Say it weighs in at around lbs with a cubic-inch engine at compression, running a relatively mild street cam like a Comp H and 3. Or a Chevy 2 door hardtop which weighs about 3, lbs. It would likely use a stall converter, like PN, to get the best performance. All of the performance torque converters offered by Speedway Motors are engineered to provide improved strength and durability.
Designed with heavy-duty heat-treated internals and high-strength bearings, you can expect longer life along with a substantial increase in performance over a factory torque converter.
See what Torque Converters are available from Speedway Motors. Products to Compare max of 3 X. Videos All Videos. How Do Torque Converters Work? How To Choose a Torque Converter. Torque Converter for Ford. 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. Stall means when the car is on the starting line, with say a 4, RPM stall converter , and the trans brake is on, which locks the transmission in first and reverse at the same time , and you hit full throttle, the engine will wind-up to 4, RPM with the car just sitting there, so when you slip your finger off the trans brake button and the tranny engages out of reverse, the car instantly launches at 4, RPM, and a race motor at 4, RPM is pretty close to its peak torque curve when leaving the line, hence the big wheelies you see on some drag cars or the incredibly low 60 Ft.
Race engines make no power at low RPM's, and are usually shy on torque, so the nastier the engine, the higher the stall speed needs to be in general anyway. Again, cubic inches, torque, vehicle weight and gear ratio have a big factor in this. Now, this doesn't get into the "flash" effect which is where a stall converter will "flash to" when your finger comes off the trans brake button.
This can mean they may want the new torque converter to help the car run quicker, run faster, idle in gear better, leave from a stop harder, "chirp" the tires on the gear changes, or pull a steeper hill. The buyer may be looking for any or all of these performance improvements.
They want to improve the dependability of their vehicle meaning they want to get rid of existing drive train failures they are currently having with either OEM or competitors products such as short life to what they perceive is a proper life , "trash" related transmission failures, overheating, hard part breakage, engine problems that they may believe is caused by torque converter and general unreliable performance. They may have been told by friends, salespeople, advertising, technical articles, etc.
This is particularly true of first time performance camshaft purchasers where the salesperson or the camshaft catalog will recommend a higher than stock stall speed torque converter. Torque converters do not function in a void by themselves. The torque converter is an integral part of the total vehicle combination. While many vehicle combinations and applications are very similar and it may seem obvious what the best torque converter selection is, it is normally a wise step to take a look at the intended application and choose the best torque converter for the particular application.
TCI uses an application questionnaire to gather the pertinent information. TCI technical salespeople also spend a large portion of their day reviewing specific customer applications and recommending torque converters for those applications. There is no "black magic" formula that the variables can be plugged into resulting in a definitive torque converter choice.
Torque converter choices are made based on accumulated historical knowledge of performance in various applications and the use of all or several basic charts and ratios derived through this historical information. As with many other automotive performance parts, torque converter design and construction is a dynamic art and can not be patterned on the results of a "plug-in" formula or solely allowed to follow the historical applications.
TCI looks at torque converter technology as an on going process of continuous improvement. Furnace brazed fins - greatly improves the strength characteristics of the fins. The furnace brazing causes the housing and fins to move and act integrally as one unit. This greatly reduces the amount of flex, which causes fins to bend and break. Also, the more rigid the fins stay while under pressure, the more consistent the behavior of the torque converter.
Needle bearings - properly selected and installed bearings withstand more pressure and provide less internal drag drag robs horsepower and increases heat than can be achieved with OEM style thrust washers. Service and time proven manufacturer - Ask for recommendations from leading car enthusiasts in your local area or check out what the racers are using.
Drivability concerns in choosing a torque converter - A performance torque converter should not compromise one aspect of car performance to achieve another. When investigating a converter purchase ask whether the particular torque converter being looked at may improve initial takeoff at the sacrifice of top end mph or other similar results, questions, etc.
With the technology and product available today a buyer very seldom needs to sacrifice one area of performance to gain in another. However, without proper selection assistance or guidance and with many under engineered products on the market today it is unfortunate that many buyers end up with a product that does not best suit his needs or expectations.
Too low a stall torque converter will not benefit the customer. If the user has an application which requires at least rpm stall and they purchase a to rpm stall range converter, it will normally not even give them the rpm stall. It will act very similar to the stock torque converter they just removed. Because the engine needs to operate in its optimum rpm range and since the chosen torque converter is below that range, it is not getting enough load from the crankshaft side to operate as designed.
Symptoms include engine stalling when in gear at a stop, low stall speed, hesitation when going to full throttle, a "bog" when leaving from stop at wide open throttle. Too high a stall range torque converter will not benefit the customer. 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.
0コメント