No bottom torque

phoenix02

Well-known member
Hey all,

Okay, so I've finally gotten her where I'm comfortable driving (mechanically...) on the freeway with no problems. She still has no bottom torque. I've heard people on here say that their birds and ponies wind up relatively fast to 60, then can eek out 70 and 80. I wind up REAL slow to 60, even when flooring it, but from 50 on up, she runs like a champ. I passed a diesel on my way to work yesterday, looked at the speedo and kinda *ulped* when I realized I was flooring a 40 yr old car with manual drum brakes and non functioning seat belt at about 98mph. She cruises at 80 all day long at 1/3 throttle. Is there any way I can keep this and also get some better acceleration? I was wondering if it's a gearing thing, but if I changed that, I'd get better acceleration, but have to push harder for the top end, right?

200,1940,LOM,C4 all stock.

-Michael

PS- I picked up the performance manual and am trolling e-bay to get a shop manual to complement my '69 Motors. I hope to build up another engine this summer- late model head, 5200 carb, and a different cam. I was thinking 5200 over 2100 for the mileage savings of having a progressive. Is the mileage that different with the 5200 over a conventional 2bbl, or is it negligable?
 
I'd have to say that an overdrive conversion with changed rear end ratio, would be the best solution to have sprightly performance across a range of speeds.

But as you observed, a few safety things first won't hurt!
 
Are you sure your trans is shifting properly? Maybe you're not getting first gear, or shifiting prematurely into third. Do you have a tach? That's a good way to diagnose where in your powerband you are making power and where not. You can get cheap ones at autozone or pep boys.
 
Try to manual shift the transmission and see if there is any differnce in the performance. The C4 in my 66 sometimes does strange things. When it works right it has decent low end performance but sometimes it decides to shift too fast and then its kinda a dog. The C4 has a vac modulator and a cable on the throttle linkage. Cable adjustment can be trickey and needs to be re done if the carb is messed with and the vacuum modulator on the transmission has a steel like that runs most of the way but there is a short bit of hose that connects to the modulator itself that often gets mushey and leaks if it gets any oil or trans fluid on it. I guess most of the modulators are adjustable by inserting a allen wrench in the vac nipple. The way it sits in my 66 there is not room to do it so I have never tried myself. Im planning on taking mine out and having it gone through. If one or both are off it will do strange things. You can also adjust things to cover up other issues. So maybe if you have fixed other issues on the car like the carb or timing you will need to get the transmission stuff set back to specs.
 
BTW..... the shifter sequence is P, R, N, D2 or dot, D1 dot with circle,& L. The D2 forces a 2nd gear start, its supposed to be to lower the torque for driving on ice to reduce tire spin but will still shift to 3rd. D1 is the 'normal' drive setting. L will keep it in 1st. There is no easy way to force it to stay in second so my theory about manual shifting will not be that usefull. When mine is acting up there does not seem to be much differnce between 1st and 2nd... but other times its fine. I will know more when I get it out of there and apart. I have read that the downshift cable link often gets bent insde the trans from improper adjustment.

The shop manuals have some fairly specific adjustments and trouble shooting but its several pages long.
 
Check your carb's acceleration pump. Look down into the carb throat, make sure there's a steady stream of fuel shooting in there when you open the throttle.
 
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