05-17-2020, 05:33 PM | #1 |
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
XHP Traction Control / Power Loss Questions
I took the car out for some test hits yesterday after running the XHP X-Delete software. The car doesn't feel any faster or any happier with the power output on the engine now that its RWD. I was hoping for less parasitic loss.
It seemed like at multiple times the orange traction control light between the two big circles on the dashboard would light up and it felt like even as the motor was revving up in the RPM range the car wasn't pulling harder/ accelerating. It seemed that something was cutting or interrupting power delivery. This was with BM3 stage 2 map, FBO, X-Delete and staggered rims and tires. The car was in "sport" and the tranny was in "manual" mode. 75 degrees outside temperature. My understanding was that the tires wont ever spin in "sport" mode but they will do anything in "sport plus" mode. Was the weirdness I was feeling the traction control cutting power? Or was it the torque limiters on certain gears because I haven't reflashed the TCU yet with the XHP maps? Trying to figure out if there is a problem with the tranny or if this is all "expected behavior". Thanks in advance.
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
05-17-2020, 06:41 PM | #2 |
Major General
5493
Rep 5,339
Posts |
Sport or Comfort means all nannies on. There are occasions where you can induce spin in Sport, especially with power mods, but the nannies will intervene quickly and cut power, boost, timing, throttle, etc. When you see those the traction control lights flicker, it essentially means nannies are now hyperactive. You never noticed this because you have AWD and the tires really won't spin or hardly as tall.
There are also occasions (more often), where the nannies will preemptively intervene and will reduce power, throttle, etc. I notice this the most. I can sometimes hit it in 1st and it feels like there isn't any boost. Then I switch it to Sport+, Traction, or DSC Off and it's a totally different animal. All those modes reduce and/or turn off the nannies. Keep in mind Sport+ and Traction modes will allow for some spin and minor sliding (maybe a 1 to 2 feet), but they still will pull the car back into line. DSC Off is by far the best driving mode but it's best left to those that understand chassis control and dynamics since these turbo motors can overload the rear tires with a surge of torque and the driver needs to understand how to deal with it. A LSD makes a HUGE difference. You're not going to notice much difference in acceleration between 2wd and AWD because those heavy front axles and front differential are still spinning, they're just not connected to the power output. That extra 60+lbs of rotational inertia sucks out power.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
Last edited by XutvJet; 05-17-2020 at 07:36 PM.. |
Appreciate
1
OldCrow7xx69.50 |
05-17-2020, 10:05 PM | #3 |
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Thanks for the reply- its starting to make sense what I have been seeing in the car.
"Then I switch it to Sport+, Traction, or DSC Off and it's a totally different animal" I thought "sport +" was my highest setting. Are you saying that "traction" and "dsc off" are above that? Or are they extensions/added on to "sport +" ? Or to phrase it another way, how do I turn all the computer controlled interventions off? I want to start with them off and slowly test adding them back in one by one and see how it goes. Thanks
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
Appreciate
0
|
05-18-2020, 04:37 AM | #4 |
Private First Class
94
Rep 147
Posts |
The correct way, if you don’t want to end up in a ditch, is to start with everything on and then slowly turn them off.
Please don’t drive with DSC off on public roads, without an LSD or experience, you are most likely to end up in a ditch. |
Appreciate
0
|
05-18-2020, 09:01 AM | #5 | |
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Quote:
I don't plan on doing any of this on a public road, while I may not yet understand my cars software I do understand physics / have driven high hp cars with the computer off on Forza. Shelby GT350 / C7 Z06 were impossible to keep going straight so I can only imagine this 450wtq car wont be much different without "the invisible hand"...
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
|
Appreciate
0
|
05-18-2020, 09:54 AM | #6 | |
Second Lieutenant
132
Rep 237
Posts |
Quote:
|
|
Appreciate
0
|
05-18-2020, 10:15 AM | #7 |
Second Lieutenant
132
Rep 237
Posts |
Also fwiw I'm RWD and traction/spinning a wheel/traction light is a fairly constant thing. LSD is on the list for me, wish the car came with atleast a VLSD from factory but such is life
|
Appreciate
0
|
05-18-2020, 11:44 AM | #8 | ||
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Quote:
What is "traction" and "dsc off" ? Are those separate profiles or just tweaks applied to existing core profiles?
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
||
Appreciate
0
|
05-18-2020, 02:08 PM | #9 |
Second Lieutenant
132
Rep 237
Posts |
They're all separate modes. "Traction" is when you press the Trac button once. "DSC off" is when you hold it for 5 seconds. All others are on the drive mode rocker switch as you already know. It can be confusing at first, I thought the same question myself but they are all separate modes.
See the extra 2 sport columns? Those are just the variations of sport mode built into idrive. You can select chassis or powertrain or both under idrive to tweak sport mode (just sport, doesn't affect sport+ or any others), so those 2 variations are included in that table. I have my sport mode set as drivetrain only, so when in sport the dampers and steering are soft. This makes a larger gap between sport+ as otherwise they're almost the same. Personal preference |
Appreciate
0
|
05-18-2020, 04:06 PM | #10 | |
Private First Class
94
Rep 147
Posts |
Quote:
|
|
Appreciate
0
|
05-18-2020, 05:30 PM | #11 |
Major General
5493
Rep 5,339
Posts |
Mode Behavior
Eco = Dear God, no. Either grow a pair or sell the car because you're a puss. Comfort = All nannies on, soft shocks, light steering, Comfort throttle (linear throttle control), eLSD off Sport in Chassis = All nannies on, stiff shocks, heavy steering, Comfort throttle, eLSD off Sport in Drivetrain = All nannies on, soft shocks, light steering, Sport throttle (quick throttle control), exhaust burbles, eLSD off Sport in Chassis/Drivetrain = All nannies on, stiff shocks, heavy steering, Sport throttle (quick throttle control), exhaust burbles, eLSD off Sport+ = Reduced nanny intervention (allows some spin and drift), stiff shocks, heavy steering, Sport throttle, exhaust burbles, eLSD off Traction = Reduced nanny intervention (allows some spin and drift), soft shocks, light steering, Comfort throttle, exhaust burbles, eLSD off DSC Off = All nannies off (full wheel spin, drifting, donuts), stiff shocks, heavy steering, Comfort throttle, exhaust burbles, eLSD on As you can see, the eLSD is ONLY active in DSC Off. The eLSD is decent, but a true LSD adds a ton more rear axle traction and control. It's apples to oranges. I've had LSDs in other cars and the M Performance LSD is so much more obvious in it's operation and the level of control and traction. I had no idea it would make such a difference. I drove my car for the first two years without the LSD. When the eLSD intervenes in a slide, it is a bit ham-fisted and can be very abrupt. I STRONGLY suggest that if you're only experience with a torque rich RWD car is via a video game, you should run the stock tune first in Sport+ for a while so that you understand what the car feels like when the rear axle starts slide in the lower gears on and off acceleration in the straight line and in the turns. Then when you get comfortable with that, then try DSC Off. When you get comfortable with that, then go Stage 1 and so forth. The biggest risk here is that the tires start spinning dramatically and the axle lifts and then slides/drift, then grips, then slides again, all the while you're adding and removing throttle and steering to compensate and keep control. Now you've got yourself in a tank slapper situation where the car sways side to side and could goes off road (or worse), usually ass first. Most every Mustang crash video on YT shows a driver getting in over their head with tire spin and then a tank slapper situation. I'm not afraid of my car's power (380whp/400wtq) and find it controllable on dry pavement and good tires and when temps are above 50, but I've been driving high torque RWD cars since the early 1990s and most of the cars I owned didn't have stability control. I've also gotten myself in over my head in the past. Luckily I've never went off road or hurt anyone. Just hurt my ego. Be careful. A RWD Stage 2 N55 F series can be a handful. Way more so than in stock form. You just can't go full throttle and hang on with RWD. There is a level of awareness and connection you need to have to feel what the rear axle is doing.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
Last edited by XutvJet; 05-18-2020 at 05:36 PM.. |
Appreciate
1
SoftShoe157.50 |
05-18-2020, 10:26 PM | #12 | |
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
This car is way more complicated than I ever knew...
Quote:
Im gathering that this car was actually much simpler in AWD mode... Also now that I finally understand the modes and the mode chart, I have a few questions. If DSC off is full driver mode with no computer intervention, why is the E-LSD activated there? Isn't the point of this mode to let the wheels spin? Then also it seems "traction" mode is actually another name for "DTC activated" mode, which seems to me to be a sports inclined setting. If thats true (and maybe Im wrong) then why are all the other settings so weak? Like the throttle, steering and suspension etc- like why have a DTC mode for soft driving? Seems in conflict to me. Finally whats the best solution for 0-60 pulls or 1/4 mile pulls? Sport would prevent the most wheel spin right but actually not have the most aggressive attack parameters in the other categories? And Sport+ would have the best attack parameters but allow for more wheel spin thus loosing time?
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
|
Appreciate
0
|
05-19-2020, 12:38 PM | #13 | |||
Major General
5493
Rep 5,339
Posts |
Quote:
LSDs are imperative to things like drifting or track driving. You can also steer the rear while in a slide/drift with throttle inputs. The eSLD is no replacement for a mechanical LSD though. They're apples to oranges. The rear axle on my M235 felt really loose with the eLSD and it would not slide/drift gracefully. With the LSD, it feels like there's an extra 500+lbs of weight over the rear axle. There's that much more traction and the rear feels far more buttoned down. When it slides/drifts, it's so damn easy to make it do what you want with throttle inputs. In a straight line, it hooks so much better from a launch or low gear roll. Quote:
Traction mode is great for snow driving where you want the suspension soft, the throttle inputs more muted, and can get some spin. This all helps with driving in the snow or slippery conditions. Quote:
With RWD, you can't launch like you can AWD. Not even close. It takes a lot of skill and practice, even with an automatic. Don't use launch control because all it will do is blow the tires off. On a launch, you can't just go full throttle. You have to feather the throttle a bit in 1st. This can be difficult with an automatic because the transmission ECU might assume since you're letting up on throttle a bit that you want it to upshift. You can try manual mode, but often times the car is quicker in true automatic mode. You'll need to research how to put the shifter in Sport mode so that the transmission ECU is less inclined to second guess your throttle inputs and upshift.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
|
|||
Appreciate
0
|
05-19-2020, 02:40 PM | #14 | ||||
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Quote:
RWD is better for track driving and drifting? I still really think the engine is overpowering the tranny in AWD mode, wondering if the XHP maps would make it better or make it worse?
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
||||
Appreciate
0
|
05-20-2020, 10:48 AM | #15 | ||||
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
DSC OFF Calibrations on Chart
Quote:
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
||||
Appreciate
0
|
05-20-2020, 12:23 PM | #16 | |
Private First Class
94
Rep 147
Posts |
Quote:
|
|
Appreciate
1
OldCrow7xx69.50 |
05-20-2020, 12:34 PM | #17 | |||
Major General
5493
Rep 5,339
Posts |
Quote:
Quote:
Quote:
Add power and you should expect issues with the drivetrain and engine as BMW didn't intend these cars to be pushing 20%+ more power than stock.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
|
|||
Appreciate
1
OldCrow7xx69.50 |
05-20-2020, 12:39 PM | #18 |
Major General
5493
Rep 5,339
Posts |
Exactly. These turbo motors make a ton of torque in the low to mid range compared to a naturally aspirated motor. Transitioning from no boost to full boost happens in a second or less. This massive surge of torque can easily overwhelm the rear tires and cause a nasty over-steer situation. With the rapid reacting Sport throttle, it is more difficult to manage the power delivery. The linear Comfort throttle used in DSC Off helps the driver manage the power delivery and keep the tires planted. The car is no slower in DSC Off. It's simply the driver needing use more of the accelerator to get the power they want.
__________________
The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
|
Appreciate
1
OldCrow7xx69.50 |
05-20-2020, 03:58 PM | #19 | |
Colonel
1330
Rep 2,214
Posts |
Quote:
__________________
|
|
Appreciate
1
OldCrow7xx69.50 |
05-20-2020, 04:13 PM | #20 | ||||
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Quote:
So like how do the coyote mustang guys strap on a blower and make 650-900hp on otherwise stock cars? Are their drivetrains just taking a major beating over time until they fail? So really in life you cant buy the cheaper model and hack/mod/build it up for less than the price of the more expensive model because you run into these situations where increasing one attribute has negative/ unintended consequences on other attributes. And by the time you replace and upgrade everything in unison you have now spent as much as the higher model to begin with.
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
||||
Appreciate
0
|
05-20-2020, 10:41 PM | #21 |
Major General
5493
Rep 5,339
Posts |
For one, 5.0 Coyote`s have a whole slew of issues. They're a great naturally aspirated motor, but they have issues with piston rings and rod bearings. I sure as hell wouldn't strap a blower to one and expect it to last longterm.
I firmly believe that if you want 20% more power than stock, you're better served buying a faster car. It's a lot cheaper in the long run and fewer headaches. Financially, it makes a lot more sense to buy a used M3/4 if you want a reliable 450-500whp in a BMW. Sure, you can buy a Pure Stage 2 turbo and make that level of power but the car will undoubtedly have far more issues and you'll have to trouble shoot a lot of things and very likely spend more money doing it. With the M3/4, it's essentially a Stage 2 setup and is plenty powerful for the street. |
Appreciate
1
KennyFSU1102.50 |
05-21-2020, 10:02 AM | #22 | |
Lieutenant
70
Rep 439
Posts
Drives: 2016 M235i Xdrive 8A
Join Date: Oct 2018
Location: 20036
|
Quote:
I wondered how that stock tranny holds DOUBLE the power lol
__________________
SOLD 23K Black 2013 F30 335XI 8A Msport | BMS Intake | BMS Front Mount | VRSF Charge Pipe | BM3 Tune
2016 F22 M235 8A HK NBTevo | CTS HEX Intake | CTS Chargepipe | Gplus Intercooler | VRSF DP | BM3 Stage 2+ | 18" CSL Replicas | XHP X-Delete |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|