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Road Trip! (Probably) Buying an E320 CDI
Unless there's anything unexpected, The Art of Diesel's next project machine will be driven back from Florida this weekend.
I’m looking at buying this machine this weekend!
Like any engineer, I’ve been working up a spreadsheet to look at the comparative costs of a couple options for the next Art of Diesel project. Before I go any further, please keep the following statement in mind:
Horsepower sells cars, torque wins races — Carol Shelby
About Torque vs. Horsepower
Many of my sources will only give horsepower numbers because that’s what people generally talk about. However, when you put the pedal to the floor in your car, the torque figure is what you are going to feel immediately, especially with a diesel where the torque figures are generally very flat. Because (after some unit conversions) horsepower is torque x rpm, an engine will achieve maximum horsepower near the upper limit of its rpm range. So, when the engine in your car reaches that magical rpm where horsepower is maximized, you are going to be there for only a split second before upshifting. This (along with efficiency considerations) is why my other Mercedes vehicles have had seven-speed transmissions, there’s a general trend toward a higher number of gear ratios, and why some manufacturers are moving to continuously variable transmissions (theoretically, CVTs give an infinite number of gear ratios).
Back to the Topic!
Both of the cars I’m looking at are contenders over which has the ultimate small Mercedes diesel engine. I wound up working on the spreadsheet because the pricing of both are quite high for 16-24 year old machines that often have 200,000+ miles on them. I intend to do a lot more than simply buy and maintain them, of course. Whatever I buy will be modified for performance!
Here’s a great video by Jay on his Jet Lag Heroes YouTube channel that does a nice job comparing the vehicles I’ve been looking at in their unmodified form.
I had to look at what my available budget could withstand as I get started, to ensure I wasn’t going to spool up only to get stopped by funding.
1998-1999 E300 Turbodiesel. These cars are on the W210 chassis and come with the OM606 engine that only produces 174 hp stock, though they are not slow. They have decent grunt with 244 lb-ft of torque. These cars are reasonably efficient, getting 32 mpg highway. What makes them super-cool is the OM606 engine is so tunable!
Check out this Benz Injectors package that will take these cars to 300 hp for around $1500! https://www.benzinjectors.com/product-page/om606-performance-turbo-kit-for-e300-w210
However, DieselPump UK also specializes in the OM606 engine and have tuned some to around 700 hp. As observed in this video, what can be done while the OM606 is installed in the W211 is actually quite limited because of the electronics and limitations of the rest of the car, especially the transmission. They’ve transplanted them into a variety of vehicles including a Nissan Patrol, Land Rovers and G-Wagons (though some late 90s G-Wagons came with the OM606 stock).
2005-2006 E320 CDI. These cars are the following generation W211 chassis that was sold for quite a few more years than what I’m showing, but the OM648 inline six cylinder was only sold in the USA for these two model years. The OM648 is also quite tunable, but it doesn’t breathe as freely and there’s a lot more difficult and expensive to make the crazy horsepower levels that the OM606 can. However, quite a bit can be done while keeping it in the W211 chassis. It’s also a common rail system which does a better job of atomizing fuel and the fuel economy on these vehicles (stock) is in the mid-30s. I’ve heard some claims of 40+ mpg. A couple interesting things to share on this engine are:
Black Smoke Racing is known for their Mercedes Drift Wagon that had an OM606 tuned to around 600 hp and was seen alongside a number of much more traditional drift cars on European racing circuits. That older wagon looked completely crazy, but I find it to be a sort of inspiration…though I’m not planning to do any drift competitions! Black Smoke has since switched to tuning OM648 engines and they’ve published a sort of recipe for achieving 300-400 hp in these engines.
I’m looking at ECU Tuning Kaunas who sell reasonably priced kits and tunes including their own hybrid turbos. They say they can get to around 400 hp and this dyno output shows just over 390 hp, along with over 340 of it to the wheels, which is quite impressive. Especially when you consider that the engine really doesn’t breathe well enough to be used above ~4300 rpm. Because I’m really after torque, though, notice that their peak figure of 803 N-m translates to 592 lb-ft. It also provides 440+ lb-ft (600 N-m) from 2200-4300 rpm — meaning that there’s an amazing amount of torque available across the usable rpm range.
I’ll share more research as I get further along. But it’s good to know that there are alternatives to sending a turbo core to Darkside Developments in the UK to have them build a hybrid turbo for $1800+.
The Option I’m Picking
The bottom line, however, is that the W211 OM648-powered E320 CDI is the best way to go for maintaining decent efficiency. We will save the OM606 ideas for a transplant operation in the future. So, I’ve been focused on those mostly. Really, though, a fantastic deal could push me in either direction!
I thought I’d found an incredible deal when I realized that Jay mentioned selling his 1998 W210 for about what the engine is worth. However, he’s concerned about some electronic gremlins and it wouldn’t be smart to just hop in the vehicle and drive it from Washington to Ohio. Shipping or trailering the car that distance adds costs and timing that I can’t deal with right now. If you are OK working out the gremlins, contact him at his email address in the video’s information text!
Then, however, I stumbled across an awesome gray 2005 E320 CDI W211 with 178,000 miles on it (nothing for these engines), that was taken good care of. The photos at the top of this article are from the Craigslist ad where I found it. There are some cosmetic issues including scratches on the door, some baked paint, and duct tape seat repairs, but the car is only $5,500. The owner died and his son is selling it for his mother.
I talked with the seller, and I’m traveling to Florida today. I’ll fly down this evening, grab a room there, and meet up with him to check it out on Saturday morning. Hopefully I’ll be finalizing a deal and starting my drive back to Ohio in it late that morning!
At this price I can afford to both (1) fix the cosmetic issues, and (2) make the upgrades I’m talking about without going beyond my budget.
Wish me luck! I’ll take video and report back soon!
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