Sound coming from back of intake

**bryceslu** · 09-21-2009, 10:22 AM

Ive got this sound that comes from the back of the intake area when i hit the throttle abruptly from idle. for example when i pull up on the throttle cable quickly or step on it while idling or very low rpm. But doesnt do it if i use the throttle normally or gradually, just when i make the equivalent of stomping on it.

It is a whooshing sound or an air sucking sound that seems to come from the back somewhere towards the top of the engine. It really sounds like its pulling in air real fast, but once the rpms catch up it stops. so in other words it is like 1 sec. and it seems like the rpms will drag for a sec and then catch up.

Has anyone had this or heard it before and can offer some insight, its a gm stock replacement LS1 long block that has about 30K on it. I guess the intake was reused from last engine which had 80K on it.?

**shady milkman** · 09-21-2009, 11:16 AM

sounds normal to me.

**bryceslu** · 09-21-2009, 12:26 PM

Originally Posted by shady milkman

sounds normal to me.

haha...thats why I posted and was hoping to hear....soo what exactly does that noise come from? it definitly sounds like it shouldnt be happening though.

**shady milkman** · 09-21-2009, 12:29 PM

i think its the acoustics of the engine ...its just in initial surge of air

**Hi-Po** · 09-22-2009, 10:40 AM

Car run poorly? Only thing back there is the OPSU.

**shady milkman** · 09-22-2009, 02:23 PM

Originally Posted by Hi-Po

Car run poorly? Only thing back there is the OPSU.

map is also back there..as is that weird thing that the brake booster plugs in and hvac too ....but if he isn't running bad...i dont think there is a problem

**bryceslu** · 10-01-2009, 06:42 PM

NO offense Shady...
But can No One else confirm this noise or at least say theyve heard it before?

**shady milkman** · 10-02-2009, 04:14 AM

well its really hard to know what you hear without audio ..our engines are very very loud

**bryceslu** · 10-02-2009, 07:40 PM

Originally Posted by shady milkman

well its really hard to know what you hear without audio ..our engines are very very loud

Ill try to get a video from my camera when its no longer raining. Its def. audible over the engine noise.

**bryceslu** · 10-05-2009, 01:56 PM

OK i just took a video of it...can kind of hear it..and it seems to be coming more from the front area of the intake. I will be making a new thread with the video.
THanks.

**bryceslu** · 10-05-2009, 03:45 PM

Ive got this sound that comes from the front of the intake area when i hit the throttle abruptly from idle. for example when i pull up on the throttle cable quickly or step on it while idling or very low rpm. But doesnt do it if i use the throttle normally or gradually, just when i make the equivalent of stomping on it.

It is a whooshing sound or an air sucking sound that seems to come from the back somewhere towards the top of the engine. It really sounds like its pulling in air real fast, but once the rpms catch up it stops. so in other words it is like 1 sec. and it seems like the rpms will drag for a sec and then catch up.

Has anyone had this or heard it before and can offer some insight, its a gm stock replacement LS1 long block that has about 30K on it. I guess the intake was reused from last engine which had 80K on it.?

Here is the video of it: (feel free to turn up your volume) you can hear it best at the 2nd rev and also the last one.

**DaddySS** · 10-05-2009, 04:29 PM

I don't hear anything unusual - the throttle body will make that sound because you're causing a sudden rush of air - am I missing something?

**shady milkman** · 10-06-2009, 05:13 AM

quick question..is your intake 100% stock or is it a lid or a cai etc ?

**tatertot91** · 10-06-2009, 05:28 AM

yeah mine does that, quick blip of the gas and it sounds like air is sucked in somewhere

**shady milkman** · 10-06-2009, 06:34 AM

sounds 100% normal..quieter then mine

**bryceslu** · 10-06-2009, 08:45 AM

Originally Posted by tatertot91

yeah mine does that, quick blip of the gas and it sounds like air is sucked in somewhere

That is exactly what i was looking for....now is this normal though?

**bryceslu** · 10-06-2009, 08:46 AM

Originally Posted by shady milkman

quick question..is your intake 100% stock or is it a lid or a cai etc ?

Ive got a SLP Lid

**shady milkman** · 10-06-2009, 09:21 AM

Originally Posted by bryceslu

Ive got a SLP Lid

yea sorry i asked before i watched the video

**DaddySS** · 10-06-2009, 11:04 AM

I think (as you can tell by the replies) that it is normal -get out there and drive it and hev some fun!

**Benner** · 10-06-2009, 11:15 AM

very possible it's just from the pressure change that's coming from vacuum being pulled on the brake booster. Sitting in class so I can't watch the video but very good possibility it's what I just mentioned.