TC Stall Speeds

Mountainman · **Posted:** Sun Apr 07, 2019 11:52 pm

WWDiesel wrote:

My Suncoast on the CRD starts pulling as soon as it is placed in a motive gear. On level concrete as soon as I put it in drive, it starts moving if the brake is not applied.
On my Dodge Cummins with the Suncoast, it is even more aggressive, placed in drive, it will idle at about 3 or 4 mph without even touching the go pedal. :lol:

I certainly think that the lower the stall speed or more aggressive the torque transfer is by the fluid dynamics between the rotor/stator in the TC the less the fluid would be worked (slippage) so less heat would be generated as a result.

Thanks for the thoughts, yeah, I think a lower stall will be a fantastic addition to long offroad jeeping

geordi · **Posted:** Mon Apr 08, 2019 11:37 am

Mountainman wrote:

TKB4 wrote:

If you wanted more heat in cold why did you delete the viscous heater? ( doubt helps economy much). Also on equipped vehicles you can turn on both seat electric heaters on high and this will not only create heat but also put a little more load on engine via alternator and might warm up a little quicker.

I deleted the VH for absolute simplicity/ reliability reasons. I drive in about 70 miles from the nearest town (remote Stanley idaho) to hunt, fish etc, and don't ever want to have to walk out. Now that I know the part number of the VH bearing, and have replaced a few, I am thinking about reinstalling the VH, but I've found getting them reassembled with the proper clutch spacing to be a bit of a challenge. I'll have to try harder...
I'm also going to get the GDE high idle soon.

Obvious question is obvious.... But have you put in one of those unobtanium thermostats from a certain Canadian? For heat in the cabin, that does seem to be the best option.
I will say that on my CRD that has recently been back on the road after getting a new piston and sleeve, I've put about 7k miles on it since the rebuild and ALL of them have been towing in winter conditions. The ability to maintain temperature while extended idling in low temps is still a bit of an issue - the gauge DOES come up when starting cold and letting it just idle... When stopping for a while after running, the gauge will slowly come down to about the 1/4 position, cabin heat is still acceptable if not sauna-like. Outside temps were in the low teens.

But while doing any kind of running, the cabin heat is great. No grille blocks were in place.

geordi · **Posted:** Mon Apr 08, 2019 11:54 am

WWDiesel wrote:

My Suncoast on the CRD starts pulling as soon as it is placed in a motive gear. On level concrete as soon as I put it in drive, it starts moving if the brake is not applied.
On my Dodge Cummins with the Suncoast, it is even more aggressive, placed in drive, it will idle at about 3 or 4 mph without even touching the go pedal. :lol:

I certainly think that the lower the stall speed or more aggressive the torque transfer is by the fluid dynamics between the rotor/stator in the TC the less the fluid would be worked (slippage) so less heat would be generated as a result.

Every automatic transmission I have ever driven will move forward under idle speed, so your description is not unusual to me... Although there is a question about how HARD they want to go / how much brake is required to keep them from ramming the car in front at a light. It might be interesting to have a comparison from someone about to install a Suncoast or other lower-stall converter, what speed the vehicle will idle at on a flat road - before and after.

Your last sentence is intriguing to me though, and I honestly don't know the answer. Thinking about the relationship between power and work accomplished, it could go either way. Does "more revs input for a given work output" make more heat with less efficient / aggressive vanes in the converter.... Or is it more heat generated because more work is done with less input when the vanes are more aggressive - but the vehicle then will require a heavier brake to keep it stopped in gear?

I don't know that my lower stall Florida converter is pulling substantially harder than the Euro that was removed - I never drove on the Euro, bought the CRD with a tossed valve. So I have no comparison with this particular vehicle, I only have my many test drives with other CRDs... And I *think* it IS pulling a bit harder at idle. There is also a substantial shift in power when I push it into neutral while stopped. But I don't have a transmission temperature gauge and my Scangauge / OBD devices can't read the transmission sensors... So I have no temperature reference either. Yet.

Mountainman · **Posted:** Mon Apr 08, 2019 12:17 pm

geordi wrote:

Mountainman wrote:

TKB4 wrote:

If you wanted more heat in cold why did you delete the viscous heater? ( doubt helps economy much). Also on equipped vehicles you can turn on both seat electric heaters on high and this will not only create heat but also put a little more load on engine via alternator and might warm up a little quicker.

I deleted the VH for absolute simplicity/ reliability reasons. I drive in about 70 miles from the nearest town (remote Stanley idaho) to hunt, fish etc, and don't ever want to have to walk out. Now that I know the part number of the VH bearing, and have replaced a few, I am thinking about reinstalling the VH, but I've found getting them reassembled with the proper clutch spacing to be a bit of a challenge. I'll have to try harder...
I'm also going to get the GDE high idle soon.

Obvious question is obvious.... But have you put in one of those unobtanium thermostats from a certain Canadian? For heat in the cabin, that does seem to be the best option.
I will say that on my CRD that has recently been back on the road after getting a new piston and sleeve, I've put about 7k miles on it since the rebuild and ALL of them have been towing in winter conditions. The ability to maintain temperature while extended idling in low temps is still a bit of an issue - the gauge DOES come up when starting cold and letting it just idle... When stopping for a while after running, the gauge will slowly come down to about the 1/4 position, cabin heat is still acceptable if not sauna-like. Outside temps were in the low teens.

But while doing any kind of running, the cabin heat is great. No grille blocks were in place.

I do have an HDS, but these engines just dont produce enough waste heat in really cold weather to stay full temp at idle. I have better than stock thermostat heat, but I have zero radiator blockage (AC fan and condenser both gone) so even a slight breeze and I'm cooling better than stock. I'm looking forward to the high idle tune

TC Stall Speeds

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