Fluttering sound on shift
07-11-2004, 01:17 AM
#62
Nordschleife Master
I got a video from Rage called "20031023 - 944 Turbo Drifting.wmv" and his car makes the exact same BOV noise.
I'd say as long as the engines works fine and boost comes on directly after gear change leave it be..
I'd say as long as the engines works fine and boost comes on directly after gear change leave it be..
07-11-2004, 02:17 AM
#64
Three Wheelin'
NZ, I have the TurboXS Recirculation valve, and it has a sping that can be adjusted with shims (washers) to make it stiffer. I did some experimenting with the stiffness of the valve whe I first got it, and I heard the same sounds you have when the spring rate was set too stiff. With a stiff spring, you might help prevent boost leaks (depending on how it is plumbed), but you also increase the amount of vac you need to open it and vent that pressure.
07-11-2004, 07:01 PM
#66
Burning Brakes
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NZ951, that is the same sound my car made. Checked the BOV by sucking and blowing on it to see if it was leaking and it wasn't. Then the gobbling got a bit worse. Checking my BOV again I could see a minute tear in the diapraghm, replaced it and get a much nicer whoosh sound. I general when you hear the turkey gobbler sound it is a good sign that not enough air is bypassing so you get some pressure waves going in the discharge side of the compressor.
07-12-2004, 01:47 AM
#67
Race Director
Thread Starter
I agree, but this is a brand new Tial and I had the same sound with my stock unit. Hard to see where the BOV may be failing in this situaltion.
07-12-2004, 04:24 AM
#68
Pro
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Originally posted by NZ951
Ok, apparantly Tial include the 13lb stiffest spring as stock, but how to determine the correct spring rate scientifically?
Ok, apparantly Tial include the 13lb stiffest spring as stock, but how to determine the correct spring rate scientifically?
07-12-2004, 05:07 AM
#69
Nordschleife Master
Isn't the tial adjustable? Almost every BOV is.
I think it would be hard to calculate the exact right spring.
The BOV is usally set by tightening it up so you get the gobble, and then back it off a bit so you get the woosh on full boost.
I think it would be hard to calculate the exact right spring.
The BOV is usally set by tightening it up so you get the gobble, and then back it off a bit so you get the woosh on full boost.
07-12-2004, 07:34 PM
#71
Track Day
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All,
This post is starting to concern me. I am about to install a 60-1 hi-fi turbo on my 951 and am running a stock BOV and was not planning on changing to a different BOV. Are other people running these large turbos with stock BOVs? Thanks,
This post is starting to concern me. I am about to install a 60-1 hi-fi turbo on my 951 and am running a stock BOV and was not planning on changing to a different BOV. Are other people running these large turbos with stock BOVs? Thanks,
07-14-2004, 04:59 AM
#72
Advanced
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nz951, try to connect the hose from the bov to the intake manifold.
if you connect the hose to the ic pipes ,when you depress the gas pedal and close the trottler body flap, the boost go to spike , and the bov dont work well. that is the reason for the turbo surge first and then the bov.
if you connect the hose to the ic pipes ,when you depress the gas pedal and close the trottler body flap, the boost go to spike , and the bov dont work well. that is the reason for the turbo surge first and then the bov.
07-14-2004, 12:05 PM
#75
Drifting
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NZ do you still have the vapor purge system in? If so, cap the line that comes off the bottom of the TB. Then plug your BOV directly into that port and see if the sound is any different.