BMR's "CB005" S550 IRS Cradle Bushing Lockout Kit - PICS & INFO!

[Mike K.]

Cool I'll give it a shot

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[BMR Tech]

NEWS!

Due to extremely overwhelming demand, we are going to continue the development and release of our S550 IRS Subframe Bracing System.

This kit is a 3-piece design, and will be priced very very competitively.

We halted the development process quite some time ago after realizing there is not much benefit to bracing the IRS Subframe once the other available modifications (such as the CB005) are installed, but people don't want to hear it!

This new bracing kit WILL be compatible with our CB005 Kit, but most importantly - those who do not use the CB005 or braces that are already available from other companies, this kit will then be a great upgrade.

I will make a new post once we are finalized with the design 100% - I have learned my lesson by posting "too much" before our finalization process is completed.

Thanks for everyone who uses our CB005!

 

[BMR Tech]

CB005 is NOT a brace. Many people assume this, but it is a kit that is specifically design to tighten up the bushings.

Braces - in our opinion, are to make the cradle more rigid IF you need it. With the CB005, bracing is redundant in all honesty.

So as said above in my post, this "brace" system is compatible with the CB005. It does not replace the CB005, nor would I ever suggest anyone use a brace over the CB005.

CB005 + The Brace System = the most rigid subframe mounting solution outside of all solid full bushing replacements. BUT, the addition of the bracing will be no where near the added benefit that the CB005 is on the initial installation.

In a high-performance application, I would say the bracing is not really the best choice as you are adding weight to the car and the return on the weight is not really significant.

Just trying to be transparent here. I am not a fan on stealth marketing or smoke and mirrors ;)

 

[Mustang_Lou]

NEWS!

We halted the development process quite some time ago after realizing there is not much benefit to bracing the IRS Subframe once the other available modifications (such as the CB005) are installed, but people don't want to hear it!

Sounds like one of those "the customer is always right, even when they're wrong" situations.

 

[Zelek]

Thanks for prefacing this as "IF you need it". I think a lot of people, myself included in the past, buy mods like this hoping you're doing something right for your car when in reality you should be treating it as, "Does it really need to be fixed? Y/N". Taking this approach now, I feel like I'm building a much better car overall.

 

[gsperaz]

Just installed my CB005 kit without any alignment or fitment issues what so ever. Took about 1.5 hrs doing it solo. As soon as the rain quits I'm gonna let'r rip ! Nice job BMR !

 

[Nac4life]

Has anyone had any issues with the 21mm bolt not cooperating in the front? I struggled for the longest time. I started to hand tighten it, then met with resistance. Pulled the bolt out and looled in the hole saw shavings. Got everything lined up best I could, drivers side went like cake. All other bolts went in great except passenger 21mm. Fought me till the end.

It's in, and I'm not sure it will ever come out. How concerned should I be, Lol? It's not a daily but I guess I'll keep an eye on it. I'm not even sure how you would fix the nut? Maybe cut from the inside?

 

[moffetts]

Depending on how mangled the threads are, you may be able to use a tap on it. Worst case, I’d take it to a shop and have them put in a helicoil and a new bolt.

 

[Nac4life]

I'm going to order some spare bolts, and a tap and see what happens. I might not even mess with it. It is super tight right now. I should have left week enough alone, but where is the fun in that?

I've got a MGW to install next. If I f that up, I'll take it in and have a shop fix both.

 

[HoosierDaddy]

I've got a MGW to install next. If I f that up, I'll take it in and have a shop fix both.

MGW is easy EXCEPT for the 10mm horizontal bolt on the top of the trans. You MIGHT not have clearance to remove/re-install it because the tunnel wall is closer to the trans than the bolt is long. If you are using a lift, you can just hang on the trans to pull it down to where the tunnel is wider. If you are on jack-stands, you can't use your whole weight to pull down. I got it lowered enough with a pry-bar to remove the bolt but couldn't use the pry-bar with the MGW in place. I finally had to get a 2nd person to help pull the trans down for 15 seconds.

 

[TheLion]

I think then numbers have been published and seem to recall that he Alpha is stiffer. Improvements from previous chassis are apples to oranges without knowing the stiffness of the previous.

Now the CTS and Camaro are not pure alpha, they are Alpha plus. The only pure alpha (so far) is the ATS the alpha plus is not quite as good as the pure alpha in a few ways but damn close. I have first hand experience with a pure alpha because I have an M6 ATS and an M6 S550. And while not scientific, my perception of them both matches the published stiffness, i.e. the ATS feels better from a handling perspective aside from factory rubber grip. Think about the ridiculous Stallone movie Driven; I believe I could pick up the quarters better in my ATS than in my Mustang PP. Then again the pure alpha ATS has lower weight and perfect 50/50 weight distribution which the Camaros and Mustangs do not.

A stock PP GT is not set up like a 1SS. Not really an apples to apples comparison. The ss is set up like a track car from the factory, GM used spherical bearings everywhere on the rear end. IRS bushings are markedly stiffer (has about 1/2 of the IRS cradle movement as the S550). Until just this year the SS also had the advantage of magnetic struts, so you can lower rid height and pre-load the coil springs for "sport" for tracking it etc. It all adds up to a tighter handling, but harsher and more noisy car.

Consequently it's also quite noisy in the SS if you do some digging on the web. As they say, you can't have your cake and eat it too...GM traded favorable NHV characteristics for handling performance where Ford did the opposite. To really tell how well the chassis performs comparably one would need to modify the S550 with comparable spring rates, strut damping rates and change out the rubber bushings all over the back end for spherical bearings and measure flex in application. Or possibly use a harmonic chassis analyzer.

If you have some numbers, i'd love to see them out of sheer morbid curiosity but I'm quite skeptical there's any meaningful difference. I think at this point knowing what I do know is that the two cars are set up for and tuned for two very different purposes and that is where the real characteristic differences in handling come from. As mentioned else where, chassis rigidity only matters if your suspension is stiff enough to cause it to flex. If the chassis is rigid enough to hold it's shape for the given torsional load it becomes irrelevant.

My point was quite simple though, saying the Alpha is a stiffer or superior chassis is not quantifiable at this point and as I said before it's more or less speculation. But it's not speculation at all to say the two suspensions are tuned with very different purposes in mind. Just look at spring rates, ride height, damping rates, the use of spherical bearings to remove joint flex etc. The two cars could not be more different in that way.

After having spent time with bone stock PP GT and after having recently done the BMR street lowering springs + cradle lockout + caster / chamber plates (spherical bearing mounts) the car's handling is completely different and that's only addressing ride height, rake angle and IRS movement. The rest of the bushings in the rear end are as they came from the factory. Spring rates of the "Performance" lowering springs are nearly identical to stock PP springs. The entire car is tight from front to back, feedback is markedly improved, the rear now tracks with the front instead of doing it's own thing...it's all about the tuning and intended purpose, but I digress, this thread was about the cradle bushings.

To that affect, the cradle bushings made about 60%~70% of the difference in the car's handling. The street lowering springs made up for the rest and provided better feedback and a more planted feel to it most likely attributed to the lower center of gravity better spring compression linearity (chrome silicon has better linearity and far greater life span than typical stainless spring steel or 'music wire'). Pending the paint doesn't wear off or separate, I'd imagine the BMR chrome silican springs should easily last the life of the car and live through multiple strut replacements.

 

[svtfever]

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[Grinder67]

I just got my CB005 kit installed tonight. The install was easy, everything lined right up, bolts when in good and took me about 1 1/2hrs. I could feel a difference just backing out of the driveway, felt more solid and a test drive confirmed that.
I know there are many other factors that contribute to wheel hop but this kit is suppose to help. I found the hop to be worse than before. I have the oem Pirelli Nero all season tires which others have said contribute but I tried a little burnout on the same road, same place as before the kit was installed and the hop was much worse.
The kit is probably worth keeping for the better feel and no added NVH but for me no help with the hop.

So the weather finally warmed up a bit here so I thought I would give the CB005 kit another try on a warmer day. What a difference 25 degrees makes! Nice long burnout and no detectable hop at all. As much as this car annoys me with all the little things, that was kind of fun!!

 

[BmacIL]

So the weather finally warmed up a bit here so I thought I would give the CB005 kit another try on a warmer day. What a difference 25 degrees makes! Nice long burnout and no detectable hop at all. As much as this car annoys me with all the little things, that was kind of fun!!

Told ya!

 

[Grinder67]

I think this is just a warm weather car. Even the dash doesn’t crackle as much in the moderate temps.

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