Torque Converter RPM Loss
06-09-2006, 01:47 AM
#1
Torque Converter RPM Loss I have been told that a Stall Converter looses Rpm when you apply the brake to get the converter to its stall? In other words a 3500 Stall would reduce to a 2500 stall when you apply the brake and let the motor rev up to the converter you have? Is this true?
06-09-2006, 05:11 AM
#2
TECH Addict
iTrader: (3)
Join Date: Nov 2005
Location: Lincoln, NE
Posts: 2,869
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ss4chad
I have been told that a Stall Converter looses Rpm when you apply the brake to get the converter to its stall? In other words a 3500 Stall would reduce to a 2500 stall when you apply the brake and let the motor rev up to the converter you have? Is this true?
Flash stall is going to be the one you see advertised. Brake stall depends on other factors so its going to be different on every car.
06-09-2006, 12:11 PM
#3
Thanks dude, then as a rule of thumb then could you say that loosing 1000 rpms on the brake is a good number? Less, higher? You seen my cars equipment and I am buying a stall and 3:73 gears (no slicks or DR) The car brakes loose @ 1500rpms right now while on the tree (love saying that) and stays stuck to the ground. I went to a wider back tire and it has helped out a bunch, well, considering the other tires were slicks with steel cords showing!!
06-09-2006, 12:49 PM
#4
Originally Posted by BlackHawk T/A
That's because Brake Stall and Flash Stall are two different things.
Flash stall is going to be the one you see advertised. Brake stall depends on other factors so its going to be different on every car.
Flash stall is going to be the one you see advertised. Brake stall depends on other factors so its going to be different on every car.
Brake stall will always be lower then advertised and flash stall. Brake stall is when you apply the brake and push the accelerator pedal to the point where the tires are about to break loose. Factors affecting this are road/track surface, condition of your tires grip and the condition of the brake pads/system. Flash stall is when you are at a dead stop and idling, then you floor the throttle ... the rpms the engine jumps to prior to actually accelerating is your flash stall. This can be seen via a scanner for a couple of seconds before the tires start to grab/spin. Advertised stall, if done properly, is tested on a Torque Converter Dyno at a certain Torque Input on the converter cover, while the output of the converter is held from spinning (similar to a trans brake). This will be the highest stall the converter can reach and without a trans brake you will never reach it. Most people will experience brake stall, followed by flash stall. Advertised/Rated stall speed is used to compare different brands of converters, if they all use the same input torque amount. Some companies do not even check stall speeds this way. I hope this helps.
06-09-2006, 07:31 PM
#5
Thanks George, I am aware that many factors are to be considered when discussing brake stall and flash stall, but here is what two Stall Companies told me. "A 3500 Stall will brake stall at around 2500 but the flash will stay the same @ 3500". I aint quite sure what Flash stall is really, you said earlier that it was when you were at a dead stop and then floored it that the car wouldnt move until, in this case, 3500rpms and then accelerate. Why would you do that? Could you be more definitive on the Flash Stall please? Thanks
Chad
Chad
06-10-2006, 02:09 AM
#7
TECH Addict
iTrader: (3)
Join Date: Nov 2005
Location: Lincoln, NE
Posts: 2,869
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 12secSS
Wrong.
Brake stall will always be lower then advertised and flash stall. Brake stall is when you apply the brake and push the accelerator pedal to the point where the tires are about to break loose. Factors affecting this are road/track surface, condition of your tires grip and the condition of the brake pads/system. Flash stall is when you are at a dead stop and idling, then you floor the throttle ... the rpms the engine jumps to prior to actually accelerating is your flash stall. This can be seen via a scanner for a couple of seconds before the tires start to grab/spin. Advertised stall, if done properly, is tested on a Torque Converter Dyno at a certain Torque Input on the converter cover, while the output of the converter is held from spinning (similar to a trans brake). This will be the highest stall the converter can reach and without a trans brake you will never reach it. Most people will experience brake stall, followed by flash stall. Advertised/Rated stall speed is used to compare different brands of converters, if they all use the same input torque amount. Some companies do not even check stall speeds this way. I hope this helps.
Brake stall will always be lower then advertised and flash stall. Brake stall is when you apply the brake and push the accelerator pedal to the point where the tires are about to break loose. Factors affecting this are road/track surface, condition of your tires grip and the condition of the brake pads/system. Flash stall is when you are at a dead stop and idling, then you floor the throttle ... the rpms the engine jumps to prior to actually accelerating is your flash stall. This can be seen via a scanner for a couple of seconds before the tires start to grab/spin. Advertised stall, if done properly, is tested on a Torque Converter Dyno at a certain Torque Input on the converter cover, while the output of the converter is held from spinning (similar to a trans brake). This will be the highest stall the converter can reach and without a trans brake you will never reach it. Most people will experience brake stall, followed by flash stall. Advertised/Rated stall speed is used to compare different brands of converters, if they all use the same input torque amount. Some companies do not even check stall speeds this way. I hope this helps.
When you look at a converter that's say, a "3600" rpm stall converter, you will be really hard pressed to brake stall that thing to 3600rpm.