BMW 1M and "LIMP MODE"

[trip]

Hey guys,

So far I have not heard of any 1M's hitting the dreaded N54 "limp mode" through the various track tests etc. This is despite the stock 335i / 335is or even "BMW Performance Pack" equipped ones hitting limp mode fairly easily after prolonged hard driving.

From my understanding, the tuned N54 (especially with piggybacks) hit limp mode MUCH more frequently than when stock, for obvious reasons even when running aftermarket oil coolers / intercoolers / radiators etc.

Would any one, tuners included, have any idea why the 1M is more resistant to limp? Could it have something to do with:

1. Cooling Hardware
2. M ECU tuning which perhaps increases the limp thresholds

I think it is important for us to ascertain this as it would then greatly impact many individual's decisions whether to tune the ECU or not. We all know that the N54 is capable of running more power without significantly decreasing engine life, but having more power is one thing, Id personally want a car that i can drive hard for prolonged periods without having to worry about triggering limp mode.

[marcel b]

Originally Posted by trip

Hey guys,

So far I have not heard of any 1M's hitting the dreaded N54 "limp mode" through the various track tests etc. This is despite the stock 335i / 335is or even "BMW Performance Pack" equipped ones hitting limp mode fairly easily after prolonged hard driving.

From my understanding, the tuned N54 (especially with piggybacks) hit limp mode MUCH more frequently than when stock, for obvious reasons even when running aftermarket oil coolers / intercoolers / radiators etc.

Would any one, tuners included, have any idea why the 1M is more resistant to limp? Could it have something to do with:

1. Cooling Hardware
2. M ECU tuning which perhaps increases the limp thresholds

I think it is important for us to ascertain this as it would then greatly impact many individual's decisions whether to tune the ECU or not. We all know that the N54 is capable of running more power without significantly decreasing engine life, but having more power is one thing, Id personally want a car that i can drive hard for prolonged periods without having to worry about triggering limp mode.

airflow I would say is the biggest difference. the air intakes for both the coolers are huge and force a lot of air through them making them much more effective. When I enlarged my intakes on my 335 (335is ducts) I noticed a significant temp reduction.

[jmunro]

I had a limp mode in my 1M but it wasn't under any sort of stress oddly enough.

[robertm]

Originally Posted by jmunro

I had a limp mode in my 1M but it wasn't under any sort of stress oddly enough.

What caused it?

[Rekraps]

For us dummies, what the heck is limp mode?

[GaryS]

If 1M's are getting limp mode less often than 135i's, one reason could be that there aren't any 1M's with automatic transmissions. If you read the gigantic thread about limp mode at e90post forum, you'll see that most of the cars that are limping frequently have AT. The AT is water-cooled and seems to make a big difference in pushing water temp past the 245F threshold for limp mode. Another reason for less limping in 1M's is that 1M's have stronger radiator fans than 135i's. And as marcel_b mentioned, there appears to be better airflow.

[EmmDrei]

In addition, I'm pretty sure 335i / 135i have isolation on the inside of the hood. A 1M doesn't. Feel how hot the hood gets. I'm waiting for the day, when the paint starts to crack. Imho the M GmbH has simply done everything they could to eliminate a known problem.

[Dackelone]

Originally Posted by EmmDrei

In addition, I'm pretty sure 335i / 135i have isolation on the inside of the hood. A 1M doesn't. Feel how hot the hood gets. I'm waiting for the day, when the paint starts to crack. Imho the M GmbH has simply done everything they could to eliminate a known problem.

My 135i does not have any hood insulation. My hood gets pretty dam hot at times - too!

Have you seen the new F20's underside of the hood - it has a metal heat shield. I think BMW did this bc the turbo on that 1.6L turbo four sits really close to the hood.

Btw... I think only some early 125i's128i's had hood insulation. But later cars did not get the insulation. I remember that bc there was two 1er forum guys at the Ring meeting this summer and they traded out the hood insulation! lol

[Robert]

I heard LIMP mode is only found on ED cars

[fastauto]

Originally Posted by Robert

I heard LIMP mode is only found on ED cars

Limp, ED, lol.

[M3 Adjuster]

LOL at the ED comment.

No limp mode due to...

Additional oil cooler
additional radiator
DCT trans case is used for 1M 6 speed trans. The DCT transmission case has it's own sump... Thus.. the trans fluid is cooled better in the 1M because the trans fluid uses this sump.

Less heat.. no limp mode.

There have been no reports of people with Tuned 1Ms experiencing limp mode... leaving the answer to your query with a single possibility..

1. cooling hardware

[MDORPHN]

Originally Posted by M3 Adjuster

LOL at the ED comment.

No limp mode due to...

Additional oil cooler
additional radiator
DCT trans case is used for 1M 6 speed trans. The DCT transmission case has it's own sump... Thus.. the trans fluid is cooled better in the 1M because the trans fluid uses this sump.

Less heat.. no limp mode.

There have been no reports of people with Tuned 1Ms experiencing limp mode... leaving the answer to your query with a single possibility..

1. cooling hardware

Mark -

Surely the cooling hardware changes are the biggest contributor, but I wouldn't rule out the additional possibility that the ecu programming was revised to increase the temps that trigger limp home mode.

Neil

[GaryS]

Originally Posted by MDORPHN

Mark -

Surely the cooling hardware changes are the biggest contributor, but I wouldn't rule out the additional possibility is that the ecu programming was revised to increase the temps that trigger limp home mode.

Neil

Hey Neil, that yellow indicator we saw on Sunday was limp mode. See I did rtfm.

[marcel b]

Originally Posted by GaryS

Hey Neil, that yellow indicator we saw on Sunday was limp mode. See I did rtfm.

you had limp mode on the 1M?

[jmunro]

Originally Posted by robertm

What caused it?

dont know. haven't scanned the ECU yet

[GaryS]

Originally Posted by marcel b

you had limp mode on the 1M?

No, Neil rode with me in my 135i. I got limp mode, pitted in, shut down for five seconds and restarted. The indicator didn't come back, so we went back out and my car was fine for twenty more minutes on track and two more sessions that day.

The same thing happened once before. I have a water temp gauge, so I could see both times that my oil and water temps were normal and nowhere near limp thresholds.

[fusion01]

Originally Posted by GaryS

No, Neil rode with me in my 135i. I got limp mode, pitted in, shut down for five seconds and restarted. The indicator didn't come back, so we went back out and my car was fine for twenty more minutes on track and two more sessions that day.

The same thing happened once before. I have a water temp gauge, so I could see both times that my oil and water temps were normal and nowhere near limp thresholds.

Old thread but same here only yesterday on the track. Had to restart 3 times to eradicate limp mode even with the DSC off and in DTC mode. Once pulling off in the middle of the track to stop / start. What's a joke is I've had tons of limp modes triggered and taken it into dealership twice. One was vacuum lines (replaced) but the second time I was told it was 'normal' and not to worry. At that time I had the DSC on which triggered limp a lot, so thought the DTC would alleviate issue. Not so it seems. Going in again - possibly sensor faults etc - I hope something is found. Owning a performance car and getting knee-capped so flipping often + visits to dealers + 2 days without a car is starting to get to me now.

[bdaddylo]

Sorry, but I'm not sure how posting to the 1M forum is going to help with your 135 issues.

[VO 1M]

The 1M stays a lot cooler then the 335i I had before. Even on the track (Ring incl. GP-track) it didn't go above 1bout 125 Celsius. My 335 DCT I got up to 148 degrees and Limpmode on the same track.
Next to the hardware (I had the Powerkit on my 335 which incl. a better fan and a secondary watercooler) I think also the better airflow through the coolers make a difference. I noticed on my 335 as well that removing the fog lights and increasing the amount of air on the 2 coolers reduced the temps.

At the moment I do not see any reason for a bigger oil cooler or an other radiator.

[clived]

Don't forget there are just far far fewer 1Ms than 135i / 335is....

[JohnCena]

Technically the limp mode has technically been resolved on our N54T motors. It's die to the extra cooling, ECU re-mapping and more evenly distributed boost from the mapping.

[silvs]

I know why! It's because all the heat is going near the drivers right leg, and cigarette tray / cubby.