Manual vs auto, which accelerates faster?

Michael_

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So lets say

1970 Dodge Coronet R/T 426 3 speed auto
vs
1970 Dodge Coronet R/T 426 4 speed manual

I imagine the 4 speed manual equipped car probably has a higher top speed because of the extra gear.

As far as i know you loose about 10% more power with the automatic but it also shifts faster...

So which is faster 0-60?
 

threewood

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In a classic with stock transmission I'd have to say the 4 speed because it doesn't absorb as much hp as the auto.
 

Michael_

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Is there some historical data (reviews etc.) on this subject? (0-60, topspeed...)
 

Builderguy

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It is my understand that auto's will shift quicker, pretty much where ever you set them to shift. I still prefer a 4 speed (so I have something to do) as it just feels better. I remember reading some time back that NASCAR checked into using automatics but at the time the durability was not there. Now ????? To answer your question: https://www.edmunds.com/fuel-econom...,shift gears much quicker than a human driver.

AND

https://auto.howstuffworks.com/manual-transmissions-faster-than-automatics.htm

Both of these say an auto is faster, but I did not see any test data listed.
 

Cranky

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I could care less about what shifts faster (today's automatics do dang good) because it's about the driving experience shifting my own gears....and when someone asks you 'where did you get that 4 speed automatic' (in the 70's there really wasn't any) or ask you if you're running a 904 or a 727 (or C4 vs a C6) and you tell them an 833 or a top loader, T-10 etc and then see the look on their face when they have to go look in your car and see 3 pedals and a metal handle sticking up out of the floor.....the look is priceless. A buddy of mine swapped out an 833 with a competition clutch from his 10.70 car for a well prepped automatic and the car didn't go any faster. And sure there's going to be some that say he didn't have the right converter and yada yada yada but at least with a stick, you can change your stall speed with your right foot. Also the car was deadly consistent with the stick in it so don't bring that up either. Some people can't drive an automatic consistently either.....
 

Nate S

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I don’t have any of my old reference stuff around but it seems to me that the 4 speeds were quicker. You could power shift the 4 speed so there’s no loss there and with 4 gears you can stay in a sweeter spot in the HP curve.

The 727 will also suck up some HP just swishing fluid around. For all those apparwnt differences the difference in acceleration was never that large.
 

davek

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street light to street light auto but I would go 4 spd
 

diesel_lv

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They will have the same top speed if the 4spd is not an o/d 4spd. Same gears, tires, redline and 1:1 final ratio equals same top speed.
 

Cranky

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They will have the same top speed if the 4spd is not an o/d 4spd. Same gears, tires, redline and 1:1 final ratio equals same top speed.
You're forgetting about converter slip.....usually a 4 gear car will mph a bit higher....
 

diesel_lv

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You're forgetting about converter slip.....usually a 4 gear car will mph a bit higher....
Possibly, but at those high rpms, the fluid would allow very little if any slippage. But I was referencing the OP saying the extra gear gave higher speed. Until o/d transmissions, 4 spds were still 1:1.
 

66 Sat

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Depends if you're talking acceleration from a standing start or "in gear" acceleration.

I reckon the auto is generally a bit quicker off the line in a stoplight drag. Just load up the converter against the brake and let it go, shifting manually from 1st to 2nd and then to D. Over a longer race I reckon the 4 spd will gain ground though and eventually overtake.

Driving down the road at say 40 mph and flooring it I reckon the 4 spd would be quicker, assuming it's already been shifted into the right ear (3rd?). Less losses, more power going directly to the wheels.

Disclaimer: I have no scientific data to back this up. Merely my opinion :)
 

Michael_

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They will have the same top speed if the 4spd is not an o/d 4spd. Same gears, tires, redline and 1:1 final ratio equals same top speed.

So 3rd gear ratio auto = 4th gear ratio manual?
Or why is that? Im a bit confused right now.
 

64BEL

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gettyimages-163092071-1024x1024.jpg
 

33 IMP

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So 3rd gear ratio auto = 4th gear ratio manual?
Or why is that? Im a bit confused right now.
Yes, in the vintage of cars we are talking about,(in other words, before overdrive transmissions), both high gear in a four speed and in an automatic were direct 1 to 1. Engine speed and trans output speed would be the same (disregarding converter slip in the automatic).
 

383man

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Yes, in the vintage of cars we are talking about,(in other words, before overdrive transmissions), both high gear in a four speed and in an automatic were direct 1 to 1. Engine speed and trans output speed would be the same (disregarding converter slip in the automatic).

Yep they both are 1 to 1 in high gear. Its just the 4 speed can gear the cars for better pick-up since they have an extra gear to use in getting to the 4th gear 1 to 1 ratio. So in theory the 4-speed should be faster but remember the torque converter will multiply torque and the converters of today work damn good. In the real world even with a very good 4-speed driver it will be very close. Ron
 
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