phatmitzu

I had the primary cats replaced with straight pipes. Secondaries are still in place. Resonators were already removed.

Now the car rattles. The whole car shakes when I decelerate.

I was think of adding flex joins/pipes on the straight pipe to try to get rid of the rattle, or maybe resonated test pipes?

Any other suggestions?



Thanks.

chiromikey

can you describe this in more detail?

LazyE55

You should have the muffler shop re-check things maybe they welded something wrong. I removed my primary and secondaries cats and i dunt have that rattle your talking about...

phatmitzu

It feels like Im driving a HEMI truck with straight pipes...
I know that the V8 rumbles more with exhaust modifications, but this was pretty bad. At 1500 to 2500 rpm, the exhaust rattles and shakes, and I can hear the vibration of the pipings. At higher RPMs, it goes away.

We checked it and there was no exhaust leak. Nothing was touching the heatshield either.

The secondary cats still have the cross-over.

Sounds great though.

Ted Baldwin

.......not sure why you are suprised.

Ted

phatmitzu

Because it feels as if I have open dump pipes...which I dont.

Zod

so what is the genral thought on cats keep or not ?
with regurd to primaries been a cheap power increase on removal

OzE55

Aside from the responsibility to society and the environment........
Get your power gain somewhere else.
IMO

Blacksport350

It really sounds to we like the exhaust is in contact with the car body somewhere. If it is rattling and vibrating all through the car, that is the typical culprit. I would not only check around the cats but all the way back, especially around the mufflers as there are lots of places for them to rub back there.

cls55

its a good thing to delete them,just check the whole system.a cow is worse than a car for the enviorment.

Blacksport350

So basically, we are all environmentally even if we each kill a cow?! I have a lot of steaks in my future to make up for my cars!

bfnnrgn

Moose to. Farts from one moose is the same as driving a car for a year.

chiromikey

i'd guess there's contact somewhere, bad welds, or somehow the pipes are causing resonance. the only thing stock on my system right now is the mufflers and tips and i get none of the problems you're describing.

phatmitzu

Thanks for the replies.

I went under the car and inspected the whole exhaust again. I don't see anywhere contacting. However, I did noticed on one side of the welding the pipings are misaligned. There is abount half an inch step where the welds are. I'm not sure if that is what causes it to resonance. I'm going to have that part re-welded along with putting on the flex-pipes to see if I can fix this problem.

stevebez

Did they leave something residual offcuts in the pipes?

I'd go with faulty bracket / welds / fitting hitting body work somewhere. You say when you decelerate ... so look for forward and backward play.