Stall convertor questions

[BeauJ]

I'm selling my ecam and getting a bigger cam so the stall swap is a must. I'm gonna go with a 2800-3200 stall speed. My question is how much hotter will the tranny get? Any other problems to be aware of?

 

[Oversquare]

The tranny temp will effectively increase the same amount as the increase in stall speed. For example, if you increase the stall sped by 3x (as you are) so will the heat generated by the torque converter. Especially if you actually use your truck on the street, where the typical RPM's are less than 3k, and you're moving such a heavy vehicle.

The things to consider when picking a stall speed are: average rpm during use, weight of vehicle, and low-end torque.

Since the average RPM of a street vehicle is less than 2000, the converter will be constantly slipping - creating HUGE amounts of heat.

The weight of an Explorer is well in excess of 4000lbs, creating more heat during accleration.

The Explorer does not product much low-end torque. Increasing cam size will only lower the low-end torque. This will reduce the power to slip the converter. This will make it harder to create heat.

My advice? don't upgrade the converter unless you're only drag racing it, or work in a tranny shop (if you did, you wouldn't be upgrading the converter). If you do get the converter, get the biggest **** trans cooler you can fit, and install a trans gauge. Anything over 200*F is hot for a trans - more-so if you're putting power through it. A trans temp gauge is necessary.

Other things to consider: Most aftermarket converters are not compatable with electronic transmissions because they can't "lock" for 3rd and 4th gears. The ones i've seen that ARE compatable are well over $500.

High-stall converters installed in street vehicles will reduce gas mileage because of the increased slippage.

Keep in mind that a larger camshaft might have problems producing vacume at idle because of the lack of compression the stock (9.0:1) engine produces. This will affect your power brakes, MAF, and emissions.

Alternatives? For the same price, try changing the gear ratios of the diff's. You could have the front AND rear changed for less than $800.

For more money, use a built Mustang AODE-2 trans. The trans is identical, but the gear ratios are closer together and will take advantage of the higher RPM HP you'll be producing.

Good luck!

-Brad

 

[blk mk8]

if you get a good PI converter i can adjust the lock up in the computer for you. this would allow you to put a loose converter with out burning up the tranny.

 

[BeauJ]

Yea, I knew my gas mileage would go down and the tranny temp would rise. I'm adding a bigger cooler w/fan and a deeper pan.

Blk, I didn't even think of the computer though. Could it still be a reasonable daily driver with it?

 

[boominXplorer]

hmm.... Blk, Do you sell the 4 program SCT's? what does a good torque converter run with the specs he needs?

 

[BeauJ]

Also Oversquare, i think the stock stall speed of the Explorer is 1800-2000. You said 3X, I didn't know if that's what you meant.

 

[Oversquare]

The stall speed of a factory converter is under 1000k RPM. As you add low-end torque to the motor, the converter will slip at a higher RPM, effectively increasing the stall speed.

For example, you have 2 motors, one with 500 hp at 7000RPM, and another with 500ft/lbs of tq at 2000rpm. If they had the same converters with the same stall speeds, the motor with more torque will have a higher ACTUAL stall speed than the one with more HP.

Manufacturers use low stall speeds to increase gas mileage, reduce trans temps, and increase trans life.

-B

 

[blk mk8]

yes i sell the sct 4 program chips. on the mark VIII's a lot of buys run converters that are higher then 3200. to combat this most guys put a superduty tranny cooler with fans and setup the computer to only be unlocked in first gear. once you are at crusing speeds out of first gear you change lock up stratigy to allow less slippage and less heat build up. i know guys running with 4000 stall converters on the street.

 

[BeauJ]

Blk, you said that you can make the convertor only lock up in first? So when it pops into second, would it be close to stock standards as far as temp. and mileage?

 

[Oversquare]

Just curious, approxametly what's the price of a high-stall lock-up converter going for these days? And then how much for the custom programmed ecu?

Thanks!

-Brad

 

[blk mk8]

a nice converter is about 750 and a 3 to 4 position chip with custom programs are 320. you only want to lock the converter after first gear other wise it would negate getting the loose converter. the converter slippage in first will get you moving and in the power band and then when you change gears you can lock up the converter so that is stays within standered operating heat ranges.