Torque split when tuned

[RS3X]

Going to preemptively apologize as I don’t know much about how torque splitters work and wasn’t able to find much info about this from a quick Google.

I was told by a tuner shop that when these cars are tuned, only the stock torque can be sent to the rear due to the Haldex system. Sounds kind of odd… Is this true?

I would think this would be more mechanical in nature, as that would imply part of the car’s computers (TCU?) would be able to detect accurate torque and only exert the rated stock torque. Which sounds odd even from the factory because each car makes slightly different torque figures with so many variables at play, especially elevation.

So for example if stock the car has 350 lb-ft:
Front: 175
Rear: 175

Stage 2 450 lb-ft:
Front: 275
Rear: 175

I would also logically think if this was detected and limited by the TCU (or some other computer system? whatever Haldex is?), then it would be possible to modify these limits or change what inputs are read by the system.

Or is this just not right?


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[b1aZe]

It is true. IROZ syvecs controller with the spring is the only way to increase power sent to the rear wheels

[RS3X]

It is true. IROZ syvecs controller with the spring is the only way to increase power sent to the rear wheels

So is this a replacement of the TCU entirely? Also would it be worth it at stage 2? I’d imagine maybe not considering it’s a front engine platform after all until you get past stage 3+.


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[mtwallace85]

So is this a replacement of the TCU entirely? Also would it be worth it at stage 2? I’d imagine maybe not considering it’s a front engine platform after all until you get past stage 3+.


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You’re going to need a haldex controller which is completely separate from the TCU tune. Iroz has the best one from what I’ve seen. Whether or not it’s worth it is up to you. I think this will shave around .2-.3 seconds off your 0-60 time.

https://irozmotorsport.com/product/i...ex-controller/

[brobst]

Unless you are doing dig races, this type of mod i not worth it in my opinion

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[NelsDMAX]

Unless you are doing dig races, this type of mod i not worth it in my opinion

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I beg to differ.
The application of slightly more power, and quicker application to the rear axle provides for better corner exiting on tight back country roads and road course duties.
It is very much noticable.
I have the IROZ Syvecs haldex controller and pump spring, has made the car a beast out of corners.

[mtwallace85]

I beg to differ.
The application of slightly more power, and quicker application to the rear axle provides for better corner exiting on tight back country roads and road course duties.
It is very much noticable.
I have the IROZ Syvecs haldex controller and pump spring, has made the car a beast out of corners.

Out of curiosity, do you have a wavetrac as well?

[8STTRS]

My only gripe with running a Syvecs for the Haldex is the need to manually adjust it. While I've become accustomed to manually adjusting things like suspension, I don't want to adjust something like my AWD system with a knob. I'm more likely to want to go back to a full mechanical system than to mess with that.

[NelsDMAX]

Out of curiosity, do you have a wavetrac as well?

I do not, but want to install in the future...

[myrder]

Going to preemptively apologize as I don’t know much about how torque splitters work and wasn’t able to find much info about this from a quick Google.

I was told by a tuner shop that when these cars are tuned, only the stock torque can be sent to the rear due to the Haldex system. Sounds kind of odd… Is this true?

I would think this would be more mechanical in nature, as that would imply part of the car’s computers (TCU?) would be able to detect accurate torque and only exert the rated stock torque. Which sounds odd even from the factory because each car makes slightly different torque figures with so many variables at play, especially elevation.

So for example if stock the car has 350 lb-ft:
Front: 175
Rear: 175

Stage 2 450 lb-ft:
Front: 275
Rear: 175

I would also logically think if this was detected and limited by the TCU (or some other computer system? whatever Haldex is?), then it would be possible to modify these limits or change what inputs are read by the system.

Or is this just not right?


Sent from my iPhone using Audizine Forum

doesn't sound right, the car sends power to the wheels that aren't slipping with up to 50% going to the rear, so once the front starts to slip the power gets pushed to the back. the Haldex controllers work as far as I read, but people still cut great 60fts without it.

[Makersmark]

doesn't sound right, the car sends power to the wheels that aren't slipping with up to 50% going to the rear, so once the front starts to slip the power gets pushed to the back. the Haldex controllers work as far as I read, but people still cut great 60fts without it.

You just said it. "Up to 50%", that's the max, and that's while stock. Aftermarket options make it work better.

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[mtwallace85]

You just said it. "Up to 50%", that's the max, and that's while stock. Aftermarket options make it work better.

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You’re not getting more than 50% to the rear.

[TheContrarian]

Or is this just not right?


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It's just not right.

[RS3X]

You just said it. "Up to 50%", that's the max, and that's while stock. Aftermarket options make it work better.

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So does that mean you can have 50% of power regardless of what the power is? Implying that if you have 450 ft lb total, in theory you could have 225 sent to the rear? Or would it be less than that because it’s limited to the stock torque?


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[myrder]

You just said it. "Up to 50%", that's the max, and that's while stock. Aftermarket options make it work better.

Sent from my SM-G991U using Audizine Forum mobile app

pretty sure aftermarket only makes it to where you can select it to be 50/50 all the time.

[8STTRS]

So does that mean you can have 50% of power regardless of what the power is? Implying that if you have 450 ft lb total, in theory you could have 225 sent to the rear? Or would it be less than that because it’s limited to the stock torque?


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No. As I understand it, it's just 50% of the maximum torque of the stock power levels. Assuming you have completely lost 100% of your traction with the front end, it will send 50% of the stock torque, which is approximately 177lb-ft, to the rear wheels. Regardless of how much power you add on the stock Haldex controller, it will continue to send only that amount to the rear.

[noseyp]

No. As I understand it, it's just 50% of the maximum torque of the stock power levels. Assuming you have completely lost 100% of your traction with the front end, it will send 50% of the stock torque, which is approximately 177lb-ft, to the rear wheels. Regardless of how much power you add on the stock Haldex controller, it will continue to send only that amount to the rear.

It seems like keeping rear max torque to 50% of stock max torque would be much harder than using 50% of total available. Isn't haldex just a clutch that can engage 0-100% and when 100% engaged it splits the available torque 50-50? I don't see how a full mechanical connection (100% haldex clutch engagement) could result in less than 50% of available torque to the rear. It seems to keep it to 50% of stock max torque, the haldex would have to avoid ever engaging the clutch to 100% which seems like computer code not worth writing.

I'm no expert so could be wrong.

[b1aZe]

It seems like keeping rear max torque to 50% of stock max torque would be much harder than using 50% of total available. Isn't haldex just a clutch that can engage 0-100% and when 100% engaged it splits the available torque 50-50? I don't see how a full mechanical connection (100% haldex clutch engagement) could result in less than 50% of available torque to the rear. It seems to keep it to 50% of stock max torque, the haldex would have to avoid ever engaging the clutch to 100% which seems like computer code not worth writing.

I'm no expert so could be wrong.

Based on internet knowledge and piecing things together, the spring included in the IROZ kit increases how much force is applied to the clutches. The controller knob changes the pump pressure which feeds the system. The spring is the key. The other controllers have been shown to not improve power delivery to the rear but can dial back how much is.

[NelsDMAX]

This...

[noseyp]

Based on internet knowledge and piecing things together, the spring included in the IROZ kit increases how much force is applied to the clutches. The controller knob changes the pump pressure which feeds the system. The spring is the key. The other controllers have been shown to not improve power delivery to the rear but can dial back how much is.

I'm not trying to challenge the logic as I'll assume IROZ is correct so this is an honest question. Does that mean the haldex clutch is slipping on tuned cars when it is 100% engaged? I would think that's the only way it's not splitting torque 50-50 and also what the spring fixes.

[b1aZe]

I'm not trying to challenge the logic as I'll assume IROZ is correct so this is an honest question. Does that mean the haldex clutch is slipping on tuned cars when it is 100% engaged? I would think that's the only way it's not splitting torque 50-50 and also what the spring fixes.

That I don’t know. I can’t imagine it’s constantly slipping. I’m not sure how the engagement system works.

[TheContrarian]

Assuming you have completely lost 100% of your traction with the front end, it will send 50% of the stock torque, which is approximately 177lb-ft, to the rear wheels. Regardless of how much power you add on the stock Haldex controller, it will continue to send only that amount to the rear.

This is not even how Gen 5 Haldex works. Good grief.

[8STTRS]

This is not even how Gen 5 Haldex works. Good grief.

I may have misunderstood the complete functionality of the system but, the sentiment remains that the stock Haldex controller, per Hank at Iroz and others, does not send any more than 50% of the OEM torque values to the rear unless you lose 100% of the traction to the front wheels.