Using the TCC.

[Pat Kelley]

I have heard that you guys are the experts on the 200-4R and really know your stuff. Having lurked for a while I can see it is true.

I have some questions about using a 200-4R. I have one installed in my 1966 El Camino. It is a stock rebuild with hardened pump vane rings, a Superior Super Servo, and a Transco kit. I have a BTO wiring kit in to to be able to lock up in 2nd and 3rd as well as OD.

My questions are about using the TCC. I have been trying to improve my gas mileage by locking the converter in 3rd while driving in town. However, I'm concerned that this may damage the converter clutch due to it engaging while under acceleration. This is normal city driving not hard acceleration. The clutch locks about 1-2 seconds after shifting into 3rd so the car is still under mild acceleration. A second concern is cycling the clutch this often. I suspect that it was designed with OD-only stable-state use in mind. Is the gas saving worth it or am I persuing a false economy by doing this? The cost of any damage would far exceed any gas mileage savings. All comments welcome.

General Specs:
350 SBC about 260 hp
3.36 gears
I tow a trailered bracket car with it
I have a momentary push button switch, mounted to the turn signal stem, to disengage the TCC when accelerating from low speed (to keep from lugging the engine).

Thanks,
PK

 

[bruce]

The TCC was just designed to eliminate the slippage of the converter when in cruise mode. I've played with the TCC management in the 200R4s, and 4L80E trannies, and haven't seen any gain in MPG by trying to lock it in anything but 4th.

And if your lugging the engine, your way down on the VE of the engine and might lose some MPG by locking it at too low of load condition.

If your using a stockish type converter, your only looking at 4-6% slippage and with all the other power robbing items, that's hardly an issue, IMO. Adding 2 PSI to you tire pressures will probably do more for you, again, IMO.

 

[Pat Kelley]

Thanks for your thoughts, Bruce. How effective locking up in town would be is also a question I had. With California gas prices over $2.25 a gallon, saving gas is a concern.

 

[bruce]

Originally posted by Pat Kelley
Thanks for your thoughts, Bruce. How effective locking up in town would be is also a question I had. With California gas prices over $2.25 a gallon, saving gas is a concern.

If your lugging the engine, it'll cost you MPG.
Best thing to do is actually try it and compare results.

 

[Pat Kelley]

No lugging. That's why I put a disengagement button in. I originally though about using the factory vacuum switch. But I understand they are set at 4" Hg which I feel is too low for street driving. If you are interested you can see my setup at my web page. The car in question is the yellow Elky. Full specs are linked near the bottom of the page.

PK

 

[denn454]

i have mine on a switch. origionally i just put it in for racing, i dropef a few 10ths and gained a few mph by doing that. later i realized it really helps when i'm just driving along. a lot of roads around here are 30mph, my tranny won't shift into 4th then, so i lock the tcc and it brings the rpm down a little (digital dash, no tach so i cant' say by how much) but it is a noticeable difference. locking it under heavy acceleration is what tears them up, but as long as they aren't slipping there isnt' any wear on it. its the same difference as a manual trasmissions clutch. I don't think the mpg savings are substantial but i think its worth doing it when you can.

again boging down is bad, and so is slipping. avoid those two and it will only help.