Suspension Upgrades Tip/Did any else experience this?

[toastedbutter]

Hey y'all.

A few weeks ago, when Lethal Performance had them on sale, I picked up BMR's cradle lock-out (CB005) and poly differential bushing inserts (BK051). (Decided to pair it with Steeda's IRS alignment inserts also, but that was simple). First off, I love the upgrade. Always expect great things coming out of BMR's shop, and the driving feel is much better now :cheers:

During the install, doing the bushing inserts, I first ran into a problem with the driver-side, front bushing. Following the instructions, the inserts slides in fine, but the cradle didn't lower far enough (for me) to even get the bolt in the hole. I had to disconnect the driveshaft from the differential (thanks American Muscle install video) in order for the cradle to drop all the way. Second hiccup was on the driver-side, rear bushing. For what ever reason, the stock bushing/bushing surround was smaller in diameter than the other 3... So the insert wouldn't just slide in. After multiple dremel sessions and test fits, about 1/16-3/32 of an inch off the diameter, the insert finally fit.

Again, just my experience, and kind of curious if anyone had the same problems. Worth the mod, if you have a free Saturday afternoon and a lift!

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[The Chairman]

I installed the Steeda lockout bushings, but had the same problem. Never did get the driver’s side front bushing/bolt in. Just no room unless the IRS cradle is darn near removed. The rear driver’s side bushing in the car is diffferent from the shape expected. I used a drill to slightly reshape the poly bushing to fit over it correctly. After that, all is good.

 

[ldp82]

Thank you for posting. I will be having these exact mods done to my car this month. I will let the shop know and see if they have this problem on my car.

 

[firestarter2]

Good post as I get older I have little patience for things that don't just work out of the box

 

[Hack]

I did my cradle lock outs when I had the car torn apart for adding coolers, but I did notice it was difficult to get the cradle aligned so the bolts would go in. IIRC I ended up using a small ratchet strap to help position the cradle. Hazards of working alone.

My advice is to definitely get a rear alignment after installing the cradle lock outs.

I haven't done the differential bushings, so I didn't experience the issue you mentioned. What is the reasoning for changing the differential bushings?

 

[Grimace427]

I haven't done the differential bushings, so I didn't experience the issue you mentioned. What is the reasoning for changing the differential bushings?

If you stuck a video underneath the car looking at the rear suspension/diff then ran the car hard you would see how much deflection is possible with the factory rubber bushings. When you install stiffer bushings for the diff you allow more of the engine torque to be transmitted to the wheels and do so more immediately, plus when the bushings deflect then spring back you get wheel hop.

 

[toastedbutter]

If you stuck a video underneath the car looking at the rear suspension/diff then ran the car hard you would see how much deflection is possible with the factory rubber bushings. When you install stiffer bushings for the diff you allow more of the engine torque to be transmitted to the wheels and do so more immediately, plus when the bushings deflect then spring back you get wheel hop.

Yeah, the videos Full Tilt Boogie has with their products is insane.!

 

[toastedbutter]

Glad I wasn't the only one... Ha!

 

[Hack]

If you stuck a video underneath the car looking at the rear suspension/diff then ran the car hard you would see how much deflection is possible with the factory rubber bushings. When you install stiffer bushings for the diff you allow more of the engine torque to be transmitted to the wheels and do so more immediately, plus when the bushings deflect then spring back you get wheel hop.

More immediately makes sense, since it takes some time (however brief) for the bushings to deflect. More torque transmitted - that doesn't compute for me.

I also see now that you mention it that wheel hop can come from these bushings deflecting and springing back.

Thanks for the explanation. I definitely am NOT changing the diff bushings on my car, but I can understand why some people might want to do it if they are drag racing or otherwise doing super hard launches.

 

[The Chairman]

You don’t have to change the diff bushings. The kits being offered mount over the rubber bushings to keep them from moving very much.

 

[1day]

Wouldn't the lockout kit negate the need for the upgraded bushings?

 

[nastang87xx]

Did you guys back out ALL 4 bolts some before removing a complete side? There needs to be a tiny bit of wiggle. Not much at all, barely discernible but just a tick enough.

EDIT: I know this sounds stupid but it's also a lot less nail biting of an install if you use two jacks supporting both sides of the cradle. You can support the cradle by the pumpkin but getting the cradle to go all the way back up can sometimes be a pain, if not impossible. There's just binding happening in the mounting points.

 

[nastang87xx]

Thanks for the explanation. I definitely am NOT changing the diff bushings on my car, but I can understand why some people might want to do it if they are drag racing or otherwise doing super hard launches.

I wouldn't either. For those of us who still drive on the streets, the cradle lockout is enough. The diff does deflect but not enough to make a difference that would ill affect us, even on the track for that matter. The big one is definitely getting the cradle under control.

If you call Kelly at BMR, he'll even say lockout lockout lockout. Anything else is just not necessary until about 700 RWHP. The reason why they produce such kits and vertical link replacements is because there are people out there who do genuinely need them such as higher SCCA classes or for those who just do wish to replace all the rubber. But in real practice, not really needed.

 

[Onyx]

nastang87xx And I did the BMR lockout kit and steeda alignment bushings at my house in jack stands in a hour, tops. The car feels much more solid in the rear now and the only issue we had was bringing the cradle back up as it was binding on something?( We had the jack under the diff and it was lifting the car off the stands) We jacked each side up individually and it went right up into place.
Very happy with the results and IMO should be the first mod you do if you want to stiffen up the rear. Very impressed with the kits from BMR and Steeda, Steeda makes a sub frame alignment kit for the BMR kit the "spacers" are different sizes with this kit.
Thanks again for the help nastang87xx!
Thanks BMR and steeda for the excellent products!

 

[tj@steeda]

Appreciate the feedback - let us know if we can ever help in the future!

TJ

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