FAST 90 Lsx Intake Help, Whistle?
05-25-2005, 07:02 AM
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FAST 90 Lsx Intake Help, Whistle? SOLVED! edit: read lower in the thread for the solution!
Hi Folks,
I finally got my FAST 90 intake with LS2 TB on my 2004 Z06. It started fine, and idles decently. It tends to stall when I clutch it, but I am working on my tune and will figure it out.
The problem is the whistle after the car warms up. Actually, it is not a whistle... it is a SCREAM. It screams at idle (950 rpm) and part throttle cruising, but (seems to) go away at 50+% throttle. The pitch of the scream does not really change with RPM. It sounds like a belt.
I have checked the MAP sensor and feel like its OK (I wiggled it at idle). My LTFT's look OK, so I don't *think* it is a vacuum leak.
I have ported the TB slightly and spent quite a bit of time porting the intake. All of this was under the supervision of a porting "expert".
TIA,
Andy
Hi Folks,
I finally got my FAST 90 intake with LS2 TB on my 2004 Z06. It started fine, and idles decently. It tends to stall when I clutch it, but I am working on my tune and will figure it out.
The problem is the whistle after the car warms up. Actually, it is not a whistle... it is a SCREAM. It screams at idle (950 rpm) and part throttle cruising, but (seems to) go away at 50+% throttle. The pitch of the scream does not really change with RPM. It sounds like a belt.
I have checked the MAP sensor and feel like its OK (I wiggled it at idle). My LTFT's look OK, so I don't *think* it is a vacuum leak.
I have ported the TB slightly and spent quite a bit of time porting the intake. All of this was under the supervision of a porting "expert".
TIA,
Andy
Last edited by mcneil141; 05-28-2005 at 05:12 PM.
05-25-2005, 07:01 PM
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A friend of mine suggested that my PCV arrangement could cause some noise. I'll start it and uncap the oil filler. Opinions?
Andy
Andy
Originally Posted by mcneil141
Hi Folks,
I finally got my FAST 90 intake with LS2 TB on my 2004 Z06. It started fine, and idles decently. It tends to stall when I clutch it, but I am working on my tune and will figure it out.
The problem is the whistle after the car warms up. Actually, it is not a whistle... it is a SCREAM. It screams at idle (950 rpm) and part throttle cruising, but (seems to) go away at 50+% throttle. The pitch of the scream does not really change with RPM. It sounds like a belt.
I have checked the MAP sensor and feel like its OK (I wiggled it at idle). My LTFT's look OK, so I don't *think* it is a vacuum leak.
I have ported the TB slightly and spent quite a bit of time porting the intake. All of this was under the supervision of a porting "expert".
TIA,
Andy
I finally got my FAST 90 intake with LS2 TB on my 2004 Z06. It started fine, and idles decently. It tends to stall when I clutch it, but I am working on my tune and will figure it out.
The problem is the whistle after the car warms up. Actually, it is not a whistle... it is a SCREAM. It screams at idle (950 rpm) and part throttle cruising, but (seems to) go away at 50+% throttle. The pitch of the scream does not really change with RPM. It sounds like a belt.
I have checked the MAP sensor and feel like its OK (I wiggled it at idle). My LTFT's look OK, so I don't *think* it is a vacuum leak.
I have ported the TB slightly and spent quite a bit of time porting the intake. All of this was under the supervision of a porting "expert".
TIA,
Andy
05-25-2005, 10:11 PM
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I didn't have time to work on the car tonight, but I'll try tomorrow, first uncapping the oil filler, then searching for a vacuum leak with unlit propane or carb cleaner.
If I had it to do over again, I would:
Use the original intake bolts so I could properly torque the back bolts.
Use RTV around the TB seal (carefully).
Use RTV inside the intake where it comes apart. (You'll see where the factory had small amounts).
Shave down the MAP sensor, so it doesn't fit quite so tightly to the firewall. (Fortunately, I used enough RTV to hold it tightly in the manifold)
I may go back and do these things anyway this weekend.
I'll post back with answers (assuming I figure something out
)
Andy
If I had it to do over again, I would:
Use the original intake bolts so I could properly torque the back bolts.
Use RTV around the TB seal (carefully).
Use RTV inside the intake where it comes apart. (You'll see where the factory had small amounts).
Shave down the MAP sensor, so it doesn't fit quite so tightly to the firewall. (Fortunately, I used enough RTV to hold it tightly in the manifold)
I may go back and do these things anyway this weekend.
I'll post back with answers (assuming I figure something out
)Andy
Originally Posted by 02SOMWS6
keep us posted on what the cause was. I am getting ready to install the same intake once I smooth out the seams inside the ports.
05-28-2005, 05:08 PM
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OK,
I figured out the problem, (if anyone cares)
I didn't have to do any of the things I listed above. As soon as I pulled the oil filler cap, I knew what the problem was.
I Tee'd the valley cover vent and the valve cover vent into the FAST port on the passenger side. Wrong move. I was pulling BIG vacuum.
I simply routed the valley cover breather into the proper port on the intake, and put a breather on the valve cover vent. Problem solved.
Also, the car stopped stalling (duh) and I cannot hear any whistle from intake or TB. Of course I do have Borla Stingers to mask any outside noises.
I will be installing a catch can on the valley cover tomorrow.
Andy
I figured out the problem, (if anyone cares)
I didn't have to do any of the things I listed above. As soon as I pulled the oil filler cap, I knew what the problem was.I Tee'd the valley cover vent and the valve cover vent into the FAST port on the passenger side. Wrong move. I was pulling BIG vacuum.
I simply routed the valley cover breather into the proper port on the intake, and put a breather on the valve cover vent. Problem solved.
Also, the car stopped stalling (duh) and I cannot hear any whistle from intake or TB. Of course I do have Borla Stingers to mask any outside noises.
I will be installing a catch can on the valley cover tomorrow.
Andy
Originally Posted by mcneil141
I didn't have time to work on the car tonight, but I'll try tomorrow, first uncapping the oil filler, then searching for a vacuum leak with unlit propane or carb cleaner.
If I had it to do over again, I would:
Use the original intake bolts so I could properly torque the back bolts.
Use RTV around the TB seal (carefully).
Use RTV inside the intake where it comes apart. (You'll see where the factory had small amounts).
Shave down the MAP sensor, so it doesn't fit quite so tightly to the firewall. (Fortunately, I used enough RTV to hold it tightly in the manifold)
I may go back and do these things anyway this weekend.
I'll post back with answers (assuming I figure something out )
Andy
If I had it to do over again, I would:
Use the original intake bolts so I could properly torque the back bolts.
Use RTV around the TB seal (carefully).
Use RTV inside the intake where it comes apart. (You'll see where the factory had small amounts).
Shave down the MAP sensor, so it doesn't fit quite so tightly to the firewall. (Fortunately, I used enough RTV to hold it tightly in the manifold)
I may go back and do these things anyway this weekend.
I'll post back with answers (assuming I figure something out
)Andy
