Topic: gears and lost acceleration
in Forum: C3 Driveline Components

so I was talking with a friend the other day...seems that he advised me against running 4.11s with the 700R4 transmission. says I'm losing acceleration potential because the motor is winding up too fast, and that the car would be faster if I went to something lower, like 3.73s. he also said that the high gearing is very likely the reason why I don't feel near as much "pinned to the seat" force when I punch the throttle in the corvette, as I do when I hit the throttle in the GTP, even though the corvette has more power.
what do you folks think about this?
Mike
My old Stingray...sure do miss it:
(click image to see a bigger version)
Do you loose traction at the tires?
Bottom line is all the motion through the drive line has to be transferred to the pavement.


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When I first started building the Pinto



Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Lifetime Member #116
Dave's '82
There are many variables that come into play with gear ratios. I had a 69 Camaro with a mildly modified motor & TH350. It ran its quickest in the 1/4 mile with 3.73:1 gears. With 4.11:1 gears the motor was reving past its power curve and was flattening out before I got to the end of the 1/4 mile. To get the maximum performance from your engine and acceleration, you need a set of gears that keeps your engine within its ideal power band. You can go too low or too high. Also keep in mind your tire selection. This will change your final ratio as well. I am running 3.70:1 with a 4 spd manual in my current 69 vette. If I went to 29 inch tall tires, then I would consider a 4.11:1 ratio. In my 76 vette, I had 3.55:1 ratio, modified 350, TH350 with a 2200 rpm stall. That car was faster than my 69.
Steve


[QUOTE=Adams' Apple]I'm no rocket scientist(but I do play one on TV), but that goes against the laws of physics, and everything I've learned. Lower gear ratios will give you more seat of the pants acceleration, regardless of the trans ratio. If your engine runs out of steam too soon, going to a higher ratio will only make it run out of steam a little later, road-speed wise.
When I first started building the Pinto I used to have, I installed the rear end first. With a 4.88 gear, and the original FOUR CYL, I could take anyone at the stoplights, for at least 60 feet!
After that, I was done. With a small block and an automatic(3spd), it ran mid-12s all day long. Not bad for a street car in the late 70s/early 80s.
[/QUOTE]
so...what do you think the difference is between the feeling of acceleration, that seat of the pants feeling, between the corvette and the GTP.
Mike
My old Stingray...sure do miss it:
(click image to see a bigger version)

editing this, cause it seems my last post went in twice.
Mike
My old Stingray...sure do miss it:
(click image to see a bigger version)
Torque is the seat of the pants feel that you are looking for. The GTP may be producing more torque at low rpm than your 406. When we start building higher rpm horsepower motors, we loose low rpm torque (1500 - 2800 rpm range). I don't know anything about your motor, but since you know the RWHP, do you have the torque curve as well?
Steve


Moderator
If you have an engine that starts producing it's major torque output at 2500-3000rpm, it's not gonna get off the line very quickly, without the aid of a lower gear ratio.
I would have to agree with the others, here, and swap the 4.11s out to 3.70s, or 3.55s.

Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
There is a good explanation of this in the September issue of Car Craft under the "Whats your problem?" column. It addresses why the taller gear does not work, especially for pulling at higher speeds.
Reid '72 T-top