asianorange

I just installed a used ZPI stage zero from Thansenite and so far, so good. I have one concern though - when I mash the throttle a bit the spool up sounds a bit choppy and the volume increases dramatically. The choppy sound seems to follow the RPMs then disappears when I let off. Is this normal or to be expected? Is that the cylinders making noise out the open wastegate? Since it's an atmospheric dump less than 12 inches from the cylinder head (log manifold) is that because it's loud or is something wrong?

athletefeet66

iTrader: (1)

fuel cut?
are you tuned or have bigger injectors or at least a wideband?

asianorange

doubt it's fuel cut - while I do have on '07 that's not it. it occurs when I'm running about 20/30 mph and I press the throttle to about 50/60% and rev from the 2000's to the 4000's

I have an AEM UEGO. At idle it seems to display closed loop operation and shows the ECU is working toward 14.7/14.8. On light throttle depression it richens up but never below the 10's.

Basically it sounds like fluttering up to before the BOV releases when i let off the gas to shift. But the sound is heavy, I'm suspecting it's just the wastegate but I'm assuming I should be hearing more than 5-10 pulses per second. At cruising the sound is nonexistent.

OuterHeaven

Do you have a boost gauge? I bet this is just the wastegate starting to open. That 16g will build boost very fast and you can be at full boost with less than 50% throttle. The wastegate does not open and close very fast. I would say only 2 to 8 times per second. If it went any faster I bet the rubber diaphragm would fail. I am guessing it is making the same noise at WOT but only louder right?

asianorange

I have a boost gauge but it's not working very well. the plastic vacuum hose won't stay put. At idle while pushing the hose into the gauge it reads -6 psi but relaxed it falls to -3. on boost it shows about 2-3 psi but the hose issue is definitely affecting the reading.

You're correct it gets louder as I approach WOT. Since it's not present in gentle acceleration I assumed it's the wastegate and I'm hearing either that flap or the open exhaust ports trumpeting through. I'm just not comfortable with it. It sounded a lot like a beater with a hole in the exhaust. I just wasn't expecting it to be so dramatic

In other news I backed everything out, reinstalled the stock header and air intake and capped the oil drain fitting. The EGT gauge also seems to be faulty. With the probe disconnected the gauge read pegged when it received switched power but with the probe attached it only reads zero. I'll revisit this when I can rebuild the turbo and install some functional gauges.

speedy000

iTrader: (2)

open dump ftmfw!!!!!!!!
it sounds like that because its just dumping your exhaust straight into the atmosphere!!!!! i personaly like it!
the cars quiet and stealthy then some one pulls up on you and you let it rip they wont know wtf happen!

scion_andrew

iTrader: (2)

^
lol