I've always driven either a stock stalled-automatic or a manual.

My question is, how does changing the stock converter affect the way the car actually drives?

I understand that it changes your launch, but how does it act in everday driving?

Do you have to rev the engine up to the stated RPM to get it moving, or can you still take off easy?

Thanks for any info, and from my brother too who is considering stalling his Parisienne.

 

The car should not have to be revved up to the stall to start moving. Depending on the stall speed it should start to move when u hit the gas. If u buy a lock-up converter then it should not affect your highway driving because once it locks up it becomes just like your stock converter.

 

It depends on the stall size and brand. I have a 2400 and I did not notice much difference in every day driving. My friend had a 3000 stall and you had to rev it up to about 2000 or so until it started moving. Other (better) brands 3000 stalls will not need to be reved up.

I would recommend a Precision Industries Vigilante stall myself.

 

the general term used most often is that the car will feel "loose". the converter will slip, but it will definitely not require stall speed rpm to move. i have 3800 stall and on level ground, mine will still creep along just at idle.

if the stall is too high, it might get a little annoying to drive around on the street only because the middle ground between driving fast and driving slow kind of disappears. in my car you're pretty much either accelerating slowly under stall speed, or getting up and moving hardcore anywhere above it.

personally, i'm so used to mine barely notice it anymore....you'll lose 1-2 mpg during city driving but otherwise, if you pick a sensible stall speed, you won't have any problems. the first drive will feel VERY weird but as soon as you step on the loud pedal and blow the tires off, you'll teach yourself to get used to it.

 

What a converter does:
1.)Higher RPM launches. While these examples are not 100% accurate because of outside factors, they will give you an idea of what happens with a stall converter.
Example 1- Your stock stall is around 1600 RPM. Get into the car and hold your foot on the brake. Now at the same time you let off of the brake, stab the throttle like you are at the track. Keep a close eye on the tach. It will jump to about 1600 RPM and start climbing from there. If you moved to a 3200 stall, it would jump to about 3200 and start climbing from there. It gives you a huge punch by launching at a higher RPM and at an RPM that is more in the meat of your powerband. Where it jumps to is called your flash stall.
Example 2- In Drive, hold your left foot on the brake as hard as you can. Now slowly rev the engine with your other foot. Notice that about 1200-1300 RPMs the tires start to break loose. Now imagine that you have a 3200 stall. You could now spin the motor closer to 3k before the tires started to brake loose. You could roll onto the throttle at 3000 instead of the old 1200 with the stock converter.

2.)Shift extension. I am sure you are familiar with the notorious dead zone our cars have. You may not have heard it called that, you may not have even noticed it before, but I know you have felt it. Take your car out and find a place to get on it up to about 60 or so from a dead stop. It will feel really strong all through first gear particularly at the top RPMs because that is where LS1s like to be. Notice immediately after the 1-2 shift (and 2-3 if you get that high) that it seems to fall flat on its face for a couple seconds. That is the dead spot. It feels weak until the RPMs get to where they should be and the power feels like it comes back. With a stall converter, the RPMs don't fall like they do with a stock converter. When I had my 4400 stall, the RPMs stayed above 5300 RPMs after the shift. With a milder converter, you could expect them to still stay WAY up there and completely get rid of the dead zone.

3.)Lighter weight. Almost every quality aftermarket converter is a 245mm conversion. That means that the manufacturer essentially took a 245mm converter and put a new back on it so that it would fit on a 300mm style car. It is then called a 245 conversion. The reason that it is done like this is because a converter works by moving fluid. The smaller internals can create more velocity enabling higher stall speeds. Also, there are TONS more internal parts on the market for 245 converters than the 300s. The 245 conversion torque converter is smaller and inherently lighter. A lighter converter gives you less rotational mass. Less rotational mass enables you to get off of the line more quickly and allows the engine to rev faster.


Picking a stall speed.
The first thing that I tell people is to be honest with yourself. What are your goals for the car and more than that, what will they be a year or two down the road. When I bought my first converter, I was convinced that I was going to keep the car relatively stock. I later went to a bigger stall to accommodate for the new power it was making from the heads/cam/full bolt ons. That worked great for a while. The next summer I decided on nitrous and suddenly, the huge stall I had was gone for a lower one. As you can see, picking a stall really depends on your plans.
If you would like, let me know about your plans for the car and we will get the right converter picked out for you.


Driveability:
When people refer to a converter being loose, they are talking about its slipping. Depending on the way the converter is set up, it could be looser than some or it could feel tight. Loose simply means that it takes more gas to get going. If you took a stock auto car and pressed the pedal in an inch, it would likely require pressing the pedal 2.5 inches to get the same effect. Basically it takes a higher RPM(more throttle) to get the car up to speed around town. A good example is that my car used to climb the driveway if I let off the brake, but now with the stall converter, it can barely stay put and even rolls back slightly. Personally, I like the feel of a stall car A TON better than a stock one.

 

Awesome explaination and welcome to the board incase no one else welcomed you.

-Dustin-

 

That's a good explanation of what can be annoying about a high stall in a street application. That loss of the "middle ground". The car will creep forward fine and accelerate quickly with no problem. But when you are in a situation where you are slowing down and speeding up constantly (like a line of heavy traffic) it can require a lot of concentration to "keep station" with the cars in front of and behind you.

Someone else mentioned "being realistic". That is very important. If you want to improve off the line and low speed acceleration on a street car, the optimum stall speed will be a lot lower than if you are trying to optimize track times. Too high a stall on the street will make it impossible to control whelspin. I would stick with something below 2,500rpm for a street LT1 and maybe a couple of hundred rpm higher for an LS1 if it were a lightly modded street car. Obviously, if it's a high revving NA combo a higher stall will be needed. And for the track, optimum stall speed will typically be a couple of hundred rpm below peak torque. For a modded motor, this can mean 4,000rpm or higher. That is NOT something you want in a daiy driver, trust me.

Rich

 

thanks everyone for all the info!