Question about car power at "idle" and rolling

[ajm786]

I have 2 cars. One is an 1995 Olds Eighty Eight Royale. The other is a 1999 of the same car. I have a question about the difference between the idle power of both cars.

On the 1995, the car has much more power at "idle". The reason for the quotes is that the car is not in really idle, as in neutral; it means it's stopped, without the brake being applied. So, if I'm sitting on a hill, even if I take my foot off the brakes, the car will not "fall" (roll) backwards. I like that because if I'm sitting on a hill, it means I won't smash into the car right behind me.

However, on my 1999, the car has much less power at "idle" speed. The car has a tendency to "fall" backwards EXTREMELY easily, leading me to have to have ultra quick response times with my foot from brake to throttle to prevent the car from rolling backwards. Same if I am reversing up a hill.

Can anyone explain how I can get my '99 to be the same as my '95 in terms of this?

Thanks!!!

[MagicRat]

This is called 'torque converter creep'. Even though you consider your '99 to be inferior, it actually demonstrates that it has a better, more efficient torque converter design,at least at idle.

I am assuming here that the engines are the same (3.8 V6?) and the transmission is the same 4 speed automatic, and neither engine or transmission is malfunctioning.

A torque converter is the device that allows an engine to idle when the car is stopped, but 'engages' and moves the car as you step on the gas. Converters are hydraulic devices and thus place a certain amount of drag on the engine.
This drag is what prevents the car from rolling back.
Also, the greater the drag, the more fuel is used to for the engine to idle when the car is stopped.

Therefore, since the '99 has less drag, it is probably more fuel-efficient at idle.

Look here for more info:
http://en.wikipedia.org/wiki/Torque_converter

Also, it is possible your '99 has a 'looser' converter, that is, one that allows the engine to rev a bit higher than the '95, when accelerating. This makes for snappier acceleration at the expense of a slight decrease in fuel economy, at least until the car reaches cruising speed.

Personally, I would consider the '99 to have a more favourable set-up, despite the hill problem you have.
Also, I think you should check and compare the idle speed of the '95. If both cars have tachometers, do they show the same RPM's at idle in gear? If the '95 is idling higher than the '99, it would 'creep' more, but also may have a problem, such as a vacuum leak or bad IAC (idle air control motor).

Finally, it would be difficult to give the '99 the same 'creep' as the '95, without changing the converter, which requires a transmission removal.

[ajm786]

Originally Posted by MagicRat

This is called 'torque converter creep'. Even though you consider your '99 to be inferior, it actually demonstrates that it has a better, more efficient torque converter design,at least at idle.

I am assuming here that the engines are the same (3.8 V6?) and the transmission is the same 4 speed automatic, and neither engine or transmission is malfunctioning.

A torque converter is the device that allows an engine to idle when the car is stopped, but 'engages' and moves the car as you step on the gas. Converters are hydraulic devices and thus place a certain amount of drag on the engine.
This drag is what prevents the car from rolling back.
Also, the greater the drag, the more fuel is used to for the engine to idle when the car is stopped.

Therefore, since the '99 has less drag, it is probably more fuel-efficient at idle.

Also, it is possible your '99 has a 'looser' converter, that is, one that allows the engine to rev a bit higher than the '95, when accelerating. This makes for snappier acceleration at the expense of a slight decrease in fuel economy, at least until the car reaches cruising speed.

Personally, I would consider the '99 to have a more favourable set-up, despite the hill problem you have.
Also, I think you should check and compare the idle speed of the '95. If both cars have tachometers, do they show the same RPM's at idle in gear? If the '95 is idling higher than the '99, it may have a problem, such as a vacuum leak or bad IAC (idle air control motor).

Finally, it would be difficult to give the '99 the same 'creep' as the '95, without changing the converter, which requires a transmission removal.

Very valuable info there.

Yes, I was doing more research, and from every indicator shows that the 99 is actually more fuel efficient and a bit more powerful.

Unfortunately, the 95 does not have a tachometer, while the 99 does, so I can't really tell what the idle speed is.

I guess I can just chalk it up and not worry about it. Besides, upgrading the air intake filter helped to compensate for that a bit, and I assume with other upgrades it will help.

Thanks!