Is subtle rattling at low RPMs normal after resonator delete?

[Bojan123]

Hi guys

I have a 2020 GT350 and recently got the LTH resonators for it. I had it installed yesterday, I wanted to make it sound just like the GT350R. I Iove the sound its great however when I went for a drive today, I noticed that as I was coming to a stop at around 1k - 2k rpms I hear a rattling sound from underneath. At first I thought I broke my transmission because I could hear a grinding sound whenever I would come out of 1st gear, and it sounds like Im grinding the gears. I opened up the windows and turned the volume down and then I could hear it.

Its weird because it isn't consistent, it does it randomly. I thought it was because the heat shields weren't removed but I checked and saw that they were. So I'm assuming that its because of the excessive vibration from the FPC engine? I can get a take a video tomorrow if that would help.

Just would like to know if this is normal, never done this before. I searched and couldn't really find anything

Thanks

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[sox3]

I didn't go with LTH but no rattles here. Not normal imo.

 

[Champale]

You might want to jack your car up and crawl under to just make sure everything is aligned right and not making contact with something else. I would run my hand over the top and sides of the exhaust from the cats all the way back to the mufflers. Also, make sure the clamps are installed correctly - the front ones have a very specific orientation so that they will slip over a tab on the factory post-cat pipe.

Hopefully it is something simple and just requires some adjustment.

 

[stanglife]

There is some more resonance with the R setup... so if it’s a very minor interior rattle...not a normal based on Fords factory “tolerances”.

 

[Bojan123]

You might want to jack your car up and crawl under to just make sure everything is aligned right and not making contact with something else. I would run my hand over the top and sides of the exhaust from the cats all the way back to the mufflers. Also, make sure the clamps are installed correctly - the front ones have a very specific orientation so that they will slip over a tab on the factory post-cat pipe.

Hopefully it is something simple and just requires some adjustment.

Okay thanks, I was going to do that after I got back but the exhaust was still hot, didn't want to burn myself. I'll make sure to checkout the clamp.

I do believe that it is a simple adjustment, because I didn't see anything out of the ordinary when I took a peak.

If I cant figure it out, i'll take it to an exhaust shop and have them look at it, since it seems to be pretty easy to replicate

 

[Bojan123]

There is some more resonance with the R setup... so if it’s a very minor interior rattle...not a normal based on Fords factory “tolerances”.

I am okay with the interior rattle, but it is definitely coming from something underneath the car. It sounds as if something underneath comes loose and scrapes the ground. When I rolled down the windows, I could hear a metallic click, definitely something from underneath and not inside.

It sounds like one of those junk cars that has been jerry-rigged, with stuff dragging. It only sounds like that for half a second sporadically, whenever a apply throttle from a stop or slow down. Im pretty sure that this isn't normal for an R right?

 

[Bojan123]

I didn't go with LTH but no rattles here. Not normal imo.

Okay thanks, which one did you go with?

 

[Champale]

Double check the clearance to the driveshaft at the back end of the LTH pipe, too. The fact that it only occurs when accelerating or braking is weird but if the noise just started with the exhaust change, it's probably something related to it.

 

[LICobra]

Another thing to look for since you replaced the resonator delete pipe, is the alignment of the tail pipes not to rub against the fixed quad tips

 

[Allan]

I installed the LTH pipe. No issues. Make sure all of the hardware is tight. As long as you are crawling under the car peel the sticker off of the drive shaft before it comes loose and you start chasing another rattle.

 

[stanglife]

I am okay with the interior rattle, but it is definitely coming from something underneath the car. It sounds as if something underneath comes loose and scrapes the ground. When I rolled down the windows, I could hear a metallic click, definitely something from underneath and not inside.

It sounds like one of those junk cars that has been jerry-rigged, with stuff dragging. It only sounds like that for half a second sporadically, whenever a apply throttle from a stop or slow down. Im pretty sure that this isn't normal for an R right?

Correct - if it’s from under the car - not normal

 

[Bojan123]

Another thing to look for since you replaced the resonator delete pipe, is the alignment of the tail pipes not to rub against the fixed quad tips

Okay thanks when I looked at it it seemed okay

 

[Bojan123]

I installed the LTH pipe. No issues. Make sure all of the hardware is tight. As long as you are crawling under the car peel the sticker off of the drive shaft before it comes loose and you start chasing another rattle.

Okay thanks, what does the sticker have to do with the drive shaft? I definitely think something is loose

 

[sox3]

Some have had the sticker on the driveshaft come part way off causing a ticking sound while driving. Good prank back in the day was to put a zip tie on someone's driveshaft.

 

[sox3]

I'm sure you didn't ruin it. Just need to get under it and figure that rattle out.

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