Quick Torque Converter Question + general transmission data - Page 7 - PeachParts Mercedes-Benz Forum

Brian Carlton · #91 09-12-2005, 09:49 PM

Quote:

Originally Posted by MB-Owner-in-ind

Could be but I feel that compared to the '69 Mustang with a 428SCJ or my '61 Buick with a 401 or even my '66 Galaxy with a 390 the 300D would lose from 0-30. My '98 Olds with a 3.8 felt a lot quicker. I didn't hesitate to pull out in traffic with the Olds like I do with my 300D or even the 300D turbo.

Well, comparing vehicles with 250-300 hp with a vehicle that has 125 hp is naturally not going to look very good for the diesel.

If you want a fair comparison, you would need to compare the 300D to an equivalent gasser with 125hp. You can't find one of those anymore. Even the four cylinders have 160 hp and are geared much lower than the 300D so they "feel good" on launch.

The 3.8 is closer to a fair comparison, but, I would guess that it has close to 170 hp.

MB-Owner-in-ind · #92 09-12-2005, 10:02 PM

Quote:

Originally Posted by Brian Carlton

Well, comparing vehicles with 250-300 hp with a vehicle that has 125 hp is naturally not going to look very good for the diesel.

If you want a fair comparison, you would need to compare the 300D to an equivalent gasser with 125hp. You can't find one of those anymore. Even the four cylinders have 160 hp and are geared much lower than the 300D so they "feel good" on launch.

The 3.8 is closer to a fair comparison, but, I would guess that it has close to 170 hp.

Yes and my point was that the torque converter on these vehicles didn't heat up the fluid and destroyed the tranny with more power than the 300D so I believe that the possibility of doing so in a 300D is extremely remote and could be poor upkeep of tranny rather than the act itself.

Brian Carlton · #93 09-12-2005, 10:17 PM

Quote:

Originally Posted by MB-Owner-in-ind

Yes and my point was that the torque converter on these vehicles didn't heat up the fluid and destroyed the tranny with more power than the 300D so I believe that the possibility of doing so in a 300D is extremely remote and could be poor upkeep of tranny rather than the act itself.

Well, I agree with you, but note that the larger engines probably have a beefier transmission sitting behind them.

So, in relative terms, the potential transmission damage would be the same.

The diesel does have more torque available at much lower rpm's than any gasser of equivalent horsepower. In fact, it's torque available at 1600 rpm is probably comparable to the torque available from a 200 hp gasser at the same rpm.

For this reason, the gasser probably has a higher stall speed than the diesel.

Pete Burton · #94 09-13-2005, 09:04 AM

Quote:

Originally Posted by Craig

Guys,

This isn't that hard to estimate. Assuming 100 shaft HP is available for 3 seconds, that's about 71 BTU/sec being put into the converter, for a total of 212 BTU. If tranny fluid has a Cp of about 1 BTU/lb/F (like water) and we guess that there is about 2 quarts of fluid being heated (about 4 pounds) the fluid will heat up about 50 F. If my guesses are not accurate, you can adjust them. Interesting discussion.

Craig's right on this. And if you adjust the #'s - like .5BTU/lb/F for hydraulic oil and assume 5 quarts at a density of .85g/cc, you still get about 50F. Conservation of energy.

But I don't give a s*** if it's 5F. I'm not doing any brake torques. I'm 44 years old. I just rebuilt my transmission. Conservation of energy.

whunter · #95 02-11-2012, 10:35 AM

Does anyone have personal transmission temperature data to add?

.

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