The headers hit and rattle against the floor board. So this is what I just did and I need your guyses advice. I cut a cuple of rubber peice off of one of my old tranny mounts. On the drivers side where it hits I pried the exhaust down with a screw driver and stuffed the rubber peice in between the exhaust and the floorboard. Someone told me they thought this might start a fire from the rubber agains the y-pipe. What do you guys think?

 

I doubt the piece of the trans mount catches on fire but you may smell some hot rubber. Your best bet is to install ES or Prothane polyurethane motor and trans mounts. Spohn make solid steel motor mounts as well.

 

I think the Y will probably get hot enough to melt it.. Can you smell it burning?
I'm guessing your having this problem because your on stock motor mounts???
If so a set of poly mounts will most likely fix your problem.

 

The car has 30,000 miles I don't think they are the problem... Everyone I have seen with headers have hit.

 

I used a piece of 1/4" rubber I had and mounted it to the rail of the car where the y pipe hit its been a couple thousand miles and a few months and it hasnt showed any signs of melting. I heard that the pipe hitting the floor can cause false knock issues so I'd think with the rubber it would cure that cause as well as the thud under acceleraation.

 

I got an idea. I was thinking about getting a u bolt and putting around the back of the y-pipe and drilling holes in the metal cross over that keeps exhaust up and tighting it to that. What you guys think of that plan?

 

To be honest, I think you should buy headers that don't hit. You shouldn't have to go to that much trouble, especially when you are trying to fix something that wasn't made right to begin with.

 

Best way to fix it....Ship me your LT's and I'll ship you my shorties

 

I've never had any of my F bodys LT's or Y pipe hit.
Nor any of my friends that I've worked on.
Poly motor mounts wont let near as much movement occur over new oem ones.
I'm sure your 11 year old rubber mounts are not helping anything.

If is the mounts allowing the motor to move and exhaust to hit then you might think about how much stress your going to put on that exhaust if your bolting it in place and not letting it move.

 

Its not because the motor is moving though. It is because the exhaust is shaking. It is hitting above not behind.

 

Pacesetter = cheap, not necessarily quality control. 'nuff said.

 

Actually Pacesetter headers are well spoken of and a very good brand of header...... People usually like them better than the 800 pos headers

 

Just a little rattling... they went in great and there is nothing wrong with the header itself

 

The exhaust is moving because the motor is moving.

 

There is nothing wrong with Pacesetter headers. I've installed numerous sets, they are super easy to install and fitment has always been great. Honestly, they've probably been about the easiest header that I've installed. Never tried a set of ARH's though and I hear those are perfect.

Anyways, to the OP, swap to Poly mounts or solids and I bet your problem disappears... Don't use a chunk of rubber or rig it up in another way. Just do it right and you'll be happier.

 

But the exhaust is connected to the motor, and is the only thing that causes the exhaust to move. How is it not related?

 

OP everyone in this thread has posted the answers to your problem. Putting rubber between really hot metal and the body of the car is not a good idea its just rigging it up. The exhaust mount you proposed is not good either, it will bind the exhaust when the motor moves and cause other problems, the exhaust needs to be able to move thats why every factory hangar is rubber and flexible.

Your problem is either A: you have poor quality/fitting headers, or B: the mounts are flexing too much and letting the exhaust hit. I had issues with this before I went to poly mounts, but it was only under full throttle. When idling etc clearance was fine with my Hooker headers. The problem is actually more likely to be the Y pipe hitting the frame rail under the driver seat area. The clearance there is very tight on most setups, I have a Lane's True dual setup, its the only setup I have seen that makes clearance in the pipe right in that area by ovaling the pipe.

And with stock engine mounts the engine moves A LOT... A lot more than you think it does. Even if the mounts were brand spankin new, they are rubber and soft so they move a lot non dependant on age or mileage. Get poly motor mounts and never look back.

 

My TSP headers and Y pipe would hit under acceleration. I had the spohn poly mounts installed and helped a lot. If you are worried about it, have a fire extinguisher in the car if the rubber catches on fire.

 

I know this has been said, but I'll chime in anyways.

Upgrade your Motor Mounts to either a set of Polys or Solids and the rattling and banging of the exhaust will be gone.

This should be done with EVERY INITIAL INSTALLATION OF LONGTUBE HEADERS.

I hate to tell you this, but I hope you enjoyed your LT Installation. In order to gain the necessary amount of room to remove and reinstall the mounts, you will pretty much need to completely remove your new Y-pipe and Pacesetters. And once you've completed fighting the new mounts into place, you can reinstall the exhaust.

Here is the writeup I followed when I did (or helped do) the mounts in my bro's 02 SS, my 99 Firebird, and a friend's 98 Z28...

https://ls1tech.com/forums/generatio...r-written.html

Don't get me wrong. Installing Motor Mounts in these cars is a pain in the ***, but this writeup is great for letting you know what to expect. That kinda helps to dull the pain. LOL

Seriously though. Upgraded motor mounts are the solution to this problem. Anything else is just a remedy.

Good luck, man.

 

I did my poly mounts with the headers in, I dont think it would have helped me any to pull mine. But overall, they are a pain to do change out.