[C5Natie]

Hey guys, just wanted to discuss this with fellow gear heads. I was curious about the percentage of drivetrain loss and converter slippage that I may be seeing. Now, Im not sure if converter slippage and drivetrain loss are the same, probably not but I'll let one of you clear that up for me. Anyway, I used TCI's slippage calculator to determine how much slippage my tc was seeing. I used the trap speed of my last time slip and I used an rpm calculator to determine rpm. I entered 122mph at 5,490rpm (3rd gear in a 4L65E, 1.0 ratio), 3.42 rear ratio and my rear tire height of 25.5in. I got a slippage of 0.005%. Does that sound right or is it too low? Just to be sure, I watched one of my track data videos and entered a lower rpm and speed when I knew I was in 3rd with the tc locked and I still got 0% slippage.

Built 4L65E with a Yank SS3600.

http://www.tciauto.com/tc/racing-calculators

[Vettezuki]

Originally Posted by C5Natie

Now, Im not sure if converter slippage and drivetrain loss are the same, probably not but I'll let one of you clear that up for me.

Drivetrain loss is anything that subtracts the output power of the engine from the tc or clutch to the wheels. Tc slippage is just one possibility. An automatic "consumes" more power than a standard transmission because of the increased friction, etc., of the more complex gear sets in the trans. However, an auto has the advantage in straight line acceleration because of speed of gear shifts and torque multiplication at stall from a launch.

Anyway, I used TCI's slippage calculator to determine how much slippage my tc was seeing. I used the trap speed of my last time slip and I used an rpm calculator to determine rpm. I entered 122mph at 5,490rpm (3rd gear in a 4L65E, 1.0 ratio), 3.42 rear ratio and my rear tire height of 25.5in. I got a slippage of 0.005%. Does that sound right or is it too low? Just to be sure, I watched one of my track data videos and entered a lower rpm and speed when I knew I was in 3rd with the tc locked and I still got 0% slippage.

A tc does not slip when it's locked up. A tc locks up at a certain rpm. This does not seem strange to me.

All this is going off memory from years ago when I looked into this, so take with a grain of salt.

[94cobra69ss396]

Ben, you are right on.

C5Natie, what is it that you are trying to figure out? Are you thinking of going with a different stall speed or are you just trying to figure out what your flywheel horsepower is?

[C5Natie]

Thank for the responses guys.

I wanted to see how efficient the tc is, or still is since its about 6yrs old and I guess to help.figure out power output as well. So, tc slippage is only when the tc isnt locked and it unlocks at wot, right? Sorry I always get confused.

I remember now, it unlocks at wot or with more throttle. Hence why rpms raise up with a little more throttle while cruising, the tc is unlocking. Duh!

[C5Natie]

Also I was looking to see if people wait for a certain amout of slippage before rebuilding the tc. Mine still feels really solid though.

[94cobra69ss396]

I really don't think you need to worry about the slippage increasing. The bigger concern is ballooning it.

[C5Natie]

Originally Posted by 94cobra69ss396

I really don't think you need to worry about the slippage increasing. The bigger concern is ballooning it.

It being a Yank and the motor being n/a, i dont think that will happen, or at least it shouldnt.