Generation IV External Engine LS2 | LS3 | LS7 | L92 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

What is this noise???

Old Oct 5, 2010 | 05:50 PM
  #1  
grey-goat05's Avatar
Thread Starter
Teching In
15 Year Member
iTrader: (1)
 
Joined: Jul 2007
Posts: 5
Likes: 0
From: Union, Mo
Default What is this noise???

I have tried just about everything to narrow down what this sound is on my 05 A4 vette. I've just about given up. Its a much more metallic sound in person. It happens under moderate acceleration in the 2 - 3k RPM range.

http://www.youtube.com/watch?v=5E-1wCRVgjM


Here's what I've tried...

Detonation - put in a brand new set of plugs and drove it around for a while - no signs of detonation on the plugs and nothing in HP tuners when the noise is happening.

Exhaust leak - I have kooks, high flow cats and 08 NPP mufflers - I swapped back to the stock exhaust, and changed header gaskets - didn't make a difference.

Anything bouncing around near the fans or pulleys - gone over this a dozen times - everything is tied back no where near being able to hit the fans or pulleys.

I put it on a dyno last week - it would not make the sound - even applied the brakes on the drum to put more load on the car... still nothing.

I regreased my caliper pins and tightened up my brake pad clips - didn't make a difference.

Pulled and looked over the valve springs, rocker arms etc...

The noise does seem to stop when I apply the brakes so the last few days I've been concentrating on them - but can't see anything wrong.

I'm not sure what else to do. My mods are listed below - I put them all on last November - it started making this noise a few months ago.

cam
3200 stall
kooks, high flow cats, NPP mufflers
DTE rear end with 3.42 gears

Anybody got any ideas?
Reply
Old Oct 5, 2010 | 06:14 PM
  #2  
mattinokc's Avatar
Staging Lane
 
Joined: Sep 2010
Posts: 51
Likes: 0
Default hmm

man I wanna say transmission pump but I might be wrong

I have heard detonation like that when i was working with a tuner on a old car of mine

sounded very similar but higher up in rpms

not sure

hope you find it man
Reply
Old Oct 5, 2010 | 07:24 PM
  #3  
c6 batmobile's Avatar
On The Tree
iTrader: (2)
 
Joined: Jul 2010
Posts: 106
Likes: 0
From: OKC OKlahoma
Default

What about an exhaust clamp hitting the frame underneath?

You said HP tuners was showing no KR?

Does it only happen when you apply the brakes or is it under mild acceleration?
Reply
Old Oct 5, 2010 | 07:47 PM
  #4  
65panel5.3's Avatar
On The Tree
 
Joined: Oct 2010
Posts: 127
Likes: 0
Default

once had a lifter that ticked but only under load like that altough if it stops when hitting the brakes its doubtful it would be that.. its tricky. maybe a longer vid with more of whe the sound comes and goes would be helpful ive also heard wheel bearings click like that too
Reply
Old Oct 5, 2010 | 08:39 PM
  #5  
grey-goat05's Avatar
Thread Starter
Teching In
15 Year Member
iTrader: (1)
 
Joined: Jul 2007
Posts: 5
Likes: 0
From: Union, Mo
Default

I've checked all the exhaust clamps, there clear of everything.

The sound only happens on acceleration - so thats why I put it on a dyno last week to try and pinpoint the noise - however it didn't make the noise on the dyno - this I think has stumped me the most...

The noise does seems to go away when I apply the brakes as I'm accelerating.

HP Tuners shows no KR when its making the noise.

I took a couple video's today - its hard to make it out on most over the road noise in the camera - but this one is a little longer:

http://www.youtube.com/watch?v=5jQxTp71o_8
Reply
Old Oct 5, 2010 | 10:50 PM
  #6  
c6 batmobile's Avatar
On The Tree
iTrader: (2)
 
Joined: Jul 2010
Posts: 106
Likes: 0
From: OKC OKlahoma
Default

coming from front or back? can you tell?
Reply
Old Oct 6, 2010 | 08:14 AM
  #7  
grey-goat05's Avatar
Thread Starter
Teching In
15 Year Member
iTrader: (1)
 
Joined: Jul 2007
Posts: 5
Likes: 0
From: Union, Mo
Default

Sounds like its coming from the front of the car. I think from the passenger side - but not sure on that.

Also forgot to mention it does not make the noise if i put it in neutral and rev it up.
Reply
Old Oct 6, 2010 | 10:30 AM
  #8  
Schwanke Engines's Avatar
LS1TECH Sponsor
iTrader: (1)
 
Joined: Dec 2007
Posts: 849
Likes: 3
From: Springfield, MN
Default

It sure sounds like part throttle pre-ignition to me. What kind of timing are you running when it is doing it?
Can you post a log file?
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-1

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-2

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-3

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-4

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-5

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-6

10 Camaros You Should Never Buy

 
story-7

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
story-8

Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

 Brett Foote
story-9

10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

 Verdad Gallardo
Old Oct 6, 2010 | 10:39 AM
  #9  
grey-goat05's Avatar
Thread Starter
Teching In
15 Year Member
iTrader: (1)
 
Joined: Jul 2007
Posts: 5
Likes: 0
From: Union, Mo
Default

It does sound very much like Detonation. However even if I soften up the tune it makes no difference. Thats also why I swapped in new plugs and checked them - no sign of detonation on the plugs.

And I figured if its knocking like that on the street - it should on the dyno as well.
Reply
Old Oct 6, 2010 | 10:50 AM
  #10  
Greekey's Avatar
TECH Fanatic
iTrader: (3)
 
Joined: Apr 2008
Posts: 1,297
Likes: 1
From: Warren, Ohio
Default

I had a similar sounding noise happening when I was accelerating. It turned out that it was a blown exhaust manifold gasket. Double check and see if you have any carbon build up around the exhaust manifolds where they bolt to the engine. You have to look very closely. It will be extremely difficult in some cases to spot an exhaust leak coming from the gaskets.

Last edited by Greekey; Oct 6, 2010 at 11:07 AM.
Reply


Thread Tools
Search this Thread

All times are GMT -5. The time now is 10:55 AM.

story-0
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-1
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-2
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-3
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-4
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-5
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-6
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-7
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE
story-8
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0

The world was a better place when it was still around.

By Brett Foote | 2026-01-23 09:20:37


VIEW MORE
story-9
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever

Slideshow: The 7.0-liter LS7 was designed for absolute cutting-edge performance.

By Verdad Gallardo | 2026-01-07 18:36:00


VIEW MORE