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Sure grip = 15% torque loss? #375796 07/15/09 12:22 AM 07/15/09 12:22 AM
Joined: Apr 2007 Posts: 1,261 ILL mark7171 OP pro stock
mark7171 OP pro stock Joined: Apr 2007 Posts: 1,261 ILL	I was told that over a open differential, the sure grips/or posi type can take up to 15% of the turning torque away. Also up to a certain level an open differential will get better acceleration on the street. That the torque advantage can be 2:1 at times, from a foot braked start. Knowing converters can do stall tricks , this might be something possible in the differential? Could a mild performance build benefit from the open rear end? Is it that you just like 2 lines?

Re: Sure grip = 15% torque loss? [Re: mark7171] #375797 07/15/09 12:35 AM 07/15/09 12:35 AM
Joined: Jan 2008 Posts: 350 CT USA N Nick Mineau enthusiast
Nick Mineau enthusiast N Joined: Jan 2008 Posts: 350 CT USA	i would say it has to do with the car. if you can launch @ full throttle with i peg leg and not spin then the possi wont help mabe only hurt. but most cars would cook the tire and a possi will duble the traction resulting i a much faster et.

Re: Sure grip = 15% torque loss? [Re: mark7171] #375798 07/15/09 12:40 AM 07/15/09 12:40 AM
Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada dave571 master
dave571 master Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada	Sorry I don't buy it. All a limited slip unit is, is a set of spring loaded clutches, that try to hold the side gears to the carrier. I don't see how it could cost any torque at all(other than the added mass the driveline has to turn). For that matter, the sure grip unit actually does nothing, if the traction is the same on both wheels. Of course there is probably some wizzy scientific explanationa as to why it is true. Last edited by dave571; 07/15/09 12:41 AM.

Re: Sure grip = 15% torque loss? [Re: dave571] #375799 07/15/09 12:59 AM 07/15/09 12:59 AM
Joined: Feb 2003 Posts: 21,318 Manitoba, Canada DaytonaTurbo Too Many Posts
DaytonaTurbo Too Many Posts Joined: Feb 2003 Posts: 21,318 Manitoba, Canada	Well it would feel like a torq loss, you can have a car that'll spin one tire 20', then you put a suregrip on and it feels like a dog because you're actually getting some traction.

Re: Sure grip = 15% torque loss? [Re: mark7171] #375800 07/15/09 01:09 AM 07/15/09 01:09 AM
Joined: Jan 2005 Posts: 12,419 Kalispell Mt. H HotRodDave I Live Here
HotRodDave I Live Here H Joined: Jan 2005 Posts: 12,419 Kalispell Mt.	No performance improvement from open diferential, unless your car is useing the wheel slipage as a way to multiply the tq because your tq converter is too tight. There is no tq multiplying though. Back before my car had any musterd I swapped from a 2.94 open to a 2.94 sg both 7.25s and it felt slower with the SG but ets were quite a bit better and on the street I could finally get a jump on my wife in her maxima. I am not causing global warming, I am just trying to hold off a impending Ice Age!

Re: Sure grip = 15% torque loss? [Re: dave571] #375801 07/15/09 01:29 AM 07/15/09 01:29 AM
Joined: Feb 2003 Posts: 10,203 Someplace you aren't S SomeCarGuy I Live Here
SomeCarGuy I Live Here S Joined: Feb 2003 Posts: 10,203 Someplace you aren't	Quote: Sorry I don't buy it. All a limited slip unit is, is a set of spring loaded clutches, that try to hold the side gears to the carrier. I don't see how it could cost any torque at all(other than the added mass the driveline has to turn). For that matter, the sure grip unit actually does nothing, if the traction is the same on both wheels. Of course there is probably some wizzy scientific explanationa as to why it is true.

Re: Sure grip = 15% torque loss? [Re: mark7171] #375802 07/15/09 02:09 AM 07/15/09 02:09 AM
Joined: Sep 2005 Posts: 6,516 Santa Cruz, California L Lefty master
Lefty master L Joined: Sep 2005 Posts: 6,516 Santa Cruz, California	Quote: the sure grips/or posi type can take up to 15% of the turning torque away. That energy would have to go somewhere and probably make a huge amount of heat, so I say no way...

Re: Sure grip = 15% torque loss? [Re: Lefty] #375803 07/15/09 10:24 AM 07/15/09 10:24 AM
Joined: Jul 2003 Posts: 63 Silver Springs, Florida C Charrlie_S member
Charrlie_S member C Joined: Jul 2003 Posts: 63 Silver Springs, Florida	I don't know for sure, but I think in a straight line, with both wheels haveing traction, there would be no power/torque loss. While turning, the clutches would slip, to allow one wheel to turn faster. This would generate heat, resulting in a power/torque loss. Come to think about it, if the clutches were doing their job as designed (to transfer power to the wheel with the most traction), there would be heat generated, and this would equate to a power loss. Charrlie_S 66 Cuda 170 nitrous 66 Valiant 225 nitrous 65 Valiant 170 turbo 64 Valiant driver 64 Valiant roller

Re: Sure grip = 15% torque loss? [Re: Charrlie_S] #375804 07/15/09 07:54 PM 07/15/09 07:54 PM
Joined: Nov 2004 Posts: 5,118 Alone in the darkness gamagoat6x6 super street
gamagoat6x6 super street Joined: Nov 2004 Posts: 5,118 Alone in the darkness	Figure a well built 440 makes 500 foot pounds. 15% of that is 75 and there`s no way the axle is gonna create that kind of drag. `02 RAM2500 SPORT V10 4x4 `06 GMC sierra NO cars

Re: Sure grip = 15% torque loss? [Re: gamagoat6x6] #375805 07/15/09 08:07 PM 07/15/09 08:07 PM
Joined: Feb 2003 Posts: 21,318 Manitoba, Canada DaytonaTurbo Too Many Posts
DaytonaTurbo Too Many Posts Joined: Feb 2003 Posts: 21,318 Manitoba, Canada	Like I said, it won't create an actual torq loss, but it can feel like one if you're using that one spinning tire to get engine RPM's up if you've got a tight torq converter. If you say had a converter that flash stalls to 4000-5000, you would not notice any torq difference between the two, other than never being able to hook with that peg legger.

Re: Sure grip = 15% torque loss? [Re: DaytonaTurbo] #375806 07/15/09 08:23 PM 07/15/09 08:23 PM
Joined: Jan 2003 Posts: 9,982 Ansonia, CT C CJK440 master
CJK440 master C Joined: Jan 2003 Posts: 9,982 Ansonia, CT	Seems to me, that there is a certain amount of drag in a limited slip when turning that is exacerbated when under power. 2017 Contusion Blue Challenger T/A 392 M6 "BLKNBLU"

Re: Sure grip = 15% torque loss? [Re: DaytonaTurbo] #375807 07/15/09 08:24 PM 07/15/09 08:24 PM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	only 1 way to prove it! if anyone is planning on putting an LSD into their axle, go to the dyno first, get a baseline. then swap in the LSD and go re-dyno to see if there's a loss. this would only work if the ONLY thing you changed was the diff, and did not do a gear change at the same time. Photobucket sucks

Re: Sure grip = 15% torque loss? [Re: CJK440] #375808 07/15/09 08:33 PM 07/15/09 08:33 PM
Joined: Nov 2007 Posts: 21,822 Kirkland, Washington Pacnorthcuda Too Many Posts
Pacnorthcuda Too Many Posts Joined: Nov 2007 Posts: 21,822 Kirkland, Washington	Ever driven a live axle go-kart? Those things are dogs at low speed with the wheel cranked. Everyone guickly learns to accelerate in the straightest line possible. Reason is simple, in a turn, the engine has to not only accelerate the mass, but over come the friction of the two rear tires having to turn different speeds. Now in a limited slip, the axle can differentiate, which GREATLY helps, but there is friction present in the cones/clutches, generating heat, all made possible from consuming torque from the motor. So yes there is some truth to it....IF (big IF) the differnetial is being forced to differentiate (its in a turn). Straight line? I wouldn't think there would be a difference, and of course if the peg-leg set begins to spin...... ...and as far as a 15% torque loss? I don't believe it.

Re: Sure grip = 15% torque loss? [Re: mark7171] #375809 07/15/09 10:18 PM 07/15/09 10:18 PM
Joined: Nov 2006 Posts: 1,457 oklahoma F forphorty pro stock
forphorty pro stock F Joined: Nov 2006 Posts: 1,457 oklahoma	i have no earthly idea. but if an open open differential requires,say, 30 lb-ft to turn, an additional 15% is only 4.5 lb-ft more. almost insignificant.

Re: Sure grip = 15% torque loss? [Re: mark7171] #375810 07/15/09 10:38 PM 07/15/09 10:38 PM
Joined: Apr 2005 Posts: 93 Jacksonville, FL burnt_o_matic member
burnt_o_matic member Joined: Apr 2005 Posts: 93 Jacksonville, FL	Quote: up to 15% of the turning torque away Was that a circle track racer telling you this? There may be some truth to it in that situation.

Re: Sure grip = 15% torque loss? [Re: burnt_o_matic] #375811 07/15/09 11:11 PM 07/15/09 11:11 PM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	Quote: Quote: up to 15% of the turning torque away Was that a circle track racer telling you this? There may be some truth to it in that situation. Good catch! TURNING TORQUE! yes, I'd believe it if you had full traction on both tires, in a turn, when you're now forced to slip the clutches in the LSD. maybe this is where a detroit true trac would be beneficial? no clutches, all gear LSD...acts like an open around a turn, until you gas it, then it acts like a locker, right? I know if I have 1 wheel up in the air, the darn thing spins around and around like an open diff! scared me the first time I did that with it installed! I didn't fully understand how it worked yet! Photobucket sucks

Re: Sure grip = 15% torque loss? [Re: burnt_o_matic] #375812 07/16/09 07:23 AM 07/16/09 07:23 AM
Joined: Jan 2003 Posts: 25,200 Upper Midwest M MoparforLife Too Many Posts
MoparforLife Too Many Posts M Joined: Jan 2003 Posts: 25,200 Upper Midwest	Quote: Quote: up to 15% of the turning torque away Was that a circle track racer telling you this? There may be some truth to it in that situation. If it was he won't have to worry about it long using a SG on the circle track.

Re: Sure grip = 15% torque loss? [Re: 70Cuda383] #375813 07/16/09 07:47 AM 07/16/09 07:47 AM
Joined: Jan 2003 Posts: 9,982 Ansonia, CT C CJK440 master
CJK440 master C Joined: Jan 2003 Posts: 9,982 Ansonia, CT	Quote: only 1 way to prove it! if anyone is planning on putting an LSD into their axle, go to the dyno first, get a baseline. then swap in the LSD and go re-dyno to see if there's a loss. this would only work if the ONLY thing you changed was the diff, and did not do a gear change at the same time. A chassis dyno simulates a straight line run. If you could find a dyno that had rollers that were different diameters I think you'd see more loss with an LS rear than an open. 2017 Contusion Blue Challenger T/A 392 M6 "BLKNBLU"

Re: Sure grip = 15% torque loss? [Re: MoparforLife] #375814 07/16/09 11:26 AM 07/16/09 11:26 AM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	Quote: Quote: Quote: up to 15% of the turning torque away Was that a circle track racer telling you this? There may be some truth to it in that situation. If it was he won't have to worry about it long using a SG on the circle track. don't the nascar guys use LSDs? I've never seen one do the one tire fryer when they do their celebratory donuts at the end of the race, and theres always 2 equal, long black marks. although I've wondered that before myself--how can they use a LSD when they're making left hand turns ALL DAY Photobucket sucks

Re: Sure grip = 15% torque loss? [Re: 70Cuda383] #375815 07/16/09 11:54 AM 07/16/09 11:54 AM
A Anonymous Unregistered
Anonymous Unregistered A	IMO, having a LSD has much more benefits than it has negatives. They may take more power to make a turn but only if power is being applied and under normal cruise conditions, they are slipping pretty easily.

Re: Sure grip = 15% torque loss? [Re: 70Cuda383] #375816 07/16/09 12:13 PM 07/16/09 12:13 PM
Joined: Jan 2003 Posts: 25,200 Upper Midwest M MoparforLife Too Many Posts
MoparforLife Too Many Posts M Joined: Jan 2003 Posts: 25,200 Upper Midwest	[quotedon't the nascar guys use LSDs? I've never seen one do the one tire fryer when they do their celebratory donuts at the end of the race, and theres always 2 equal, long black marks. although I've wondered that before myself--how can they use a LSD when they're making left hand turns ALL DAY No they do not use a limited slip perse'. Depending on what you want to call it I guess: "Regarding the "diff", the only style that can be run per the rules is a "detroit locker" type." Using the Locker and tire stagger achieves the needed slippage in most cases. http://stockcarscience.com/blog/index.php/2008/04/01/p52

Re: Sure grip = 15% torque loss? [Re: MoparforLife] #375817 07/16/09 12:45 PM 07/16/09 12:45 PM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	so it's a true trac, gear style slip? or the ratcheting locker type that a lot of 4x4 guys use? Photobucket sucks

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