HIGH STALL CONVERTERS
Posted: 10 Dec 2002 5:33In a previous posting, I mentioned that I work in the Transmission/Converter industry.
I'd like to pass along to the group the following to assist those of you that may be thinking of purchasing a high stall converter. To some this information may be old hat, but after 20 years in the business, I find a lot of unhappy high stall owners because no one has helped them in the correct selection for their particular application. They have sold them a converter just to make the sale in some cases.
First of all there is always confusion as to what stall is. Very simply, stall is the rpm where the converter locks up the motor to the drivetrain and multiplies the torque at a 1 to 1 ratio. All converters have stall built in to them. A good converter, when the engine has exceeded the stall speed, should give you less than 10 percent slippage. Any thing greater that this 10 percent figure will produce excessive heat, and of course excessive heat can and will lead to transmission failure. Typically most factory converters have a stall range of between 1400 and 1600-rpm. Some a little more, some a little less, and ocacasionally, the factory will actually provide a high stall converter for a true high performance vehicle. For those of us into Chrysler vehicles, a 440 powered New Yorker wagon may have the same converter in it as a 440 powered Road Runner. Surprised? There are only two factory high stalls in the Chrysler stable, to the best of my knowledge, one for the HEMI of course and the other for some of the early 340's. The 340's stall speed is about 1700 rpm. By the way, these are not the converters that may be found in the Accessory Parts Catalog, but rather the ones that came with the car from the factory.
OK, now how do you go about getting the right converter for your pride and joy? Here's what the converter manufacturers would like you to tell them.
Engine size, transmission type, rear axle ratio, rear tire size, vehicle weight, camshaft profile, and if you've had the engine on a dyno, the rpm the engine makes maximum torque and maximum horsepower. DO NOT use information from a PC dyno program. Working in conjuction with one of the high performance engine companies, we've seen a huge difference in projected PC Dyno horsepower and true dyno horsepower. We'd also like to know what you use your vehicle for, street, race, or a combination of both. Armed with this information, we are now able to assist you in getting the RIGHT converter for your application.
Some suggestions I'd like to pass along.
If your car is mostly used for cruising and the odd trip down the drag strip, go with a cam that starts working about 21/2200 rpm, a 26/2700 rpm stall converter, single 4 bbl carb, 3.55 or 3.73 axle ratio and some 235 x60 tires. Now admittedly this combo wont make you competative with ••••/AA Dart or a Pro Stock Neon, but you will have a cruiser that will give you not bad gas mileage and properly set up, a high 13 second race car.
Your converter should stall at about 500 RPM over were the cam starts making power. We find many performance buffs have cams that start making power at 3000 RPM +, and wonder why their 2200 rpm high stall doesn't work right and their car is a slug.
ALWAYS install a quality auxiliary transmission cooler, and run it in conjunction with the cooler that is installed in the rad. REMEMBER -HEAT KILLS- and any high stall converter produces lots of heat.
I hope that this has been of some help to the group. If you have any questions, or would like my input as to what converter would best suit your needs, please feel free to email me.
I'd like to pass along to the group the following to assist those of you that may be thinking of purchasing a high stall converter. To some this information may be old hat, but after 20 years in the business, I find a lot of unhappy high stall owners because no one has helped them in the correct selection for their particular application. They have sold them a converter just to make the sale in some cases.
First of all there is always confusion as to what stall is. Very simply, stall is the rpm where the converter locks up the motor to the drivetrain and multiplies the torque at a 1 to 1 ratio. All converters have stall built in to them. A good converter, when the engine has exceeded the stall speed, should give you less than 10 percent slippage. Any thing greater that this 10 percent figure will produce excessive heat, and of course excessive heat can and will lead to transmission failure. Typically most factory converters have a stall range of between 1400 and 1600-rpm. Some a little more, some a little less, and ocacasionally, the factory will actually provide a high stall converter for a true high performance vehicle. For those of us into Chrysler vehicles, a 440 powered New Yorker wagon may have the same converter in it as a 440 powered Road Runner. Surprised? There are only two factory high stalls in the Chrysler stable, to the best of my knowledge, one for the HEMI of course and the other for some of the early 340's. The 340's stall speed is about 1700 rpm. By the way, these are not the converters that may be found in the Accessory Parts Catalog, but rather the ones that came with the car from the factory.
OK, now how do you go about getting the right converter for your pride and joy? Here's what the converter manufacturers would like you to tell them.
Engine size, transmission type, rear axle ratio, rear tire size, vehicle weight, camshaft profile, and if you've had the engine on a dyno, the rpm the engine makes maximum torque and maximum horsepower. DO NOT use information from a PC dyno program. Working in conjuction with one of the high performance engine companies, we've seen a huge difference in projected PC Dyno horsepower and true dyno horsepower. We'd also like to know what you use your vehicle for, street, race, or a combination of both. Armed with this information, we are now able to assist you in getting the RIGHT converter for your application.
Some suggestions I'd like to pass along.
If your car is mostly used for cruising and the odd trip down the drag strip, go with a cam that starts working about 21/2200 rpm, a 26/2700 rpm stall converter, single 4 bbl carb, 3.55 or 3.73 axle ratio and some 235 x60 tires. Now admittedly this combo wont make you competative with ••••/AA Dart or a Pro Stock Neon, but you will have a cruiser that will give you not bad gas mileage and properly set up, a high 13 second race car.
Your converter should stall at about 500 RPM over were the cam starts making power. We find many performance buffs have cams that start making power at 3000 RPM +, and wonder why their 2200 rpm high stall doesn't work right and their car is a slug.
ALWAYS install a quality auxiliary transmission cooler, and run it in conjunction with the cooler that is installed in the rad. REMEMBER -HEAT KILLS- and any high stall converter produces lots of heat.
I hope that this has been of some help to the group. If you have any questions, or would like my input as to what converter would best suit your needs, please feel free to email me.