torque converter heat

[burt ragio]

I have considered installing a 3000 rpm converter to maximize out put but if that is the case unless I'am driving 85mph plus the converter is still not locked and builing heat between o-85mph. Do torque converters lock up at the manufacters approximate stall speed rating am I missing something ? Other than a tranny cooler what keeps the converter from getting fried ?

[rumble]

I have considered installing a 3000 rpm converter to maximize out put but if that is the case unless I'am driving 85mph plus the converter is still not locked and builing heat between o-85mph. Do torque converters lock up at the manufacters approximate stall speed rating am I missing something ? Other than a tranny cooler what keeps the converter from getting fried ?

Lock up is determined by the setting in your "tune". Lido just cranked mine back to 50MPH on my 91 tune. Works great for kicking around town. I have a 2500 stall TC.

Stall speed and lock up are two different things.

Good luck

[thePunisher]

yes dont get lockup and stall speed mixed up. they are 2 separate events.....and a 3000 conmverter is plenty streetable. i wouldnt give heat a second thought.

[jonroe]

In regard to torque converter heat when not locked, I have experimented. Driving on the hgihway at about 60 - 65 mph steady without lock up creates about 190*F - 195*F when the outside temp is about 60*F. The same test with the converter locked runs 20*F to 30*F cooler. I had my lock up dialed back to 56-57 mph so I can be locked on the freeways around home.

[burt ragio]

So stall speed is seperate from lock up and can be altered by our tune ?

[thePunisher]

stall speed is mechanical. it cannot be altered with a elec device. converter clutch lockup is mechanical also but is electrically applied. its timing can be changed via a tuning device.

[Aren Jay]

As I understand it:

1. Stall speed is the automatic transmission version of a clutch drop. If you have a High Stall Torque Converter it means you can do such a "clutch drop" up to the rated speed without damaging your transmission. Basically rev from a stop up to the rated RPM and when your light goes green let go the brake floor it and away you go.

2. High Stall Torque Converters will multiply your torque as you get to the rated RPM speed when launching. Stock HSTC for the Marauder are between 1.92 and 2 times torque ratings. Upgraded version are usually around 2.5 times.

3. Torque converter lockup is a fuel economy thing where by you enter into a fuel saving mode that creates that "sweet spot" where you do not down shift when accelerating unless you really accelerate hard. Saves gas mileage. IIRC Lidio sets this to be off until 63MPH, Dennis uses a different system depending on your gear and other factors. Lidio's tunes will use more gas, not much more, at slower speeds but you will not have the so called sweet spot when driving.

Hope this helps.

Heat shouldn't be that much of an issue, as you will probably burn your tires or brakes up first.

[Darrin]

Well, 'not exactly' on a lot of stuff here.

The stock stall on a Marauder is rated directly from Ford for a range between 2372 and 2808rpm. Some converter manufacturers are either under the false assumption that the factory stall speed is around 1800 or so, or they have given up the arguments that inevitably occur when this is brought up and have decided to cater to that false notion. If you purchase say a 2800rpm stall converter from one of these manufacturers then you will get a converter that will stall approximately 1000 rpm over stock. To get an equal stall speed converter from me you would have to order a 3800rpm stall.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comhttp://www.mercurymarauder.net/forums/ /><o:p></o:p>
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2800=155X where X=square root of torque.<o:p></o:p>
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2800/155=18.06<o:p></o:p>
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18.06*2 = 326 ft/lb torque.<o:p></o:p>
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Now how about 1800<o:p></o:p>
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1800/155=11.6<o:p></o:p>
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11.6*2 = 134ft/lb torque<o:p></o:p>
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Which do you think is closer to what these cars produce? LOL<o:p></o:p>
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Then, there is torque multiplication. Torque multiplication on the stock converter is ~2.4:1. A performance converter can vary depending on what components are chosen and what it is built for and you can get the same stall in different ways. So, you can have a converter with any given stall speed have a different torque multiplication ratio than another converter with the same stall speed that is built using different components. That needs to be up to the converter builder and based on the application and use of the vehicle. <o:p></o:p>
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A lockup converter has what is called a lockup clutch. This is an actual wet clutch that has a piston, an apply surface and a friction surface. There is an electronic lockup solenoid in the transmission that is controlled by the computer. When the computer commands lockup the solenoid will modulate at a varying rate until it reaches full lockup where it has mechanically locked the input and the output components of the torque converter providing a 1:1 ratio between engine speed and transmission input speed. Just like a mechanical dry clutch on a car with a stick.<o:p></o:p>
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Tuners will change the rate and timing of the converter clutch lockup events depending on their philosophy. I am not going to get into which I think is better :)<o:p></o:p>
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But, when the converter is locked up, heat buildup form the converter isn't an issue. You only have to worry about extra heat buildup from a converter that is open. Also, the higher the stall the more heat that will be generated when it isn't locked.<o:p></o:p>
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<o:p>That should both answer some questions and start a whole lot more. LOL</o:p><o:p> </o:p>
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Darrin<o:p></o:p>

[ctrlraven]

The "Man" has spoken.

Yes the tuners philosophy does play a very big part. I've driven first hand differences in tunes with having to deal with the lock-up with the converter and it was another awesome member who helped me fix my problem that a "tuner" couldn't.

I have a 3500 stall and love it now. I do a good mix of city and highway, with a lite press on the gas it will go from 60 to 90 mph like nothing. I am going to really have to watch myself when I put 4.10s in lol.

[Darrin]

I will never be able to accept being called the "man" when it comes to these particular transmissions. I am just a very attentive follower of the real "Man" on this stuff. That title rests with Jerry W and no other.

Darrin

[ctrlraven]

Well Jerry W. isn't posting here so your close enough lol.

[burt ragio]

I must agree, Darrin your the man when it comes to tannys and torque converters. So what % of the marauders engine power is the oem torque converter utilizeing before lock up?
Would it make sense in selecting a converter to achieve 85-90% of engine max power ability on a daily driver 40% city 60% hwy a converter with a stall sped of 3000 rpm ? What torque multiplication higher than stock with noticable difference in feel and ET. with no great loss of gas milage and 4:10 gears would you recomend ?