Olders diesels slooooow. Is retrofitting possible? - PeachParts Mercedes-Benz Forum

gregp1962 · #1 11-27-2006, 05:48 PM

I realize that electronic fuel injection made a HUGE difference in diesel engine performance. But, I don't understand why older diesels are soooo slow. Is there any retorfitting that can be done to an older diesel to make it burn cleaner and have more power?

gsxr · #2 11-27-2006, 05:57 PM

No retrofitting needed. Buy an older TURBO diesel (emphasis on TURBO) and you can make it as fast as your wallet allows, no electronics required. Search this forum for the term "superturbo" for some examples of very, very fast diesels. Some movies are here:

http://www.w124performance.com/movies/Mercedes/SuperTurbos/

vstech · #3 11-27-2006, 05:58 PM

it's all about efficiency. older Diesels dumped fuel into a Prechamber, and the explosion had to fit out small holes into the combustion chamber.
newer ones spray the fuel high pressure directly into the combustion chamber. no energy wasted squeezing through small PC holes. Could a 617 head be modified? maybe how much compression loss would their be?
John

gregp1962 · #4 11-27-2006, 06:13 PM

Actually, I'm not trying to make a car fast. I'd like to get an early 70's Diesel that does 0-60 in less than a day...

Thinking out loud here....VStech, You mention modifying the head of a 617. Is a 617 an early 70's diesel? I'm guessing that you're talking about modifying it by enlarging the holes from the prechamber to the main chamber. And, you're concerned that that would lower the compression ratio. Could the head be shaved just a little to bring the compression ratio back into line? Would it defeat the function of the prechamber?

Surely someone has thought of this?

rudolfgreen · #5 11-27-2006, 07:10 PM

can you squeeze a 602 into a 115?

(kind of seriously)

DieselAddict · #6 11-27-2006, 07:18 PM

I wouldn't call the older diesels "sooo slow", but surely they're not for everyone, especially for the performance-minded individuals. The main reason older diesels aren't as peppy as the newer ones is that many of them are naturally-aspirated, i.e. no turbo. There were some that did have turbos. Look for an 82-85 300D or 300SD for example. The 87 300D was the most powerful passenger car diesel of its time. The secondary reason why the newer diesels are more powerful is their direct, electronic, high-pressure fuel injection. I think taking an old diesel and modifying it is a waste of time and potentially a costly project. I'd just get a newer diesel if performance is your primary objective.

gregp1962 · #7 11-27-2006, 07:29 PM

I hear what you are saying about the turbo engines. But, I REALLY like the early 70's models. I wonder if an 80's turbo Diesel engine and tranny would fit into one of those. Is that what Rudolph is suggesting? I don't know the engine numbers.

vstech · #8 11-27-2006, 08:10 PM

actually, I was talking about removing the PC altogether, and maybe adding a swirl DI adapter into the PC location... I don't think the Compression Ration would change... hmm just thinking outlouddd