Suspension upgrade NVH questions

[NvrFinished]

Hey everyone. I've just finished some suspension changes and upgrades last night and have some questions on what I should expect as "normal NVH" for what I have done. This car is not a DD though I do like to like to use it for that from time to time. I also plan on doing HPDE's with it, hence the upgrades. The following is the list of changes to date.

RideTech 2 coilovers - 350 lb fronts / 450 lb rears
BMR rear LCA bushing
BMR rear adjustable tow rods w/knuckle bushing upgrade
BMR vertical vertical links (spherical both ends)
BMR cradle bushing lockout kit
Steeda rear adjustable camber arms
Steeda rear subframe alignment kit
Steeda rear differential bushings (red)
Steeda front and rear sway bars


I only test drove it around the block and brought it back into the garage for some measurements. I need to adjust the coilovers some to get the height I want before I take it in to get it aligned. The only rubber bushing in the rear is the inside rear lower control arm. I didn't bother clocking it because I could get full smooth movement without binding of the control arms after everything was torqued and before I bolted up the coilover unit.

I knew I was going to get some NVH with the parts I've installed in the rear, I'm just curious as to what I should expect. As an example, I was a bit surprised when I first started the car. After startup when I released the clutch in neutral, I could actually hear the transmission turning as the clutch was engaged. I wasn't even moving yet. Is this to be expected?

Also, I now have the famous "clunk" when shifting into first or reverse. My car never did that before. Lastly, a couple of times when engaging the clutch in first I felt something that was almost like a shudder for a moment, though I could not make it happen on purpose. Is this a result of firming everything up in the rear?

There is a nasty, bumpy road a few miles from my house where I plan to run the car to check for anything unusual after I get the height adjusted to my satisfaction and before I get the alignment done.

Oh, I also have a BMR 4-point front subframe brace that I have not installed yet. I'm thinking about going with the 2-point brace instead. I'm not thrilled about the some of the complaints about creaking and squeaking with the 4-point brace.

I also have an MGW shifter sitting in the box along with a Solo Mach Thunder catback exhaust. I'm just waiting on the DSS carbon fiber drive shaft to arrive to make the shifter install that much easier. My hopes when I ordered the drive shaft is to reduce some of the NVH I knew that I was going to incur. Lethal's 12 days of Xmas sale pushed me over the edge on that one

As I said, I knew I was going to get NVH. I can live that. I'm just trying to get an idea of what is normal. I'm one of those guys that is extremely in tune with all the noises and idiosyncrasies that a car makes and I want an idea of what to expect so that I know what is not normal.

Any feedback is appreciated!

[MENTION=9985]BMR Tech[/MENTION]

Sponsored

 

[BmacIL]

With all that, you'll get more road noise, you'll feel and hear all the little bumps in the road (even if not harsh). The bigger bumps are most definitely harsher, as I can attest to, particularly drop offs rather than bumps. Everything should be more controlled and solid feeling, though.

The clunk sound is pretty muted stock but the diff bushing inserts will amplify it.

 

[MtnBiker]

The only rubber bushing in the rear is the inside rear lower control arm. I didn't bother clocking it...
[MENTION=9985]BMR Tech[/MENTION]

Assuming you did the front inner LCA bearing and that you aren't referencing the knuckle toe bearing upgrade. Pretty sure the rear inner LCA is a spherical bearing too. The OEMs have rubber dust boots so they look like bushings. You should be fine. Just finished a similar install 2 weeks ago and clocking everything was a pain.

Keep us posted. That will be one turnin and burnin Mustang!

 

[NvrFinished]

Pretty sure the rear inner LCA is a spherical bearing too.

Yes, you are right! I was pulling up everything by memory and now that you mention it, I remember have to line that spherical bushing up as well when installing lower control arm.

 

[NvrFinished]

With all that, you'll get more road noise, you'll feel and hear all the little bumps in the road (even if not harsh). The bigger bumps are most definitely harsher, as I can attest to, particularly drop offs rather than bumps. Everything should be more controlled and solid feeling, though.

The clunk sound is pretty muted stock but the diff bushing inserts will amplify it.

Yes, I've been expecting most of that. Hearing the transmission turning while in neutral caught me by surprise, however. That and the definite "clunk" shifting into first or reverse.

 

[MustangGuy]

Didn't replace the LCA bearing as part of my suspension upgrade but am hearing clunking when going over rough roads at lower speeds. Don't hear it as much on highway but it sounds like a component didn't get tightened but I've checked all bolts. Maybe I need to address some other suspension upgrades. Any thoughts from anybody?

Steeda swaybars
Steeda progressive springs
Steeda struts and shocks
Steeda subframe alignment kit
Steeda subframe bushing kit
Steeda subframe braces
Steeda vertical and toe links

 

[SteedaTech]

Didn't replace the LCA bearing as part of my suspension upgrade but am hearing clunking when going over rough roads at lower speeds. Don't hear it as much on highway but it sounds like a component didn't get tightened but I've checked all bolts. Maybe I need to address some other suspension upgrades. Any thoughts from anybody?

Steeda swaybars
Steeda progressive springs
Steeda struts and shocks
Steeda subframe alignment kit
Steeda subframe bushing kit
Steeda subframe braces
Steeda vertical and toe links[/QUOTE

pm your contact info, I will call in the am.

Thanks MIke D

 

[Mootang]

I recently installed everything you guys have too. I am getting the famous "clunk" noise, but only over bumps and rolling into it at 5 mph. Glad to here that you also have to raise you ride height on one of your four corners. It reassure me that I didn't do something wrong. I have the Roush single adjustable ride height coil overs and my passenger rear is sitting about 1/2 inch lower than before. Funny that the rest of the height is where it should be.

Installed all at once:
BMR Rear LCA Specirical Bushing
Steeda Rear Adjustable Camber Arms
Steeda Rear Adjustable Toe Rods (Upgraded Knuckle Bushing)
Steeda Rear Vertical Links
Steeda Rear Subframe Alignment and Bushing Lockout Kit
Steeda Rear Differential Bushing (Red)
Steeda Rear Subframe Braces
Steeda Front K-Member Brace
UPR Engine Mount (lowered by 1/4")
DSS Carbon Driveshaft
FPRP Halfshafts
MGW X-Spec Shifter
Whiteline Transmission Mount
Whiteline Front and Rear Adjustable Endlinks
Eibach Front and Rear Sway Bars (Both Middle Settings)

I am thinking of removing the the Whiteline transmission mount to see if there is a noticeable difference. Planning on re-torquing everything down again and double checking the halfshafts axle nut (I think I forgot to add the extra 45 degrees turn after torqued). Will raise the passenger rear ride height and check the torque values on the drive shaft to see if the NVH will lower. There is some slop in the driveshaft that may be causing extra noise :shrug:.

 

[NvrFinished]

Update - I was chasing ride height around until I realized it may be sway bar bind. Sure enough, when I disconnected the sway bar links I was able to dial in the height without issue. I ordered some adjustable links and solved the problem.

Next I installed the DSS carbon fiber driveshaft, MGW shifter, and Solo Mach Thunder exhaust. The driveshaft did a great job of eliminating a lot of the clunk and transmission noise, however, I found that I'm getting some vibration. It's barely detectable around 60 mph (rear view mirror starts to blur), but it progressively gets worse as speeds increase. At well over 100 mph it creates a roaring sound like tires on bad pavement.

I shimmed the transmission brace 3/8" and it has helped some, but the vibration is still there. I talked with Kelly at BMR and he concurred that many are getting the same issues from 1-piece driveshafts due to the driveline angles. He said shimming his transmission mount 1/2" did the trick for him, but I would need to get longer bolts for that. My next move is to put a call into DSS and see what they recommend.

I'm bummed about this and hope I can solve the problem. I'm real happy with how the driveshaft tuned out a lot of the NVH at the lower speeds.

 

[wildcatgoal]

Driveline vibration that occurs during acceleration only is typically a U-joint angle issue - front and back angles should be as close to the same as possible and within 1*. Driveline vibration that occurs while cruising or otherwise when heavy torque is not being sent to the wheels is typically a balance issue that is more appropriately addressed first by clocking (rotating) the driveshaft at the differential side, starting by rotating two bolts (~90*).

Your original post's description of NVH sounds normal, especially since you have a Torsen. The primary causes are the IRS lockout and differential inserts IME. I am not a fan of the BMR 4-point brace's front mounting location (I had one before) and, after experiencing issues, went to a Steeda 2-point brace instead. But, plenty of people have installed that BMR 4-point without issue and I'll be honest, I really don't think it's going to be a primary noise issue now that Kelly resolved the front mounting point bolt hole being oversized issue that I was the center of controversy regarding. I assume that hole is now the same or damn close to the diameter of the bolt going through it and, if so, my primary concern about that 4-point brace is effectively resolved.

Installation of the MGW shifter - if done properly using dynamat material - will help dampen a notable amount of transmission NVH. I have even more hard bushings/spherical bearings than you, an MGW shifter, and an aluminum driveshaft in my car... it's not bad at all. I actually want to drive my car MORE now than I have all these bits and pieces that I was scared of getting mad NVH from before.

You may chase clunks here and there for a while, but you'll figure it all out. Just realize, as the saying goes, race car parts make race car noises. I don't have clunks anymore except on very rare occasion and in situations where it's too be expected.

 

[Mootang]

Driveline vibration that occurs during acceleration only is typically a U-joint angle issue - front and back angles should be as close to the same as possible and within 1*. Driveline vibration that occurs while cruising or otherwise when heavy torque is not being sent to the wheels is typically a balance issue that is more appropriately addressed first by clocking (rotating) the driveshaft at the differential side, starting by rotating two bolts (~90*).

Your original post's description of NVH sounds normal, especially since you have a Torsen. The primary causes are the IRS lockout and differential inserts IME. I am not a fan of the BMR 4-point brace's front mounting location (I had one before) and, after experiencing issues, went to a Steeda 2-point brace instead. But, plenty of people have installed that BMR 4-point without issue and I'll be honest, I really don't think it's going to be a primary noise issue now that Kelly resolved the front mounting point bolt hole being oversized issue that I was the center of controversy regarding. I assume that hole is now the same or damn close to the diameter of the bolt going through it and, if so, my primary concern about that 4-point brace is effectively resolved.

Installation of the MGW shifter - if done properly using dynamat material - will help dampen a notable amount of transmission NVH. I have even more hard bushings/spherical bearings than you, an MGW shifter, and an aluminum driveshaft in my car... it's not bad at all. I actually want to drive my car MORE now than I have all these bits and pieces that I was scared of getting mad NVH from before.

You may chase clunks here and there for a while, but you'll figure it all out. Just realize, as the saying goes, race car parts make race car noises. I don't have clunks anymore except on very rare occasion and in situations where it's too be expected.

Do you expect NVH going over bumps with so many rear suspension upgrades like OP?

 

[wildcatgoal]

In some occasions I'll hear a mild clunk going over abrupt dips. Not so much upward bumps. So no, I don't typically EXPECT NVH when going over ALL bumps.

Spherical bearings transmit noise. Quality bearings don't knock (clunk).

 

[NvrFinished]

Driveline vibration that occurs during acceleration only is typically a U-joint angle issue - front and back angles should be as close to the same as possible and within 1*. Driveline vibration that occurs while cruising or otherwise when heavy torque is not being sent to the wheels is typically a balance issue that is more appropriately addressed first by clocking (rotating) the driveshaft at the differential side, starting by rotating two bolts (~90*).

Your original post's description of NVH sounds normal. The primary causes are the IRS lockout and differential inserts IME. I am not a fan of the BMR 4-point brace's front mounting location (I had one before) and, after experiencing issues, went to a Steeda 2-point brace instead. But, plenty of people have installed that BMR 4-point without issue and I'll be honest, I really don't think it's going to be a primary noise issue.

Installation of the MGW shifter - if done properly using dynamat material - will help dampen a notable amount of transmission NVH. I have even more hard bushings/spherical bearings than you, an MGW shifter, and an aluminum driveshaft in my car... it's not bad at all.

You may chase clunks here and here for a while, but you'll figure it all out. Just realize, as the saying goes, race car parts make race car noises. I don't have clunks anymore except on very rare occasion and in situations where it's too be expected.

Great timing.... I was just getting ready to comment on your ShaftMaster thread. I'm glad you got the vibration issue worked out.

Yes, it's not a vibration under heavy acceleration, but one while cruising or decelerating from high speeds. I figure as much that DSS will want me to start by clocking the driveshaft first. I think clocking is more a remedy for incorrect installation than it is for anything else however. I'm not a fan of the adapters as you mentioned in your thread, but I took care to wire brush all mounting faces before installation.

As far as the clunks go, I feel most is caused from the larger backlash that these Torsen differentials require. I was just surprised how much the carbon fiber shaft helped with this as with the other expected NVH stuff.

Regarding the MGW, I'm way ahead of you regarding the Dynamat. :cheers: I purchased some extra which I applied to various areas of the shifter and transmission tunnel. I think it's one of the reasons why I have less noise and vibration from the shifter and transmission than I had with the stock unit. If I can get the driveline vibration under control I will be a happy camper.

 

[wildcatgoal]

You'll figure out what the issue is with the driveshaft. I would start with rotating, though. Do be sure to clean out the threads with a chase because I'm sure you used loctite.

My impression of CF driveshafts is that they would end up having LESS NVH when right...

 

[NvrFinished]

Yes, reduced NVH was one of the main goals for the purchase. The only reason I haven't clocked it yet is because I ordered a tap and die set. I keep finding the need for one so I finally busted out the wallet.

Sponsored