BK054 Review / complaints / compliments/ Problems

[FivepointOHYEAH]

Well I couldnt wait till the weekend to installs these diff lockouts. I wish I would have. This job probably could take a single person 90 minutes if they knew what they were doing. But if you are somewhat of a novice like myself it takes 2+ hours at least. Very doable, just not easy IMO.

Initial impressions :
Car hooks much better, there is significantly less wheel hop and more scwheeeeeling but I thought I broke my diff,half shaft,drive shaft , neck the first time i gunned it. I heard the loudest thumps ever at first, stopped my car and look under, everything is ok but NVH went up. 90% of the NVH is when pushing your car. I can hear what sounds like metal rubbing metal when I listen my absolute best and turn down the radio. I suppose its the aluminum pucks moving slightly or something idk what because i torqued everything pretty high, like really high. There is a hard thud nose now when I just go WOT all of the sudden, I hope that is normal.

More driving impressions: Corners better, like i can feel the rear end hold to the ground alot better, I accelerate better because less hop, there is less hop. But when it does hop its harsher. Viking shocks for me next. Braking has also surprisingly been better since installing. Throttle response is much better, the car from a roll now has unbelievable ability to just go when you tell it to.

If you have a GF/wife who already doesnt like your "toy" she wont be none the wiser, if you drive with the intention of following the law, lol, then you cant barely tell a difference.
30 mile review.

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[GTBOB]

Do you have any other modifications done to your IRS? If you don't, I'm going to say that your diff housing is really beating up your cradle now. The wheel hopping is going to be more violent until you address the cradle bushings/lockouts too.

 

[stoli]

Well I couldnt wait till the weekend to installs these diff lockouts. I wish I would have. This job probably could take a single person 90 minutes if they knew what they were doing. But if you are somewhat of a novice like myself it takes 2+ hours at least. Very doable, just not easy IMO.

They come out a lot easier than they go in. ;)

Initial impressions :
Car hooks much better, there is significantly less wheel hop and more scwheeeeeling but I thought I broke my diff,half shaft,drive shaft , neck the first time i gunned it. I heard the loudest thumps ever at first, stopped my car and look under, everything is ok but NVH went up.

I experienced the same thing at the track when I hit it with drag radials. I was sure something was broken/coming through the cabin via the rear end on the 1-2 and 2-3 shifts. It was so bad I contacted Kelly @ BMR about it... I wasn't able to reproduce the same 'thud' on the street, only when beating it at the track.

I agree that nvh wasn't bad. There was a definite hum/whine that came through the cabin at times, but nothing intolerable. There was also a more pronounced 'thud' / noise from the drive shaft at parking lot speeds when letting on and off the gas. Nothing bad at all.

...Then I added a solid drive shaft and it went to shit. NVH went up exponentially. There was new whine/drone at lower rpms and pre-existing whine just increased. Then above 75/80mph there was increasing vibrations throughout the car. After a couple weeks of this I took out the diff lockout (leaving the cradle lockout) and I am happy with the car again.

-stoli-

 

[BMR Tech]

Mostly normal.

The chirp/squeal I am not sure about though.

As for the other NVH characteristics - it will depend on the specific modifications. As stoli mentioned the DS causing the NVH to be worse and vibrations - I experienced the opposite on my car, as far as vibrations. I took the car to OSW (stolie filmed it btw, thanks man!) and the car wanted to shake me out of the seat after 120mph. The first thing I did when I got back to the shop was install the BK054 and all the sharp harmonics/vibrations were eliminated. I then took it up to 146-148 MPH at the next race and it was smooth as butter.

As any suspension item that basically attaches to the diff and solidly reinforces it, NVH is going to be compromised, and is very subjective.

OP, if you have any more questions about your set-up don't hesitate to give me a ring! Happy modding!

 

[FivepointOHYEAH]

Do you have any other modifications done to your IRS? If you don't, I'm going to say that your diff housing is really beating up your cradle now. The wheel hopping is going to be more violent until you address the cradle bushings/lockouts too.

I have the cradle lockouts as well, CB005 i think. Both together are a great combo for corner carving and reducing hop. But with all this metal on metal is just scares me when i hear that thud, Kelly told me via phone call a few minutes ago its from the slack in the driveline going form loose to tight real fast. So im hopeful nothing is wrong. The tiny chirp has to be a little metal/metal rubbing most likely a washer moving slightly. After work today im going back under and double checking everything it torqued right.

 

[FivepointOHYEAH]

update upon tightening/adding another washer to each front diff bolt so that it would make the frame and diff flush, the squeak is gone, the ride is better and ive noticed 75% wheel hop, crazy less amount, that mod is better than the CB005, now both together is a match made in heaven. Still cant use launch control with a clutch side step without some wheel hop. But seriously 90% less than stock, vertical links or shocks next.

 

[FivepointOHYEAH]

Mostly normal.

The chirp/squeal I am not sure about though.

As for the other NVH characteristics - it will depend on the specific modifications. As stoli mentioned the DS causing the NVH to be worse and vibrations - I experienced the opposite on my car, as far as vibrations. I took the car to OSW (stolie filmed it btw, thanks man!) and the car wanted to shake me out of the seat after 120mph. The first thing I did when I got back to the shop was install the BK054 and all the sharp harmonics/vibrations were eliminated. I then took it up to 146-148 MPH at the next race and it was smooth as butter.

As any suspension item that basically attaches to the diff and solidly reinforces it, NVH is going to be compromised, and is very subjective.

OP, if you have any more questions about your set-up don't hesitate to give me a ring! Happy modding!

After owning these a couple weeks Ive noticed that their design is flawed IMO. Meaning the washers in the rear do stay in place and do not make a noise themselves (yes NVH is up but thats from the drive-train not the lockout) but then after 15 minutes or however long it takes the original rubber in the differential to warm up and thus become more flexible. Causing the washer and to push out of the hole rubbing metal on metal, its not overly loud so I didnt notice for a couple days but once I went under the car again I saw metal shavings from the rubbings, this is only for the 2 back diff washers, front one are fine because the the twist of the drivetrain causing the bolts/diff to want to go down/back a little bit. Unless BMR fixes this issue asap I will be going with Steeda for their differential bushings.

Still a good company with several good products, just do not believe even for $50 this is ok. I also do not believe this is only occurring in my car , I think it is an unforeseen flaw in the thickness of the washer.

 

[BMR Tech]

Thanks for the feedback.

I will look into this.

One thing I can tell you is, I made over 800ftlbs TQ and cut many 1.4 sixty foot times with my BK054 installed, so up to this point I have been very confident in them. (and have not experienced your issue)

I think there may be more involved, besides just the thickness being the culprit. For example, someone who has OEM Cradle bushings may have a higher chance at having the issue you describe, before someone with cradle bushing or lockout kits.

This has been a pretty high volume part for us, with minimal complaints or negative feedback. However, we have definitely considered making the pieces thicker to prevent any, as you called "unforeseen" issues from possible flaws in the design.

Thanks again for the feedback!

 

[FivepointOHYEAH]

Thanks for the feedback.

I will look into this.

One thing I can tell you is, I made over 800ftlbs TQ and cut many 1.4 sixty foot times with my BK054 installed, so up to this point I have been very confident in them. (and have not experienced your issue)

I think there may be more involved, besides just the thickness being the culprit. For example, someone who has OEM Cradle bushings may have a higher chance at having the issue you describe, before someone with cradle bushing or lockout kits.

This has been a pretty high volume part for us, with minimal complaints or negative feedback. However, we have definitely considered making the pieces thicker to prevent any, as you called "unforeseen" issues from possible flaws in the design.

Thanks again for the feedback!

I have the CB005 lockouts too, Im a fan of BMR. These lockouts DO work , very well i might add, I hit .88 in the acceleration G force. Best before was .8 so They do work but for someone who wants a spirited DD. I dont think these are it because of the metal on metal rubbing that I dont think can be fixed except by changing the design. I would love to resolve this though with you guys if possible.

 

[BMR Tech]

We will get ya fixed up.

 

[Jeffy_2010]

I've developed the loud thud while flooring the car, power shifting, or just quick shifting, I'm sure it's just slack in the driveshaft or something of the nature, still makes me always worry tho!

 

[FivepointOHYEAH]

I've developed the loud thud while flooring the car, power shifting, or just quick shifting, I'm sure it's just slack in the driveshaft or something of the nature, still makes me always worry tho!

The thud has always been there, its alot easier to hear now with the lockout kit, but doesnt worry me, the grind does though because its only to get worse with time.

 

[Jeffy_2010]

I don't hear the grind noise your talking about, I get some serious gear whine but that's about it other than the thud while speed shifting or the weird click sound while making a slow speed turn

 

[FivepointOHYEAH]

I don't hear the grind noise your talking about, I get some serious gear whine but that's about it other than the thud while speed shifting or the weird click sound while making a slow speed turn

When you get a chance look under your car and see if the washers in the rear have scraped some of the metal/rubber away in the hole they sit. My theory as to why you might not experience it is that you might be in cold climate, 80's in houston yesterday, heard the grind and tested it with tape, today cold front in houston hit low 50's no grind for my 25 mile bumper to bumper to commute till about an hour in because it took much longer to get the stock rubber to become flexible. So once 50's and under is the norm I do not beleive ill have any issues till it warms back up. Or this could be only privy to me. IMO it seems more like design issue, but thats great to hear you are not getting the same issue.

 

[FivepointOHYEAH]

I don't hear the grind noise your talking about, I get some serious gear whine but that's about it other than the thud while speed shifting or the weird click sound while making a slow speed turn

just saw your tag, you are in Missouri , So I do still think it is a temperature/design related cause. Could be wrong but thats never happened jk lol

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