactured engine(1990) with 25k on it and I've seen the receipt, so it's just barely broken in. It looks like it also. It is rated at 210hp (prior to the turbo addition) so it's one of the long lived versions. For a heavy vehicle (35k lbs) it seems to move it along smartly. It would easily give the 300dNA a good run for it's money and probably beat it.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That would be quite a race

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

That was caused by high EGT's? You sure it wasn't just cylinder scoring? BTW you fried those oil rings!

Just curious. What EGT's were recorded while doing that damage

3 cylinders looked more or less like that. it's a result of 25psi of boost and 5500rpm at 4th gear... NA pistons can't handle that.

next time i'll have EGT connected...

You must have been in one hell of a place to be repping 4th gear wide open like that...

I think I hold the highest record (on this forum exluding finns) for revving a 617 turbo.

5750!

Poor engine...it never gets a break