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Cobb and Boomba RMM Review

Zissou

Active member
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Location
Charlottesville
#1
Now that I've had both rear motor mounts on my car I figured I would post a review for those who can't decide which is the right one for them.
I had the stock RMM for around 7-8k miles and got sick of wheel hop and the occasional engine hitting the firewall. I had made it to stage 2 with the stock mount, and remained stage 2 through owning both mounts.

I bought a Boomba RMM and ran it for about 2k miles. My thoughts were that it eliminated the engine hitting the firewall and nearly eliminated wheel hop at the cost of a great deal of noise, vibration and harshness (NVH). It also made shifts feel tighter or "crispy" as I've described it; an improvement in shift feel. But seeing as how I'm not taking my car to the track and most of my driving is around town, I grew tired of the cabin shutter taking off from a stop.
Side story I tried to get rid of some NVH by tightening things up and sheared off one of the downpipe studs. That was not fun.


Next I purchased the Cobb RMM. This one was also used and broken in. I see this mount as the compromise between stock and Boomba. Shifts don't feel as tight and it just doesn't seem to put down power as well as the Boomba, but the engine doesn't hit the firewall and wheel hop is controlled nearly as well as the Boomba. And there is way less NVH. On a scale of 0-9 for NVH, stock is 1, Cobb is 2, and Boomba is 6. I can only sense any vibes with the AC on at very low rpm and even then they are minimal. This is what I have now and what I decided to keep.

I snapped a pic of the 3 lines up, and I think this illustrates the difference between them.

The Cobb is nearly the same size as stock with smaller voids. The Boomba has no voids and much less dampening which translates to more vibrations in the cabin, but less engine movement.

So end of story, one isn't strictly better than the other but one will be better for (insert italics) you that the other. So you might want the...

...Boomba RMM
if you are willing to sacrifice NVH for superior engine movement restriction and "because race car" lol. This one is probably better for the track (not my wheelhouse so I don't know) or large power increases. It's personally not for me, but that is just me.

...Cobb RMM
if you are only willing to sacrifice the slightest NVH for a reduction in wheel hop and engine movement. This one seems better for the daily driver with modest additional power.

...stock
if you want the absolute most minimal NVH and you are fine with trading off for engine movement.
 


OP
Zissou

Zissou

Active member
Messages
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Location
Charlottesville
Thread Starter #2
Ah man I knew I would forget something! One thing I really liked about the Boomba is that they include the bracket that connects to the downpipe bracket. The Cobb you have to smash off the stock one with a hammer to use it. It works, but the Boomba just seems nicer that they include that and it fits up to the RMM perfectly.
 


OP
Zissou

Zissou

Active member
Messages
540
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Location
Charlottesville
Thread Starter #7
Did you fix that sheared downpipe stud?
I did not personally fix it, I had to take it to an adult as that one was over my head.
Local wrench ended up blasting it with heat and hammering on it to get the stud out. We replaced it with a bolt and nut/lock washer.

And looks like I have a picture of that too:
 


Messages
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Location
Orange county
#8
Some days my Boomba mount vibrates like crazy other days I don't notice it. I'm learning to live with it because I lobe the feel you described!!!!
 


OP
Zissou

Zissou

Active member
Messages
540
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137
Location
Charlottesville
Thread Starter #9
Some days my Boomba mount vibrates like crazy other days I don't notice it. I'm learning to live with it because I lobe the feel you described!!!!
Yeah that's something I noticed too. Some days there were no vibrations. I could never figure out what it was; it seemed to be independent of temperature.
 


XuperXero

Active member
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125
Location
Wuxi
#10
Some days my Boomba mount vibrates like crazy other days I don't notice it. I'm learning to live with it because I lobe the feel you described!!!!
Yeah that's something I noticed too. Some days there were no vibrations. I could never figure out what it was; it seemed to be independent of temperature.
Glad to see I'm not the only one. I've also discovered that it's not temperature dependent... I have absolutely no idea what causes it and it annoys me.
 


MPA

Member
Messages
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84
Location
STL
#11
Good review - I found them to be the same.

I had a Boomba shortly, and while it looked beautiful and worked great,the NVH was a lot to deal with, and I wasn't willing to wait until it broke in to see if it got better since my car only had 879 miles on it.

As a DD, I like my Cobb. I barely notice the NVH I get, and it's only at those times that I remember it's on the car.
 


Messages
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13
Location
FL
#12
I have the Boomba, my car is a 2018 and just have 700 miles now , the Boomba has been there for a week, I'm getting annoyded with the vibrations , I'm gooing to give it another week, if it doesn't get better, I'm putting the stock one back in
 


Boomba Racing

1000 Post Club
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Location
Wood Dale
#13
I have the Boomba, my car is a 2018 and just have 700 miles now , the Boomba has been there for a week, I'm getting annoyded with the vibrations , I'm gooing to give it another week, if it doesn't get better, I'm putting the stock one back in
They take roughly 1,000 to 2,000 miles until fully broken in.
 


Messages
8
Likes
1
Location
Casper
#14
I’ve had my Boomba mount for over two months. About 2500 miles on it. And the harshness doesn’t go away. I’ve been doing an ton of research so I don’t buy the wrong product for me again. I think this post finally just pushed me to buy the Cobb rmm so thank you
 


TyphoonFiST

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Premium Account
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Rich-fizzield
#15
I have 50k on my Motor mount by Boomba.....Great mount ....but it did take more than 1,000 - 2,000 miles for it to break in...I think it was more like 5k.
 


Messages
8
Likes
1
Location
Casper
#16
Boomba made a quality product, and it honestly would be great for track. For me I think it was a bit to much for my taste. I just daily drive it and like to have fun with it.
 


Messages
8
Likes
1
Location
Casper
#18
Do you have any other stiff mounts? I was wondering if maybe I upgraded the other mounts it would even out some and the vibrations wouldn’t shake my side mirrors down
 




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