M5/M6 at 700hp - reliability?

[Pulse00]

I'm looking for people to put me off buying a 2016 M6 GC and doing downpipes & map. I want to hear stories of yours/your mates that blew a gearbox or something!

Stories of reliability also welcomed but please know you'll be fueling the fire...!

Also in true pistonheads fashion... how fast are they at 700hp? Genuinely interested in how they match up to the competition.

Thanks

[theboss]

Had my 2015 F10 mapped by DMS at 25k miles and ran with it until I had an expensive repair bill which BMW covered just out of warranty and returned car with factory map. The work wasn’t blown transmission or turbos or anything - rather blocked crankcase breathers that necessitated new cylinder heads and injectors for some reason (probably the dealer spotting a good will authorisation to abuse). I felt at that point I wouldn’t tempt fate with a high mileage keeper and thus left it as standard.

Overall about 70k miles covered on the map. Car is now at 140k and has been totally reliable.

Stats were 752bhp / 666lb.ft and it went like stink.

Mine was also done in a group session with a handful of other M5/M6 owners and the cars were generally all putting out in excess of 600bhp standard, with a few exceptions at around 575-590 which had barely had running in services. They all mapped to 725-730bhp. Mine was probably the outlier as it had the highest mileage.

Edited by theboss on Wednesday 30th December 19:00

[JMBMWM5]

Times have moved on and BOSS was lucky , new tech in BMW spots and looks for Remapped cars , BMW no longer stand the bills for altered performance cars, it can be found easier these days removed or not, tell tail signs are always left behind.
You take your chances with remaps now. Good luck.

[theboss]

JMBMWM5 said:

Times have moved on and BOSS was lucky , new tech in BMW spots and looks for Remapped cars , BMW no longer stand the bills for altered performance cars, it can be found easier these days removed or not, tell tail signs are always left behind.
You take your chances with remaps now. Good luck.

I think this was still the case when I had a mine looked at by BMW and indeed I was lucky, which is exactly why I decided not to tempt fate by having the map reinstated at 95k miles and kept it in standard form. This was only two years ago in 2018. I’m not sure what has changed since with the arrival of newer cars and ECU.

I also had a dealer pull me up over a warranty claim with a mapped E65 in 2011 so this risk isn’t entirely new - i think they have always had the ability to detect ECU maps if looking hard enough. (I managed to blag this one)

[TheAngryDog]

Tuned ones are starting to go pop more often. The owners pages are apparently littered with them.

So easy for BMW to detect if the car has been mapped now (requested torque / boost etc) which cannot be hidden.

Also, need an "enhancement"?

[Juber]

As you will see on the M6 GC thread i recently picked up my M6 and thought of having DMS tune it.

To be honest, i honestly dont think it needs it for every day driving unless you are using it up a drag strip.

The car standard is plenty quick.

The only thing i wish to alter is aesthetics such as genuine MPE diffuser, exhaust and a carbon lip spoiler (the GC come without spoilers).

[VeeTenM]

Don't you just sit there burning rubber with all that bhp? 500 is enough isn't it? Not like it can put all that power down like an F90 M5 or M8

[luigisayshello]

Same as oem. Get bootmod3 at least you will know when something eventually goes wrong.
I would sort oem reliability first before toying around with tuning. Get your oil sorted (thick proper oil, these cars run 105c on a normal occurence, the oem oil just doesn't cut it), your thermostat (90c ftw), check your wastegate (rattle is getting ever me normal) as it bleeds boost, run a injector cleaner and hope you don't fall into the injector/hpfp/lpfp failed $tat$.
Check if your recalls and updates are up to scratch, check/change your rod bearings for something like acl with a tiny more clearance, check your coolant and see if it's not chugging.

If all is well doesn't really matter if you are oem or running 700 (not even that much, that's low-ish boost), just make sure your torque/boost doesn't come all at once and stays flat and limited. HCP/bootmod3 last map is perfect for oem and pulling like a train on high revs and actually being as fast as the figures sugest (not a thing for years on turbo cars with Chocapic tunes all midrange no top end).

[w8pmc]

Had my second F10 M5 'enhanced' by DMS to Stage 2 & as per others the car ended up with around 750bhp & ran that for 2 years with no issues. Did require a little fine tuning to the torque delivery as initially the higher torque levels 'could' over power the clutches when pushing hard, but this was quickly resolved.

My First F10 M5 (totally standard) was rejected cue to contaminants in the fuel rail which kept blocking several injectors & dealer/BMW UK couldn't diagnose the fault for many weeks, hence the rejection.