FrontEngineDragsters.Org Forum
Technical => Dan Dishon's Transmission Den => Topic started by: Mister_Fitz on December 03, 2016, 07:48:51 AM
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I'm planing to get a new torque converter for the PG in my FED.
The local converter builder I have spoken with says that the only info needed to build the converter is the maximum torque and the engine speed where max torque occurs. Other converter builders wants a ton of info.
Therefore I feel like I need to understand how a torque converter is designed.
When I look around the internet I only find advertising from transmission companies and basic articles in magazines.
Where can I find true scientific information about the design of a torque converter? I'm thinking of SAE papers, literature for the university and similar, or other technical information.
Does any one has any suggestions?
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Even built by the pros they are a crapshoot at best--dragsters like loose--you want it to MPH good and thus be pretty efficient on that end but you need loose on the other end--get that engine in the RPM band it is happy at--
I slapped an 8 inch flea market gamble in mine and it has worked out wonderful--I got lucky!
Kenny at PTC is good and reasonable, ATI uses all new parts--they are awesome and the list goes on!
loose 8 inch and away you go--try a good budget used unit from a pal first---FWIW your guy should be asking car weight because the diff in 1600 lbs and 3200 lbs is night and day everything else being the same
also--I raced a door car for three decades---this dragster has proven to be way less sensitive to converters--a Ton less!!!! Almost anything you toss in there will do OK--Converters are best explained as rubber bands--throw more TQ at them and they soak it up like a rubber band stretching out
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The more info the better. It makes the difference between a converter that works and one that's just close. Changing of fin angle to stator combo can effect torque application vs stall speed. Two converters can have the same stall but "hit" the chassis completely different. TSI spec builds all converters for me, as do many other of the name brand companies. When it comes to building a new converter, there is no such thing as infomation overload.
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thanks for asking the question. i would like to understand more as well. great info. ty dean
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I agree with Dan ! A converter can make a huge difference in the performance of your car ! I have 2 converters an 8 inch that stalls at 6700 and a 7 inch that stalls at 8200 . There is almost 2 tenths difference in the 2 converters ! There are a lot of good converter guys out there and every one has a favorite guy . I would pick one who asks a lot of questions and also be as honest as you can with your estimates on torqe and rpm range of the motor ! Last year we tried my 8 inch in my sons r.e.d. that has a 572 big block that weighs 1900 lbs . Mine is a small block that weighs 1450 . It stalled at 7200 behind his motor and it was about 2 tenths slower in his car than his normal 9 inch converter . Keep us posted on your progress ! Bill
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when looking at the convertor itself, is it the stator design (blade angle, count) that determines the stall? dont they take a oem convertor, split it, then do they change other things other then stator? i watched some vid's on oem convertors, just dont understand what they are changing inside to get the desired affect. do they change blades etc on the housings?
ty
dean
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It's a combo of the fin angle of the drive turbine, and stator configuration (number of blades and the angle). This determines both stall speed and the multiplication of torque.
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Great discussion.
Does anyone has any books about converters that you could recommend?
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doing a little reading this morning. convertor size, how do you now or what determine the diameter of convertor to get. in reading this site http://www.ultimateconverter.com/torque-converters-for-drag-racing (http://www.ultimateconverter.com/torque-converters-for-drag-racing) about 'how do i select the right torque convertor' they list the following
7-Inch Converter - Ultra-high performance from 6000 to 9000 rpm stall speeds.
8-inch Converter - High performance with stall speeds from 4000 to 7000 rpm as dictated by your engine combination.
9 and 10-Inch Converters - High performance applications, especially for engines with power adders, such as nitrous injection, super and turbo-charging. Generally for engines with 1200 hp. Stall speeds can be designed according to application.
im confused with the statement between the 8" and 9-10" converters. in the 8" statement they talk about RPM and in the 9-10" statement they talk about power adders and HP. based on this then blown use 9-10" even though HP might be below 1200hp.. say 1000hp? so non-poweradder use 7" or 8" and with poweradder use bigger?
whats the determining factor between using a 8" or 9" lets say. what would be used for a bbc blown making 1k hp versus 1200-1400hp? ... or would you use the same convertor?
ty
dean
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We run a 9 inch converter in a Camaro we make approximately 950 naturally aspirated horsepower. guys they're making 12 to 1400 horsepower would be in the 10 inch converter range. Each converter size has its own natural stall speed range.