bw1339

Hello,
I have a '66 Toronado. I'm not sure this is an engine transmission issue but this is what happens:

When I'm in 3rd gear and and I floor it, the transmission downshifts and the engine just seems to be gutless, just making noise and providing very little acceleration. I know the secondaries are opening, as the car accelerates fine when taking off from a stop. It will leave plenty of rubber on the road. Engine is a 455 (Olds) with a quadrajet.

The strange thing I noticed today is that when flooring the gas from a stop, I am lifting my foot from the gas by 5K RPMs (Don't want to rev the engine higher - I think this reopens the kickdown circuit) and judging from the big drop in RPMs, from 5000 to about 2500, it seems to be shifting from 1st gear to 3rd.

Driving normally, the transmission shifts fine through all the gears, smoothly and at the right times. It's just this weird downshift situation.I rebuilt this transmission myself, so there is always a chance I did something wrong. I Think either the engine somehow loses all top end power, or there is something strange happening in 2nd gear. Any ideas?
Thank you.
Mikel

rjohnson442

What kind of Transmission do you have? Could just be the kick down switch needs adjusted. By any chance you have a rev limiter on there by chance?

droldsmorland

Can you shift it manually and get it to do what you want it to do?

bw1339

Hello,
I'm embarrassed to admit that the secondaries were barely opening. I am amazed how much power that engine made with just the primaries It certainly fooled me.
Thank you.

Koda

No problem. I have a car which had clogged secondaries. Did awesome until 60.

bw1339

Out of curiosity, how much do the primaries in a QJ flow? 250-300 CFM? The car could burn rubber and get out of its own way with just those.

Koda

http://www.hotrod.com/how-to/engine/...et-carburetor/

This link says 180-210 ish

BlackGold

Proof positive that most people are overly obsessed with carburetor flow. The more restricted a carburetor is the higher velocity the air will have and the better the carb will perform -- until it becomes too restrictive, but that's only at really high RPMs.

Have you ever noticed how much more off-the-line torque your engine demonstrates when it's cold and the choke is engaged? Likewise, you can often accelerate quicker by easing into the throttle on a Q-jet then by flooring it. Of course, you can also tune the Q-jet to do this automatically so that you don't have to *****-foot around.