[XCellent]

Hello,

I'm wondering if the AWD system on my car routes more power to the rear while the car is in Sport Mode. Does anyone know?

I'm seeing that under normal conditions with the car in Drive, the power distribution is like 90-95% FWD unless traction is needed at the rear. But some cars are programmed to alter that power delivery depending on driving mode.

Thanks in advance!

 

[billqueenis]

Hello,

I'm wondering if the AWD system on my car routes more power to the rear while the car is in Sport Mode. Does anyone know?

I'm seeing that under normal conditions with the car in Drive, the power distribution is like 90-95% FWD unless traction is needed at the rear. But some cars are programmed to alter that power delivery depending on driving mode.

Thanks in advance!

You are correct, during normal driving the car is FWD, until it senses that there is no traction, or is slipping. Then it sends power to where it needs it to keep the car steady and moving.

In sport mode, I believe(somebody correct me if I'm wrong) that it only affects the throttle response, and the time/RPM for gear changes. In normal mode, the car will basically "Overdrive", it will put the car in the highest gear possible for the lowest RPM's for the best fuel economy. In sport mode, the car will try to keep the car in a lower gear, keep the RPM's higher where your kind of in the middle of your hp/torque curves, so that you can get er going bettter. In sport mode the throttle will be more reactive and quicker, resulting in "I am speed".

The only way that something will affect your AWD, is when you shut off DSTC and traction control. First of all, when you shut it off, it doesn't actually disable, it just let's you slide around more. So basically, when you shut off DSTC, the car will let you have some fun, then when it thinks you've had enough fun it will kick in and help you out. What this means in Haldex terms is: When DSTC is on, the haldex system will take something like 0.7 of a slipping wheel rotation to kick in, and fix/correct the slip. When DSTC is off, the system will let you get away maybe 2-5 of a slipping wheel rotation before it kicks in and stops the fun.

I hope I cleared some things up, and didn't make anything worse.

 

[XCellent]

The only way that something will affect your AWD, is when you shut off DSTC and traction control. First of all, when you shut it off, it doesn't actually disable, it just let's you slide around more. So basically, when you shut off DSTC, the car will let you have some fun, then when it thinks you've had enough fun it will kick in and help you out. What this means in Haldex terms is: When DSTC is on, the haldex system will take something like 0.7 of a slipping wheel rotation to kick in, and fix/correct the slip. When DSTC is off, the system will let you get away maybe 2-5 of a slipping wheel rotation before it kicks in and stops the fun.

Thanks! That is insightful.

So, really the only thing DSTC in Sport does is allow for more wheel slippage and doesn't route any more power to the rear.

 

[billqueenis]

Thanks! That is insightful.

So, really the only thing DSTC in Sport does is allow for more wheel slippage and doesn't route any more power to the rear.

The only that I can see more power to rear, is if you were put some baldies on the front, but slap on some high performance dragsters on the rear. (Seriously don't do this)

 

[GrecianVolvo]

You are correct, during normal driving the car is FWD, until it senses that there is no traction, or is slipping. Then it sends power to where it needs it to keep the car steady and moving.

Well, sort of. Under normal driving conditions, 95% of the power goes to the front wheels and 5% to the rear. The only time when the car is purely FWD is when the brakes are applied at which time the rear drive is disengaged.

In sport mode, I believe(somebody correct me if I'm wrong) that it only affects the throttle response, and the time/RPM for gear changes. In normal mode, the car will basically "Overdrive", it will put the car in the highest gear possible for the lowest RPM's for the best fuel economy. In sport mode, the car will try to keep the car in a lower gear, keep the RPM's higher where your kind of in the middle of your hp/torque curves, so that you can get er going bettter. In sport mode the throttle will be more reactive and quicker, resulting in "I am speed".

Yes, sport mode doesn't affect Hadlex's programmingm, per se. However, in regular Volvos (not R-design models) under sport mode and full throttle, the power to rear wheels can be up to 50% in dry conditions. In slippery conditions, and fractionally, up to 100% of the power could be directed to either rear wheel although that would engage the AWD and the front wheels would take over and balance the imbalance.

The only way that something will affect your AWD, is when you shut off DSTC and traction control. First of all, when you shut it off, it doesn't actually disable, it just let's you slide around more. So basically, when you shut off DSTC, the car will let you have some fun, then when it thinks you've had enough fun it will kick in and help you out. What this means in Haldex terms is: When DSTC is on, the haldex system will take something like 0.7 of a slipping wheel rotation to kick in, and fix/correct the slip. When DSTC is off, the system will let you get away maybe 2-5 of a slipping wheel rotation before it kicks in and stops the fun.

I hope I cleared some things up, and didn't make anything worse.

Sort off. DSTC is NEVER shut off even when it indicates it's "shut off". Its traction is reduced and DSTC is more of a protection toward a car's loss of direction, meaning skidding, slipping sideways, going off its axis. Turning it off (reducing it) is not suggested as in slippery conditions one would lose that "invisible protective hand" that would prevent the car from losing total control.

The 0.7 wheel spin happens in 2nd generation Haldex AWD systems. Starting with MY04 (3rd generation Haldex) and forward, all AWD Volvos have a non-return hydraulic valve in the AWD system (vs a mechanical in 1st or 2nd generations). In this system, A non-return valve allows us to use software to control the base torque that is programmed into the AWD system, and when starting off from standstill, 80 Nm or about 59 lbs-ft of torque is pre-charged in the system (since the non-return valve prevents the unit from becoming totally drained of hydraulic fluid).

 

[billqueenis]

Well, sort of. Under normal driving conditions, 95% of the power goes to the front wheels and 5% to the rear. The only time when the car is purely FWD is when the brakes are applied at which time the rear drive is disengaged.

Yes, sport mode doesn't affect Hadlex's programmingm, per se. However, in regular Volvos (not R-design models) under sport mode and full throttle, the power to rear wheels can be up to 50% in dry conditions. In slippery conditions, and fractionally, up to 100% of the power could be directed to either rear wheel although that would engage the AWD and the front wheels would take over and balance the imbalance.

Sort off. DSTC is NEVER shut off even when it indicates it's "shut off". Its traction is reduced and DSTC is more of a protection toward a car's loss of direction, meaning skidding, slipping sideways, going off its axis. Turning it off (reducing it) is not suggested as in slippery conditions one would lose that "invisible protective hand" that would prevent the car from losing total control.

The 0.7 wheel spin happens in 2nd generation Haldex AWD systems. Starting with MY04 (3rd generation Haldex) and forward, all AWD Volvos have a non-return hydraulic valve in the AWD system (vs a mechanical in 1st or 2nd generations). In this system, A non-return valve allows us to use software to control the base torque that is programmed into the AWD system, and when starting off from standstill, 80 Nm or about 59 lbs-ft of torque is pre-charged in the system (since the non-return valve prevents the unit from becoming totally drained of hydraulic fluid).

Thank you for clarifying, I really appreciate it. I had no idea of the pre-loaded torque, and I have no idea where you even find that information. I also know that within each updates haldex system, the amount of wheelspin before it senses a slip is reduced.

Really appreciate all the information!

 

[GrecianVolvo]

Thank you for clarifying, I really appreciate it. I had no idea of the pre-loaded torque, and I have no idea where you even find that information.

No idea either but there are people who are Volvo geeks here

I also know that within each updates haldex system, the amount of wheelspin before it senses a slip is reduced.

Really appreciate all the information!

Prior to this version, yes. With the current systems, it still takes about 1/4 of a wheel turn if the slipping overwhelms the Instant Traction feature and before the AWD system is fully engaged.

 

[Seamus]

Well, sort of. Under normal driving conditions, 95% of the power goes to the front wheels and 5% to the rear. The only time when the car is purely FWD is when the brakes are applied at which time the rear drive is disengaged.

Yes, sport mode doesn't affect Hadlex's programmingm, per se. However, in regular Volvos (not R-design models) under sport mode and full throttle, the power to rear wheels can be up to 50% in dry conditions. In slippery conditions, and fractionally, up to 100% of the power could be directed to either rear wheel although that would engage the AWD and the front wheels would take over and balance the imbalance.

Sort off. DSTC is NEVER shut off even when it indicates it's "shut off". Its traction is reduced and DSTC is more of a protection toward a car's loss of direction, meaning skidding, slipping sideways, going off its axis. Turning it off (reducing it) is not suggested as in slippery conditions one would lose that "invisible protective hand" that would prevent the car from losing total control.

The 0.7 wheel spin happens in 2nd generation Haldex AWD systems. Starting with MY04 (3rd generation Haldex) and forward, all AWD Volvos have a non-return hydraulic valve in the AWD system (vs a mechanical in 1st or 2nd generations). In this system, A non-return valve allows us to use software to control the base torque that is programmed into the AWD system, and when starting off from standstill, 80 Nm or about 59 lbs-ft of torque is pre-charged in the system (since the non-return valve prevents the unit from becoming totally drained of hydraulic fluid).

Is the haldex in r-design models tuned differently?

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[GrecianVolvo]

Is the haldex in r-design models tuned differently?

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No. But since the ECU and transmission are programmed differently, Haldex also behaves differently.