Rennteam 2.0 - EN - Forum - Re: Diverter valves - Page1

Jun 16, 2002 11:27:40 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002

Whistle like noise over 290km/h

Hi everybody on board. I'been following this board for some time and decided to post for my 1st time today,Before I throw my question,I like to thank RC & his team ansewering all the questions that people ask on the board,&the generous way they run this board I like to give my respect.Even after owned many 911's or other sport cars I still have alot of things I d'ont know.This board really helps me to keep me updated. And now my problems..!?
I now have completed my break-in on my polar x50 and today was my 2nd time to rev the engine all the way (6900)in 6th.But as Ireached 290 on my speedo (degital)a whistle like sound was coming from the rear ,I stopped to check the car but everything seems perfect,so I went again ,this time I took the engine all the way and saw 319km/h on the speedo.But the whistling noise apeared from 290 and jst became bigger &bigger as I went faster.&when going slower than 290 it just goes away! anoying.Last week when I went up to this speedrange it was just fine...a walk in the park.(German autobahn is great.) Only thing I did in between was wash the car,?Ilooked at all of my rubber packings(in between the window glasses) and found the rubber sealins in the rear glass was loose,Can this be the cause? Or is there any thing else you guy's know of causing this noise? any idea's RC? I dont feel too safe when I hear this sound at this kind of speed.... I have to admit the 6th gear is too too short on a x50!! sks

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Jun 16, 2002 3:26:53 PM

RC: Rennteam Administrator; Loc: Rennteam HQ , Germany; Posts: 59607, Gallery; Registered on: Mar 26, 2002; Reply to: sks

Re: Whistle like noise over 290km/h

You're welcome.

What tire brand do you have on your car? Pirelli or Continental?

I'd go to the dealer to check everything is alright. I suppose it might have to do something with engine/turbo charging system (BO valve, etc.) but I can't exclude it has something to do with defective window sealing or something else. You said you washed your car shortly before the fast run on the Autobahn? Maybe the water has entered somewhere and is causing this noise. Drive your car again at that speed in a few days and don't wash it until then. Sorry I can't help you more but I never heard about such a problem on the 996 Turbo.

The shorter 6th gear makes it pretty easy for the X50 to reach it's top speed much faster than on the standard Turbo. Top speed is actually limited by the rev limiter and no stock Turbo (no matter if standard or X50) runs over 320 kph on the speedo.

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Jun 16, 2002 6:35:55 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: RC

Re: Whistle like noise over 290km/h

Thank you very much for the reply RC! I will take the car to the dealer 1st thing in the morning tomorrow & get it
connected to thier laptop to see what the problem is.I jst hope that it's not the engine or bo valves,forgot to tell you that the sound doesn't come out in any gear even at full boost(0.9 1.0)exept when I'm exceeding 290 on speedo...strange.. My tires are pirelli's..YES the max speed on my speedo is 319-320 I keep my foot planted untill 319 which revs 6900 but foot off than to avoid hitting the rev limitter at these speed,But I hit the limit some time today & the shock was much softer than I thought,so I might keep it planted all the way from next time.The car is so stable even at these speed I love it,the 550ma was pretty good. I allways had 335km?/h on the SPEEDO..I'm sayi'n SPEEDO,but tt's stability with 4wd is in the other league,jst amazing. By the way you are right on the x50 buy or not buy topic, I would have not bought it if the Werk disclosed info's in detail(especially the short 6th gear)but imade my decision almost 3yrs ago,info's were scarce than.Ihad same kind of expieriences on the 964rs &the 3.8, or 964 3.2 turbo s & 3.6 turbo..it's how it goes but still doesn't make me smile.I think I'm old enough to take it though ..GT3 GT3 3.8..I'm not inn this but they will make some people upset ...but still they will like the new 3.8 right !!?. Can you tell me a good tunning program for the x50 RC?

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Jun 16, 2002 7:11:04 PM

RC: Rennteam Administrator; Loc: Rennteam HQ , Germany; Posts: 59607, Gallery; Registered on: Mar 26, 2002; Reply to: sks

Re: Whistle like noise over 290km/h

There is nothing bad with the X50 ... with the exception of it's price tag. I can't find any justification for the X50 price tag. Let me do some little calculation: the X50 gearbox costs same as the TT gearbox. The turbo chargers cost only slighlty more than the TT chargers. The intercoolers are even cheaper than on the TT. I just don't get it.

Development cost? Porsche can't be serious.

Tuning the X50 is pretty easy: with ECU mods only, you gain easily around 40 HP. Add a different exhaust system with highflow cats to it and some other minor mods and up to 540 HP are possible. Everything over 540 HP isn't actually worth it, unless you want to spend big money and open up the engine.

Where are you living? Send me a private mail.

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Jun 16, 2002 8:05:14 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: RC

Re: Whistle like noise over 290km/h

Yes Porsche is serious..too serious to make money easy.There were some models I would of not touched if I just new things before.&(this time on x50 friendship was also involved tell you later..)better disclosure by them.Maybe Ineed to learn the hard way..I'll face it because I love Porsche cars.But Porsche must think a better trick next time because I'm getting better & poor all the time.!!!!!!? Watch out!!
Where do I find your E-mail address ? sorry RC I'm kind of new Boarding.

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Jun 16, 2002 8:41:46 PM

RC: Rennteam Administrator; Loc: Rennteam HQ , Germany; Posts: 59607, Gallery; Registered on: Mar 26, 2002; Reply to: sks

Re: Whistle like noise over 290km/h

Porsche isn't a cheap product and I guess it is getting even more expensive every day.

If you want to send me a mail, just click on RC Germany in my messages. You'll have the option to send me a private mail or you find my e-mail address which is rc@rennteam.com .

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Jun 17, 2002 1:31:30 AM

FixedWing: Veteran; Loc:; Posts: 870, Gallery; Registered on: May 25, 2002; Reply to: sks

Re: Whistle like noise over 290km/h

I cannot add much to this conversation but I'll try to add the little that I can.

Firstly, I wonder if it could be the diverter valves? This is a known problem with the Turbo but usually shows up in a slightly different way. I would also be surprised if you could hear it over the wind noise at that speed. The fact that you hear the sound means it must be loud.

Ok, if you have the car at 320km/h and you partially or fully lift the throttle does the noise go away immediately? Or does it go away only once the car has slowed some?

If the answer is yes, it goes away immediately then it is likely drivetrain related (engine, transmission, differential, etc.).

If the answer is no then it is likely to be some sort of wind noise or wheel noise.

Either way, I would be very careful with this car at speed until it is sorted out.

S.

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Jun 17, 2002 6:05:29 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: FixedWing

Re: Whistle like noise over 290km/h

Thanks for the reply Fixed Wing.The noise does not come out untill 290..even at full boost in any gear..so it must be something else ? I HOPE NOT THE ENGINE OR BO-VALVES!!..it is very loud like you said,I'm going to look around with the mechanics today for this.. sks

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Jun 17, 2002 9:23:02 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: RC

Re: Whistle like noise over 290km/h

As I took the car to the dealer & checked everything ,could not find the problem..but what the mechanic said was if I drive the car witout the aircon completely off,from certain speed there will be a big differents in pressure from outside & innside of the car & could create this kind of noise if I dont let any air inn..As I remember from yesterday.I had it completely off..I learned today that I should jst press the frost button,when I need maxpower & air inside (air con compressor-off),I'll blast the car on the week-end & check it out. But thanks guys for the help I e-mail you later today RC. sks

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Jun 17, 2002 12:04:11 PM

FixedWing: Veteran; Loc:; Posts: 870, Gallery; Registered on: May 25, 2002; Reply to: sks

Wind noise

So it does sound like some sort of a wind-noise issue (though it could still be some sort of harmonic with the wheels or suspension/driveshafts so be careful).

FWIW, in Belgium I rarely need to run with the air-con on. But I do always have some airflow through the car with the various vents on. I rarely am satisfied with the automatic mode. I would think as long as you have some air flowing through the inside of the car you should be ok.

On the track I will usually leave the windows down to get some air and then when I enter the track I will close them. On one occasion the passenger window did not close fully (probably because I was already going very fast by the time it got to the closed position). I got a banging sound that seemed to me to be a lot like a front spoiler come loose and scraping the ground whenever I was at high speed. I was so sure that was what it was that I even stopped on the track to check it out.

So yes, various air leaks can make some very strange sounds....

S.

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Jun 18, 2002 8:09:54 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: RC

Re: Whistle like noise over 290km/h

Did you recieve my private mail RC? my sent E-mail shows 0 on MY HOME..strange..

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Jun 23, 2002 7:14:45 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: FixedWing

Re: Wind noise

THE NOISE jst doesn't go away,I took care of the defected sealings & aircon but it is still making noise over 290,I heard similar noise at lower speeds today but much quiet,my next guess is tyres..its a bit anoying with a good weather like this....

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Jun 23, 2002 7:12:41 PM

oak: Newbie; Loc:; Posts: 8, Gallery; Registered on: Apr 9, 2002; Reply to: sks

Re: Wind noise

sks, What type of exhaust do you have? I have heard, some exhaust tips cause a whistling sound. If the tips are mounted too far away from the bumper. Try and mount your exhaust tips closer to the bumper.

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Jun 23, 2002 9:19:18 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: oak

Re: Wind noise

Thanks for the info,oak My exaust is normal factory ex.Are they also sometimes mounted like that?The 550 maranello's exhaust always came out about 3cm from the rear spoilers when it got hot..but..hmm. I will check them out.

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Jun 29, 2002 3:46:38 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: sks

Re: Wind noise

The noise is still there ..dealer saids to take out the front glass & replace rubber sealing with more glue..I don't think it will solve the problem.. IT's starting to get on my nerve . I try to be patient though.

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Jun 29, 2002 8:25:36 PM

RC: Rennteam Administrator; Loc: Rennteam HQ , Germany; Posts: 59607, Gallery; Registered on: Mar 26, 2002; Reply to: sks

Re: Wind noise ... try this ...

... you have private Mail, Shin.

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Jun 30, 2002 3:27:37 PM

Ruffian: Newbie; Loc: Southern CA; Posts: 2, Gallery; Registered on: Apr 6, 2002; Reply to: RC

Noise source

Last year my Ruf Turbo R developed a strange wind noise at any speed above 175mph. The noise started after I installed A pillar fairings!Ruf said ignore the noise. Last week we inadvertently ran a long race with the rear window wiper blade improperly folded! Guess what? The noise went away! I unfolded the wiper arm and set it back properly and the noise came back.The source is definitely the rear wiper arm assembly.Only happens when the arm is folded properly after a wash.We shall run all future high speed races without the wiper!

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Jun 30, 2002 6:36:39 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: Ruffian

Re: Noise source

Thanks .I will check it out..It's so strange this noise, the engine is getting better I saw 321km/h on the degital. I was hitting the limiter for a quite sometime after that .not fast like you or RC's rocket but good enough for a slow x50 ha? but going flat out with this noise this speed...you got a be brave...

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Jul 20, 2002 1:16:54 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: sks

Re: Noise source

The source of the noise is coming from the engine,I think it's some kind of air leak some where in the turbo system,div valves i suppose.But the local dealer doesn't take any action!! They said they are waiting instructions from the factory..I personely think thier intranet is having a break-down..It's taking too long .the dealer also tells me the factory never heard of problems with div valves in Germany...PLs do somthing Porsche.. ..or you will lose a big Fan!!

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Jul 21, 2002 8:16:49 AM

FixedWing: Veteran; Loc:; Posts: 870, Gallery; Registered on: May 25, 2002; Reply to: sks

Diverter valves

For what it is worth, my money is still on the diverter valves as the likely source.

S.

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Jul 21, 2002 8:35:36 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: FixedWing

Re: Diverter valves

Yes..I even told the dealer change the div valves & send the invoice to me if it wasn't the cause..but they said Porsche even doesn't know this problem for German cars........strange.

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Jul 21, 2002 9:53:51 AM

FixedWing: Veteran; Loc:; Posts: 870, Gallery; Registered on: May 25, 2002; Reply to: sks

Re: Diverter valves

Yes, strange.

I got the same sorts of looks when I told my dealer that the problem was diverter valves but it didn't take them long to find out about it. Porsche is well aware of the problem.

If you really need to pay for your own diverter valves then probably better to replace them with something else than the original Bosch units. There is lots of info available on this topic on other boards.

If the diverter valves are leaking enough to make noise at speed then I would think it would effect your power. What sort of boosts are you seeing at top speed? How is the responsivness of the engine when you come off the power and back on again (for example, when you shift or when you just back off for a moment for a corner or for traffic)?

S.

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Jul 21, 2002 2:35:24 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: FixedWing

Re: Diverter valves

The noise come when I put on full load on the engine for prolonged period.(flat out in 6th gr)above 6200rpm..on the speedo around 290km/h ..It doesn't happen in other gears because you can't keep always full load & full boost on lower gears, we need to shift up .The noise get bigger as I rev the engine up .The boost is 0.8 or 0.7..& comes down quickly to 0.6. I recognize the boost doesn't shoot up to 1.0 any more in any situations. (max prolonged boost is 0.9,catalog spec) The over shoot for the x50 is 1.0(dealer confirmed it with factory) which I saw frequently for a second or so,but after this problem I don't see it any more & feel a bit of loss in the power when reved over 5500...but the car still goes 321km/h on the speedo & the dealer jst can't tell the loss of power physically ,they think it's fast enough or good enough..but it's not...With a big support from some of the people on this board ,I try to be patient..,but I am really unhappy about all this..Are you listening to the real Fans Porsche?? as a company you need to find a better system to attack after mkt problems....dealers &customers need more info's & data's imediately..I never would leave my clients with problems & go on holidays....they do this & still sell cars,, which is the problem...I alway admire if buissnes was so so easy..

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Jul 21, 2002 2:54:42 PM

FixedWing: Veteran; Loc:; Posts: 870, Gallery; Registered on: May 25, 2002; Reply to: sks

Re: Diverter valves

If you are seeing and feeling changes in the power and especially, if the overboost is not hitting 1.0 anymore then this is very likely to indicate a diverter valve problem. The diverter valves are leaking which is why you aren't building the pressure in the system for that moment before they open to relieve the back pressure.

No doubt, they are leaking all of the time which is robbing you of a bit of the early boost which means less responsivness to throttle application and slower spool-up on the turbos. The reason that they make a noise at high velocity is that there is a harmonic at that frequency. But they will be leaking all of the time. There is probably a rip in one of them.

It doesn't surprise that you can still hit top speed. Porsche lowered the 6th gear to prevent the car from going faster. So it is easy for you to hit. Also, once the turbo is spooled up, it can likely make up for the defecit caused by the leak. Which is why you are still seeing 0.9 bar boost.

S.

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Jul 21, 2002 3:11:04 PM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: FixedWing

Re: Diverter valves

But the dealer lacks the brain even to speculate these things.. They were going to change the front glass sealings you know..If I didn't tape my glass & confirm every thing was all right they would of operated on ...so anoying...You said your dealer confirmed the existance of this problem with the factory..can you ask your dealer whom they confirmed with at porsche? If you can get the tel number & send them through private message it would be super helpfull.I'll let the technical guy call from the dealer .I know there are tons of problems with the div valves,I even copied other boards hoping they would get some idea's..but they jst don't get it..

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Jul 21, 2002 10:15:37 PM

RC: Rennteam Administrator; Loc: Rennteam HQ , Germany; Posts: 59607, Gallery; Registered on: Mar 26, 2002; Reply to: sks

Re: Diverter valves ... Shin

... you know what you have to do.
Do it NOW and forget about your dealer. Trust me.

Good luck!

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Jul 22, 2002 7:21:36 AM

sks: Newbie; Loc: subway station; Posts: 37, Gallery; Registered on: Jun 16, 2002; Reply to: RC

Re: Diverter valves ... Shin

I know RC.. ..I 'm working on it . I jst wanted to play with them for the time being.thats all..thanks for paying attention but I will do exactly what counts this time.

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Jul 22, 2002 11:41:43 AM

Goodwood: Junior; Loc:; Posts: 62, Gallery; Registered on: Apr 11, 2002; Reply to: sks

Re: Diverter valves ... Shin

If my DV's go bad, I would positively insist they put in the DV's of MY choosing, be they Bailey (prefered), or even Forge, but Never the OEM Bosch again. From what I hear, they are on their 6th version of them and STILL can't make them to hold up very long. It's due to their inherint poor Bellows design, as compared to the Bailey's that don't have a rubber bellows to tear.

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Whistle like noise over 290km/h

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