I know that if the fuel charge is cooler you can crank up the boost whether it is gas or diesel. Forum member GSXR may have some insight into intercooling diesels. I think the injection pump has to be messed with to really extract more power out of the engine but no matter what you do, there is a max EGT that you shouldn't go higher than. So it becomes a balance between intercooler efficiency, increased fuel volume and increased boost until you reach the max. EGT. I think when Porsche went to an intercooler they were also able to run higher compression as well as higher boost and more fuel. I don't know about raising compression on intercooled turbo diesel engines.

There is also a Dutch company that makes intercoolers for MB turbodiesels but I don't think they go back to the OM617 engine. But the fundamentals would still be the same.

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Doug

1987 300TD x 3
2005 E320CDI

that all makes sence. any pictures of your p car?

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83' 300SD Turbo, intercooled,
71' Porsche 911 T Targa.
85.5' Porsche 944 euro
87' Fiero cp.
Lamborghini Diablo replica V8 4spd.

It is a sad story but it is outside now and looks fairly bad. I saw that you too have Porsches. My engine is apart and needs a rebuild but the pistons and liners are in great shape. Of course I would go for the timeserts and the raceware studs. I would also like Webers because I know that putting mechanical injection would just be too problematic and expensive. I have my hands full with my 120 year old house and I still have to put a head on a 1987 300TD wagon that I picked up this summer. I want to do the Porsche right and strip the paint, replace rusty panels, powder coat all the suspension parts etc. If I ever get it done it will be a sunny day summer car only.

It all comes down to time and money and unfortunately I don't have enough of either for all my hobbies and family activities. By the way fixing the house and the cars are a couple of my hobbies.

I remember the Dole Pineapple Fieros when they were racing IMSA GTA. They were all four cylinder injected engines. I think Pontiac was supporting the cars also. But as is typical for GM, as soon as they get it right, they stop making it.

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Doug

1987 300TD x 3
2005 E320CDI

As with all of my cars. i see it as a hobby. if they dont get finished its fine. its still something to look forward to and do in my freetime.

I would also choose the webers. Mine has a new set of PMO carbs up top. and arent must more then a pretty version of webers.

Thanks for the kind word regarding my midengine passion. Many people would rather post a reply about the rumors they heard about the car.

most dont know, or dont belive that the car infact then and even today holds the highest non airbag equipt safety rating. see here: http://www.crashtest.com/explanations/archive/crash.htm

and they think they all had fire issues. when infact that was related to 1984's and they recalled and repaired the problem by adding heat sheilds to the catalitic converter and removed the front deck lid weather strip.

but by then it was too late and the word was spread. and like anything else the rumors started to brew.

every once in a while i get asked, or told something about my car and i cant help but to roll my eyes. btw. ive owned 13 fieros and every single one is still on the road.

thanks again for the kind words.

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83' 300SD Turbo, intercooled,
71' Porsche 911 T Targa.
85.5' Porsche 944 euro
87' Fiero cp.
Lamborghini Diablo replica V8 4spd.

It is amazing that in politics people forget withing a few years but with cars it is forever. I think diesels are still shunned here due to GM adventure into diesel conversions in the 70's and 80's. My cousin had a couple of Fieros and they both ran like champs with very few problems.

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Doug

1987 300TD x 3
2005 E320CDI

Turning up the boost increases the amount of excess air. The more excess air you have the higher the specific heat ratio of the combustion gases. The higher the specific heat ratio the more power you extract from the cycle because it behaves more like an ideal gas. In other words you get more power out from the same amount of fuel burned.

Turning up the boost also reduces combustion chamber temperatures. With the lower combustion chamber temperatures less heat is lost to the cooling system hence more energy is retained in the gases that do the work. Additional efficiency results from this hence you get more power out as well.

These two effects have diminishing returns as the boost increases. So you will reach a point at which it takes more energy to create the additional boost than you get back from the efficiency increase. According to the fins, no gains are seen after 14.5 psi of boost with the stock turbo as its efficiency drops off. If you want to run higher than 14.5 psi of boost you'll want a better turbo.

So turning up the boost or adding an intercooler alone gets you more power up to a point.

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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

Uh oh

Ergh? W123 only gets 2 and 1? WTF?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Why doesn't anyone use an open paper filter?

Plenty to choose from at McParts. Newer Vipers have them, Trailblazer SS, Ford trucks, etc. They're just friction fit.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

becuase they dont come with cool stickers, and arent as pretty

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83' 300SD Turbo, intercooled,
71' Porsche 911 T Targa.
85.5' Porsche 944 euro
87' Fiero cp.
Lamborghini Diablo replica V8 4spd.

Ah, the truth comes out.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

paper filter? do tell me more. I'm not set on my cone filter... but i like hearing the turbo... thats the real reason its on the car.

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What do you want to know? They are a round, conical paper filter.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

If you want three more HP, then follow this advice and you might get that three- then again maybe not.

not saying its just you, its not. there are several others.
but it seems that many members of this forum really try to discorage others from enguaging in any kind of project that may possibly make the car a better performer.
Now its been made clear that these engines are very durable, its been made clear that that almost all diesel powerplants are making some seroius power with modifications.
Now why are other people, many MB owners themselfs saying its a bad idea to do something untraditional with a luxury car?
Imo if it has potental use it, or waste it. Im a motivated person who much like the engineers who devoloped these cars. beleaves, that if it can be better, make it better.

Or maybe im the only one that is willing to sacrafice some unneeded reliablity for enough fun factor to make you actully want to drive the car for its life? These cars are well known to go 500K now if i had to give up as much as half that to make it enjoyable for that period then im fine with it.

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83' 300SD Turbo, intercooled,
71' Porsche 911 T Targa.
85.5' Porsche 944 euro
87' Fiero cp.
Lamborghini Diablo replica V8 4spd.

You can up the performance all you want, it's just not cost effective.

Hypothetical scenerio:
You pay $5000 for a very nice 1983 300D.
120HP stock.

Boost and Pyrometer gauges: $250
Intercooler and associated parts: $400 average.
Water injection: $200
Turbo back exhaust $200
Rework the intake manifold: $75
Custom air filter $50
Boost controller: $20
Total: $1,740
Total (real) power: about 128HP (4 of that from the methanol in the water injection)
A stock 87 300D or 87 190D will still walk all over you.

You want to up the fuel rate?
Upgraded turbo compressor wheel: $80
Tools and new gasket to adjust the IP: $50
Total: $130
Total power: roughly 190HP at the flywheel (MAX).
So far: $1,870

Want more HP than that?
M-type euro injection pump: $250
Myna custom pump plungers and tuning: $2500 after American-Euro currency conversion
Mandatory turbo upgrade: $500 (average)
Custom manifold and oil lines to mount the turbo: $250
Power: 200-350HP
Total: $3,500
Total to get an extra 80-230HP: $5,370
Overall: $10,370
Now, drag race a bone stock 560SEL (That would cost about $6,000) and it will leave you crying in the dust.
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Now, you ask, "Why do you do it?"
Because I love to do it. So what if a 560 will beat me, it's my passion.