c250d

First up hi all recently found this place wich looks like the most active/usefull mbz site yet, quick lowdown on my car a euro c class 5 cyl 20v with no turbo, yes it lacks oomph not being a turbo so im determined to get hold of a turbo and all ancillaries hopefully as cheaply as possible as my budget is a little restricted by my new home. Good news is ive found a cheap manifold and turbo from a sprinter 310 312 van/truck im hoping this will fit as there both a 5 cyl merc diesel engine, can anyone tell me if it will work or will i need the exact turbo/manifold or is there a better turbo to look out for, any help or advice much appreciated.

240D 3.0T

I assume you have a C250, but what year?

You car and the Sprinter use two completely different engines. Yours is a 2.5L 20v OM605 while the Sprinter should have a 2.9L 10v OM602. While the turbo on the sprinter is a good size match for your engine, the manifold will not work.

Untertürkheim

What you need are parts (manifold, turbo, IP, etc) from the OM605A engine, should be in the W210 E250 Turbo. To the scrapyards!

On a side note, the C250 was supposed to be a healthy performer, are you sure you it's not a problem with your engine? If all else fails, pushing harder on the accelerator often works for me ;-)

c250d

Well performance isnt bad it just lacks torque, maybe i shoul remove the cat converter as i bet thats clogged by now, thanks for pointing out the engine difference with the sprinter guess il be searching some more, i live in a partcularly hilly area of dorset [lyme regis/ west bay coast] and for a car that should make 115 hp it needs to be thrashed to get moving. Oh yeah its a 96 model showing 117,000 miles would it need any valve adjustment or something like as i know four stroke dirt bikes tend to tighten up on the valves and lose performance.

Untertürkheim

Those engines have hydraulic lifters, no adjustments needed. Assuming all of your filters are clean, you may want to check your injectors, timing, and/or timing chain stretch. The OM604/5/6(A) were the last generation of indirect injection diesels, but they were excellent, having 4 valves per cyl with variable valve timing and intake manifold runner. They had the best torque curves because of all that. I had a 250D Turbo (OM602A) that produced barely more HP, 121 I think, and 165 Torque, and that car moved quite well (I also consider myself a demanding driver). Your engine is in an even smaller car, which is why I think it should move adequately. All that being said, adding a turbo to a NA engine will not produce the same result as a C250 Turbo, so it may be a lot of work for a relatively small payoff.

c250d

Well i learnt a lot there thanks Untertürkheim, i never new my car had variable valve timing for one and can you explain what a intake manifold runner is and how it helps performance? Il get someone to check my timing as soon as is possible and id better get my injectors checked also, gonna go look in my manual this evening too.

240D 3.0T

A manifold runner are the long tubes that go to the engine. When the intake valve is open on the engine, air is being sucked into the engine, so the air in the intake runner is moving rapidly toward the cylinder. When the intake valve closes suddenly, this air slams to a stop and stacks up on itself, forming an area of high pressure. This extra pressure helps cram more air into the cylinder.

Here are some picture examples from my engine. The short log manifold is stock, the second one has intake runners.

khaug

I wouldn't even think of doing a turbocharger add-on, if I were you. For starters, you'll need to do internal engine changes, such as new pistons to reduce the compression ratio. Then, consider that an M-B turbocharged engine is engineered as a whole, and all facets must correctly work together. You'll also need to change intake plumbing, add an intercooler, change exhaust plumbing and incorporate whatever measures M-B used to regulate boost pressure. Most likely, you'll also need to change injectors to accommodate the greater fuel demand turbocharging will create. And you'll need to upgrade the cooling system to get rid of the additional heat your turbocharged engine will be generating. No doubt I've overlooked some important details, but I hope you get the idea I'm trying to convey.

I'm a fairly accomplished amateur mechanic, but I'm not an engineer and I'd never consider tackling something like this. I think you'd be far better off to sell the car you have and find a turbocharged model that came from the factory.

Best regards.

240D 3.0T

It all comes down to cost. After all the time and money you have invested in all the necessary changes to assure engine longevity and adapt a turbo, you could have traded in your car for one that came stock with a turbo.

Untertürkheim

I agree with the previous 2 posts, adding a turbo yourself will be less effective and more expensive than getting a different car. If you really want to have fun, go with a '97-00 C270 CDI, that's quite a diesel rocket. Probably more efficient too.