Any long term dangers to BOOTMOD3 stage 1 on stock car?

[overlook637]

The negatives are-

tire wear, speeding tickets, increased wrinkles on your face from smiling.

[overlook637]

Originally Posted by HyeM3

Downshifting isn't the actual cause of it but it can be what sets it over the edge when it's hanging on by a thread. The cause is from having more power than the stock hub can handle thus causing it to back out over time or overpower the friction plate holding it together. From what I've seen it usually happens soon after someone does a pull

Engine Power effects the drivetrain: clutch and tires. Not the rotating overhead cam chain.

[HyeM3]

Originally Posted by overlook637

Engine Power effects the drivetrain: clutch and tires. Not the rotating overhead cam chain.

It's the load on the hub from all the torque the engine produces. Those are the words from all the companies that have been studying this issue for years

[Shubacca]

The new multi map for stage 1 has 4 different tunes. You could run the CS for piece of mind and if you wanted to step it up you can switch to the 91 or 93 tune via cruise control buttons in about 7 seconds, then back if you choose.

Not sure if it helps, but I was in the same boat (decision wise) and really wanted bm3 because it's a sick way to tweak, tune, diagnose and gather data. Did the multi map and was running the CS tune until the VTT CBC went on. Now I feel confident to run any map I have as hard as I want. Granted I do not do hard kick downs, launch or use anti-lag. I would guess that track-esque driving, being smoother generally, than slamming the pedal to rip a pull, is a little better for the crank hub. Bolt needs ~440ft/lbs to break loose. Not sure how or if that number plays into spinning the hub, but my goal is to avoid sharp impulse above that value.

[goto35]

What's the horsepower and torque bump on the cs tune?

[Shubacca]

Originally Posted by goto35

What's the horsepower and torque bump on the cs tune?

All the data you could ever want. My summary wouldn't do it justice.

https://f80.bimmerpost.com/forums/sh....php?t=1542700

[overlook637]

Originally Posted by HyeM3

It's the load on the hub from all the torque the engine produces. Those are the words from all the companies that have been studying this issue for years

What load on the hub? Rotating overhead cam, chains, and valves springs is the only load demand.


Now increasing power at the crankshaft will greatly increase load on the transmission clutch and tires depending on traction available.

[White340XDriveInCt]

Originally Posted by overlook637

What load on the hub? Rotating overhead cam, chains, and valves springs is the only load demand.


Now increasing power at the crankshaft will greatly increase load on the transmission clutch and tires depending on traction available.

Mechanic at a local shop said, in studying these failures for years now, said that he fully believes it's the extreme inertia caused by quickly spinning up after downshifting (especially with a modded car). Certainly, a stock car can (and have) failed due to excessive/aggressive downshifts, but he feels it's the boosted power combined with such actions that are largely responsible for the failures, and that definitely seems to make sense. There are guys that have modded cars but claim they generally only push hard through normal upshifts, never use kickdown or hot dog it much, etc., and they haven't failed, so that would further support this theory.

Still debating doing my CH before I go with Stage 1, which is all I plan to do (for now) lol.

[overlook637]

Seams like the hub would spin while in neutral revving up. That's when is spins up quickly. 1000rpms to redline in much less time than when in 1st gear.

[goto35]

anyone running stage 1 without downpipes?

[Lesanna1]

Only need it if you are agressive on downshifts.BM3 stage 91 2017 ZCP no issues !!

[Shubacca]

Originally Posted by goto35

anyone running stage 1 without downpipes?

My guess is most running stage 1 are stock DP. I am.

[Vegetable]

I hope I'm not going to jinx myself here, but I have been running Stage 1 Bootmode for 106,000+ miles and have not had an issue. I redline my M4 at least once/twice per day, almost everyday since 5,000 miles after I took delivery. Seems to be a very safe tune.

[goto35]

Originally Posted by Vegetable

I hope I'm not going to jinx myself here, but I have been running Stage 1 Bootmode for 106,000+ miles and have not had an issue. I redline my M4 at least once/twice per day, almost everyday since 5,000 miles after I took delivery. Seems to be a very safe tune.

Holy shit that's incredible lol

[rmanm4]

Originally Posted by overlook637

Seams like the hub would spin while in neutral revving up. That's when is spins up quickly. 1000rpms to redline in much less time than when in 1st gear.

hub wouldn't spin at all in neutral. Engine needs load for torque and that is when the hub can spin!

[Suds]

I have to BM3 stage 1 93 octane tuned M’s with 3500 or so track miles on each.
I sold my 2015 M4 6mt last year with over 3500 track miles on it with a stage 1 93 octane tune for the 2019 M4.

You can probably guess how many redline shifts go into 3500 track miles, it’s a bunch. On the two DCT cars I own now I always downshift with the paddle shifters.

[goto35]

Originally Posted by overlook637

The negatives are-

tire wear, speeding tickets, increased wrinkles on your face from smiling.

best comment here lol

thank you everyone...ordered the bm3.

[damos]

Originally Posted by Suds

I have to BM3 stage 1 93 octane tuned M’s with 3500 or so track miles on each.
I sold my 2015 M4 6mt last year with over 3500 track miles on it with a stage 1 93 octane tune for the 2019 M4.

You can probably guess how many redline shifts go into 3500 track miles, it’s a bunch. On the two DCT cars I own now I always downshift with the paddle shifters.

I see this referred to on the forum here a bit but also see conflicting posts about letting the car downshift itself.

Whats the best approach? Downshift at the right RPM based on speed/gear, or let the car do the downshifting when the RPM goes down to around 1000?

[Shubacca]

Originally Posted by damos

I see this referred to on the forum here a bit but also see conflicting posts about letting the car downshift itself.

Whats the best approach? Downshift at the right RPM based on speed/gear, or let the car do the downshifting when the RPM goes down to around 1000?

I think what Suds is referring to is paddling down for more aggressive acceleration vs just downshifting as car slows stopping at a light.

Some opinions about SCH causes stem from very high impulse torque, like during a DCT kickdown (flooring the pedal and allowing the car to select the lowest avail gear). This can also happen if you are impatient when you paddle downshift; you're already hard on the gas when you select 3rd from 5th. The car puts your throttle request on hold while it completes the shift, once in gear you get a massive torque surge.

I am not saying that any of the above stuff is specifically a cause for SCH. Can't ignore that it may be a causal factor though.

[damos]

Originally Posted by Shubacca

I think what Suds is referring to is paddling down for more aggressive acceleration vs just downshifting as car slows stopping at a light.

Some opinions about SCH causes stem from very high impulse torque, like during a DCT kickdown (flooring the pedal and allowing the car to select the lowest avail gear). This can also happen if you are impatient when you paddle downshift; you're already hard on the gas when you select 3rd from 5th. The car puts your throttle request on hold while it completes the shift, once in gear you get a massive torque surge.

I am not saying that any of the above stuff is specifically a cause for SCH. Can't ignore that it may be a causal factor though.

Ok thanks, that makes sense.
I always downshift to the gear I want before accelerating for a pull and I never use the kick down feature.

[6spd4lyfe]

Is the Crankhub a concern on the 6MTs or just DCT transmission?

[Shubacca]

Originally Posted by 6spd4lyfe

Is the Crankhub a concern on the 6MTs or just DCT transmission?

Here's the avail data from a relatively small sample size (enthusiasts who participate in this forum).

Ultimate Spun Crank Hub (SCH) Poll: ALL Members Please Vote! https://f80.bimmerpost.com/forums/sh....php?t=1560274