Turbo vs. Non-turbo - PeachParts Mercedes-Benz Forum

DieselGrrl · #1 05-03-2008, 10:11 PM

So if you read my post last week i rear ended someone with my 85 300DTD, luckily i found a great mechanic who im hoping can fix it up. I bought a 1981 300D (not turbo) today. The body is amazing, not a spot of rust, needs minor things like a new antenna, pasengers side window motor, etc. Anything i should know about the 300D that is different from the turbo? The pick-up is great, i didnt notice that its any slower. It has mechanical breaks though, but i dont mind.

Also, any New York 300D meet-ups? If not, we should organize one!
Sabrina
______________________
1985 300D Turbo 210k - in the shop
1981 300D 135k

Joe Bauers · #2 05-03-2008, 10:21 PM

Having had several non-turbos and one turbo, I would say that I generally prefer the non-turbo. I find them peppy enough around town and less trouble. On my turbo, there were issues with ALDA adjustments and turbo lag and such. Also, my turbo developed low compression on three cylinders--have no idea why. Car only had about 130,000 on it at the time. Might just have been an issue with my particular car; others rave about turbo performance for many miles.

The turbo was nice on the road, however, and it actually delivered slightly better fuel economy--something like 45% more power with the turbo boost, yet maybe 5-8 more mpg, especially on the road.

But overall, I just like the simpler non-turbos. Adjust the valves periodically, change oil regularly, and it should run a good long time, assuming the engine is sound to begin with. Good luck.

Joe B.

DieselGrrl · #3 05-03-2008, 10:42 PM

what would it cost to put a turbo in there..ballpark?

2.5Turbo · #4 05-03-2008, 10:51 PM

Cheaper to get a turbo engine and do a swap. The turbo engines have modifications that allow them to last with the extra stresses the turbo creates. Sodium filled valves and cooling oil jets underneath the pistons are some that come to mind.

kerry · #5 05-03-2008, 11:48 PM

Quote:

Originally Posted by DieselGrrl

. It has mechanic breaks though, but i dont mind.

______________________
1985 300D Turbo 210k - in the shop
1981 300D 135k

I'm not sure what you mean by this. If you mean that it doesn't have power brakes, I don't see how that is possible. I think all the 123's had power brakes.

tobybul · #6 05-04-2008, 01:48 AM

Quote:

Originally Posted by DieselGrrl

.......It has mechanic breaks though, but i dont mind.

Sabrina
______________________
1985 300D Turbo 210k - in the shop
1981 300D 135k

This is a new one to me - mechanic breaks? Can you elaborate?

Also, I would keep the non-turbo as its.... for one thing, too many components involved to convert.

DieselGrrl · #7 05-04-2008, 06:21 AM

that was a type-o i meant to say mechanical breaks, as in not power breaks, atleast thats what it feels like, then again, maybe it just needs a break change

i understand that sometimes a bad vacuum pump affects the breaks, but the power locks work too, and those are controlled by the vacuum pump as well, correct?

#8 05-04-2008, 06:35 AM

Brakes, not breaks.

All models have power brakes, Mercedes hasn't made a car for the USA without it since the 50's.

vstech · #9 05-04-2008, 07:38 AM

if your brakes are hard to push, and you have working vacuum door locks, then it's likely you have a bad booster on the MC... open the hood, look for the thing with the whitish plastic reservoir with a cap on it. between that and the firewall will be an approximately 10" round doohickey (who would have thunk that the spell check would include doohickey in it...) with a vacuum line going to it. that's your booster. aside from that, you could have a pair of front calipers stuck...

Mark DiSilvestro · #10 05-04-2008, 10:31 AM

Quote:

Originally Posted by Joe Bauers

Having had several non-turbos and one turbo, I would say that I generally prefer the non-turbo. I find them peppy enough around town and less trouble. On my turbo, there were issues with ALDA adjustments and turbo lag and such. Also, my turbo developed low compression on three cylinders--have no idea why. Car only had about 130,000 on it at the time. Might just have been an issue with my particular car; others rave about turbo performance for many miles.

The turbo was nice on the road, however, and it actually delivered slightly better fuel economy--something like 45% more power with the turbo boost, yet maybe 5-8 more mpg, especially on the road.

But overall, I just like the simpler non-turbos. Adjust the valves periodically, change oil regularly, and it should run a good long time, assuming the engine is sound to begin with. Good luck.

Joe B.

Probable reason the turbo can get better highway mileage (and the non-turbos don't feel alot more sluggish) is the difference in rear-end ratios - 3.07 on 82-84 turbos and 2.85 on the '85, vs 3.46 on the non-turbo 300D/TD. However, if you can find one, the Euro non-turbo 300D/TD was availible with a 5-speed manual, gaining an overdrive gear that wasn't availble on US-market automatic versions. I'm hoping to test my 5-speed non-turbo 300TD on an upcoming trip to Virginia Beach, and see what my actual highwway mileage is.

Happy Motoring, Mark

toomany MBZ · #11 05-04-2008, 05:16 PM

You may want to measure the vacuum your pump is achieving, then check the booster before replacing they're pricey.
One of the biggest concerns about repairing these things, is finding the problem, vs. the symptom.

tobybul · #12 05-04-2008, 08:26 PM

Quote:

Originally Posted by vstech

if your brakes are hard to push, and you have working vacuum door locks, then it's likely you have a bad booster on the MC... open the hood, look for the thing with the whitish plastic reservoir with a cap on it. between that and the firewall will be an approximately 10" round doohickey (who would have thunk that the spell check would include doohickey in it...) with a vacuum line going to it. that's your booster. aside from that, you could have a pair of front calipers stuck...

I can concur with this analysis

. Possible stuck caliper(s). If vacuum pump, test for vacuum in the booster line. If there is vac then pump is ok especially if you also have vac in locks. If no vac, you may have a dbl diaphragm pump and one side went bad. Is there a vacuum Tee off the booster line that goes to the locts etc? If so, you have a single diaphragm pump and there should be vac to your booster.

P.E.Haiges · #13 05-04-2008, 10:25 PM

I would never go back to a non turbo engine. More power, more mileage, never had any trouble with turbos in hundreds of thousands of miles. Almost all Diesel trucks on the road have turbos, so there must be advantages.

P E H

DieselGrrl · #14 05-04-2008, 10:58 PM

Quote:

Originally Posted by vstech

if your brakes are hard to push, and you have working vacuum door locks, then it's likely you have a bad booster on the MC... open the hood, look for the thing with the whitish plastic reservoir with a cap on it. between that and the firewall will be an approximately 10" round doohickey (who would have thunk that the spell check would include doohickey in it...) with a vacuum line going to it. that's your booster. aside from that, you could have a pair of front calipers stuck...

the BRAKES (thanks!

) are not necessarily difficult to push, it just feels raw, i cant describe it any other way. Driving my 85 300D turbo i could feel the assisted brakes, on this car i dont. Also, i feel the wheel as its turning rubbing on the brake, but not in one smooth motion, its a little choppy. ill see what the mechanic says, i dont mind doing cosmetic work myself but i need to learn a little more about diesel engines before i go fiddling around in there myself.

P.E.Haiges · #15 05-04-2008, 11:43 PM

DieselGrrl,

When U can feel the rotation of the wheels from the brake pedal, its usually caused by warped rotors. Sometimes machining the rotors will correct but they usually have to be replaced.