Benefits of a 5Speed

[1985 Ford F-150]

So I didnt have to put the clutch in to start it. It was just somethin that always bugged me about that truck.

 

[Fellro]

When the torque converter in an automatic is "locked up" there is no hydraulic loss because it is now a direct mechanical connection. In addition, modern automatic transmission are more efficient than past automatics because the control systems are much more sophisticated and precise. The other factor that will effect an automatics efficiency is the stall speed of the converter.

I was not referring to the torque converter, check my post, no mention of it at all. (in regards to the loss) I was referring to the fact that the hydraulic system, IE front pump, is always drawing some power. This has to be since the clutches are hydraulically applied. A clutch does not have this loss due to the clutch being applied by spring pressure.Even the lockup clutch is hydraulically applied. The pump runs as soon as the engine is fired, and doesn't stop until the engine is shut off, so there is some power loss due to hydraulic pressure production.

 

[polarbear]

True- but the losses are minimal. Combine electronic controlls and typically "higher" axle ratios with automatics (they can do this because of the torque convertor), and the manual will wind up being equal or less efficient. Actually, less efficient is a safe generalization. Reason: the manual is theoretically more efficient if you drive in the proper gear at all times. Problem is, no one drives like that- they drive according to traffic. The Automatic, on the other hand, has a computer selecting gears based on a variety of parameters. Guess which one is generally more efficient?

 

[F 150Cobra]

So I didnt have to put the clutch in to start it. It was just somethin that always bugged me about that truck.

mine never came with that.. maybe the PO removed it?
and also removed the speed limiter

 

[conanski]

The Z06 and ZR1 Corvettes are six-speed manuals simply because GM didn't have an off-the-shelf automatic stout enough for the power output.

That's entirely possible but I suspect it's also because they got real tired of everybody laughing at them through the 80's and 90's for only offering an automatic in what is supposed to be a "sports car".

Auto trannys universally consume about 20-25% of the engines TQ output versus only 10-15% with a manual, so a manual is always more efficient regardless what the gear ratios are.

 

[flareside_thunder]

That's entirely possible but I suspect it's also because they got real tired of everybody laughing at them through the 80's and 90's for only offering an automatic in what is supposed to be a "sports car".

Auto trannys universally consume about 20-25% of the engines TQ output versus only 10-15% with a manual, so a manual is always more efficient regardless what the gear ratios are.

Hm, so an automatic IS a parasite.

 

[Lost]

The trucks all have 5 spds .

What it comes down to is if u can drive a MAnual well then u can get benifits out of it . Where autos r more floor it and go .

Mpg is no biggie for me . Its the not going into passing gear all time to tow anything . Those v10s sure scream . Just drop a gear to what want and go .

 

[polarbear]

That's entirely possible but I suspect it's also because they got real tired of everybody laughing at them through the 80's and 90's for only offering an automatic in what is supposed to be a "sports car".

Auto trannys universally consume about 20-25% of the engines TQ output versus only 10-15% with a manual, so a manual is always more efficient regardless what the gear ratios are.

One of the fascinating things about this thread is it's being posted as if it was 1980, not 2009. The last year the Corvette was offered with an Automatic only was '82, for instance. Right now, manual vs. Automatic sales are just about an even split- and that's taking into account that two models are sold as 6-speed manuals only.

As far as the 10% parasitic loss between an Automatic and a manual- that was true a few decades ago. Riddle me this- why is there typically a 1 mpg difference between comparable Automatic/Manual comparisons (unless were's talking sub-compacts, but that's another issue), and the automatic often comes out with higher mileage ratings?

 

[conanski]

Riddle me this- why is there typically a 1 mpg difference between comparable Automatic/Manual comparisons and the automatic often comes out with higher mileage ratings?

Two things.

1) It's rarely a straight up comparison since both trannys won't have the same ratios.
2) Manufacturer fuel consumption ratings are pure fiction and don't represent real world use.