Aftermarket turbo question - 1980 300D - PeachParts Mercedes-Benz Forum

driad_98 · #1 02-24-2004, 09:27 PM

I got my 300D from an old lady in trade for some yard work and trim painting... at some point, someone'd put a RayJay Industries turbo on it. It has a K&N filter, and PCV gasses are routed through a vapor condensing canister, then through the airfilter into the TC. This conversion started my tranny woes, I think.. with the installation of the new TC, the EGR system was removed. The vac line south of the 17degC switch was simply capped off. When I disconnected it, the tranny started shifting like a dream, better than I've ever felt on on a 300D. Too much vacuun to the Modulator.

Anyway, this buddy of mine who works at A&F said that having a TC on a 300D not manufactured with one is bad... sez there're oil jets under the pistons missing in the NA that the TC'd motors have. He tells me it'll probably burn a piston. Of course the story he'd heard was about a 220D, I think, with a manual.

Comments? Thanks.

Ash

kerry · #2 02-24-2004, 09:35 PM

Your friend is correct on the piston oil jets. However, there are quite a few NA MB diesels out there with aftermarket turbos that have lasted a long time. There's a company in the UK that specializes in adding aftermarket turbos to MB diesels in trucks that for years were never turbo'd. I've talked to people who had it done on the 616 or 617 who were very happy with it.

driad_98 · #3 02-24-2004, 10:05 PM

Well, I'm definately another one... at least until I melt a piston. Hehehe. Thanks!

rwthomas1 · #4 02-24-2004, 11:12 PM

Aftermarket turbos have been bolted on many NA diesels over the years with mixed results. Since the pistons are not oil cooled you have to be very careful as there is no room for error. If the EGT's get too high for any substantial amount of time you will melt your pistons. The generally accepted limit for EGT's is 1000*F post-turbo and 1250*F pre-turbo. A decent EGT gauge costs about $100 and will allow you to avoid damaging your engine. If the EGT's are kept below the limits then the engine should last a long time. RT

driad_98 · #5 02-24-2004, 11:32 PM

Ok, fair enough, but how do you control your EGT? It's been running great for years, so it's bound to continue unless something affects the turbo's parameters?

#6 02-25-2004, 12:37 AM

Quote:

Originally posted by MapleLeaf
...It reads a constant 350F when cruising and no more than 500F when accelerating hard. ...

That sounds way low to me. I don't have a gauge so I can't compare.

Did you get your boost gauge in?

psfred · #7 02-25-2004, 06:54 PM

Unless they swapped in an injection pump off a 617 turbo, it's not doing a thing but pumping in some extra air.

Keep the boost under 7 psi and you will be OK, I think. Won't get a whole lot more power, either.

Peter

driad_98 · #8 02-25-2004, 07:07 PM

Fair enough... I didn't install the turbo, it was there when I got the car. I'm more concerned about reliability than performance. I'm impressed, though, if it's not gaining any poop from the current setup. I was under the impression that NA 300D's were total dogs. Mine's not. How do I know how much boost I'm getting?

Ash

psfred · #9 02-25-2004, 09:55 PM

You must install a boost gauge.

If they did the intallation properly, there will be a boost signal line (hard white plastic is factory) from the rear of the intake manifold to the ALDA (altitude adjuster) on the injection pump. Splice the guage into that line and see what you get.

Even a non-turbo 300D isn't a total dog -- the 240 is adequate at 70 some hp.

Peter

rwthomas1 · #10 02-25-2004, 11:07 PM

"Unless they swapped in an injection pump off a 617 turbo, it's not doing a thing but pumping in some extra air"
Not neccessarily.... While I am not entirely familiar with the inline Bosch pumps it is possible to turn up/increase the fuel delivery on most pumps fairly easily. This may have been done by the intaller or previous owner. I have turned up a Bosch VE rotary which is simple, there is an external adjustment and also on a Stanadyne DB2. The Stanadyne was more difficult requiring opening the pump up and finding the correct screw but performed while on the vehicle. Performing a mod like this is a calculated risk as the fuel is increased across the entire rpm range regardless of load. Believe it on not many diesels do without ALDA's, simply relying on the pre-programmed fuel curve for enrichment. This is where an EGT gauge is very helpfull. When you start messing with mods over stock fuel settings, bolting on turbos, increasing boost, etc. then you better know whats happening inside the motor. BTW, Mapleleaf, put 4-5 people in the car and run it up a long grade at highway speeds. That will give you a much better idea of the max sustained EGT's than quick 0-60 type sprints. RT

#11 02-26-2004, 03:55 PM

MapleLeaf, until you can get a boost line run through the firewall, hook up a temporary boost gauge that enters the cabin through the door jam or an open window.

psfred · #12 02-27-2004, 08:32 PM

Can you say "Smoke"? turning up the pump won't help much anyway, not enough fuel to really boost the power, and it will smoke like a Mack truck until the turbo comes up.

Are you sure this isn't a complete transplant of a turbo 617?

Peter