How does a 2500 stall converter work

Lockup converters have an internal lockup clutch that will lock the two halves of the torque converter together, eliminating any slippage where the engine and trans cannot physically operate at the same speed.

This, in turn, eliminates any wasted power and so improves fuel efficiency by as much as 65 percent. As for stall speed, Greg Ducato, of Phoenix Transmission Products, explained that "a torque converter is like a clutch.

Imagine when a clutch is fully released, and you get all the power from the engine. That's stall speed. A 2, stall speed doesn't mean you need to rev the motor to 2, rpm for the vehicle to move. By disallowing further gain, the increase in engine rpm "stalls. You can roughly check your converter's stall speed by putting the car in Drive, pressing firmly on the brake, and depressing the throttle fully for a couple of seconds.

Stall speed will be the maximum rpm shown on the tach. Of course, the tires may spin, as the engine will likely overcome the brake system's ability to hold them back.

This method is referred to as brake stall speed, which is lower than true stall speed, but it'll get you close enough, though it's not recommended. A number of factors should be taken into consideration to determine what stall speed is suitable for your project, such as engine-peak torque, the shape of the engine-torque curve, vehicle weight, rearend ratio, and cam specs.

Weight and resistance has a great bearing on stall speed. According to Greg, "A 2,rpm stall speed converter in a T-bucket will probably stall around 1, rpm, but put the same converter in a pickup and that'll go up to around 2, rpm. Keep in mind, if you put that same converter behind a nasty big block, in a car that has serious traction or is quite heavy, the torque of the engine will drive the stall speed up to a higher RPM, and an engine with less power will have the opposite effect and won't be able to stall the converter out as high.

It's all relative to torque, vehicle weight, traction and rear gearing. It isn't an exact science as far as an exact stall RPM goes. Stock cars have anywhere from 1, to 1, RPM stalls from the factory. The reason a stall converter works is simple; an engine at 1, RPM is only making about 80 or so horsepower on average , but at 2, RPM it could be making to HP, and obviously trying to get a car moving using HP is going to be much easier than one trying to launch at 80 HP or so.

Most performance engines don't make power until 3, or so RPM, hence why when you have a higher horsepower engine with a big cam, you need a higher stall speed so the engine is closer to it's "power band" when taking-off from the line, otherwise it will fall on its face and be a turd off the line. Some people believe that "stall" means the car won't start moving until the engine reaches that particular RPM, and that isn't even close to being true. We build race cars with 6, RPM stall converters and when you put the car in gear and let it idle, it WILL roll along at 5 - 10 MPH, just like any other car will when put in gear and with the brake off.

Stalling means that whenever the car is on the start line, and the trans brake is on, and you hit full throttle, the engine will rev up to RPM with the car sitting there, so whenever you slip that finger off the trans brake, and the tranny slips out of reverse, the car will launch at RPM, and a race motor at that RPM is close to hitting the peak torque curve when it leaves the line, which is why you get big wheelies or low 60ft times whenever the traction is good.

Race engines will have no power at a low RPM, and will be shy on torque, so the nastier that the engine is, the higher the stall speed will need to be.

Gear ratio, cubic inches, weight, and torque have a factor in this. It is a pretty complicated process, so I will keep it simple. This is true for a RPM converter. Most mild race cars will use between to stall speeds on average. Plus, the higher the stall speed, the more heat the converter will make with hydraulic fluid inside of the converter.

Most street performance cars running your typical "performance" cam should be running a stall converter in the 2, - 3, RPM area. For mild performance cars with something like a HP engine, a 2, - 2, stall is about right. The basic rule of thumb is; if your engine "comes alive" at say, 3, RPM, then you want a stall converter with about 3, of stall to it. Most people tend to over cam their cars Big thing is matching stall to your cam.