my oh my.. L99 burnout with yank torque converter installed

[SonnyakaPig]

Originally Posted by camaro1

the torque converter is basically a fluid coupling from the engine to the input shaft of the transmission, there is slipage that is built into the converter, this is what allows an automatic trans to be in gear but able to come to a stop without killing the engine(high stall coverters have more slipage built into the design of the vanes/fins in the converter = more heat)

also inside the converter is a piston assembly and a clutch plate(like a manual trans clutch disk), when the tcc solenoid/ tcm command fluid pressure to the tcc piston in the converter , the clutch plate locks the converter housing directly to the input shaft of the transmission(just like a manual trans car), now you have 0 rpm difference from the engine to the input shaft of the transmission and the converter is no longer slipping or making heat,, the trans runs cooler and you get a more efficient transfer of engine rpm to the trans

the tcc control on the 6l80e is pwm(pulse width modulated) so it can turn on and off at a varying %,, the factory tcc command in the tcm has the converter locked at very low speeds and at wot(which can and does effect performance)

Thank you for the detailed explanation. I'm still a little hazey on the what this all means, but I think what you're saying is when the tc is locked the engine rpm translates unobstructed to the transmission, which means each gear of the transmission really takes advantage of the engine's rpms, which like you said affects performance.

But I still have some questions...

Lets say you have a 3200 stall speed torque converter. What happens before 3200 rpms in the rpm band? If you are driving around at 35 miles per hour in 3rd gear (lets say the rpms are at 2500) and you mash the gas, what will the 3200 rpm stall speed torque converter do at that moment?

This is where I'm mainly confused: If when the tc is locked the transfer of engine rpm to transmission is the most effective, then wouldn't you want a tc that locks at lower rpms? But at the same time, I understand what you said when you stated that the higher stall speed of a tc is from more "veins/fins" (I know what those are from reading a GMHTP magazine haha), which creates more slippage, which means the trans can remain in gear without killing the engine. So does this mean that the higher the stall speed of the tc, the higher you can rev the rpms at a complete stop, when the car is in 1st gear, so you can take off (launch) higher up in the power band?

I have read on different forums where people were discussing trap speeds for quarter mile runs and they were saying that the speeds would be different if something was locked verses unlocked. I was thinking it had to do with the torque converter. Is that the case?

[DanD]

a torque converter is just a slipper clutch in reality.. how much it allows the slip before getting close to 1:1 but will not get 1:1 until it is locked... locking it is mostly for mileage on the highway.. some lock them on the drag strip, but with high HP cars, it can burn the clutches up in the converter.. I wouldn't.

the car will move just like normal in all cases, except just slips a bit more to allow the engine higher in its powerband.. the slip will be more or less depending on the converter specs and engine size and power.... IMO 15 minutes after driving a car with a converter it feels totally normal. I ran a 4k in one of my 02's for 2 yrs and felt stock after a day.. but mash the pedal and you then know it spools up the power much faster.


there are so many things you may use everyday that can help understand a converter... from RC car clutches, to go-carts, snowmobiles, and even lawn tractors.. they all kind of use the same principle just different.. lol

[SonnyakaPig]

Thank you for the good explanation. I'm getting it now.

[speedster]

Originally Posted by SonnyakaPig

Thank you for the good explanation. I'm getting it now.

Here is a really good torque converter explanation that Spike did a while back: http://www.camaro5.com/forums/showthread.php?t=37093
The first post has a ton of good stuff in it.

[SonnyakaPig]

Wow, that was a great read. I think I want a torque converter.

[CAP'N B]

I have a vigilante 9" 3600 stall in my truck and I don't have much slip until I really get on it. I have a decent size cam for a 5.3 226 duration .585 lift on 112* LSA , and If I'm getting on it, it will go through the gears without much change in RPM at all, until it locks and when that happens it almost feels like another gear. I have mine tuned not to lock at WOT but will lock at 30 mph and above in partial throttle. Think of a fan blowing air into another, fan that's how a converter works, except oil is being used to drive it instead of air. A lock up converter will lock just like a clutch will in a manual transmission, the slippage will keep the engine in the power band of the cam so the engine won't lug, my cams power band is 2200 to 7000, I tried a 2800 stall converter but it wasn't enough, so I sent my converter to get restalled , most converter companies will offer one restall for free. I know Vigilante does. Is a Yank a looser converter than a Vigilante? Anybody on here have used both in the same vehicle.