Saab 92 Forum : Saab92x.com / Wastegate noise on linear *solved

2JZ · 2012-04-13 00:42:04

During WOT anything above 4000rpm my linear unleashes its hidden 'wastegate'. Basically makes a whistle tip noise, and goes wooooooooooooooooo. But not woooo wooooooooo.
I checked the history and Bub Rub was definitely not the previous owner.

It's definitely very audible it's loud and it's high pitch tone is keeping up people at night. I don't really go that high up on the rpm often so i have no idea when it started but I don't EVER recall it doing this.
Only thing that's different is i changed the oil, 5w-20 was the only thing left. Exhaust leak? Vacuum leak? All stock 2.5i

Last edited by 2JZ (2012-04-15 12:20:26)

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Azrael · 2012-04-13 00:51:33

Exhaust would be my first guess.

2JZ · 2012-04-13 01:01:15

Azrael wrote:
Exhaust would be my first guess.

might as well throw it out there. I got a pretty shitty heat shield rattle.

for the mileage and salt belt region, the heat shield is in really good shape and not rotting at all. Just rattling..

Linear Man · 2012-04-13 08:25:16

I cut mine off. All of them. Your patience (or possibly fear of a CEL) apparently exceeds mine. Those heat shields were designed by a child of Satan.

2JZ · 2012-04-13 10:27:20

Linear Man wrote:
I cut mine off. All of them. Your patience (or possibly fear of a CEL) apparently exceeds mine. Those heat shields were designed by a child of Satan.

No CEL doesn't necessarily mean everything is running okay. It's definitely there for a reason, i went to a shop to get them removed but the mechanic insisted to leave them on. It also helps with the overall efficiency of the cat. Im afraid of removing them because I basically decided on the driving my car for another 4 years which means another 80,000 miles of reliability would be great.

from everything i read, the whistle noise can be a cat or a muffler.

tonka92x · 2012-04-13 13:46:04

2JZ wrote:
No CEL doesn't necessarily mean everything is running okay.

Actually it does. Or, more correctly, the engine and emissions system is operating within an acceptable window that allows the permitted emission performance. If the engine and/or emissions system allows greater than the permitted emissions AND the CEL does not light the manufacturer is liable for some pretty hefty fines as well as fixing every last one of the vehicles. And additional scrutiny from the EPA & CARB. It's a manufacturer's worst nightmare.

Note that an engine operating within an acceptable window doesn’t necessarily mean the engine is operating at its absolute peak performance, but, given the emissions levels modern vehicles need to hit, it is going to be damn close.

Currently working on OBD compliance for a hybrid drivetrain.

2JZ · 2012-04-13 14:09:51

tonka92x wrote:
2JZ wrote:
No CEL doesn't necessarily mean everything is running okay.
Actually it does. Or, more correctly, the engine and emissions system is operating within an acceptable window that allows the permitted emission performance. If the engine and/or emissions system allows greater than the permitted emissions AND the CEL does not light the manufacturer is liable for some pretty hefty fines as well as fixing every last one of the vehicles. And additional scrutiny from the EPA & CARB. It's a manufacturer's worst nightmare.

Note that an engine operating within an acceptable window doesn’t necessarily mean the engine is operating at its absolute peak performance, but, given the emissions levels modern vehicles need to hit, it is going to be damn close.

Currently working on OBD compliance for a hybrid drivetrain.

lol you convinced me, it's coming out. But come on, all that heat has to has some sort of negative effect, why else waste all that time and money putting it there in the first place?

Linear Man · 2012-04-13 14:55:40

I think it's there to get the cat warmer faster, helping with emissions. I don't know that for a fact, but seems likely. I hated them rattling all the time, so I cut them off.

Bryan · 2012-04-13 15:14:55

Check your exhaust hangars, too. I was tracing what I thought was a heat shield rattle, and discovered that the welds on one of the hangars had cracked, and was able to separate it from the pipe by hand. When I got it all fixed, the odd exhaust note I heard when coming off the throttle went away.

2JZ · 2012-04-14 02:16:12

Bryan wrote:
Check your exhaust hangars, too. I was tracing what I thought was a heat shield rattle, and discovered that the welds on one of the hangars had cracked, and was able to separate it from the pipe by hand. When I got it all fixed, the odd exhaust note I heard when coming off the throttle went away.

I lifted the car on a hoist and kept banging the heat shield. sounds like it's on the down pipe area sad

i'll check that out though, thanks