need more diesel power - PeachParts Mercedes-Benz Forum

juggernaut · #1 03-19-2007, 10:10 PM

i own a 1983 300D turbo diesel. does anybody have experience in tuning them to crank some power out of them? i don't have much experience with the mercedes diesels, so im looking for some advice or tips. im also considering a propane injection system sometime in spring.
so far, i got a exhaust dump pipe to relieve exhaust back pressure, i disconnected the wastegate hose so im running 20-25 psi boost, and i fiddled with the adla a little. is there anythign else i can do? any aftermarket parts, or custom modifications? im open to any ideas.

300SD81 · #2 03-19-2007, 10:14 PM

20-25psi boost will kill your engine! adjusting the alda, a proper boost gauge and controller, and intercooling will help...

log673 · #3 03-19-2007, 10:15 PM

Put a gasoline engine in there.

tobybul · #4 03-19-2007, 10:40 PM

Quote:

Originally Posted by 300SD81

20-25psi boost will kill your engine! adjusting the alda, a proper boost gauge and controller, and intercooling will help...

I agree..... at least adjust the alda... search for articles

RUN-EM · #5 03-19-2007, 11:15 PM

They are from Finland and boy how those guys know how to make em run. Their ideas are discussed on this forum. Some of our guys have hopped up our turbo-diesels.....just not to the extent of those video cars. Like it has been said, don't turn up your boost until you have an accurate guage. Anything over 13-14 pounds pressure is really a loss....you need to crank up the fuel (at the alda AND the injection pump if really hot rodded) to compensate for the excess air anyway. To do that you need a pyrometer to watch exhaust gas temps...keep them under 1200 degrees F.
When you have the boost/fuel cranked up and engine is getting too hot internally (note exhaust gas temp) you need to run alcohol/water injection or intercool it (air-air or water-air intercoolers have been discussed). If you run out of turbo, then you can put a T3/T4 set up or if really into it, can go up to a really big holset turbo. The stock bottom end of our cars can handle about 400 to 450 HP and prolly over 500-600 ft.lbs torque (but the head at this level is usually ported/polished/larger valves/better springs, etc).

Speed costs money--how fast ya wanna go?
Also true-- the only thing that beats cubic inches displacement, is cubic dollars.

Regards,

Run-Em
1983 300SD-aka-SPARKY THE DIESEL

#6 03-20-2007, 12:26 AM

Put your wastegate hose back on!!!! 25psi is in the speed range where you are on the hair line of fragging the turbo's compressor wheel!

You will get 0 benefit from more than 13psi of boost until you have adjusted the injection pumps internal settings.

You want good performance tips? go here: http://schumanautomotive.com/forums/forumdisplay.php?f=19

pawoSD · #7 03-20-2007, 12:27 AM

Keep running 20-25psi boost (I don't even think the stock turbo can generate that much, so I question those numbers)....and you can kiss the engine goodbye, then you won't have to worry about tuning it. You're going to bend a rod, fracture the turbo, or something and then it will be all over. Put it back down to 14psi or less where it belongs. More boost does nothing to increase power, you need more fuel too, which you don't have, thats only attainable with very skilled adjustments of the inner workings of the injection pump....and turning up fuel/boost = more heat in the engine, = damage. Buy a different car if you're looking for performance like that.

gsxr · #8 03-20-2007, 03:30 PM

There's no way the stock turbo can produce 20-25psi. You haven't measured actual boost yet, have you. Removing the wastegate hose will get you 15-18psi at most, but that will make ZERO additional power without increasing fuel delivery from the pump. The ALDA is a red herring, it will only increase part-throttle and off-idle power, not peak full-load power.

We're not going to walk you through this, it's all been posted before... read up at this link (go to the SuperTurbo forum).

Bottom line: You can get ~20% power gain with an intercooler and the stock pump. Beyond that, it will cost you $$$$, starting with a Myna Diesel pump rebuild in Finland. First, I'd start by making sure you are getting the factory rated power output... your 0-60 time should be about 14 seconds. If you're slower than that, get to that point first, no modifications required...

winmutt · #9 03-20-2007, 03:54 PM

Quote:

Originally Posted by gsxr

Beyond that, it will cost you $$$$, starting with a Myna Diesel pump rebuild in Finland.

We should do a group buy on that pump and have someone here dissect it and figure out whate changes they make.

gsxr · #10 03-20-2007, 04:02 PM

We already know basically what changes are made. The problem is sourcing the parts, properly installing them, properly modifying the governor, and then calibrating it to custom specs. So far, nobody has been willing to risk grenading a 603 with a hand-tweaked pump with 7mm elements. Maybe if I had access to a Bosch calibration bench where I could fiddle with it for hours. I wouldn't want to attempt this on the car though.

Alastair · #11 03-20-2007, 04:31 PM

When looking to extract extra power from a Diesel engine, a few things must be remembered or it will all end in tears....

IF you really ARE developing 25 PSI boost which I seriously Doubt, For god's sake, have pity on it before you destroy or seriously damage either the Turbo OR the engine. At the moment, its a 'Runaway' waiting to happen when the turbo self destructs....

Reduce the boost-pressure to an Absolute-Max of 15 PSI untill you do further work.

Starting with a Good Turbo engine (regardless of make) its possible to gain good improvements just by getting all the settings to Correct, factory spec, and ensuring that the engine is in a good state of health.-There is No use or benefit of 'just upping the turbo-pressure' on an engine with say, Mis-set fuel-timing, or a stretched timing-chain or bad compression.....

Things that especially effect the power, would be Injection Timing, Valve-Clearances, good clean air-filter etc...Just the essensial 'service-work' before you even Think of 'Modding/Adjusting'--Doing this work is pretty cheap and should be done anyway and can in some cases drastically improve the drivability/livelyness of your car.

Moving on, assuming that your engine is in good to great health to start with, the boost-pressure can be raised, BUT as others have said, little benefit will be had if the fuelling adjustments Inside the injection pump are not altered. These are difficult to carry out with the pump on an engine, and should be carried out on a proper pump Test-Bench by someone who really knows what they are doing....

If you raise the Turbo boost-pressure More than around 15 PSI, then its really mandatory to fit an Intercooler, to reduce the thermal-loadings on the engine. It also improves the power capabilities as well, as the cooler the intake-charge, the more dense, therefore contains More Oxygen...

More Oxygen, Plus More Fuel, equals More Power--Within Limits....!

(Case in point,-That hideous BMW I own, has an Intercooled 2.5 Turbo-diesel. The Non Intercooled version of the same car develops 125 BHP. The Intercooled engine can run a slightly higher boost pressure safely and develops 147 BHP in standard form....)

Much more than the above considering the Mercedes OM617 engine and its Bosch PES 5M pump and you are looking at extensive IP work, increasing the size of the elements (The Elements are the pumping-plungers and barrels that actually supply the fuel....)--from 5.5mm to 6 or even 7mm sizes. These elements would have to be 'specials' as the way the 'Scroll' is cut in them also affects the timing at different loads and speeds in conjunction with the pump drive gear mounted 'Timing-Device'....The Governor and other parts in the IP would need alteration and appropriate settings to run these new elements correctly. Looking at Lots of dosh for this sort of work, and Huge amounts of power to be gained--How fat is your wallet!!....

benzforlife · #12 03-20-2007, 04:34 PM

or u could just add acetone and straight diesel prurge.....
but seriously, if ur going to do anyhting u need to add more fuel as u increase the air charge, along with cooler air and propane wouldnt hurt either.

juggernaut · #13 03-20-2007, 05:57 PM

alright, met me clarify some things.. i do have all the important gauges. i got a boost gauge, and a pyro, but the probe is behind the turbo. im planning on making it pre-turbo for more accurate readings cuz i know the turbo is a couple hundred degree heat sink. the turbo IS making 25 psi, but thats all it will make.. ive had it pinned on the highway, and its all that 42mm is capable of making. but dont worry, i rarely bring it up past 17-18 psi. if i see it begin to climb up to 20 i let off. so i'd like to do injection timing, but i hear thats an extensive process, which im not really eager to jump into. ive been thinking about intercooling it because i know it can make a good percentage of more power, but looking at the turbo setup and downpipe, it doesnt seem possible.
ive got a brand new air filter in it, and i run powerservice thru it. keeps the fuel from gelling up in cold weather, while cleaning the injectors, lubricating the pump, and boosting the cetane a couple points. so ill go check out those links you guys posted

Brian Carlton · #14 03-20-2007, 06:06 PM

Quote:

Originally Posted by juggernaut

. but dont worry, i rarely bring it up past 17-18 psi. if i see it begin to climb up to 20 i let off..........

Are you aware that running any boost greater than 13 psi does absolutely nothing for performance and simply heats up the intake charge to much higher levels than desired?

Do yourself a favor:

Run a 0-60 time at 20 psi.

Then dial the boost back down to 13 psi and run a 0-60 time again on the same stretch of roadway.

Report back with results.

winmutt · #15 03-20-2007, 07:21 PM

Quote:

Originally Posted by juggernaut

alright, met me clarify some things.. i do have all the important gauges. i got a boost gauge, and a pyro, but the probe is behind the turbo. im planning on making it pre-turbo for more accurate readings cuz i know the turbo is a couple hundred degree heat sink. the turbo IS making 25 psi, but thats all it will make.. ive had it pinned on the highway, and its all that 42mm is capable of making. but dont worry, i rarely bring it up past 17-18 psi. if i see it begin to climb up to 20 i let off. so i'd like to do injection timing, but i hear thats an extensive process, which im not really eager to jump into. ive been thinking about intercooling it because i know it can make a good percentage of more power, but looking at the turbo setup and downpipe, it doesnt seem possible.
ive got a brand new air filter in it, and i run powerservice thru it. keeps the fuel from gelling up in cold weather, while cleaning the injectors, lubricating the pump, and boosting the cetane a couple points. so ill go check out those links you guys posted

First do a diesel purge if you haven't. In order to intercool you have to clock the turbo and you can make something fit. Plenty of others have. Haven't you seen the supercharger+BF turbo wagon?