For owners of SLP LT's
 

I got my SLP LT's installed last week.

They sound bad ass, but one thing is annoying the hell out of me. During idle and at low speeds (35mph and lower it seems) the Y-pipe is banging against the bottom of the car. It sounds like it's right underneath the passenger seat. Anyway, I take a look under there, and right where the catback and the Y-pipe meet, it looks like the pipe is sitting really close to the frame. This is where I suspect the banging coming from.

I asked the shop that installed the LT's for me... and they told me there really isn't much you can do with moving the Y-pipe further from the body of the car, because where they sit is at the mercy of the LT's.

My question is... if you experienced this noise, how did you fix it?

I was thinking if all else fails, go to the muffler shop here in town and have them cut that piece of pipe out, and re-fab a different shaped one, one that works around the suspected trouble spot.

Interesting. I agree that the Y-pipe is 'at the mercy of the LT's', but... in my case, the Y-pipe hangs lower, away from the frame, than it did stock. Sorry, I was no help, I just haven't heard of anyone else (with SLP LT's) with your problem. Usually, people complain about just the opposite - they hang too low. Good Luck.

Exactly. SLPs issue is teh y-pipe hanging too low. Mine has not chassis clearance issues. maybe you shoudl get a look under there for you self and see if the geometry looks right. Im betting that everything just needs to be loosened up and clearanced and then snugged back down .


GOod luck

I agree get under there and take a look and loosen it back up and re-adjust it mine have no clearance issue's except with the ground. :eek2:

Although a former SLP LT owner...ditto.

Shove/wedge a piece of heat shield laminated rigid insulation or duct insulation (yes, the home depot stuff). The stuff lasts for quite some time. Once it wears/burns away, replace with another piece. Sounds silly, but it works!!!

(Learned this from one of the top exhaust guys in town- it's a last resort rig that he uses when all other means of routing/contorting/hanging the pipe are tried but a clearance issue is unavoidable).

The padding of the insulation also buffers any bangs which set off the knock sensors.

I think I'm going to have to jerry rig it somehow...

I took a look at it myself the other day. Basically, there is less than 1/8" clearance from the pipe to the floor pan (I know I said frame earlier... sorry). The banging is right where the Y-pipe and the cat-back are welded together, directly above the crossbrace. So it looks like a real bitch to get to.

I swung by the shop that did the install for me. They took a look at it and said there isn't much adjustments that can be done to it that would fix the problem. These guys are pretty reputable, so I don't think they're trying to sham me.

You can't really hear it on the outside, but man can you hear it on the inside. It just bangs away at low idle and from shifting from N to 1st, directly under the passenger seat it seems.

Ah well... I'll get it to quiet down somehow.

On a side note... as far as the rest of the Y-pipe goes... I have PLENTY of clearance. There's tons of space between the floor and pipes the further you move up the pipe towards the engine, so no problems there.

Just to add a little to Joe's reply, to adjust the y-pipe correctly you'll need to unloosen the header bolts first.

Here is a $40 fix for it. www.thunderracing.com. part # 95-LS1-HR MUFFLEX LS1 HEADER BUMP STOP. i just got mine havent put it on yet though.

My SLP LT's don't have a problem with the frame but like with most other people they have issues with the ground.

mine did the same thing. just loosen up the all the clamps on the y pipe and disconnect the i pipe by undoing the bolt and bracket on the muffler. then pull the y pipe back and forth side to side untill you get the most clearance. it usually bangs right where the y starts to merge into 1. just move it back some and see how it does. it worked for me.

They tightened the header bolts down before putting the Y-pipe on. I took my car back to the shop and asked them to loosen the header bolts and re-adjust the Y-pipe.

It worked. :)

It didn't move the Y-pipe that much, but it was enough to keep the pipe from banging up against the floor.... and well, that's what counts. :)

It's amazing how much 1/4" make a difference!

Hey Grave, are thoes dyno numbers in your sig w/the longtubes installed

Yep. :nod:

I know it's sort of late, but I had the same problem, which the installer said it might be my motor mounts. I had him change them with a polyerythane one. It seems to have fixed the problem.