Torque Converter?

ticopowell · #1 Fri, May 14th, 2010, 01:13 AM

Ok so i have seen a lot of posts mentioning the Torque converter, but I am not exactly sure what it is, nor what it does. I know that it will lock and unlock depending on what gear you are in, and what your speed is, and how hard you are pushing the engine, but other than that all i can tell from reading is that my truck has it. I was looking at the gear selection display thingy on my gryphon and I noticed that sometimes, when driving steadily in 4th gear down the freeway, a lock symbol would appear. I assume this is the torque converter locking. So yeah any explanation would be great

***907DAVE*** · #2 Fri, May 14th, 2010, 01:43 AM

Ok......So in an automatic transmission there is no mechanical link between the engine and tranny. The only link between engine and tranny is the fluid itself (without converter clutch).

Imagine for a second you set up two fans fasing each other, now imagine one of these fans is your engine and the other is your tranny. Now start the engine and rev it up a bit, fan starts spinning fast, which in-turn starts to spin the other fan. Now connect this other fan (tranny) to some gears and voila........work can be done.

A torque converter is basically two fans fasing each other, and using fluid instead of air.

Problem is that there is alot of heat created inside the converter, and it become inefficient because of the fluid coupling and the "slip" it allows.

The cure is to add a clutch inside that will lock the "fans" together at cruising speeds, or when you are trying to lay down some powa. This clutch now become a mechanical link, which means less power lost and less heat.

Of course there is much more going on inside a TC, but this should give you a basic idea and its about the best way I can think to describe it.

ticopowell · #3 Fri, May 14th, 2010, 01:48 AM

That makes sense, I knew about the "fans" inside the AT, so the torque converter basically locks the engine to the tranny. but why then does it only lock when I am going at a steady speed? if I floor it at 65 with it locked, it unlocks as the truck shifts to 3rd, or 2nd(forgot which), then it doesnt lock up again until I am cruising again... that normal?
oh and thanks for the quick reply!

***907DAVE*** · #4 Fri, May 14th, 2010, 02:03 AM

Quote:

Originally Posted by ticopowell

That makes sense, I knew about the "fans" inside the AT, so the torque converter basically locks the engine to the tranny. but why then does it only lock when I am going at a steady speed? if I floor it at 65 with it locked, it unlocks as the truck shifts to 3rd, or 2nd(forgot which), then it doesnt lock up again until I am cruising again... that normal?
oh and thanks for the quick reply!

Nope... the torque converter clutch locks things up.

When you stab the throttle you are demanding lots of power, which means you will need to get the rpms up into a higher range. If the TC stays locked all that will happen is you will lugg the engine and not get anywhere, unlock it and it will "free" up the engine to build some R's. I believe the main purpose of the converter clutch is fuel economy (emissions

), with it locked in there is no more wasted energy.

Your truck is acting perfectly normal.

ticopowell · #5 Fri, May 14th, 2010, 02:20 AM

makes sense... now my question is why am i getting 13mpg's on the highway...

my gryphon is set to 87 towing (canned... cant afford custom ones yet, plus im gonna do some more upgrades) and I previously had it on 91 perf, and both have shown about 13 mpg's... I measured the miles with the odometer and divided by gallons used when i filled a full tank each time, and the gryphon showed an average of 15ish. granted I havent had them on for very long, but the time they have been there they havent done anything for mileage

... any ideas? I did just put on a cat back gibson exhaust and that helps with weight and sound... but idk if it will do much for mileage...
any ideas? I am thinking of doing E-fans, and UDP's but those will wait for a bit, had to replace tires this week so im kinda strapped

thanks for the help.

***907DAVE*** · #6 Fri, May 14th, 2010, 02:38 AM

Well anything you can do to help the engine breath easier should give you increased efficiency, which means more MPG's. Problem is with more power on tap it is very hard to resist using it. One the nostalgia of the extra power worn off you will start to see an increase in mileage.

I will have to let someone with more experience with the gassers to help you as far as programming goes. If its anything like our oil burners, custom tune are FAR superior in all ways.

Good Luck