[ptwob311]

UPDATE,at bottom of thread. Just ran the PROcede data log feature. Need some help!!



So, Driving the car today with the windows down i notice under a load, or aggressive acceleration, i can hear a very loud hissing noise coming from what sounds like directly under the engine bay. I have never heard this before and it is VERY LOUD! Louder than the exhaust, engine, and wind combined. However, I have never really punched it with the windows down.

Is this normal? The only logical thing in my mind is maybe the wastegates venting, but our cars vent into the system and not the atmosphere... correct?
My only other thought is that i recently put in a K&N filter... could i be hearing the turbos spooling? But that doesn't make much sense as the intake is a closed unit....

No codes, no cautions, just noise....

Anywho, those that are far more experienced than i please let me know what you think.

Thanks

[Zeph]

I have heard some say even a K&N drop-in filter will slightly increase turbo sound. Biggest question is, are you running a tune? I would find it hard to believe you are hearing stock boost. If you are running higher boost (like 12+ psi) maybe you are hearing the turbos and/or the diverter valves. They still vent, just closed loop so quieter.

Also if you are running catless DP's those can hiss a bit, but not as noticeable as test pipes (cat deletes) on a N/A car where you hear it hiss when you let off the gas.

[Blk07335i]

Definitely sounds like induction noise but you say you still have the OEM intake, correct? Maybe, the top is not on all the way. With DCIs you will hear a loud hiss under load or during acceleration. Recheck the lid of the intake.

[ptwob311]

I have the PROcede installed (standard map for stock 335) and yes, the OEM intake is completely closed. It just seems like a LOT of air is being forced out of something (diverter valve...etc) on the bottom side of the engine bay. A very loud hissing above 3K RPM. It was louder than the road noise and other cars at 40 MPH. Although i could not get it to replicate sitting still in my garage.

Actually I bet other cars probably think i have a giant air pump propelling my car down the road.

Thanks for the replies.. I am just trying to gauge whether this is something i should be worried about/take it in to BMW as the car only has 20K on it.

[Dan335i]

Check all connections where you could have a boost leak,like the intercooler connections,by the throttle body area,the diverter valves,etc.If have someone who knows how to do a boost leak check thats the way to go.It can be done with a bicycle tire pump.All you need is like 12-15 psi to check for the leak,and listen to where its coming from.

[ptwob311]

Thanks, I'll go look at the car in the garage... check all the connections and such

If i had a boost leak at any of the above mentioned locations would that throw a code? Just seems odd that if the connections are spilling enough air to make that much noise the car would not detect that somehow.

does anyone else ever hear this when driving?

[gerardm]

i mean i have a jb3 and before i put my DCI on if i had the music off and windows open i could def hear the turbos spool up and release upon accelerating or load. i drove around for 3 months with a tune only and could hear them with no codes or errors not loudy but if i listened for them i could def hear it. but now with the DCI i hear them very loudly and love it.

[Sniz]

Originally Posted by ptwob311

Thanks, I'll go look at the car in the garage... check all the connections and such

If i had a boost leak at any of the above mentioned locations would that throw a code? Just seems odd that if the connections are spilling enough air to make that much noise the car would not detect that somehow.

does anyone else ever hear this when driving?

if your losing enough air to hear it, you should throw a code. I found the 335 to be very tempermental w boost leaks.

do you have a boost gauge? Since you have the procede hooked up can you datalog and check your boost logs? If your spooling quickly and holding your target boost without any dips thru 3rd gear, chances are you do not have a leak.

or look up my post on a boost leak test and give that a shot.

best of luck

[ptwob311]

Originally Posted by Sniz

if your losing enough air to hear it, you should throw a code. I found the 335 to be very tempermental w boost leaks.

do you have a boost gauge? Since you have the procede hooked up can you datalog and check your boost logs? If your spooling quickly and holding your target boost without any dips thru 3rd gear, chances are you do not have a leak.

or look up my post on a boost leak test and give that a shot.

best of luck

I'll try the boost logging with PROcede... thanks for the insight.

I guess i should be a little more descriptive of the sound. As i accelerate and build boost (along with RPMs) the whoosing noise grows louder and louder. Sounds like a cubic ass-ton (actual scientific unit) of air is being forced somewhere. Not sure if that is actually out of the system and into the atmosphere... or just echoes thru the intake.... but with OEM box that seems highly unlikely.

[Sniz]

Originally Posted by ptwob311

I'll try the boost logging with PROcede... thanks for the insight.

I guess i should be a little more descriptive of the sound. As i accelerate and build boost (along with RPMs) the whoosing noise grows louder and louder. Sounds like a cubic ass-ton (actual scientific unit) of air is being forced somewhere. Not sure if that is actually out of the system and into the atmosphere... or just echoes thru the intake.... but with OEM box that seems highly unlikely.

best idea would be to drive/hear another stockish 335.

and do those Procede logs

[ptwob311]

Originally Posted by Sniz

best idea would be to drive/hear another stockish 335.

and do those Procede logs

absolutely, only problem is.... i don't know anyone in my area that has one. I have only seen a few.... Maybe I'll try the rocky mountain forum. Thanks for your help

[ptwob311]

OK, SO, i ran the PROcede data logging application and here is what i get.

First off the noise is definitely coming from the turbos or really close too em. With the windows up it was much easier to pinpoint the location of the whoosh/hissing. I am almost completely certain it is coming from somewhere near the passenger side of the engine bay by the tire somewhere. (Surprise surprise... exactly where the turbos are!!)

With the PROcede off i am only building 6.8psi; it tends to stay in he 4-6psi range. With it on (setting from Vishnu) i get about 13psi peak and it tends in the 5-8 range. I will attach the graphs. Also, The car keeps giving me the Half lit engine in the caution light area. I got the code 83 and 90 to pull up on the PROcede, from the CANbus channel... but i can not find where to turn that into a BMW code. Anyone know what these mean?

i am kinda new to the whole turbo tuning thing and i am almost certain this is clearly a boost leak.... but as i have stated before there are those out there far more skilled and experienced than I. To those please let me know what you think. Should i take the car in??

First two graphs are boost and RPM with PROcede OFF. Second two are PROcede ON

[Sniz]

got ur PM, pretty darned sure thats a boost leak.

curious what the codes you are getting mean.

now to find it.

start looking closely at all connections and there is a good chance that you can find it just by looking for small amounts of oil/oil vapor collected at the connection.

pressurizing the whole system is a more thorough approach.

[ptwob311]

Originally Posted by Sniz

got ur PM, pretty darned sure thats a boost leak.

curious what the codes you are getting mean.

now to find it.

start looking closely at all connections and there is a good chance that you can find it just by looking for small amounts of oil/oil vapor collected at the connection.

pressurizing the whole system is a more thorough approach.

Thanks man, you RAWK! I guess I'll put it on a lift tomorrow and take off that undercarriage tray. You think I'll be able to see it from that angle any better. I wonder if one of the fittings might have blown off or something.... its sounds like to much air for a small leak, but again I'm a rookie with turbos.

Also, I gotta find where the codes are listed by Vishnu.

[kaba]

I think i may have a similiar sound after installing fmic with larger maps (jb3 1.3). How can i upload audiofiles?

kaba

[kaba]

Originally Posted by kaba

I think i may have a similiar sound after installing fmic with larger maps (jb3 1.3). How can i upload audiofiles?

kaba

I found a crack in a tube so boostleak it was...need to order a new tube and hope the sound is away

[gqmd]

Originally Posted by kaba

I found a crack in a tube so boostleak it was...need to order a new tube and hope the sound is away

which exact tube did u find the crack in? was your issue fixed?

[N54lr]

So I just bought a 2007 e90 335 6mt ,I wanted a 335 for years but I was just too afraid to buy one ,everyone told me not to buy one because they are super unreliable ,the car has 81k miles bought it at 79k miles I bought the car for 7 k from some older gentleman , being super paranoid I did a lot of stuff to the car before I started tuning it,I change the indx 1 that where on the car with index 12 ,valve cover gasket, ofhg,serpentine belt and pully's,7.5 vrsf intercooler down pipes,and a tile bov the car had this noise even before I start to do al the maintenance ,and I can't figure it out what it could it be it's like a hissing noise when I let of the throttle ,and it's not the bov

[studio54]

Originally Posted by N54lr

So I just bought a 2007 e90 335 6mt ,I wanted a 335 for years but I was just too afraid to buy one ,everyone told me not to buy one because they are super unreliable ,the car has 81k miles bought it at 79k miles I bought the car for 7 k from some older gentleman , being super paranoid I did a lot of stuff to the car before I started tuning it,I change the indx 1 that where on the car with index 12 ,valve cover gasket, ofhg,serpentine belt and pully's,7.5 vrsf intercooler down pipes,and a tile bov the car had this noise even before I start to do al the maintenance ,and I can't figure it out what it could it be it's like a hissing noise when I let of the throttle ,and it's not the bov

Hi,

can you start your own thread and describe exactly what is going on ?

I mean when the hissing starts ? if the hissing is when you let off the throttle after boosting, it's likely to be a normal sound of the BOV, it just dumps the excess of boost and it does a "woosh" sound.