cammed05pbm

I need your help LS1tech. So, I just installed long tube headers in my 01 T/A. Had some issues, cracked a plug on removal so I replaced them all, header hit on steering knuckle so I ground the knuckle down and dented the primary, had to fabricate EGR/AIR block off plates, and y pipe would not mate with the rest of the stock exhaust so I cut a bit off of both.

Everything is buttoned up, and I still have a slight exhaust leak where the y pipe mates up to the over axle pipe, but I think I have a bigger issue. At idle (seems to be idling at 500 rpms) theres is a HUMMMMMMMMM noise and a vibration throughout the whole car. Putting it in neutral or park MOSTLY eliminates the problem.

Any ideas?

02 NHRA

Where does it sound like its coming from? The whole car? First thing that comes to mind would be contact between one of the pipes and the undercarriage or suspension/axle?

ncorrell

iTrader: (3)

did you do poly motor mounts? had a very similar issue except it was under acceleration when i heard the vibration. the stock motor mounts are very flexible and were allowing the engine to rotate and the y pipe would hit the floorboard.

cammed05pbm

Under acceleration it's actually fine aside from the leak. I did not do poly mounts.

It is the whole car. Is 500rpm normal for in-gear idle? I guess I'll have to get under and see if its hitting the k member. Headers really are a PITA

DREAMZ28

iTrader: (1)

I have a vibration on my car too. I scrapped backing out of my driveway and the left tailpipe ripped off the rubber hanger (not sure what to call it) so now it vibrates at a few different rpms. Might want to check to make sure theres no loose pipe vibrating freely.

omarrakeen

iTrader: (2)

this.

since its continuous humming its mostly a header shaking against the K member or even the floor. if it was your I or Y pipe it would be banging or casual scraping on acceleration/deceleration. go under there and have a closer look. what long tubes are they? you seem to have a lot of fitment issues.

libertyforall1776

iTrader: (2)

Driver side k-member needs to be notched, and the driver y-pipe seems to be a common touch point against the floorboard. I am still trying to get my metal on metal issues resolved with ARH -- going to a 2nd shop to clearance them on Friday…

I put in new OEM motor mounts, and ARH says poly should not be required, but I am starting to believe that poly mounts are a pretty good idea…

demonspeed

iTrader: (7)

Just as an FYI -- I put in poly mounts when I did my PaceSetters a few weeks ago. Fitment is perfect and there is no noise/banging. The poly mounts did not change a thing with vibrations or how the car feels compared to the way it was with the factory rubber mounts. My verdict for anyone looking at long tubes (or even just replacing mounts): don't be a sissy and just get the poly mounts!

black79transam

I know this a revive but thought I would share my experience.

Got my speed engineering, TSP Y, and poly mounts installed today. I noticed that I still am getting a slight and somewhat random bang of the y pipe. The biggest issue is that when slowing down I get some major vibrations from what sounds like the rear of the car. It sounds like I have a crappy sub in my car. The vibrations stop once the car comes to a complete stop and has idled back down. At first I thought maybe it was drone from the muffler but it vibrates so much.

I did notice that the drivers side of the y pipe was close to the floor (could get a finger in there barely) could that be the cause? disappointed about it because I did go with the poly mounts and I'm still having issues.

ncorrell

iTrader: (3)

I have the same issue, except I have Pacesetter LT and Y. I do believe that the section there by the drivers side is the issue. This may sound crude but I used a rod and tried to manually bend the y pipe down slightly in that section. I was able to gain SLIGHTLY more clearance. It did help some, although I still get the bad vibes starting hard or starting up a hill.

Eventually I am going with a custom true dual set up so hopefully I won't have to worry about it then.

Full-Force

iTrader: (11)

mark the y pipe where it is contacting the car then take the y pipe back off and put it in a vice. Use a block of wood or some rags between the jaws of the vice if needed. Then compress the section of the pipe you marked and make it oval.

Put it back on the car and enjoy