Automatic Discussion Area

[MetroMPG]

Here's an automatic driving tip someone reminded me of recently:

Most cars with a lockup torque converter lock up at a higher speed than you can typically cruise in the city.

But once locked up, you can typically bleed off speed (not coast - it may unlock again), significantly below the lockup point.

I've tried this in a Camry and my dad's Corolla. I think the Camry locks up around 75-80 km/h, but it'll hold the lock while cruising as low as the high 60 km/h range.

Something to consider anyway. Get it locked up, then bleed off speed and cruise slower. Might enable you to use lockup in lower-speed areas you normally think you couldn't.

[omgwtfbyobbq]

I've also noticed that some tend to lock up at odd speeds. For instance, I can hit the cruise at ~55mph in the Camry and turn a shade over 2000rpm, bump it up to ~56mph and it drops to 2000rpm right on the dot. Pretty weird... But it locks up np when warm and cruising at 40mph/1500rpm, so no troubles there.

edit- Anyone know the efficiency difference in locked up versus normal operation?

[LxMike]

Originally Posted by MetroMPG

Here's an automatic driving tip someone reminded me of recently:

Most cars with a lockup torque converter lock up at a higher speed than you can typically cruise in the city.

But once locked up, you can typically bleed off speed (not coast - it may unlock again), significantly below the lockup point.

I've tried this in my a Camry and Corolla. I think the Camry locks up around 75-80 km/h, but it'll hold the lock while cruising as low as the high 60 km/h range.

Something to consider anyway. Get it locked up, then bleed off speed and cruise slower. Might enable you to use lockup in lower-speed areas you normally think you couldn't.

i try to use this when possible. my TC locksup at 42 mph. I can bleed of speed and as long as stilll giving some gas it's ok, but let off gas and it unlocks and rpm's rise.

[Silveredwings]

Well, the GS population may be something like 10% automatic but the real world (in N. America) is probably far greater than 50% automatic.

I personally don't want to own an auto. but I still think it's an important topic and I do read about automatics with interest.

[psyshack]

Our Accord is a slush box. Being a I4 I think its a lot better slush box than whats in the V6 Blow Up Tranny Accords. I run M1 ATF in ours. I know its suppose to have Z1 in it. But it then shifts like a Chevy.

Anyway when I drive the Accord. I hypermile it about like the Civic MT.

Of note it locks into 5th at about 45 mph. Give or take 2 mph. Once locked you can bleed it down to 30 mph or so and keep it locked. This is very useful on level ground and way good on a slight down hill.

I high and low speed fas the car at will. The AT plays right along. i can top a hill at 50, to 75 mph, slip it in neutral, key off and key on and enjoy the no gas use down to any speed I choose. Fire the ICE and drop it into drive. Its all electronic controlled. Never so much as a bump or grind. The tach jumps up and relocks in 5th and off you go for the next fas. slow speed fas'ing is the same as high speed. Doesn't seem to bother it one bit.

I haven't been able to find a way to mess with its shift points much that amounts to anything.

I know I could do much better with a 5MT in the Accord. But its the wifes car. She can and will drive a MT. but she had to have a ^%$@%$%&*())@#@^% Automatic.

On the maint. side of things. I do the standard 3qt. tranny fluid dump and refill every 3rd oil change and also replace its little side stream tranny fluid filter.

Long live MT's!!!!!!!

psy

[occupant]

I've owned a number of GM vehicles with the 2.5 liter engine and TH125C automatic transmission.

1988 Century
1992 Century
1986 Celebrity
1987 Celebrity
1989 Celebrity
1989 Ciera

The 1989 Oldsmobile Ciera seemed to have the highest speed before lockup would occur, typically around 40-42mph. The converter would unlock below 40 even if the throttle was not released. The Buick would lock around 37mph and unlock around 32. The Chevrolets from 86 and 87 would lock as low as 28 and release around 25. The 89 Chevrolet I have now won't lock until 35-36mph and releases as low as 25 but usually before dropping below 30. The 89 has issues, so maybe if it was running properly it would do better. The 89 ALSO will NOT go into lockup unless the SERVICE ENGINE SOON light is on. Driving on the highway can be amusing as the light goes on and off and the lockup kicks in and out. The car definitely has issues.

[rh77]

My Pop's 1988 Olds RWD Cutlass has a terrible overdrive -- it kicks in and totally kills any momentum at cruise. At around 40-45 it kicks-in and drops the RPMs to where it can't continue at 45 without losing power and downshifting back and forth. At 55+ it works, but otherwise it almost dies on hills.

What's cool is the TC on the TSX. If I'm running in manu-matic 5th getting on the highway at 3000 RPM with about 60% throttle, despite going up a hill, it drops to 2200 RPM, takes-off and the FE climbs as the throttle is lifted.

Now the Integra is a different story. It has to be 100-degrees outside before the TC completely locks. It does a partial lockup at 20% throttle in the Winter (which is its most efficient position) -- but that's about 100 RPM -- useless!

Looking at the shop manual, more throttle locks it up tighter -- but it kills FE. Coolant temps are over stock, but the tranny fluid temp is probably marginal. Warm weather is MUCH NEEDED!!!

RH77

[95_corolla]

what are you talking about locking up and bleeding speed I don't understand I drive an auto 1.8

[rh77]

Originally Posted by 95_corolla

what are you talking about locking up and bleeding speed I don't understand I drive an auto 1.8

Simply put, most newer automatics have a "lock-up" style torque converter that allows the engine to spin at higher speeds without a direct connection to the wheels -- on a manual, when you let the clutch out, it directly locks-up the rotation from the engine to the wheels.

A torque converter has a clutch mechanism that uses fluid to either indirectly connect the engine and the wheels from when idling (so it doesn't stall-out), accelerating through gears at slower speeds, or once you reach certain conditions (like a higher speed, engine temp, and throttle input), the "TC" locks-up and makes a direct connection to let the engine do all the work. Why it doesn't work immediately would be hard on shifts and increase emissions.

It's often confused with "Overdrive" which is essentially another gear to shift into. The TC is more of a "sliding" engagement feeling. Once it locks-in, gentle pressure on the throttle can keep it locked for superior FE "bleeding". If you gas it too much, it unlocks for better acceleration, but higher engine RPMs and lower FE.

For a professional definition: Torque Converter.

RH77