Mercedes Race Diesel

[squid1351]

hello, after seeing so many fast trucks with an oil burner under the hood i and a friend of mine toyed with the idea of a race MB diesel. right now im at a point where im practicly planing it out on paper. im sure its going to be a while before the project rolls out of the garage. but im a firm bielever of starting out on paper. i know the OEM 617 has been tuned but never modified for a high profomance aplication. at this point its in planing stage. never actualy done this before im trying to seek as much input as possable on what to do to make a diesel go fast. the big things i need to find out about are turbo info. i need to look in to how much air the engine can actualy deal with before its too much. im also planing on puting a propane system on this beast. i could go on for days and days about what im going to do to this thing but the parts i relly need help on are the TURBOCHARGERS, PROPANE INJECTION, AND FUEL SYESTEMS. thank you for the help

 

[TooMuchBoost]

Great idea.

If you want to go fast skip the propane.

In your situation initially you need to increase two things to make power: fuel and timing. How much in a MB I have no clue. Figure out how the fuel pump can be turned up to flow more fuel and start advancing the timing. Diesel's don't need perfect air to fuel ratios like gas burners.

Too much fuel really doesn't hurt a thing and will potentially result in thick black exhaust smoke and higher egt's. Not a big concern in your situation.

Too much timing and the injectors will clatter among other things so back off a degree or two at that point.

Black smoke (over-fueled) is good because you can add a DRY nitrous kit for cheap HP. The nitrous will help burn the fuel in the over-fueled situation you have. If you can get the MB to the point where it is making more hp and pumping so much fuel that the exhaust is black under throttle the spraying of dry NO2 will give you that propane effect you are looking for and lower your egt's.

I personally would worry about turbo cfm after you figure out how much fuel can get into the cylinders. You may just find out that you'll need new (larger) injectors before you need a new turbo.

just my .02

 

[The Warden]

Hey Seth, good to see you came over

Originally posted by TooMuchBoost
Great idea.

If you want to go fast skip the propane.

Why is this? I was under the impression that propane was a "standard" power add-on...? Or is the dry NOS just that much better? I know that propane injection is a fairly common add-on in the 6.9l/7.3l IDI world...

In your situation initially you need to increase two things to make power: fuel and timing. How much in a MB I have no clue. Figure out how the fuel pump can be turned up to flow more fuel and start advancing the timing.

FYI, the OM617 is an IDI engine with a 21:1 compression ratio. So, before doing too much to the fuel system, it would be a good idea to lower the compression ratio enough to get enough air in to make the fuel usable (a stock engine can't safely handle more than 15 psi). Ken at DPS did this with a 6.9l and, while it was a cast-iron bear to start, apparently he was able to get quite a bit of power out of the engine before the bottom end let go

I know Seth knows this; just wanted to state it for posterity.

I personally would worry about turbo cfm after you figure out how much fuel can get into the cylinders. You may just find out that you'll need new (larger) injectors before you need a new turbo.

I figured new injectors were a given...although they'd need to be custom-made; the performance market for M-B diesels is even smaller than the market for Ford IDI's The turbo IP has a diapharam on the back that's connected to the intake manifold...more turbo boost puts pressure on the diapharam which, in turn, increases the fuel output. This diapharam is known as an ALDA (don't know what it stands for; something in German would be my guess ), and can be turned to get more fuel. I'm not sure if you can turn up the fuel in a way where it'll be putting out extra fuel without the boost...be worth looking into, though; I think that ALDA adjustments can only get you so far.

 

[TooMuchBoost]

I didn't realize a MB of this era was an IDI as I ASSumed MB would have been a little more ahead of the game. I'm looking at this from a modern diesel perspective.

Propane will add power and timing, but it isn't your best bet on increasing short bursts of power for drag racing. I would find the safest way to over-fuel this motor and add a dry NO2 kit to burn the un-combusted diesel fuel.

Quick, simple and inexpensive.

If your set on 'pane run it. I'm just saying how I would do it.

Once again my .02

 

[The Warden]

Originally posted by TooMuchBoost
I didn't realize a MB of this era was an IDI as I ASSumed MB would have been a little more ahead of the game. I'm looking at this from a modern diesel perspective.

I think M-B actually pioneered the IDI engine, although that info could be off. All of their passenger cars were IDI's, even up to '99. The new 320 CDi that's coming out is the first direct-injected engine they've offered in a passenger car. Note that it's also the first diesel they've put out that can outrun a comtemporary M-B gas engine.

Propane will add power and timing, but it isn't your best bet on increasing short bursts of power for drag racing. I would find the safest way to over-fuel this motor and add a dry NO2 kit to burn the un-combusted diesel fuel.

I see...didn't realize what NO2 did exactly. Here's one thought...could they be run together? Or is it worth the trouble?

BTW, AFAIK, this is all experimental...some people in Europe have done some performance stuff with the OM603, but I think this is the first effort to do anything serious with an OM617...I was figuring, once the compression ratio was lowered, following the path forged by the racetruck group would be the most logical course of action...

 

[squid1351]

thank you. all this info will be very helpful but can any one tell me about turbos? the system i was comtinplating was a duel turbo system in sequence also using a intercooler. i know that in order to obtain the boost needed i would have to machine the piston tops to lower the compresion to the 17-18 : 1 range. in adition the pistions would also need to be made from or coated with ceramic. all though this is just a small dent in the componets i would have to modified you have to start some where.;p

 

[The Warden]

I was hoping someone else would step in...

Seth, for the turbo info, you might try lurking in the Dodge section on this site. I think that most of the people who are doing turbo mods (particularly twins) are Cummins guys...once you're there, identify a couple of people who seem to be real knowledgable and send them a PM. They may be able to help you better...also, if you could get them to see this thread, they can post the info for anyone who may want to follow in your footsteps.

IIRC, most "ceramic" pistons have a coating, as opposed to actually being constructed of ceramic. Also, I think I mentioned this before, but you'd be better off with custom pistons than with machining material off a stock piston face. Losing material will make the face weaker, and I imagine that that's the last thing you want.

One other thought would be to see how thick the cylinder sleeves are...if there's enough material that you can safely bore-out, might be woth it to up your displacement slightly. But, gotta be careful...don't want to run into cavitation...