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Topic: I learned something yesterday...

in Forum: C3 Driveline Components


I learned something yesterday...

Posted: 7/30/04 7:10am Message 1 of 3
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Canada
Joined: 11/27/2003
Posts: 147
Vette(s): 1974 T-top 454/400 auto w/delux interior, power windows, white w/black int.,American Racing mags w/Goodyear tires. previously owned... 1969 convertible - 427/390 auto w/hardtop 1965 coupe - 327/300 4 spd
Haven't seen this covered here. A chap at a cruise nite told me if you leave you auuto trans in 1st. gear, it will shift automatically into 2nd. I thought "ya, right" (especially since he says his stock '74 has a 350/300) but decided to try it. Pull shifter down into first, take revs up slowly, when reach about 5300,neck snapping chirp, which I never get normally.This is on a TH400.
Couldn't get it to shift 2nd to 3rd tho.But I thought to myself, this would be an advantage if drag racing (which i would never do of course).
How about it Ken/Ben. Is this normal/safe? Is this a built in safety measure?



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I learned something yesterday...

Posted: 7/30/04 8:30am Message 2 of 3
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CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
Posts: 6424
Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
This is a built in safety feature to keep you from overrevving the motor. Not all, but several automatics do the same thing. Most will not go to 3rd at any speed unless you move the shifter.

It could work to your advantage when racing. But that depends on your motor power band. It will give you a very consistant shift, which makes you more precise on the drag strip.

The disadvantage is if the engine runs out of power, and acellerates weakly before shifting. In that case it could slow you down. Times would be consistant, but slower. Where you run out of power depends on the set up. If the engine was modified for high rpm, it works well. A stock engine usually will run out of good acelleration and start producing less power before you hit the shift point.
A set of headers, duals, carb, timing, cam, could all make the difference.

A bit of trial and error is in order. Hey, It's fun research |thumb|


I learned something yesterday...

Posted: 7/30/04 11:37am Message 3 of 3
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
in general this isnt that useful for the reason ken described above.

if your going to shift manually you want to do it at the top of your power band..

you want to set up your car so that when you shift from the top of the band that you remain in band with the new gear.

this is one of the reasons why optimizing your engine for area under the torque/hp curve is better than optimizing for peak. peak is only good for bragging.


in Forum: C3 Driveline Components


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