Howling Noise, Something Doesn't Seem Happy...

[SS8_Gohan]

Hi guys'n'gals

I have this elusive howling noise that i just can't seem to get rid off... and it seems to be doing funny things.

The main problem is that it doesn't seem to howl on the dyno anymore (where it use to) and you can't tell or it's harder to hear it when on the dyno, as opposed to in the car on the road. This is annoying, as we can't really check something when it's just not there (dyno)

On the street, the howl builds as boost builds and if you really give it some stick, something seems to "give" or "let go" before rev limit. Like a muffled whump, as if perhaps something is blowing off... but doesn't Hard to explain. First time it happened, i was thinking "that must be what it sounds like when a cooler hose blows off, etc", but everything is fine and in one piece

Ok, now the weird thing, one day was at the tuners, a loose hose was spotted, fitted it more tightly, tightened clamp and i went to take a test drive. The difference this time around is that i had removed the front bumper in case we needed to get access to the FMIC. When i took the car for a drive, without the front bumper it did not howl at all I'm like sweet, that loose hose must have been it, and we're all good. Get back, chuck the bumper back on, drive home and you guessed it... howl is back.

The front bumper has a fair whack of room around it on the inside, so it doesn't seem to be pushing up against anything,etc but i can't explain why no bumper would make any difference.

The other weird thing is that it won't howl on the dyno anymore, just on the road, which again, doesn't make much sense to me. (It has howled on the dyno before, but was easily audible)

It's near impossible for the tuner to fix because the only want to test/fix it is when it's on the dyno, but it won't howl on the dyno. Can't fix something that's not really there to begin with.

I'm trying to get the car ready for a track day on Saturday, but i'm not taking the car out as is as i'm concerned something might just blow up/off, it's a horrible sound.

Oh, and i've got a stock BOV, but i've noticed when you really give it some stick, and the howl ends up with that muffled "whump", the BOV sounds like a damn chapel st spec HKS, it's like sututututu... :blink: "sutututu" from a stock BOV?? Was under the impression that is a bad sound for the turbo...

I'll try and get to the tuners tomorrow, but would welcome any thoughts

cheers,

daniel

[R31Nismoid]

If you are getting comp surge then the BOV isn't working correctly.

[kwickr33]

Well I guess when the car's not moving you don't get air travel through the bumper so it won't make any noise. I guess its not some thing to worry about. You should get a proper BOV before hitting the tracks.

Edited July 2, 2009 by kwickr33

[SS8_Gohan]

it has howled on the dyno before, and i'm pretty sure it's not just air passing through the bumper because the noise is dependent on your right foot, not speed, if that makes sense. ie, i could cruise at 100km/hr and not hear anything, but put my foot down, wait for boost to build and it will make itself apparent.

that and i'll rack up the 'warnings' on my boost controller when it happens, and get 'peak warnings' when i get that muffled whump sound. Almost certain it's a boost related issue, as opposed to air around the bumper (which has never been an issue until we've started upping the power/boost on the car)

is there a certain level that the stock BOV out lives its usefulness? i thought it was fine for some fairly decent power

[shaunvlc]

i have the same issue. but only because i removed my AFM to my intercooler piping to allow me to get a custom intake made up without the hassles of mounting an afm then filter. Im uncertain what the noise is but it is a slight howling sound, sounds like not enough air flow is making it to the intake or something. hard to explain.

[SS8_Gohan]

i'm going to take the bumper off now and go for a drive, and hope i don't attract too much attention with the shiny FMIC sticking out the front

[geraus]

howling noise.. have you checked your manifold for leaks? have you checked your gaskets?

[lineskee 33]

how loud is the howl? do you think the timing belt or any of the other auxilary belts could be too tight?

[SS8_Gohan]

wouldn't know how to check for manifold/gasket leaks

howl can get pretty damn loud and wouldn't have the foggiest about the belts

trying to get the car ready for a track day tomorrow, but just don't want to chance it...

went for a drive with bumper off, howl is there.

Came back, fiddled with and tightened up the pipe the tuner spotted one time (i think it's slowly working it's way loose) went for a drive, seem to have gone.

Bumper back on, went for a drive... doesn't seem like it's there. Let it cool, to come back and check pipe again...

Checked pipe, looks to not have moved... went for a drive, howly mc howl howl again - come back, completely loosen pipe/clamp, shove in, tighten up.

Go for a drive, slightly better but not my boost controller is beeping at me which i guess means something is spiking a bit and my BOV is still thinking it's on chapel st.

so combo of BOV and howl, going to have to skip the track day tomorrow

at what power/torque would we be expecting the BOV to give up?

[R31Nismoid]

much more than you are making

its probably just failed - parts do that. Just replace it, or put a GTR BOV on there

[SS8_Gohan]

any GTR bov? or does it have to be R34?

and i take it a GTR has two, so i'd only need one?

[Flecher]

is that dosing noise? my mate's r34 give out 'su...tututututu' noise too when boost builds and it's normal bov~

[toddlls]

I have had a howling/screaming when on high boost/revs for a while too, have just been fitting some extra goodies around exhaust section & noticed loose bolts on exhaust manifold, maybe worth a check on yours too

[TerryL]

my gtr makes that howling noise too... i thought it was the intake sound