Hi Mad Ness
Here is a quick one to think about.
Have you ever driven with a hose blown off, there is a distinctive sound of turbo pressure blowing out, the turbo sounds different as well. Its not under any load and has a distinctive no load whine/wush. If a check valve has blown else where would you hear it? The k24's are capable of producing great boost pressure but also very high air flows at those pressures. That much air going some where must be heard? If its is being reduced through a small bore pipe then the pressure will rise and the sound will get louder. Is a very small check valve burst enough to vent off that much boost? A split rubber hose will give the devils hell of a squeal.
Frank

Ps I dont even know your first name.

Just a quick one on injectors , I see where its going, but wouldn't standard injectors still make boost but cause detonation as the air flow/boost outpaces the fuel rate. A duff injector will show up and again you could run on 5 cylinders and still be able to produce some boost even with a misfire.

 

(A)

(B)


first picture you can see a setback valve...second picture i miss the setback valve ....

 

that start up issue may be due to the RC injectors... and they are 58lbs not 60s...
thats just a guess but we have had some issues with those...
but that still would not be a problem and We have a car with them on... maybe the program is not calibrated for them....

 

at this picture i miss the setback valve

 

frank, please excuse the oversight... how could i be so rude. magnus here.

if there was a misfire situation or like, I'd think DTCs would be popping left and right? doesn't feel like the car's running on 5.

yes on a jdm (map sensor) supra, had a leak, yes you can hear it. complete power loss if the hose pops off. but nothing like this on the 996 it drives perfectly normal and no suspect noises. can hear the turbo "buzz" spool up (to 0.4bar)

thats why suspecting the diverter valves. i wouldn't hear them leak re-circulating boost.

 

right, may be the file could be fine tuned to compensate for start up. But sometimes it's ok, so i dunno... flash is supposed to provision for these exact injectors.

 

where's waldo?

which one's the "setback valve"?

is it the one with red arrow? thanks

 

Hi Magnus,
Alas I have little experience with divert er valves, most of my last Turbo cars Run Anti-Lag systems so cant have Blow Off or Recerc Valves. it would contrary to the idea that you are trying to create boost even with your foot off the Gas.
Still good luck, I hope its just the DV's that would be so simple a Fix !
Frank.

 

Thanks for the advice - will do. It's fairly cool (e.g. dense) here with temps in the high 50's and moderate humidity. But I'll ask. I noticed it again yesterday - pretty consistent on this gas.

I figured it was crappy 92 oct gas, was going to see if MS109 did the same at the track later this week. I have a drum, and I'll pump it in, unless its another cold, wet day, then I won't waste it.

EDIT: Ah ... I see Kevin's post on pg 2. thanks Kevin. Good to know. Unfortunately, I have to live those K24s for a while. No new spinners for me anytime soon.

 

I would flash it back with oem file if possible so you're sure the new flash isn't the problem.

 

thanks but dont think can do this cos injectors and TB are larger now

 

I think it won't do any harm to try once with oem software,you'll run a bit richer but you won't destroy your engine.All you have to do is make one pull to see the difference.

 

Yes that is the valve, at this point you loose boost

 

hmmm. couple questions come to mind. you think that little hose can cause boost pressure drop from 1.2bar to 0.4bar? and what's this check valve for because there isn't one to begin with stock. this valve is part of the AP TB addition. does the standard 996tt have this built into the plenum? thanks

 

hope my english is good enough to explain it

the oem intake plenum has its own valve inside on top...you can check it if you blow into the fitting but you cant sug air out...so you loose boost without a external valve on after market intake plenum
i dont know if the ap intake plenum have this valve in that place...but i know the ipd plenum doesnt have the valve and so you must use a external valve...

yes you loose all your boost at this hose..if this is the air ventilation of oil reservoir....

again sorry about my english ...hope it helps