Toblin

OK I just gota jump in here and say I am also a admirer of the naturally aspirated engine. I realize the boost you get from the turbo comes at little extra cost in maintenance or anything else for that matter as long as things are running well. However if you started with two new cars, (turbo & non turbo) and both engines were treated the same, I believe the non turbo would last longer and be ALOT cheaper to rebuild. ALSO I like shifting gears , which pretty much eliminates a turbo for me. On the other hand if I had a freeway commute every day I would be driving a 116 and put off the enjoyment of shifting gears till later

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

I wouldn't say that all Garrett turbos are that great, I believe my Talon has a Garret turbo in it from the factory but it is a bargain chrylser one. :-/ It has 102k miles on it, no coking in it, but somehow a few months back oil stopped going through it. It works fine again now, but I need a new one, a bigger one.

The Mercedes Garrett turbos seem troublefree the only thing I'd think that adds hassle is the ALDA and the line to it, I can surely put up with cleaning it out every year or so for the extra power. Since I drive only turbo vehicles I get used to driving them very softly for the last mile or two, normally I don't let the MB idle at all before shutting it off. Only time I do is if I just got off the expressway or something like that. The talon however I have a gauge of what the exhaust gas temperatures are coming out of the motor and gauge it off of this. Once it hits 1000*F I shut it off.

No, there is no functionality for a blow off valve on a diesel since the air is free to flow where as in a gasser the throttle plate is there to restrict it. However you could get a turbo timer for a Mercedes diesel just like any other turbo car as all it does is delay the shutoff of the vehicle by watching when you shut it off and adding a certain time to that before it shuts the igntion off.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

This would be interesting, considering that the Mercedes diesels we're speaking off have no electronic ignition controls whatsoever, and to add to that, the engine shutoff is vacuum actuated.

Perhaps I'm assuming something I shouldn't but aren't our igntion locks just normal electrical ignitions, I have no idea where that other side of the vacuum hose which goes to the IP goes or how it gets its business done.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

It would be very simple. Insted of shuting off the ignition, just activate a solonoid with a vacuum valve.

To throw more gas (diesel?) on the fire...

1- Letting it idle for a bit before shutdown won't hurt anything, as long as it's 2 minutes or less. MB has stated that if a diesel engine will be required to idle for longer than that, it's better to just shut it off. Again, it's just not necessary for normal driving, but if it makes you sleep better - go for it!

2- In my limited experience with turbos, the Garrett used on the OM603 tends to leak oil a lot - annoyingly so. They work great, just leak externally. They're also a little noisier. My KKK turbo is bone dry externally, dead quiet, and has an externally adjustable wastegate which I love. Both seem to last almost forever though.

3- A turbo engine will last just as long as the non-turbo. The internals are seriously beefed up so there is no compromise in longevity. I almost think the turbo engine might last longer. But yeah, it probably would cost more to rebuild. You don't hear about many people needing to rebuild them though - the chassis normally dies long before the engine *needs* a rebuild! :p

4- The non-turbos are just too damn slow! (yeah, yeah, I'm a power junkie - I admit it...)

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I think that rule goes for almost all diesels, they shouldn't idle for a long time rather the speed should be picked up if they need to set.

When you are talking about 0-60 in 13seconds rather than 20seconds I don't see much of a comparison. I don't think 13seconds would fall into the category of power junkie perhaps your 87 300Ds could though with the right mods.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Speaking for turbos IMHO the best ones come from KKK and Warner-ISHI. They have both been extensively used in race cars and KKK is OEM to Porsche and MB. The Warner-ISHI was used in the dominating F-1 Honda engine where it ran a boost pressure of 40psi and from 1.5 liter engine, 1200+ bhp was generated. It was of a variable vane ceramic blade design.

That sounds like fun!! My little 2.0L is only mid to high 200s (0-60 in high 4s or low 5s). I need a huge turbo to boost up 30psi and have some real fun, like real AWD burnouts. (~500hp) I have a good deal of the setup done, but the biggest pieces are missing, huge turbo and huge frount mount intercooler.

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Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Just wondering, if you were to increase the boost pressure, wouldnt you need to improve the cooling system, lubrication and the pistons accordignly, apart from that the head gasket, studs, higher quality pistons as well as improved valves.

When MB turbocharged the OM616, almost all internal parts including the crank, oil pump, pistons, valves, radiator was redesigned and the head was re-designed for improved coolant circulation, now all this for a mildly turbocharged engine developing 91bhp from the original normally aspirated 65bhp.

The cooling system normally isn't a problem as a result of raising boost, but it does become a problem if you add a front mount intercooler as it is getting warmer air. At this point the radiator may have to be replaced with something thicker and more effiecent. The lubrication doesn't really need any improvement to speak of, the pistons aren't normally a problem (unless you are talking a huge increase) but sometimes the connecting arms need upgrading if they are the weaker style. The head studs always need to be upgraded with a huge power increase, my car can handle 400hp until the motor needs to be opened and beefed up.

One of my favorite examples of a modded, or as they say "bombed" vehicle is the dodge ram CTD. Take the diesel motor and swap different turbos on it, build up the motor a little, triple the boost and go from a stock output of ~300hp & 550ft/lb to 950hp & 2000+ft/lb!

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

> turbo timer and idling to cool the engine

I guess I'd be concerned if I lived at the bottom of an off ramp.

> blow-off valve

This device is only for air throttled engines. A BOV on an MB Diesel wouldn't blow if you sidestepped the pedal at WOT at 5000rpm (or 4800rpm in my case).

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Yes, they are worth having. I almost bought a 1983 300SD last summer, and I could tell a huge difference between it and my n/a 300CD. Instead I bought a 1993 Subaru Legacy Turbo, and I can tell a huge difference between it and the 300SD. For one, the subaru doesn't have the tourque, however, it is much quicker, and faster.

Now Eric, I'm SURE that your Subaru can benefit from a larger intercooler, free flowing intake / exhaust, blow off valve, etc!

so has few of the problems a gas turbocharger has...Frank Barrett has nothing but good to say about them..."free" extra power.

BUT...ANY extra part is something that potentially can go wrong...it can't screw up if it's not there.