Sequential turbos - Page 2 - PeachParts Mercedes-Benz Forum

derherr65 · #16 03-16-2007, 01:31 PM

230 was the peak HP ever produced by the C111 diesel. The first ones only had 190HP. I'd be happy with 200HP.

"cylinder head made out of light alloy, detachable, 2 valves per cylinder" 17:1 compression and +30PSI of boost. I'm going to have to disagree about 4 valves per cylinder. It was an optimization of the normal head, not even cross flow, and the alloy was to disipate heat I'd bet.

psfred · #17 03-16-2007, 01:38 PM

Hmm, sorry about that. It's been a few years!

Just think of what you could get out of a 603 then! It's got 150 hp stock....

Peter

derherr65 · #18 03-16-2007, 01:57 PM

Very true. But then you have a computer.. I think? I hate computers in cars. Also I like the round headlights and body contours of the early 80's diesels better. They just seem more elegant... more classic than the new aero look.

But the mercedes experts apparently agree with you. You get more power out of a 617 by upping boost, but you need to decrease the compression ratio. But if you decrease the compression ratio much cold starts get difficult. Damn laws of physics never cooperate with me.

Black smoke bad, gotcha. I've heard, generally, a light haze at WOT means you are about right.

I thought you couldn't get pre-ignition in a diesel because ignition started when the diesel was injected. I know you can bump the IP timing too much and blow everything apart. Wouldn't a red hot prechamber have the same effect on combustion as a red hot glow plug? Not that they're meant to glow, but you get my jist I think.

psfred · #19 03-16-2007, 05:19 PM

You won't get pre-ignition unless you have fuel in the air, which is exactly what adding propane to the air in the intake ("propane fumigation") will do. You should never have enough to cause ignition, but if you do, godallmighty hot piston crowns.

The old MB rule was that you should see just noticable black smoke over the deck lid at full throttle and 3500 rpm, full load. (on the older cars, 45 mph in third). More is either not enough compression, too much fuel, or incorrect injection timing. The inky blasts from old Macks is due to fixed injection timing -- at any rpm other than 2200 plus or minus 200 rpm, they rattle and smoke, terrible. New engines are MUCH better.

All MB diesels have had variable injection timing, its a centrifugal device under the vacuum pump. They have also always had overhead cams in automotive applications, at least since 1935 or 36.

No computer until the OM603, and up to 1990 that was only for idle speed control

I agree, computers in cars are grossly overdone, the old analog ones are much better than the digital ones. Best way to control automotive pollution is to not drive them -- and believe me, if I could take public transit to work rather than drive 2 hours a day, I would. I would even walk the two miles to the village to catch the train! I'd probably weigh 40 lbs less and be much healthier, to say nothing of less grouchy!

Peter

Peter

MTUpower · #20 03-16-2007, 08:10 PM

Well MTU (motor and turbine union- MB's off road arm that is now owned by a conglomerate) still uses sequential turbo's- so they cant be on the total road out the door. I'd give up the idea unless you won the lotto however.

derherr65 · #21 03-16-2007, 08:17 PM

Deal.