[TiAg335i]

After installing the Cobb a short while after I started to hear the infamous 'siren' noises coming from my turbos while under load at low RPM's. There has been a huge amount of debate as to whether or not this is indicative of turbo failure - with some saying that it is a sure sign of the turbos on their way out while others saying there is no cause for concern and that it is normal. What is known, however, is the fact that the sound came on ONLY after running increased boost levels. The sound has remained even after flashing back to stock. That says something in and of itself I think.

I would like one of the vendors or Cobb themselves to explain this one.

[Joe@TopGearSolutions]

Tuning your vehicle and adding boost has its consequences. Any tune that increases boost has the potential for your turbo's to go out sooner then later.

[N54bimmer]

Originally Posted by TiAg335i

After installing the Cobb a short while after I started to hear the infamous 'siren' noises coming from my turbos while under load at low RPM's. There has been a huge amount of debate as to whether or not this is indicative of turbo failure - with some saying that it is a sure sign of the turbos on their way out while others saying there is no cause for concern and that it is normal. What is known, however, is the fact that the sound came on ONLY after running increased boost levels. The sound has remained even after flashing back to stock. That says something in and of itself I think.

I would like one of the vendors or Cobb themselves to explain this one.

WOW, Im surprised Cobb did not respond to this.
Did you bring it in to the dealer and see if theyll replace your turbos?
How long did you run Cobb for before you got a siren sound?

[TiAg335i]

Originally Posted by N54bimmer

WOW, Im surprised Cobb did not respond to this.
Did you bring it in to the dealer and see if theyll replace your turbos?
How long did you run Cobb for before you got a siren sound?

I'm not under warranty so I'm getting no more freebies (warranty expired). The noise came on shortly after having the Cobb installed - I'd say 4 or 5 days after install. I'm going to check my intake and replace it with DCI tomorrow to see if that might remedy the noise (I've installed/reinstalled the stock intake box a couple of times and there might be a gap somewhere causing the noise under high boost)...it's a LONG shot but it's worth a try. I can also check for oil in the intake tubing...if there is oil that's def a sign of turbo failure.

[O HELLA BMW]

^have you ever had your turbos replaced under warranty???

how many miles on your 07?

[TiAg335i]

Originally Posted by O HELLA BMW

^have you ever had your turbos replaced under warranty???

how many miles on your 07?

Only 19.5k miles and they are the original turbos

[hotrod182]

I seriously believe most people are overreacting and paranoid about blowing up their engines. I have run hundreds of 1/4 mile and 0-130 runs. If there is anyone out there that runs dozens of 1/4 miles runs a week, I haven't heard of them. And on average, my runs are all in the 120-130mph+ range. I have CPS, and have never used it on any of my faster runs. I have been running close to 120mph on a high boost run on meth, and then accidentally unplugged the meth pump on the next run. I have overrevved on nitrous. Engine still ran as strong as any engine out there. I think the average user with a tune running at power levels much less than I am really don't have too much to worry about. Where are the blown engines from these casual users? Probably no more common than the norm for this car line.

[N54bimmer]

Originally Posted by hotrod182

I seriously believe most people are overreacting and paranoid about blowing up their engines. I have run hundreds of 1/4 mile and 0-130 runs. If there is anyone out there that runs dozens of 1/4 miles runs a week, I haven't heard of them. And on average, my runs are all in the 120-130mph+ range. I have CPS, and have never used it on any of my faster runs. I have been running close to 120mph on a high boost run on meth, and then accidentally unplugged the meth pump on the next run. I have overrevved on nitrous. Engine still ran as strong as any engine out there. I think the average user with a tune running at power levels much less than I am really don't have too much to worry about. Where are the blown engines from these casual users? Probably no more common than the norm for this car line.

Yes I have seen your impssive videos hotrod!
What do you do to maintain your cars "health"
Do you change the oil very often and the spark plugs?
Do you warm up and cool down your engine every time?
If Im not mistakrn you have 2 335is and both modded, any tips
To share with me if I decide to mod(tune) and want my car to ladt a long time?

[hotrod182]

Originally Posted by N54bimmer

Yes I have seen your impssive videos hotrod!
What do you do to maintain your cars "health"
Do you change the oil very often and the spark plugs?
Do you warm up and cool down your engine every time?
If Im not mistakrn you have 2 335is and both modded, any tips
To share with me if I decide to mod(tune) and want my car to ladt a long time?

Im actually at the point where the trans is probably going to be the limiting factor. The engine is pretty stout, and the JB3/JB4 has served me well. As far as turbo longevity, I think one of the most important things to do is to wait till the engine is warmed up before running higher boost. The JB4 automatically limits the boost when its cold, which is frustrating to me at times, but a good thing nonetheless. I change my oil at about 1/2 the recommended interval.

I may possibly use CPS in runs above 128mph on nitrous. I will have to do some experimenting. But at normal runs below 123mph traps...I never use CPS if I want to get the best performance.

[gian335]

wow ppl are paranoid lol. some of you guys worry way to much and learning from ppls experience on this forum and from my own, this motor is pretty solid, but i always take into account that something can and may go wrong. And the only time things have gone wrong, are hardware issues, ie; fuel pump, plugs, injectors. o2 sensors.

Tunes really bring this motor to life and give it that much more with bolt ons. But if the motors hardware is not in proper working condition, than you will throw codes and your motor will not run right. Ive been tuned for 50,000 miles with jb3, and currently procede and Ive had issues here and there, but there usually with beta maps and hardly EVER with public maps. But things happen and all you can do is problem solve, adequately and intelligently. Not jump to conclusions and be a baby about it.