Base C7, does it have LSD?
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,948
Likes: 12,362
From: NE South Carolina
Reminded I brought my C6 Z51 in for that "clicking issue" in turns. They replaced the dif fluid and it was fine after. Had the same issue with the Currie 9" Ford rear TCI supplied with my Street Rod Tubbed chassis. Called Currie and the recommended changing the Lub and the proper additive to use to make the slipping Posi clutches stop stick/slip operation on turns. Did and worked.
PS: Found this:
• LSD: There is a clutch mechanism within normal LSDs that engages when the first wheel starts to slip. This is old-skool derived and called "Positraction" in the muscle car world. The C6 and most all other Corvettes use this friction based clutch pack. They are spring loaded on the C3, C4, C5, and C6, and on the base C7.
• eLSD or "E-Diff": Corvette C7 Z51 option: A smart electronic limited-slip differential (eLSD) that continuously makes the most of the torque split between the rear wheels. The system features a hydraulically actuated clutch that can infinitely vary clutch engagement and can respond from open to full engagement in tenths of a second. It shifts torque based on a unique algorithm which factors in vehicle speed, steering input and throttle position to improve steering feel, handling balance and traction.
Last edited by JerryU; Sep 26, 2024 at 08:20 AM.
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
Of course, the eLSD is a superior system that no one is denying but is it a necessary part of a street car? I don't believe so and just like the cooler on the Z51 package, it isn't necessary on a street car. But if it breaks, it becomes an unwanted extra that was never needed. There are a lot of wonderful systems available for racing that make no sense for an everyday driver like carbon brakes and a dry sump oil system. The extras that I prefer are covered by the LT2 package and that would be my recommendation.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,948
Likes: 12,362
From: NE South Carolina
^^^
You can justify not spending the money for a Z51 for a lot of reasons BUT if you read what eSLD does it's as much for the non racer as those who Track. Just depends how stable and successful you MIGHT BE avoiding a deer, other animal, 18 wheeler tire treads in the road or driver who cuts in front.
Your choice don't care what folks buy BUT for the those who are seriously trying to decide Z51 or not and don't have their mind made suggest reading this long post by Tadge and eLSD engineer presented in full in the appendix and my summary, easier to understand: http://netwelding.com/eLSD_VS_Posi.pdf
BTW recall the Corvette race team when the C7 came out with eLSD said they wish they could use BUT IMSA Rules did not allow! In fact those who have experienced torque steer with a FWD car may find it interesting GM patents show eLSD was going to be introduced on FWD cars to deal with Torque Steer!
SIDEBAR
This is a short comment from the GM eLSD software engineer:
“There is a lot going on behind the scenes in the software to come up with the eLSD coupling. A number of algorithms that are running at the same time to collectively decide how much coupling is needed for the different vehicle dynamics situations that they each monitor and control. Logic is used to decide which one of them wins out or which ones add together to deliver the final command that you see on the display and feel in the car.” “The eLSD can have subtle but profound effect on handling of the c8. It’s considered a ‘basic chassis’ component. It something that plays a big part in setting up the character of the car. Off-throttle, more eLSD coupling adds stability, but too much can be a bad thing. The eLSD is connecting the two wheels so in a turn it's trying to slow down the outside wheel and speed up the inside wheel. In other words, the eLSD clutch coupling is trying to oppose the direction that the car is turning, so setting this off-throttle level is pretty important to keeping the car feeling agile. In a steady turn this can help tune the amount of understeer the car has. In highly dynamic maneuvers, this results in something that we call yaw damping where it will reduce the rotation rate of the car. “When the driver is on-throttle, the eLSD clutch can shift torque from the inside wheel to the outside wheel. This has the combined effect of minimizing or eliminating inside wheel spin, but it also controls how much it feels like the car turns with the throttle. More torque on the outside and less on the inside will help the car turn - to a point, but that's the balance we're constantly searching for while we tune the software. You can read Tadge and Jason Kolk full Forum Post comments in the Appendix.
You can justify not spending the money for a Z51 for a lot of reasons BUT if you read what eSLD does it's as much for the non racer as those who Track. Just depends how stable and successful you MIGHT BE avoiding a deer, other animal, 18 wheeler tire treads in the road or driver who cuts in front.
Your choice don't care what folks buy BUT for the those who are seriously trying to decide Z51 or not and don't have their mind made suggest reading this long post by Tadge and eLSD engineer presented in full in the appendix and my summary, easier to understand: http://netwelding.com/eLSD_VS_Posi.pdf
BTW recall the Corvette race team when the C7 came out with eLSD said they wish they could use BUT IMSA Rules did not allow! In fact those who have experienced torque steer with a FWD car may find it interesting GM patents show eLSD was going to be introduced on FWD cars to deal with Torque Steer!
SIDEBAR
This is a short comment from the GM eLSD software engineer:
“There is a lot going on behind the scenes in the software to come up with the eLSD coupling. A number of algorithms that are running at the same time to collectively decide how much coupling is needed for the different vehicle dynamics situations that they each monitor and control. Logic is used to decide which one of them wins out or which ones add together to deliver the final command that you see on the display and feel in the car.” “The eLSD can have subtle but profound effect on handling of the c8. It’s considered a ‘basic chassis’ component. It something that plays a big part in setting up the character of the car. Off-throttle, more eLSD coupling adds stability, but too much can be a bad thing. The eLSD is connecting the two wheels so in a turn it's trying to slow down the outside wheel and speed up the inside wheel. In other words, the eLSD clutch coupling is trying to oppose the direction that the car is turning, so setting this off-throttle level is pretty important to keeping the car feeling agile. In a steady turn this can help tune the amount of understeer the car has. In highly dynamic maneuvers, this results in something that we call yaw damping where it will reduce the rotation rate of the car. “When the driver is on-throttle, the eLSD clutch can shift torque from the inside wheel to the outside wheel. This has the combined effect of minimizing or eliminating inside wheel spin, but it also controls how much it feels like the car turns with the throttle. More torque on the outside and less on the inside will help the car turn - to a point, but that's the balance we're constantly searching for while we tune the software. You can read Tadge and Jason Kolk full Forum Post comments in the Appendix.
Last edited by JerryU; Sep 26, 2024 at 02:01 PM.
Burning Brakes
Joined: Mar 2021
Posts: 998
Likes: 388
From: Tyrone, GA
I would like for one of you to detail how an eLSD makes dodging a semi or an animal on a highway so much better than a mechanical LSD. I have swerved and skidded many times in my driving life and cannot think where the LSD even came into play. No-lock brakes have saved me several times.
E-Ray, 3LZ, ZER, LIFT
Joined: Sep 2007
Posts: 34,948
Likes: 12,362
From: NE South Carolina
I would like for one of you to detail how an eLSD makes dodging a semi or an animal on a highway so much better than a mechanical LSD. I have swerved and skidded many times in my driving life and cannot think where the LSD even came into play. No-lock brakes have saved me several times.
If you watch some of the video's in the Links I provide you'll see Positraction today is not much different than it was in 1960. It's a simple mechanical system that is useful if one tire is on a poorer traction surface than the other BUT only operates when one tire is slipping, However, eLSD controls power to each rear wheel all the time with hydraulics operating the rear wheel clutches as dictated by a computer and complex algorithms.
From the short statement I selected by Jason Kolk the GM eLSD engineer made these even shorter points that may help. My words in Bold
In a transient maneuver, like steering around a deer, car that cut you off etc. he notes: "The eLSD connects the two wheels so in a turn it's trying to slow down the outside wheel and speed up the inside wheel. In other words, the eLSD clutch coupling is trying to oppose the direction that the car is turning, so setting this off-throttle level is pretty important to keeping the car feeling agile.
In highly dynamic maneuvers, (my note like trying to steer around a deer, etc) this results in something that we call yaw damping where it will reduce the rotation rate of the car. (my note, so that quick steering maneuver doesn't cause the car to spin off the road) “When the driver is on-throttle, the eLSD clutch can shift torque from the inside wheel to the outside wheel. This has the combined effect of minimizing or eliminating inside wheel spin, but it also controls how much it feels like the car turns with the throttle. More torque on the outside and less on the inside will help the car turn.
Last edited by JerryU; Sep 26, 2024 at 05:42 PM.
