OK- The car has only 15K on it and to date has been running perfectly even with minor mods-

well, today I go and avoid a large truck but by doing so hit a HUGE pothole in the road, and wow did she scrape. I mean, not just a little scrape, but sounded definitely like metal ---ouch.

Anyhow, It didn't concern me all that much until I hear this siren type sound. ummm..that's strange...maybe I'm dreaming it up? no.

In every gear, from approx. 2,800 RPM UP -you hear it....it's not incrediblly audible, but enough to be noticed. It sounds just like a siren- I looked in my rearview a couple of times as I swore there was a cop near by.

I'm fearful it is the turbo...why you ask? if you hold any gear, let's say 3rd and drive the RPM's up to a middle range (say 4,500) and then hold it, the siren noise tends to just fade

alternatively, if you stay on the throttle through the revband, it simply keeps on increasing in pitch. - the whole time.

I did a quick check under the hood- nothing that stands out as being a problem, no hoses look off, everything seems tight- but this was a direct change based on that huge pothople I hit.

Anyone have any clue???

 

Have you checked under the car??? Any could of got loose when you hit the pot hole and just rubbing against the tire. Or it might of f*** something up and your transfer case is gone. Take it to Mitsu and have them check it out...better safe than sorry

 

The turbos in my old S4 made a siren sound when they were on their way out (think its from the air rushing over bent blades). Dunno how you would damage your turbo from hitting a pothole, unless something physically struck it.

 

Maybe you damaged your intercooler or the lower pipes on either side.

 

You trashed your transfer case! you knocked the pinion in there way outta wack!

 

I think there is a great possibility that it's the transfer case- as the pot hole I hit was just a huge bastard- and I wasonly going about 5 mph (huge truck near me)

But, the reason why I am concerned that it's the turbo, is that if i'm at 3500 rpm, and give it about half throttle, the boost comes on and the siren whine goes right up....even thorugh I maybe only increased up to 4,500 rpm's.

in other words, it would like the whine is directly released to the turbo and the amount of boost I'm making. obviously I am fearful -

I almost laugh at taking it to the dealer to see what they will think considering my mods- they will end up blaming it on a boost controller or something stupid.

any other thoughts anyone?

BTW- Zarathustra- I too had an S4 and it is the same exact noise - I had the same issue in my S4- but being the EVO is a single snail- with more boost, it's a lot louder.

 

Yup most likely the transfercase

 

+1 I think

 

My guess would be you tore an ic hose or knocked a hole in your intercooler. I bet it's an IC hose. Can you rev the car in neutral and get the noise? Jack the car up and look to see what scraped.

 

Its the TC, it is nothing else! if it was the hoses, it wouldnt run worth a crap, your ECU would put it in "limp-home" mode, and barely run. My "siren" started at 50 mph and got louder until 80 mph, then it died down. its DEFINETLY THE T.C.

 

If you're really concerned about the dealer, you could contact your insurance company and make a claim. I know this may effect your insurance rating, however simply explain it was a pot hole and they should recognize that it was an unavoidable incident. This way, Mitsu can't give you crap for your mods and they'll have to fix the car. It's a tough situation, but that's why you pay insurance, right? It may be helpful to get pics of this pothole before it's fixed, in case you need proof. Just a thought.

 

First thing you do is crawl under the car and check the pipe from the turbo to the intercooler; it's held on by 2 bolts and when they become loose you will hear a shrill whine coming on boost that will diminish at steady throttle. tighten those two bolts ( I forgot the actual torque numbers) and see if that stops the problem. If it was the transfer case (which so many of the other pundits claim) you would be having all kinds of problems; the whine would be the least of them. It may also be a loose intercooler hose that was knocked loose.

 

I had a broken TC which gave way and started to whine out of the blue, and I drove it for 600 miles (was on a trip in Michigan) My ONLY problem was the whinning noise, kinda like the ones YOU are making now! Have you, my friend , BROKE a TC? and did you have ALL KINDS OF PROBLEMS? Trust me showard, If your not sure what it is, Which your not, dont get involved!!

P.S. whats a pundit?

 

now now gents-

I really think it could be either. the pot hole was killer and i have lowering springs which didn't help my clearance.

I realisticlly think that it is either a loose IC pipe or the transfer case. I actually have a call into the dealer and spoke to a tech there to see if it is worthwhile coming in. He stated that he has heard of this problem and will be talking to other techs there and get back to me.

However, what makes me think it could be the transfer case is that I am having NO ISSUES AT ALL with boost. it spikes to 23 and then calms to 20 psi all the way through to 7K.

I would guess that an IC hole, or looseness of any brackets would have a significant inmact on the amount of boost I was seeing.

I can't get under the car since it's 92 blazing degrees here now, AND with the springs I'd have to be a Keebler elf to fit. I don't feeling like lifting it up quite yet...so i think I may wait to see what the dealer says.

THanks for all your input...I really appreciate it.

 

Ok Devo,
but me and my arguing "brother" are awaiting for the cause of the noise! I'll stay in my room, and he stays in his until the verdict! No more fighting