Need full scoop on engine drag control feature
Thread Starter
Burning Brakes
Joined: Sep 2007
Posts: 1,040
Likes: 0
Need full scoop on engine drag control feature
Hey guys, I need to figure out a problem with my car. I have a list of things i learned about the engine drag control feature, please make a comment if you know for a fact that I am wrong. (Please dont post about how you never see it, especially automatic drivers since they don't really get into a high vacuum high rpm situation).
#1 Using JUST the speed sensors, the computer reads the speed differential between the front and rear wheels to determine if engine drag control is needed. (yaw sensors not part of the process?)
#2 Engine drag control only works in normal mode, doesn't work with TC off, Comp mode, TC/AH off mode?
#3 Engine drag control feature controls the amount of engine braking by changing timing on the engine, it doesn't apply brakes? Matter of fact, it applies gas to compensate?
That's as far as I know, please add comment if you know something about the feature that I didn't list here.
Thanks
Thanks
#1 Using JUST the speed sensors, the computer reads the speed differential between the front and rear wheels to determine if engine drag control is needed. (yaw sensors not part of the process?)
#2 Engine drag control only works in normal mode, doesn't work with TC off, Comp mode, TC/AH off mode?
#3 Engine drag control feature controls the amount of engine braking by changing timing on the engine, it doesn't apply brakes? Matter of fact, it applies gas to compensate?
That's as far as I know, please add comment if you know something about the feature that I didn't list here.
Thanks
Thanks
Le Mans Master
Joined: Oct 2007
Posts: 6,149
Likes: 11
From: Greater Detroit Metro MI, when I'm not travelling.
Here is a patent for the system.
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
Last edited by PowerLabs; Jun 15, 2008 at 01:50 AM.
Thread Starter
Burning Brakes
Joined: Sep 2007
Posts: 1,040
Likes: 0
I have a RF speed sensor short somewhere in the system that is intermittent. They replaced the sensor and hub, but it is still throwing the RF speed sensor code. Although I dont get the code immediately, but I can see the car is acting up due to my engine drag control being active almost all the time. I just want to make sure it is only adding gas and not applying brakes. Also I didnt know the system doesn't work with the TC off and in comp mode and the whole thing off
Here is a patent for the system.
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
Safety Car
Joined: May 2000
Posts: 4,824
Likes: 351
From: Albuquerque NM
Here is a patent for the system.
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
http://www.google.com/patents?id=9kM...BAJ&dq=6952638
Looks like it detects excessive engine braking in much the same way traction control does; by looking at the ABS signal of the rear wheels in relation to the front ones and deducing wheel slip from a speed difference... It will limit engine braking by decreasing the rate the throttle body closes at or even holding it partially open.
Do you have any issues with TC?
Got any mods?? I don't know anything about your setup but I am going to guess you have aftermarket tires of a different size from stock. That being the case your ECU thinks your tires are constantly spinning... You can tune it out if the difference isn't very large... I've heard 3% on this forum. Hopefully tuners can chime in and give you a better answer?
On this Youtube Video engine drag control comes on when the driver lifts at circa 190MPH...
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
Kind of reverse Traction Control? Uses the Drive By Wire computer to keep the throttle blade open so the rear wheels don't lock up? Remember, your right foot doesn't control the throttle opening, it makes a suggestion to the computer and the computer decides how far to open or close the throttle. Open throttle means less engine braking.
I wish one of the tuners could log what happens when the "Drag Control Active" happens.
I wish one of the tuners could log what happens when the "Drag Control Active" happens.
Le Mans Master
Joined: Oct 2007
Posts: 6,149
Likes: 11
From: Greater Detroit Metro MI, when I'm not travelling.
I have a RF speed sensor short somewhere in the system that is intermittent. They replaced the sensor and hub, but it is still throwing the RF speed sensor code. Although I dont get the code immediately, but I can see the car is acting up due to my engine drag control being active almost all the time. I just want to make sure it is only adding gas and not applying brakes. Also I didnt know the system doesn't work with the TC off and in comp mode and the whole thing off
).Kind of reverse Traction Control? Uses the Drive By Wire computer to keep the throttle blade open so the rear wheels don't lock up? Remember, your right foot doesn't control the throttle opening, it makes a suggestion to the computer and the computer decides how far to open or close the throttle. Open throttle means less engine braking.
I wish one of the tuners could log what happens when the "Drag Control Active" happens.
I wish one of the tuners could log what happens when the "Drag Control Active" happens.
Racer
Joined: Apr 2008
Posts: 276
Likes: 1
From: Temecula Ca
Hey guys, I need to figure out a problem with my car. I have a list of things i learned about the engine drag control feature, please make a comment if you know for a fact that I am wrong. (Please dont post about how you never see it, especially automatic drivers since they don't really get into a high vacuum high rpm situation).
#1 Using JUST the speed sensors, the computer reads the speed differential between the front and rear wheels to determine if engine drag control is needed. (yaw sensors not part of the process?)
#2 Engine drag control only works in normal mode, doesn't work with TC off, Comp mode, TC/AH off mode?
#3 Engine drag control feature controls the amount of engine braking by changing timing on the engine, it doesn't apply brakes? Matter of fact, it applies gas to compensate?
That's as far as I know, please add comment if you know something about the feature that I didn't list here.
Thanks
Thanks
#1 Using JUST the speed sensors, the computer reads the speed differential between the front and rear wheels to determine if engine drag control is needed. (yaw sensors not part of the process?)
#2 Engine drag control only works in normal mode, doesn't work with TC off, Comp mode, TC/AH off mode?
#3 Engine drag control feature controls the amount of engine braking by changing timing on the engine, it doesn't apply brakes? Matter of fact, it applies gas to compensate?
That's as far as I know, please add comment if you know something about the feature that I didn't list here.
Thanks
Thanks
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Le Mans Master
Joined: Jan 2005
Posts: 5,611
Likes: 5
From: Thousand Oaks California
#3 Engine drag control feature controls the amount of engine braking by changing timing on the engine, it doesn't apply brakes? Matter of fact, it applies gas to compensate?
Assuming this does not cause an over speed of the engine, the ECM adds throttle to eliminate rear wheel skid.
However, a skilled driver will always match engine rpms to driveshaft speed on down shifts.
Assuming this does not cause an over speed of the engine, the ECM adds throttle to eliminate rear wheel skid.
However, a skilled driver will always match engine rpms to driveshaft speed on down shifts.
Last edited by calemasters; Jun 21, 2008 at 04:08 PM.
Le Mans Master
Joined: Dec 2004
Posts: 5,492
Likes: 808
From: West coast CA
I suspect the purpose of engine drag control is to assist AH in preventing lift-throttle oversteer -- which has to be the #1 cause of high-speed spinouts. It has to work by getting back on the throttle -- otherwise, we're just talking about another facet of AH.
Last edited by torquetube; Jun 23, 2008 at 12:08 AM.
