What about the other way around- if you have a high stall speed for the fun part- but want to lock it around town, like literally putting around? If you have a decent converter and a fully manual 4l80e, will just getting up to speed very gently hurt it? As in, take off easy from idle, let off slightly and lock the converter when there's zero load, and accelerate gently from there?
Thanks for the video, I finally understand! Art Carr recommends non lockup on my car. I didn’t understand why, after hours of research trying to understand. Thanks for taking the time!
One thing on the plot was a bit confusing for me for a while - you said more than once this is showing wheel power, ok. And then overlapping the torque on that shows there are points when power is higher but torque lower and my brain said whaaaaat? But I finally realized that this was not wheels torque but rather the engine torque running at completely different RPM in case of locked and unlocked TC for the given wheel speed. In the end what matters is the wheel power so as log as it's higher...
So for people wondering about the power being higher at a given speed, what's happening is that with the TC unlocked the engine is running at a higher RPM than with it locked. So here's how to understand this. Energy is conserved. So because power is rates of energy flow power is also conserved. What this means is there's only 2 ways you can see an increase in output power. Either through efficiency or increased power input. Pretty much the whole point of a lock up TC is increased efficiency so that's not the answer.(Because we're seeing higher power on the unlocked one.) Also TCs don't store energy so the only place to get increase power is through the input shaft. This means that the engine must be generating more power since that's the only thing putting energy into the input shaft. (Assuming a standard gas powered vehicle and not a hybrid.) If you want to generate more power from a given gas engine with a given configuration you pretty much have one method, go for higher RPMs. So pretty much he's seeing what he's seeing because the unlocked TC is allowing higher revs (at lower efficiency) than the locked TC. FWIW There is no such thing as a TC that will increase power. (IE more power out than put into it) All TCs will always show less power out than put in. (Because that would break energy conservation and no system is perfectly efficient.)
great video. I wish more people would see this because locking the torque converter will always burn up some clutch material and little by little will end up destroying your transmission. Think of the TCC as a wet clutch, if you use it, it is a wear item and will need replacement at some time, but also the used friction material goes straight into the transmission. It’s your choice but for my street strip I will leave all gears unlocked at all times. Modulate trans temp with a good cooler and don’t forget to change your trans fluid regularly! Great video!
What do you think happens when the transmission shifts? Obviously a wet clutch of some type is used for every gear, there's technically wear every time you change gears. The real issue is if you have a weak lock up clutch and you burn that up.
@@braaap6292 Yes, there are frictions that are used when shifting gears and the transmission is programmed to shift gears with as little torque as possible across those plates. The TCC is different, it is made with a different material that should be able to take prolonged torque differences across the plates and is specifically made to be a wear item. The stock program in all trucks and cars using this system are specified for driver comfort and will engage smoothly according to the manufacturer program. Some clutch setups are better than others and some programs are better than others but all are wear items and in general will wear more than the shifting frictions because it is designed for a different type of engagement. The performance gains using the TCC does not outweigh the detriment IMHO. But if you like it, use it.
Awesome explanation! Unlocked definitely seems like the way to go. That's one of the biggest benefits of automatic transmission. Having the torque converter. Like in the case of my Tundra 3.4l m/t... The automatic transmission version of my truck has much better power off the line. It's utilizing the engine's power band much better
Totally agree, the TC must be unlocked before the HP & TQ cross each other, and it's is better to be locked right after the cross, this is to maintain speed in the beginning of the RPM band
What’s the formula for figuring which stall speed to get including converter size and what’s the limiting factor for a road worthy vs street strip converter more for muscle car let’s say rather than a dedicated race car? I can add bigger or more coolers for a trip but most people don’t use perf.vehicles for trips.
What about the other way around- if you have a high stall speed for the fun part- but want to lock it around town, like literally putting around? If you have a decent converter and a fully manual 4l80e, will just getting up to speed very gently hurt it? As in, take off easy from idle, let off slightly and lock the converter when there's zero load, and accelerate gently from there?
Great explanation man, now it all makes sense as to why my car feels slower since I started locking it up at wot in 2nd gear.
Greta job Karl! Thanks for taking time for me on this. I am completely sold on this method after driving the truck unlocked.
Thanks for the video, I finally understand! Art Carr recommends non lockup on my car. I didn’t understand why, after hours of research trying to understand. Thanks for taking the time!
One thing on the plot was a bit confusing for me for a while - you said more than once this is showing wheel power, ok. And then overlapping the torque on that shows there are points when power is higher but torque lower and my brain said whaaaaat? But I finally realized that this was not wheels torque but rather the engine torque running at completely different RPM in case of locked and unlocked TC for the given wheel speed. In the end what matters is the wheel power so as log as it's higher...
So for people wondering about the power being higher at a given speed, what's happening is that with the TC unlocked the engine is running at a higher RPM than with it locked. So here's how to understand this. Energy is conserved. So because power is rates of energy flow power is also conserved. What this means is there's only 2 ways you can see an increase in output power. Either through efficiency or increased power input.
Pretty much the whole point of a lock up TC is increased efficiency so that's not the answer.(Because we're seeing higher power on the unlocked one.) Also TCs don't store energy so the only place to get increase power is through the input shaft. This means that the engine must be generating more power since that's the only thing putting energy into the input shaft. (Assuming a standard gas powered vehicle and not a hybrid.) If you want to generate more power from a given gas engine with a given configuration you pretty much have one method, go for higher RPMs.
So pretty much he's seeing what he's seeing because the unlocked TC is allowing higher revs (at lower efficiency) than the locked TC.
FWIW There is no such thing as a TC that will increase power. (IE more power out than put into it) All TCs will always show less power out than put in. (Because that would break energy conservation and no system is perfectly efficient.)
great video. I wish more people would see this because locking the torque converter will always burn up some clutch material and little by little will end up destroying your transmission. Think of the TCC as a wet clutch, if you use it, it is a wear item and will need replacement at some time, but also the used friction material goes straight into the transmission. It’s your choice but for my street strip I will leave all gears unlocked at all times. Modulate trans temp with a good cooler and don’t forget to change your trans fluid regularly! Great video!
What do you think happens when the transmission shifts? Obviously a wet clutch of some type is used for every gear, there's technically wear every time you change gears. The real issue is if you have a weak lock up clutch and you burn that up.
@@braaap6292 Yes, there are frictions that are used when shifting gears and the transmission is programmed to shift gears with as little torque as possible across those plates. The TCC is different, it is made with a different material that should be able to take prolonged torque differences across the plates and is specifically made to be a wear item. The stock program in all trucks and cars using this system are specified for driver comfort and will engage smoothly according to the manufacturer program. Some clutch setups are better than others and some programs are better than others but all are wear items and in general will wear more than the shifting frictions because it is designed for a different type of engagement. The performance gains using the TCC does not outweigh the detriment IMHO. But if you like it, use it.
What about HEAT. I run a 3500 stall with a Trans cooler. In a 72 Dart street car. 69 340 with 3:91 gears & a Gearvender OD. Safe?
Awesome explanation! Unlocked definitely seems like the way to go. That's one of the biggest benefits of automatic transmission. Having the torque converter. Like in the case of my Tundra 3.4l m/t... The automatic transmission version of my truck has much better power off the line. It's utilizing the engine's power band much better
Totally agree, the TC must be unlocked before the HP & TQ cross each other, and it's is better to be locked right after the cross, this is to maintain speed in the beginning of the RPM band
What’s the formula for figuring which stall speed to get including converter size and what’s the limiting factor for a road worthy vs street strip converter more for muscle car let’s say rather than a dedicated race car? I can add bigger or more coolers for a trip but most people don’t use perf.vehicles for trips.
Great info! Thanks!
I think it is crazy how they can multiply power
Sorry but do you have the link to the video where you talk about Torque Converters and how it "cheat" the dyno run, please
Nice!!!
Thanks
Badass!
Must just be for racing? Daily driving with no lock is gonna heat things up...
A locked converter wont torque multiply.