Cobb Rear Motor Mount for Fiesta ST - Installed Review

[DaveG99]

Ate you guys using a torque wrench? I don't have a torque wrench and plan on installing this rmm soon

 

[JWA]

So does the AC ON vibrations ever go away or settle down dramatically... or it is what it is?

I checked for that, since I've seen it mentioned, but I don't have any difference with or without the AC on. I've had stiff motor mounts that increased nvh to uncomfortable levels. This one is like factory on a sportier car. Essentially unnoticeable.

 

[JWA]

Ate you guys using a torque wrench? I don't have a torque wrench and plan on installing this rmm soon

The Cobb instructions don't mention torque values. I had to look them up. If you have a Harbor Freight in town, their torque wrenches are pretty accurate and you can often get them with a coupon for $9.99. As with all torque wrenches, set them back to zero after you use them and they're surprisingly good.

 

[westcoaST]

Ate you guys using a torque wrench? I don't have a torque wrench and plan on installing this rmm soon

Its a good idea to purchase one. I believe you can get a good one from Harbor Freight. 50 Ft-Lbs is what is the recommended torque.

 

[anthonyarmstrong]

So does the AC ON vibrations ever go away or settle down dramatically... or it is what it is?

I think it is what it is. When you look at what you're taking out, you can tell they care 0% about performance and 100% about vibration reduction. No middle ground. I think the small amount of vibration is a good trade off considering the huge leaps and bounds of positive clutch/shift feel. IMO *no* car should have such motor roll/bad clutch engagement off the production line, but I'm not everyone.

I guess it isn't for everyone. But I think it was the best thing I've done for my Fiesta. I don't think I've ever used 3 or 4 on my climate control except for testing for "at-idle vibrations". This is where you'll find a big difference. Just don't have your air at 4 when you're sitting at a standstill

 

[stuntdoogie]

So does the AC ON vibrations ever go away or settle down dramatically... or it is what it is?

It will settle down. I barely notice it anymore except for cold start ups.

 

[OrangeFiST]

It will settle down. I barely notice it anymore except for cold start ups.

I bought mine brand spankin new just a bit over a week ago, didn't forget the spacer and torqued to 50. Without A/C there is a bit, but only because I was looking for it. Engine is pleasantly louder while driving, more planted and all those good things. Shifts are more precise with a lot less slop. Clutch grabs faster so I have to get used to that.

Idling with A/C max sounds like a 32ft organ pipe. Think the beginning of "2001 A Space Odyssey," Sort of like this from 0:06 to 0:23 https://www.youtube.com/watch?v=q-LbTUvfVn8 , only a lot more faint so I'm fine with that. A lot more faint than this video. There is no I'm way switching back to that stock rubber donut.

Before buying, I asked one the of the online reps at Cobb (Kyle) about the NVH and whether there is a break in period. He said it will not soften much, if at all. It seems opinions on this is across the board so I'll keep a watch on it and report back with my own experience.

 

[BiigMe]

I do not experience much else other than vibrations through the steering wheel and shift knob. Even though it was installed by a Cobb dealer, I would still make sure it is torqued to the appropriate 50 ft/lbs that Ford recommends those engine studs to be at. The upper nuts connecting the downpipe bracketing should be tightened with a "heft and a half" sort of effort in my opinion. Tightening those too much can sheer them off. Ask me how I know.

Where did you find those torque specs? I'm worried about over tightening and fucking something up...

 

[commonplatypus]

Where did you find those torque specs? I'm worried about over tightening and fucking something up...

If you google around you'll find the answers.

I've seen it in a few places. Can't recall exactly where. Different places have different ratings, but my consistent findings is that mount to engine is always around 50 ft/lbs. Boomba recommends like Mountune claims 48 nm, which is like 35 ft/lbs, but that seems WAY too loose to me. The bracket bolts should just be a good turn of the wrench and not much more.

 

[BiigMe]

If you google around you'll find the answers.

I've seen it in a few places. Can't recall exactly where. Different places have different ratings, but my consistent findings is that mount to engine is always around 50 ft/lbs. Boomba recommends like Mountune claims 48 nm, which is like 35 ft/lbs, but that seems WAY too loose to me. The bracket bolts should just be a good turn of the wrench and not much more.

Thanks man, did you put copper grease or loctite on it? In not sure if I should do one or the other or both

 

[commonplatypus]

Thanks man, did you put copper grease or loctite on it? In not sure if I should do one or the other or both

I didn't, but it probably would have helped when taking it off. It was a real pain to break loose.

 

[Zissou]

I do not experience much else other than vibrations through the steering wheel and shift knob. Even though it was installed by a Cobb dealer, I would still make sure it is torqued to the appropriate 50 ft/lbs that Ford recommends those engine studs to be at. The upper nuts connecting the downpipe bracketing should be tightened with a "heft and a half" sort of effort in my opinion. Tightening those too much can sheer them off. Ask me how I know.

Haha yeah I sheared one of my downpipe studs off to doing the same thing. They 100p cant handle much more than 20 ft lbs. I had to get a mechanic to knock out what was left of the stud so I could put a bolt in there. And then I replaced the downpipe haha

Sent from my iPhone using Tapatalk

 

[A7xogg]

Heat cycles also wear out the strength of the studs.

 

[Rhinopolis]

I was doing some spirited driving this evening, and I did an aggressive acceleration in 1st and in to 2cd gear hard upshift. As soon as I completed the 1-2 upshift, I heard a slight "bang" and saw a piece of "something" shoot out from under the back of my car and in my rear view mirror.

The car didn't feel weird (yet), I pulled over and popped the hood, and I inspected the TTR motor and transmission mounts. Nothing looked out of place, and I thought that my mind was just messing with me.

I got back in and drove the car, and I started getting aggressive again to test it out. I noticed that the shifting wasn't as tight, and I was hearing a weird noise coming from under the car.

I got out again and got low on the concrete to look under the car, and that's when I noticed that the "narrow" piece of my Cobb RMM was hanging down. Initial inspection tells me that the bolt sheared off (sucks and it's broke off inside the engine mounting point), and now I am going to have to figure out how to get that piece of sheared bolt out.

I'm not blaming Cobb's RMM at this point, and it appears to be a weak bolt. Anyone else have this happen!?

 

[KraZe]

I was doing some spirited driving this evening, and I did an aggressive acceleration in 1st and in to 2cd gear hard upshift. As soon as I completed the 1-2 upshift, I heard a slight "bang" and saw a piece of "something" shoot out from under the back of my car and in my rear view mirror.

The car didn't feel weird (yet), I pulled over and popped the hood, and I inspected the TTR motor and transmission mounts. Nothing looked out of place, and I thought that my mind was just messing with me.

I got back in and drove the car, and I started getting aggressive again to test it out. I noticed that the shifting wasn't as tight, and I was hearing a weird noise coming from under the car.

I got out again and got low on the concrete to look under the car, and that's when I noticed that the "narrow" piece of my Cobb RMM was hanging down. Initial inspection tells me that the bolt sheared off (sucks and it's broke off inside the engine mounting point), and now I am going to have to figure out how to get that piece of sheared bolt out.

I'm not blaming Cobb's RMM at this point, and it appears to be a weak bolt. Anyone else have this happen!?

It seems Blue Bomber's FiST blew his engine from a series of events that stemmed from a snapped RMM bolt (oil cooler lines got yanked and oil starvation killed it). At the time it is believed he was using Mountune's RMM so now we have 2 people who suffered RMM fails from weak bolt studs. Maybe slightly-stiffer-than-stock RMMs transmit too much stress to the bolts?

 

[Rhinopolis]

It seems Blue Bomber's FiST blew his engine from a series of events that stemmed from a snapped RMM bolt (oil cooler lines got yanked and oil starvation killed it). At the time it is believed he was using Mountune's RMM so now we have 2 people who suffered RMM fails from weak bolt studs. Maybe slightly-stiffer-than-stock RMMs transmit too much stress to the bolts?

I agree and I ordered the CP-E RMM since it comes with the mounting bracket that was lost when my bolts sheared while using the Cobb. I am going to keep a close eye on things which will be easy be cause I don't daily the FiST and when not in use its in my garage on race ramps.