03-04-2024, 05:17 AM | #1 |
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Bootmod3 XHP and factory torque Limit
I am not sure why this is not discussed widely before. I may have seen some posts mentioning in the m340 forum, but only slightly related
TLDR: For those that have Bootmod3 and stage 2 or higher engine tune, you may really need the XHP to lift the torque limit to fully harvest the additional power. If you don't, the torque is gonna be limited <550nm all the way (under LC, it's even <500nm), while stg2 torque can easily go beyond 620nm. ============================= Before XHP, I had been running stage 2 93 on a 2020 model for a few weeks. One thing I noticed is that the boost target and boost, when doing a 3rd gear WOT pull, was only around 16-17 psi at < 6000 rpm. This is as low as the stock boost, and much lower than the ACN91 boost (which is all the way >20 and boost target is 22.4). I was confused why stg 2 93 was so much more conservative than stg 1 ACN 91. It made no sense to me. Although with stg 2 93 the car certainly runs faster, but the displayed "torque actual / target after clutch" is merely <550nm, while the torque predrivedynamics is 670nm. This is abnormal since with stock tune or ACN91 stg 1, these 3 torque values are within 30 nm different. Also these estimated torque values should be relatively accurate when compared between maps, meaning a 20% gain in these values should reflect on a real dyno run. The facts are implying that the engine held up power somehow while it could do much better. I have asked ptf but they didn't find anything wrong, or explain the reasons why torque is limited https://www.bootmod3.net/log?id=65dd...bc901ce26e3fe6 ====================== And then I installed the XHP. I didn't even purchase the TCU map and was just trying out basic settings to fine tune shift behavior. And then immediately I did a BM3 stg 2 93log with updated XHP settings, and the car felt obviously faster. Upon checking the log I realized now the torque can easily go above 550nm, reaching 650nm easily. And boost target was right on at a constant 22.4 with actual boost 21-23 mostly. I then did a 0-100 pull. Guess what, even with the wet road under the rain and an entire wheel spinning 1 st gear, it did 0-100 (62mph) in 3.68s, easily beating smoking the fastest time I did before XHP on perfect road 3.97s. https://www.bootmod3.net/log?id=65e5...912436fb2ff41a Now things make sense. Somehow the BM3 stg2 93 map did not remove the torque limit inherently from ZF8HP51. It achieved this by pre-calculate how much boost it should reduce, and apply the different boost target curve when you do the pull. Every pull is very repeatable and you won't find a sign that it cuts off power abruptly because DME redefines the curve in advance. So it is still confusing why PFT did not make a simple switch in BM3 so you can switch off the global or by gear torque limit (it does allow you to further REDUCE torque, though). From what I know, if you get a custom tune, your tuner should be able to control if the torque limiter is active, and for that reason, a lot of people sing custom tune do not need to resort to XHP to release the hidden torque. If you stick with OTS BM3, this is a must If you want to use true stage 2 or even Ethanol maps. And maybe this is B58TU specific issue? But anyway if not for XHP I would never realize what the true power of BM3 OTS map. |
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03-04-2024, 07:14 AM | #2 |
Cowboy Astronaut Millionaire
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Cool write up. So you need XHP with BM3 OTS. But my custom tune does not.
What B58 engine code do you have on your 2020?
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earlgsxbusa130.50 |
03-04-2024, 09:59 AM | #3 |
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You really need xHP on both, when you bypass those torque limits on the trans it can cause traction control and a few other things not to properly.
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2019 BMW X3M40I
Paul Johnson Tunes/ACX Solutions Shop/Development Car, XHP stage 3 with custom settings, CTS Downpipe, intake, Chargepipe, turbo inlet, coils, Nostrum Stage 1 Injectors and Nostrum Big Bore HPFP, Vargas PCV and Oil cap, HnR springs, ACX Rear poly bushing, ACX Intake scoop |
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earlgsxbusa130.50 |
03-04-2024, 03:53 PM | #4 | |
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In BM3 it's listed as B58-TO-D. Not sure what code type this is . It is commonly referred to as B58M30O1, the one with 382hp rated. |
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03-04-2024, 03:57 PM | #5 | |
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Quote:
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03-04-2024, 03:59 PM | #6 |
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Right on. I haven’t adjusted anything on XHP. Just stage 3. Set it and forget it. Summer setup and maintenance coming in a few weeks.
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03-04-2024, 05:06 PM | #7 | |
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bTW, what oil do you use after you got the tunes? |
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03-05-2024, 07:37 AM | #8 | |
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Oil I use is Liqui Moly 0W20 Top Tec 6600. In the summer every 5K miles. And in the winter every 7K miles.
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earlgsxbusa130.50 vrships102.00 |
03-05-2024, 04:16 PM | #9 | |
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03-05-2024, 04:19 PM | #10 |
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Quarter mile at a time. 😁
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03-05-2024, 07:11 PM | #11 | |
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Quote:
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03-05-2024, 07:22 PM | #12 |
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I used 5w-40 and honestly it burns less oil and the engine sounds better. I’d look at EU approved weights.
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2019 BMW X3M40I
Paul Johnson Tunes/ACX Solutions Shop/Development Car, XHP stage 3 with custom settings, CTS Downpipe, intake, Chargepipe, turbo inlet, coils, Nostrum Stage 1 Injectors and Nostrum Big Bore HPFP, Vargas PCV and Oil cap, HnR springs, ACX Rear poly bushing, ACX Intake scoop |
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03-06-2024, 01:23 AM | #13 | |
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That's almost 6 psi boost gain for low to mid range rpm, and 100 Nm torque too. Which amounts to at least 0.4s 0-100 time repeated many times. |
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Rottweiler4333.00 joebie3458.50 |
03-06-2024, 02:42 AM | #15 |
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03-06-2024, 08:01 AM | #16 |
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My foot ruins my mpg more than oil does😂😂
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2019 BMW X3M40I
Paul Johnson Tunes/ACX Solutions Shop/Development Car, XHP stage 3 with custom settings, CTS Downpipe, intake, Chargepipe, turbo inlet, coils, Nostrum Stage 1 Injectors and Nostrum Big Bore HPFP, Vargas PCV and Oil cap, HnR springs, ACX Rear poly bushing, ACX Intake scoop |
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03-06-2024, 08:39 AM | #18 |
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2019 BMW X3M40I
Paul Johnson Tunes/ACX Solutions Shop/Development Car, XHP stage 3 with custom settings, CTS Downpipe, intake, Chargepipe, turbo inlet, coils, Nostrum Stage 1 Injectors and Nostrum Big Bore HPFP, Vargas PCV and Oil cap, HnR springs, ACX Rear poly bushing, ACX Intake scoop |
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Alias1431806.50 |
03-06-2024, 08:40 AM | #19 |
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Doesn’t matter the order, I’d do both at the same time, make sure to cycle ign or it will fail the second flash
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2019 BMW X3M40I
Paul Johnson Tunes/ACX Solutions Shop/Development Car, XHP stage 3 with custom settings, CTS Downpipe, intake, Chargepipe, turbo inlet, coils, Nostrum Stage 1 Injectors and Nostrum Big Bore HPFP, Vargas PCV and Oil cap, HnR springs, ACX Rear poly bushing, ACX Intake scoop |
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03-06-2024, 09:01 AM | #20 |
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I didn't see any log here. Without knowing how your AFR, Timing and most importantly whether you're getting any knock retard is more important than just turning up boost.
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03-06-2024, 11:05 AM | #21 | |
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Quote:
https://www.bootmod3.net/log?id=65dd...bc901ce26e3fe6 |
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03-06-2024, 12:30 PM | #22 |
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This was before XHP existed on the M40i. I can show you the time stamp of the datalog. So no XHP installed at all here...
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