How often does your 617 diesel see 4400 RPM? - Page 7 - PeachParts Mercedes-Benz Forum

jim messina · #91 08-03-2007, 04:55 AM

Sorry for the double post

Ara T. · #92 08-03-2007, 05:14 AM

Did you install new lower control arm bushings too? Always wondered if changing those + balljoints would give me a better ride.

Cervan · #93 08-03-2007, 08:06 AM

Quote:

Originally Posted by mespe

I don't wanna burn gasoline,, I do this burning 100% WVO. Granted it the car doesn't accelerate like a 60's chevy, but it sure sounds awesome. Expensive game NO WAY, this car will be a parts car if and when she croaks. (She's been in surgery since the front right wanted to occupy the same space as something else (previous owner). And at $1000 (what I paid for the car) I won't lose any money on this one either.

On a side note, I bet I have the cleanest injectors on this forum

I NEVER drive like a bat outta hell until the temp reads close to 80,,, I'm NOT that stupid.

4400RPM in 1st gear is around 20 MPH, 2nd gear around 45 MPH, 3rd around 70 MPH, don't know what 4400 is in fourth, never been there in this car. If you look at your speedo, you'll see 1 dot, 2 dots, and 3 dots, those indicate redline.

I don't feel like I'm doing anything bad to the car, as German engineers would never make a car that would break as the engine approaches redline,,, belts are another story.

worst you could do is blow a head gasket.

Brian Carlton · #94 08-03-2007, 09:14 AM

Quote:

Originally Posted by ForcedInduction

Even better, 400 lb-ft @ 1,600-2,400 rpm

Presumably it has a point of peak torque. It might be 425 lb-ft @2385 rpm.

I don't believe the 2400 rpm figure. Peak torque must be higher than this speed.

The Germans rated the 617 at 2400 rpm as well. It's a blatant mistake.

klataklatacoupe · #95 08-03-2007, 01:30 PM

I have a 300cdt and i drive it the same way. mine redlines at 5200 though, in neutral that is. no mater how much i beat my benzo, i never seem to hurt it. it truely seems bulletproof.

DslBnz · #96 08-03-2007, 02:13 PM

Quote:

Originally Posted by Brian Carlton

Presumably it has a point of peak torque. It might be 425 lb-ft @2385 rpm.

I don't believe the 2400 rpm figure. Peak torque must be higher than this speed.

The Germans rated the 617 at 2400 rpm as well. It's a blatant mistake.

If I remember correctly, that peak torque figure at 2400 rpm for the 617 was from 2400 rpm - 3300 rpm or around there. With hp flat as can be after that, and the torque curve falling off quite a bit, and then REALLY diving after 4400 rpm (peak hp).

Brian Carlton · #97 08-03-2007, 02:17 PM

Quote:

Originally Posted by DslBnz

If I remember correctly, that peak torque figure at 2400 rpm for the 617 was from 2400 rpm - 3300 rpm or around there. With hp flat as can be after that, and the torque curve falling off quite a bit, and then REALLY diving after 4400 rpm (peak hp).

There can be only one "peak". Sure, it can be reasonably flat while it climbs............but, the peak is at a single rpm.

The peak HP is also at a single rpm.

The new approach to specifying a "range" where the torque is applicable is strictly a marketing gimmick.

winmutt · #98 08-03-2007, 02:19 PM

Quote:

Originally Posted by Craig

I've thought about a 2.88, but I do drive up some significant hills. It would help my mileage a bit and be easier on the engine, but I do like being able to cruise up 6% grades.

I've got the 2.88. I would like a 2.47 mated with the 4spd manual that had a real short first gear. 4th gear wouldnt be a prob with IC and 20psi I would think.

winmutt · #99 08-03-2007, 02:20 PM

Quote:

Originally Posted by klataklatacoupe

I have a 300cdt and i drive it the same way. mine redlines at 5200 though, in neutral that is. no mater how much i beat my benzo, i never seem to hurt it. it truely seems bulletproof.

funny name

deerefanatic · #**100** 08-03-2007, 05:24 PM

Quote:

Originally Posted by jim messina

I never run the crap out of my lovey, a smart guy once told me she will last a long time if I don't run her like a Ferrari. I shift at around 3 grand and run her at 70 on the highway,one italian tuneup a week on the steepest grade I can find. I thought it was a luxury car not a race car and am really into seeing how many miles I can get out of her. Just put my new lower ball joints on her and she really rides nice.

Jim

Yah, and with a car like yours......... I can see why!

Mine sees 3800 quite a bit, and every once in a while I'll let her hit 4500 just to hear the turbo scream (and that's about all it's doing!

)

GREASY_BEAST · #**101** 08-03-2007, 05:25 PM

I run a 2.47 rear in my 300TD (617) with an A/W intercooler, boost at 16psi, and full load screw turned all the way in. I get about 18 second 0-60... I drive around with it in D most of the time (at around 1800rpm (or lower) on back roads, up around 2700rpm at 75 on the highway, IIRC, its been a while since I have driven my car

), drop it down to S on the steeper hills below 55mph (yielding more than 2400 but less than 3K rpm). I can say for sure I know the engine makes torque well below 2000rpm if you give it fuel, but it won't build max boost until 2400rpm, so I suspect the torque peak is somewhere between 2400 and 3000rpm... Also, I find that if I wind it way up on my 0-60 it doesn't go a whole hell of a lot faster than if I stay under 3100 or so... thats what makes me think peak torque is between 2400 and 3000. Oh, btw, with all the mods I think I am getting BETTER fuel economy... I have to do more testing to make sure.

Another thing: you can make the automatic tranny serve to your benefit with the 2.47 rear if you adjust the shift points via the bowden cable, and the TC acts like a crawl gear!!! I wouldn't even think about putting a 2.47 in back of a manual 4spd unless the gearing was just right. I think I would rather have more like 6 speeds if it was manual.

#**102** 08-03-2007, 10:12 PM

Quote:

Originally Posted by winmutt

I've got the 2.88. I would like a 2.47 mated with the 4spd manual that had a real short first gear. 4th gear wouldnt be a prob with IC and 20psi I would think.

I don't know about 20 psi.

I'm sure 2.88 (even 2.47) is more than adequate for flatlands at sea-level, but I spend a fair amount of time driving up significant hills at altitude. Today I drove from WA state to WY on I-84/I-80, several 5% grades with 75 mph speed limits. Tomorrow morning I drive across WY to denver, over the continental divide. Even with 3.07 gears, I can't maintain 80 mph on all the grades.

BTW, I drove most of the way across OR with a pretty cool looking Maybach (a 57, I think). I didn't try to race him.

mespe · #**103** 08-03-2007, 10:20 PM

I really haven noticed that above 4000 RPM the acceleration is that good, so I've decided to shift the automatic at around 4000 RPM and that seems to get her moving faster,,,

All you hijackers talking about 2.88's and 2.47's and 15 inch tires etc START YOUR OWN POST!!!

LOL Never thought my thread would get to 7 pages,,,

#**104** 08-03-2007, 10:23 PM

Quote:

Originally Posted by mespe

All you hijackers talking about 2.88's and 2.47's and 15 inch tires etc START YOUR OWN POST!!!

LOL Never thought my thread would get to 7 pages,,,

Sorry.

Brian Carlton · #**105** 08-04-2007, 12:36 AM

Quote:

Originally Posted by mespe

I really haven noticed that above 4000 RPM the acceleration is that good, so I've decided to shift the automatic at around 4000 RPM and that seems to get her moving faster,,,

Torque falls off dramatically above 4000 rpm so, you'll notice the lack of "go". But, remember, you still have the benefit of the lower gear. The moment you shift, you give up close to 33% of the available torque to the wheels.

Therefore, the HP peak is always the preferred shift point, if the lowest ET is desired. In the case of the 617, that's 4400 rpm.