I was just wondering what you all experience with installing a higher stall converter, and the effects on gas milage. I just went from a stock converter, to a PI Vigilante, and had it built to stall 2800-3000, for mainly street and some strip use. As you all know, takes a bit more pedal to move car, and especially going up hills. I think on flat straights, with TC locked, it running the same rpm. The car is definitley more responsive, and seems to keep the motor more in the "happy zone". I think the brakes will hold it to about 2050-2100 before moving forward. Only put 1 tank of gas thru it, and got 17.3mpg. But it was old gas. That number a bit low compared to last year. I havent gotten on the pedal too much, want to to let the tranny break in.
TIA!

 

If I not mistaken, with that stall you should be able to hold it to 2800-3000 before the car overcomes the brakes. You may have a braking issue.

 

Yea Vip, I know what you mean, but I think my brakes are ok. I havent really pushed the limits of the stall. But I know PI told me that a new converter wont exactly stall at the speed they build it for. Depends on alot of factors based on the individual car. But 2100 is alot lower than 28-3000!! I gonna have to investigate this now. I do know I need more rpm to get up the backroad hills. In fact it wont go into 4th going up this hill i drive everyday. I know the motor can pull it in 4th, used to before. It's looking like I need to adjust some things in the PROM.
What about the gas milage?? Anyone??

 

The stall speed changes with engine power. A 2800 stall in a V6 might stall at 2000 while a 2800 stall in a 383 supercharged LS1 might stall at 3500.

My spouse had an LT1 with a Vigilante 2800 and it would brake stall somewhere around 2200 RPM if memory serves correct.

I'm guessing about 2 mpg loss in fuel mileage, but I can't really say for certain.

 

I know a lot of TC companies fudge their stall speeds to "protect" the customer but PI and Edge should actually be pretty close to their advertised stall rates. If you're running a trans brake you don't want an inaccurate stall.
So why would engine power change a converters stall speed? The stall is built into the converter. Enlighten me. I guess i've always ASSumed but maybe i'm wrong.

 

Actually it most of it has to due with torque of your motor. If you dont have enough *** in your engine then the converter wont stall at the right speed.

 

Would you go into more detail? Torque converters are supposed to be ordered with whatever stall to compliment the engine. So why would a 2800 stall stall at 2100 if it was ordered according to the engine specs?

 

Here is a good article expalining it all. Let me know what you think. But in this case I think MikeT 88IROC350 vbmenu_register("postmenu_3370784", true); didnt buy a converter to match his cam and power band.


http://members.aol.com/agspeed/torque-converters.htm

 

Miket 88iroc350 whats your cam specs ? I am guessing your car is close to stock?

 

And the light goes on.
IF the TC was ordered to compliment the engine, (in my case 2800 Edge behind 497 tq (ordered converter for said torque & hp)), then mine should actually stall ~2800 mark.
In the article it states that brake torquing to the stall does not work. There goes that old wives tale. Apparently, there's no way of measuring stall speed. I hate trusting people in that I get exactly what I ordered. Been burned too many times.

 

Good replies, boys. Keep em coming. I confirmed tonight that I can only hold up to about 2100 with the brakes on hard. From what Reid said the more power you make(and torque) the higher it will stall at. So you could have too much power/torque for the converter. Most folks I read about go with higher stall than they really need.

Just for fun, if you had a fixed stall converter, and you could just adjust the power/torque of your motor, then you could find the correct power level to stall at your fixed converter.

My cam and heads are still stock. I have heavily modified intake system, headers, and opened up exahust. I also do my own PROM work, so it is really tweaked a bit. You would be amazed what you can do with your own PROM!
I am guessing around 250-260hp with my setup. I told the PI folks someday I will be doing a cam/head upgrade, and he said with 2800-3000 Vigilante, I still would be ok, and not even need a re-stall.

 

I have a 406 TPI with a smaller cam. I wanted all torque and lots of it. I had an ACT 2200 lockup and got right at 20 mpg at 75 (straight freeway driving on vacation). I switched to a 1900 lockup and now get 24 at 75 mph. The readings were taking a year apart, but on the same trip on the same route (to Woodward).