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I'm curious to know people's impressions of those who installed the UM haldex flash on their vehicles. Its something that I plan on doing, but was curious to hear a few reviews first.

Thanks. :beer:
 

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I have it.

There is not much published info out there regarding the flash, as UM have not put it up on their website. Because of this I emailed back and forth with one of the main guys at UM for a while, getting an idea of the features and how they stack up against the HPA comp controller. The UM flash operates similar to the stock Haldex software, but is just more aggressive all around. It will still keep a strong FWD bias during highway cruising to maintain gas mileage, but based on a number of inputs will make faster and more aggressive use of the rear wheels during spirited driving. The UM flash also keeps the rear wheels engaged under hard braking similar to the comp controller, allowing more aggressive braking technique.

A lot of people who do AWD software mods whether through UM or HPA route, will testify that it is a night and day difference. Personally, I wouldn't go that far because during normal around town driving conditions you don't notice it that much. For example you have to be really pushing it around a turn to notice that the car understeers much less. That said, I really got a sense of the UM flash in action this past winter when there was some snow on the ground, and a couple weeks ago when I did my first autocross. On the stock Haldex tune, sliding in snow was an odd process. Turning into a slide, the car would first understeer horrendously and then eventually the computer would react by adding in back end, until finally the back would come around resulting in a 4 wheel slide. With the UM flash, the power delivery to the back is more instant resulting in a more natural slide to begin with. Coupled with ECS defeat, you can really have some fun in the mall parking lot with 4-5 inches of snowfall.

During autocross I was mostly at half or max throttle in 2nd gear, or all-out braking. During these aggressive driving conditions the AWD is much more apparent. Lift-off / braking oversteer were very apparent, and something I had to learn to anticipate, control, and use to my advantage quickly. Throttle-on oversteer coming out of the front and back sweepers was also very apparent and really helped bring the car around the last bit of the turn as I was able to throttle on earlier.

I am very happy with the UM Haldex flash because it is a little cheaper, non-invasive, and seems to work great when you need it. The obvious advantage of the HPA comp controller is the ability to remove the part and sell it down the road to recoup part of the cost. Not ever having used the comp controller I cannot compare the two directly, but my understanding is that they have very similar function (although the comp controller may be more of a "full time" 50/50 split, comparatively?).

When I was shopping between the UM and HPA options, what finally sold me was Tyrolsport switching to the UM flash and claiming that they were unable to tell the difference between the UM and HPA software on the track (paraphrasing, but this was posted in a thread on this forum). So between the price, fuel economy, non-invasiveness, and no apparent loss of performance to the HPA product, I feel I made the right choice for myself. I think the UM flash is a great product, but honestly I think the HPA controllers are great products too - with AWD mods it seems the main thing to consider is what works best for your personal priorities (price, resale, etc.). I have almost 7k miles on the Haldex flash but still under 30k miles total so I have not yet serviced the Haldex fluid. At this point no idea how the flash affects normal wear and tear on the Haldex unit.

Sorry for the long post, but I like to give thorough responses. Hope this helps.
 

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Nice review... I'm struggling with this decision too.
Would you happen to know if possible to retain APR software while adding UM haldex flash?
I think not, but figured I'd ask.

I have it.

There is not much published info out there regarding the flash, as UM have not put it up on their website. Because of this I emailed back and forth with one of the main guys at UM for a while, getting an idea of the features and how they stack up against the HPA comp controller. The UM flash operates similar to the stock Haldex software, but is just more aggressive all around. It will still keep a strong FWD bias during highway cruising to maintain gas mileage, but based on a number of inputs will make faster and more aggressive use of the rear wheels during spirited driving. The UM flash also keeps the rear wheels engaged under hard braking similar to the comp controller, allowing more aggressive braking technique.

A lot of people who do AWD software mods whether through UM or HPA route, will testify that it is a night and day difference. Personally, I wouldn't go that far because during normal around town driving conditions you don't notice it that much. For example you have to be really pushing it around a turn to notice that the car understeers much less. That said, I really got a sense of the UM flash in action this past winter when there was some snow on the ground, and a couple weeks ago when I did my first autocross. On the stock Haldex tune, sliding in snow was an odd process. Turning into a slide, the car would first understeer horrendously and then eventually the computer would react by adding in back end, until finally the back would come around resulting in a 4 wheel slide. With the UM flash, the power delivery to the back is more instant resulting in a more natural slide to begin with. Coupled with ECS defeat, you can really have some fun in the mall parking lot with 4-5 inches of snowfall.

During autocross I was mostly at half or max throttle in 2nd gear, or all-out braking. During these aggressive driving conditions the AWD is much more apparent. Lift-off / braking oversteer were very apparent, and something I had to learn to anticipate, control, and use to my advantage quickly. Throttle-on oversteer coming out of the front and back sweepers was also very apparent and really helped bring the car around the last bit of the turn as I was able to throttle on earlier.

I am very happy with the UM Haldex flash because it is a little cheaper, non-invasive, and seems to work great when you need it. The obvious advantage of the HPA comp controller is the ability to remove the part and sell it down the road to recoup part of the cost. Not ever having used the comp controller I cannot compare the two directly, but my understanding is that they have very similar function (although the comp controller may be more of a "full time" 50/50 split, comparatively?).

When I was shopping between the UM and HPA options, what finally sold me was Tyrolsport switching to the UM flash and claiming that they were unable to tell the difference between the UM and HPA software on the track (paraphrasing, but this was posted in a thread on this forum). So between the price, fuel economy, non-invasiveness, and no apparent loss of performance to the HPA product, I feel I made the right choice for myself. I think the UM flash is a great product, but honestly I think the HPA controllers are great products too - with AWD mods it seems the main thing to consider is what works best for your personal priorities (price, resale, etc.). I have almost 7k miles on the Haldex flash but still under 30k miles total so I have not yet serviced the Haldex fluid. At this point no idea how the flash affects normal wear and tear on the Haldex unit.

Sorry for the long post, but I like to give thorough responses. Hope this helps.
 

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haldex flash

I contacted Jeff at UM and asked if I could run the flash even though im tuned APR 2+, he said yes because the haldex module is seperate from the ECU so they wont interfere with each other.

That being said, I never ended up getting the flash because of the lack info, reviews etc on it.

Jon
 

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Nice review... I'm struggling with this decision too.
Would you happen to know if possible to retain APR software while adding UM haldex flash?
I think not, but figured I'd ask.
Yes it is, the tune goes on the Haldex itself not the engine's ECU.
 

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I contacted Jeff at UM and asked if I could run the flash even though im tuned APR 2+, he said yes because the haldex module is seperate from the ECU so they wont interfere with each other.
Yes it is, the tune goes on the Haldex itself not the engine's ECU.
Yep I am running the Haldex flash and APR Stage 1 at the same time. Confirming the above.


Thanks, Super .:R-Type for the thorough review. I really appreciate it.. and everyone else for their help! :)
No problem, glad to help. If you decide to do one or the other, come back and provide your thoughts on it here.
 

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Curious; if you do the UM Haldex flash, will the dealer be able to tell and then void any driveline-related warranty claims? The HPA controller can always be removed and replaced with the stock controller.
 

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Curious; if you do the UM Haldex flash, will the dealer be able to tell and then void any driveline-related warranty claims? The HPA controller can always be removed and replaced with the stock controller.
If the dealer has a tool that they can use to do a flash scan of the Haldex unit itself, then yes I suppose it could void the warranty. Any dealer that wanted to do that could just as easily point to my Stage 1 tune and say "you grenaded your [drivetrain part] by running all that extra power". So IMO its a moot point if you have any other mods, and I wasn't too concerned about it. However, its clear that people have widely differing comfort levels when it comes to voiding warranty, so that's just one more thing to consider when shopping Haldex mods.
 

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I have a port flasher so I can go back to stock (from Stage 1) every time I take my car in.
Probably safer to do that than leave the tune on the car, but its my understanding that newer VW protocols have a flash counter, so its possible they can tell you've been in there messing around anyway. Not positive on this though - thought I read something about it here one other time.
 

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Switchnig UM Haldex flash to stock setting

Does UM Gen4 Haldex flash has switch function back to stock in a somewhat similar manner as APR with use of cruise control button? I don’t care so much about what dealer will see, it is really concerning Haldex fluid premature wear. I heard those who installed Haldex controller without switch to stock go through Haldex fluid changes every 7-10K. That is really quite excessive if you really not intending to use it, as in everyday driving.
 

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Does UM Gen4 Haldex flash has switch function back to stock in a somewhat similar manner as APR with use of cruise control button? I don’t care so much about what dealer will see, it is really concerning Haldex fluid premature wear. I heard those who installed Haldex controller without switch to stock go through Haldex fluid changes every 7-10K. That is really quite excessive if you really not intending to use it, as in everyday driving.
No there is no switchable functionality for the Haldex flash. The software is flashed to the Haldex unit itself, not the ECU, so there is no means of accessing it through any of the car's other control systems. As I mentioned, the UM flash is part-time just like the stock Haldex software, just more eager to get aggressive. My understanding is it actually has a greater front wheel bias while cruising than the stock software, so you could argue it puts less wear on the Haldex clutch/fluid during normal driving than the stock software does.

Factory service interval for the Haldex fluid is every 30k or 40k, and the first one is free with your final no charge service at 30k miles. Given that I do run an AWD mod I will probably service the Haldex on my own every 20k or so just to play it safe. Not sure how people determined they NEED to service it every 7k-10k? There is really no indicator of when the unit needs service. There are also guys changing their engine oil every 3k-5k miles... probably the same guys who are servicing the Haldex every 7k. Seems excessive to me.
 

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No there is no switchable functionality for the Haldex flash. The software is flashed to the Haldex unit itself, not the ECU, so there is no means of accessing it through any of the car's other control systems. As I mentioned, the UM flash is part-time just like the stock Haldex software, just more eager to get aggressive. My understanding is it actually has a greater front wheel bias while cruising than the stock software, so you could argue it puts less wear on the Haldex clutch/fluid during normal driving than the stock software does.

Factory service interval for the Haldex fluid is every 30k or 40k, and the first one is free with your final no charge service at 30k miles. Given that I do run an AWD mod I will probably service the Haldex on my own every 20k or so just to play it safe. Not sure how people determined they NEED to service it every 7k-10k? There is really no indicator of when the unit needs service. There are also guys changing their engine oil every 3k-5k miles... probably the same guys who are servicing the Haldex every 7k. Seems excessive to me.
What I heard regarding full time use of Haldex controller without switching, the Haldex fluid goes really bad and its change is just necessitated by care for the Haldex clutch itself. I know HPA offers switchable function at additional price.
 

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Is this still true after you already have a UM Stage 2 Loaded tune? Or is it like getting another flash from UM that's something like $200?
I asked UM directly before I got it done because I was considering getting their stage 1 tune as well... they seemed okay with offering a little discount if I got both done at once, but nothing that major.
 

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No there is no switchable functionality for the Haldex flash. The software is flashed to the Haldex unit itself, not the ECU, so there is no means of accessing it through any of the car's other control systems. As I mentioned, the UM flash is part-time just like the stock Haldex software, just more eager to get aggressive. My understanding is it actually has a greater front wheel bias while cruising than the stock software, so you could argue it puts less wear on the Haldex clutch/fluid during normal driving than the stock software does.

Factory service interval for the Haldex fluid is every 30k or 40k, and the first one is free with your final no charge service at 30k miles. Given that I do run an AWD mod I will probably service the Haldex on my own every 20k or so just to play it safe. Not sure how people determined they NEED to service it every 7k-10k? There is really no indicator of when the unit needs service. There are also guys changing their engine oil every 3k-5k miles... probably the same guys who are servicing the Haldex every 7k. Seems excessive to me.
There is a way to access the haldex flash via Vag-com I forgot how but UM will tell you. My impressions on the UM haldex flash is exactly the same as yours. I'm APR stage 2 engine flash with UM haldex flash.
 
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