Jasc

I have had the flp's on for couple of months, every time I hit a sharp bump in the road I get a smacking sound under car?? Have checked everywhere they or the Y pipe could be hitting and have put rubber there, can't figure out whats causing this. Was wondering if anyone else had "run" into this problem?

Thanks
Steve

BIGBOS

Its the Y-pipe, mine smacks all the time, my car is lowered though...stock suspension cars usually don't smack them....what kind of suspension do you have?

Jasc

Stock suspension. Sometimes on one side then the other. Have put soft rubber above everywhere it could be hitting...does it with cats in or out. Begining to think it is the pipes "clanging together" at the V-band clamps, although they seem tight as could be?

Steve

WSlow6

Mine flaps around under hard acceleration (the y-pipe <img src="gr_grin.gif" border="0"> ) You need to do the infamous HEATER HOSE MOD. Yes, pay $1300 for headers but be sure to save the $2.50 for band clamps and some hose <img src="gr_eek2.gif" border="0"> I go under my car every few weeks and adjust the hose so the freekin things stay quiet and to avoid false knock retard. I read that if you use a poly transmission mount the flex in the driveline will diminish and stop the flapping too. I wouldn't mess with a poly transmission mount on a daily driver though.

Rob

[ March 02, 2002: Message edited by: WSlow6 ]</p>

Trevor @ Texas Speed & Perf.

iTrader: (3)

I'd definitely check the y-pipe, particularly the drivers-side of the y-pipe. FLP has remedied the situation, but some have had problems with this in the past. I've had mine bang once, but it was when I was at WOT and found a "washboard" in the road. Needless to say, that jarred about EVERYTHING on the car! <img src="gr_images/icons/mad.gif" border="0">
The tolerances on the f-bodies vary, and that's why you'll see some guys have problems and some not. Also, let's remember that there's a reason why GM flattens the stock y-pipe into an oval. Using round pipe and trying to keep it tucked up close to the car is really going to push the tolerances of the cars. The above case is the only time I've ever had my y-pipe bang, but I've heard of others having repeated problems. Let's face it: GM doesn't spend a wad of cash on the f-body, so quality and tolerances aren't the best. Just look at our incredibly cheap, plastic interior. <img src="images/icons/rolleyes.gif" border="0"> At any rate, look at the bottom of the car just above where the y-pipe runs, and see if you can see any rubbing or hitting going on. The heater hose seems to be working quite well for those w/ problems.

ARTY99z

Did you reinstall the tunnel brace if so it is probably hitting that. I pop riveted hose to the brace and padded it down with rubber grommets. Check your exhaust where it goes over the axle in case something has shifted. I have a 1LE tranny mount and its worth every penny (SLP). If all else fails check endlinks on sway bars to make sure there tight, had that problem once.

Jasc

Cross member not installed. Rarely does it on hard accelaration, mostly just once and a while on a sharp "bsd" ridge in the road. Have thought about the poly trans mount, but didn't know how bad vibration would be...daily driver. the 1LE mount sounds like a good idea.

Steve

O2BQIK

[quote]Originally posted by Jasc:
<strong>Cross member not installed. Rarely does it on hard accelaration, mostly just once and a while on a sharp "bsd" ridge in the road. Have thought about the poly trans mount, but didn't know how bad vibration would be...daily driver. the 1LE mount sounds like a good idea.

Steve</strong><hr></blockquote>

I have also heard that the 1LE mount is a good compromise between stock and poly. Planning on doing that soon <img src="gr_stretch.gif" border="0">

ARTY99z

JFYI the nut on the stock tranny mount will not fit the 1LE mount so get a nut for it before you start the installation (very easy installation).

Jasc

Just looked up the 1LE mount on the SLP site, says it will not fit a 2000 up...bummer.

Elite_Hot_Rod

You never did say what exhaust system you have. I have the FLP LT headers and a Corsa cat back exhaust and had the same problem. My banging was coming from the hanger bracket over and slightly aft of the axle. Heated the bracket with a torch and bent it up and aft giving me about 3/8" clearance between the axle and the pipe and now all is quiet.

Mark

Jasc

Have the Corsa too, had some noise at first with it also. Did the same as you, heated and bent...no noise then. New noise started after the flp's went on. It only does it sometimes and normally only when I hit a real sharp bump, what gets me is sometimes it sounds like it is on the passenger side and sometimes on the driver side(almost sounds like it is right under the seats). Does it with cats on or off.

Jasc

Finally found the problem! Lower control arm bolts were just barely loose, letting noise tranfer up the SFC's. Made it sound like it was right under seats. Tightened them up just a little and voila! no more noise! Thanks for your replies and suggestions.

Steve

Elite_Hot_Rod

Good to hear. I just got my tubular LCA's back from having the bearings replaced, will re-install them tomorrow and hope not to have anymore rattling. I almost think boxed LCA's are the way to go.

Mark