Dslbnz,

I agree that simpler is better. I wonder if my '87 300SDL isn't too complicated.

I would rather have an all aluminum engine than an iron block and an aluminum head. I always wondered about the difference in temperature coefficient between the aluminum and iron. Aluminum expands about 3 times as much so there has to be a sliding action between an iron block and an aluminum head.

Of course I would rather have an iron head and block.

P E H

Iron block and iron head are the best, indeed.

Would you really trust an all-aluminum diesel with all the stresses going on at an 18.5:1 compression ratio to do the miles? Maybe an aluminum gasser, but a diesel? I wouldn't, but I might be too harsh about the CDI's. I have never owned one. I'm just basing a lot of my opinion on people I've talked to about these engines. My personal opinion is always quite neutral.

I'll tell you why,

There are a lot of people who seem to like the W211 E55. They say it is the best car in the world. Most of the people who make these comments have never sat in the cockpit of one of these cars and mashed the pedal themselves. Or experienced what creature comforts the W211 may provide. Experience is key for the most intellectually informative opinions on cars. But HONEST reviews; not gloating about how the car is the best car ever made in the history of automobiles, or how it can dust a Ferrari 360 spider, or whatever.

I know I am getting off topic, but my conclusion is this: the only way we will know for sure, if ANYTHING is reliable or not, we must experience it first hand. So until you drive a CDI, our opinions may be null to fact.

DslBnz,

The best car in the world when new may not be the best car in the world after it has 100,000+ miles on it if it continually needs repair. The 300SDs have proved themselves reliable in 100,000s of miles of actual operation. I wonder it the new CDIs will do as well when they get as old and have as many miles?

There's a long string of threads about troublesome MB in the Tech Help section.

P E H

are the 'iron' engines really iron? or are they steel and youre just saying 'iron'?

Grdenlo,

The older Diesel engines are made of castiron.

P E H

My advice is to leave the engine alone, unless you are smarter than the guys that designed it. Just get a good independent mechanic to make sure it is doing everything it is supposed to. Sometimes a valve adjustment will make a difference in power. I would also recomend an Italian tune up. I ran my 240D up a bit of a grade last week and pushed ti to 55MPH in 3rd gear. It ran better afterward than it has in years, smoother too. Just don't overdo it

If you want to increase performance, get a donor 4 speed 240D and transplant the transmission.

Um, you did notice that you are answering a 4 year old thread? ;)
And the poster hasn't been on the forum since January of 2004....:eek:

I bet this question wasn't/isn't going through the head of the thread starter only :) , hence any idea might benefit other users.

My input would be a propane injection. Propane injection does help increase power, but it doesn't work in the same way as nos works. You can install nos in your car though as it's been proved in this vehicle it does work with diesels as well.

NOS injection increase oxygen in your car. It's the same as installing a larger turbo, but you also need to give the engine extra fuel to achieve more power.

Propane injection introduces more fuel in the engine. Propane is a fuel. Diesel engines by design have more air than needed for the combustion. By adding propane, you're replacing some of this air with an other fuel (propane). This increases power. It also increase mpg, but that is because you're burning another fuel as well thus you don't need to burn as much diesel. Overall gains in mpg are not as great as one might think because you have to fill the propane tanks as well, but because propane is cheaper than diesel it does come out cheaper.

A cheaper option is to just turn up the full load setting and increase your boost psi to match.

Propane: $$$
Nitrous: $$
Full load/boost adjust: Free.

How can you increase boost with the stock turbo? How much performance is expected with that "mod"?

Also don't you need an intercooler to do that? A dead engine is certainly more $$$ than a propane/nitrous mod (if done properly) :D .

Yes,
I noticed.
I did not notice that the original user has not been on the forum since he posted his question though.

Of course I get a lot out of old threads. Some of which the original user may be long gone.

I haven't run propane in my MB but in both my Audi and my Isuzu diesels, 9 gallons of diesel and 1 gallon of propane would go farther than 10 gallons of diesel by itself.

That's interesting because lpg has much lower BTUs than diesel. Over here in Europe a lot of people run their gas engines on lpg and they always say that their performance and mpg does suffer.

I want to install a lpg system to my car as well. Was the power increase noticeable on your cars? Do you mind sharing your system :D .

Very true about the less BTU per gallon but it's also about combustion efficiency. At cruise, I got more miles per total gallon up to about 30% propane. Total homebrew system with mass flow of the propane controlled by a fuel map with inputs of throttle position and rpm. Very similar to an EFI gasoline computer with throttle body injection but no butterfly.

Noticable but not much power increase. Both engines were NA.

I did the same recently. Engine has a growwwwllll to it when accelerating. Fuel economy up about 2 or 3 mpg. eBay has some sellers who have this sort of thing -- search for 300sd air intake or soemthing like that.