Joewee3.5

So your exhaust moves when it's hot? Strange.

Centexguy

As metal gets hot, it expands. When stuff expands, it gets bigger. When it gets bigger, it occupies space that it previously didn't occupy before.

You could try putting a small dimple in the pipe where it's rubbing or grinding down the part that its rubbing on.

focus289

I exhaust doesn't move. I doubled checked all the connection points and all are tight. As far a putting a dimple in the exhaust I may go that route. Or I may sell my current set up and go with another company. I have been looking at pics that I could find online and it seems that the clearance is better on other systems.

Roughneck12

I to have a vibration. From time to time it sounds like I am driving on rough pavement. Take my foot out of it a little, minor change in rpm and it goes away. Seems to be from the passenger side. Can feel a minor vibration through the floor also.

Olli

Have you contacted Livernois? The Livernois downpipes are made exclusively for them by American Racing Headers. Is the vibration only associated with the hi-flow cat version? If that is the case maybe there is something vibrating within the cat itself.

Olli

Joewee3.5

I know about expansion and contraction with hot and cold. I'm just doubting that the pipe is swelling to the point it's touching a part that it wasn't previously touching when cold. If that were the case then why would we put larger diameter pipes on at all when all we would have to do is warm up the exhaust to achieve that larger diameter. If the clamps aren't tight after a few heat cycles then retighten.

Centexguy

Around my transmission I've got about a 1/4" of clearance. It's not a far reach to say that with everything getting hot and shifting around that that 1/4" of clearance can disappear.

focus289

I am sure it is not the cats themselves. I had my dad look at it he is a ford mechanic for over 30 years. If I go out right now and look at the exhaust it will not be touching. As soon as it gets hot it touches. I am surprised that it expands that much. The more I think about it I think I am going to grind a little of the crossmember and see how that works. Thanks for all the feedback guys.

Motosoal

I think giving a little grinder love to the crossmember a) won't impact structural stability as long as you're reasonable with the grinder b) is a very food solution to the problem. I say go for it

nolagtime

Are all of the issues on trucks with hiflow (3") cats or catless downpipes... all emptying into stock 2.5" exhaust? If so I think there is the problem... the 2.5" section is causing backpressure, which sets up resonance at certain flow and rpm...

Once i put a larger exhaust (non-stock) behind the 3" downpipes, I will report if this goes away.