I installed some motorydne art pipes about 2 or 3 weeks ago. They were fine when i first got them on but now the the weather is starting to reach 100 degrees I'm running into issues.
Upon first accelerating (siting at a red light to green) i get this nasty vibration that i can feel in the gas pedal. The exhausts tune will sound off as well. Even sitting at idle I can hear the exhaust area of my car vibrating. I went down there to check it out and everything looked fine? I suspect I have an exhaust leak coming from the art pipe to the y-pipe (i hear hissing). Could that in any way cause the issue?
Again this ONLY happens when the car is very hot (stuck in traffic or long drive in extreme heat).
Any ideas?

 

Not sure why it would only happen when hot, but you could check:

a) Re-check clearance between pipes and subframe
b) Gaskets (mine were leaking a while ago, talking about the gaskets between the ART pipes and y-pipes, the ones connected to the headers should be metal so they last forever)
c) Any cracks in the actual ART pipes

Try lightly revving your car at idle and having someone outside listen for vibrations on either side.

 

My best bet is that it is because its leaking between the art pipes and y pipe. I reused the oem gaskets which were in horrible condition only because none of the auto part stores around me had them in stock at the time of install.
I still have no idea why it would only do this when the car was hot though?

a) clearance is fine. I actually got the U-brace back on there too.
c) no cracks whatsoever.

 

Usually when when you feel it in the gas pedal it means the stud underneath the floor board wasn't trimmed off. Its described in the installation sheet.

If its not trimmed off it will make all kinds of noise in the floor board right under your feet.

 

Meaning the stud for the heat shield? I trimmed that. Does it have to be trimmed all the way to the nut or just an inch or two off?

 

Enough to make sure its not making contact. Make sure nothing is contacting the floor board or it will make a lot of noise.

 

I'll have to double check. The odd thing is that it only makes noise and gives me problems when the car is hot. Is it possible the pipes may move around more when the car is hot?

 

Possibly.

Does it only do it when you hit the gas? In 1-3 gear? When the engine is under load it twists in the engine bay from all the torque. Especially when in low gears.

The rubber motor mounts limit the movement in the engine bay but they do wear out over time. Temperature may or may not affect them.

 

It only does it when I hit the gas. Usually only in 1st gear but sometimes in 2nd.

 

OK, that helps alot.

Engine twist is the reason. When the engine twists in the engine bay the pipe on the driver side is moved up toward the floor board and making contact. And that will make a ton of vibration and noise.

At least now we know the cause. (Torque twisting of the engine.) The fix can be addressed a couple of different ways.

Your motor mounts may be worn out and lose. Fixing that isn't exactly easy unless you bring it into the shop.

One other thing to try is to maximize clearance between the ART pipes and the floor board. Starting with the stud.

Trim that stud down all the way and then check for the next closest point of contact. See if you can move the heat shield away from the pipe if necessary. This will be the first and easiest thing to try.

 

I'll give that a shot. So only the driver side twists?
Appreciate all the help. I'll let you know if it solves that problem

 

Both sides move but the driver side moves up while the passenger side moves down.

 

if that is the case of the engine twisting, you could get an engine dampner to help limit that

 

A damper doesn't limit the travel it limits the speed of travel.
It may or may not help in this case.

 

Okay so that didn't solve the issue. I trimmed the stud down all the way to the nut. Then i actually completely removed the heat shield thinking it may still be touching that. With all that removed it still has that rough vibration in 1st gear when the car is hot. Any other ideas?

 

Found this post on 370Z forum...might be of help?

 

I think of things at the weirdest times....op, get under your car and look at the silver heat shield that the art pipe runs along.... see if it is touching it anywhere, I remember that mine was doing the same thing and It was barely touching that shield. I got a pry bar and bent the shield a little and it never happened again

 

something not mentioned...make sure your o2 sensors are tight...ive had my z1 hfc's back out of the threads and cause a rattling noise dependent on rpm....

 

I actually have that brace already installed. The fit isn't dead on like the cats so I had to get smaller bolts to make it fit.

I tried the playing with the heat shield and had no luck. I got so fed up that i removed the heat shield completely and yet I'm still getting vibrations and such when the car is hot.

This, I have not tried yet. I'll have to give this a shot tomorrow.


Thanks for everyones input.

 

Well, heat =expansion of metal so it could be metal on metal, or just expansion alone which may alter the SIZE and induce harmonic vibrations.
Make sure ALL clearances are adequate when car is HOT. I would also look at the brace bolts and maybe add rubber washers/bushings to both the lower and side cat bolts.