Help Me Decide - Cradle Bushings

[rts9364]

Current setup:

2015 A6 3.55 ProCharger car, 802whp

Rear of car:
Weld 17x10 w/ MT ET Street S/S
BMR CB005
Steeda Diff Inserts (black, standard bolts)
BMR Spherical Vert Links
Viking Crusaders (newer ones with the top "T" bracket)
BMR drag springs

The car is actually behaving really well as is so far, but I want to push it. I am in the process of tearing the car apart now for some upgrades. I want the IRS to be solid. These parts are either in the garage or en route:

FTI converter (off subject, but will add at least a little stress to the system during launch)
DSS 2000hp axles
DSS Alum. DS
BMR BK050 Solid diff bushings
BMR BK055 LCA bearings
FRPP toe tink bushings
BMR toe links
Steeda IRS alignment dowels
BMR UTCA064 Delrin Camber links

>> My question: Do I stick with the CB005 lockout that I already have, or do I move to the BK048 delrin cradle bushings? I am already committed to dropping the cradle, so it's really just a matter of $150 and cutting 4 more rubber bushings out. There is also the issue of NVH and overall behavior with my other mods. This car is only a weekend/fun/track car, so I am not too concerned with noise (see also: LT's, no cats, etc.). There is already some significant gear whine with the "hard" Steeda diff inserts. BUT...at the same time, if I won't really gain anything with the BK048, then I will probably stick with the CB005 I'm already running.

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[BmacIL]

You will gain very little, if any. There are cars running 1.2, 1.3 60 ft with the CB005 and BK055/081.

 

[BMR Tech]

You will gain very little, if any. There are cars running 1.2, 1.3 60 ft with the CB005 and BK055/081.

*1.18 too.

 

[wildcatgoal]

Replace every bushing with aluminum... man up baby.

 

[rts9364]

Replace every bushing with aluminum... man up baby.

Maybe just weld everything together?

OK, thanks guys. You are confirming what I was thinking. I'll stick with the sufficiently-awesome CB005 that is already working.

 

[NoVaGT]

NVH is easy to cure; grab some Dynamat and put it inside the car where the cradle bolts to the chassis.

 

[BmacIL]

NVH is easy to cure; grab some Dynamat and put it inside the car where the cradle bolts to the chassis.

That won't do almost anything for structure-borne noise. It's very different from exhaust resonance.

 

[Racerx009]

I just posted about powerflexusa bushings and I like the fact they are longer tabs the fill the void in the stock bushings. I don't know how hard they are compared to steeda but filling the void in the bushings makes sense to me..I bmr suspension has something similar to their product..

 

[NoVaGT]

That won't do almost anything for structure-borne noise. It's very different from exhaust resonance.

I'm pretty sure noise and vibration is......noise and vibration, and it doesn't matter where it's coming from.

I've seen Dynamat used to amazing effect to dampen vibration and noise, and it would work in this application too.

 

[Brian V]

Exactly how much torque are you producing at the rear wheels OP ?

Why all of the dramatics about NVH ?

Bushing incerts ..Fuck that . The diff is going to torque itself out of position and destroy everything in the process .
Spend the $$ on the correct bushings or weld er up proper ..

 

[BmacIL]

I'm pretty sure noise and vibration is......noise and vibration, and it doesn't matter where it's coming from.

I've seen Dynamat used to amazing effect to dampen vibration and noise, and it would work in this application too.

Major facepalm to this comment.

 

[Brian V]

Class , class . Shut up . Which reminds me of the New age drag races with the big wheel low profile tyre late model hoopties for time slips .. if you want a laugh watch em ... funny stuff happens at launch . Rear wheels spinning off .

 

[Lightning Struck]

Major facepalm to this comment.

He's right. Explain how a CLD panel would know where the sound is coming from? All it's doing is transforming a movement into heat. And it would actually be more efficient, due to the lower frequency of the rear end, compared to an exhaust drone.

 

[Reds197]

Procharged auto car is fine with what you have. Even the axles are overkill for your power level. Pushing it as in running at the track? Any track times.

 

[Norm Peterson]

He's right. Explain how a CLD panel would know where the sound is coming from? All it's doing is transforming a movement into heat. And it would actually be more efficient, due to the lower frequency of the rear end, compared to an exhaust drone.

Might not be where it's coming from so much as what the specific modeshapes involved look like/where else they pop up. At minimum, I'd expect that by the time a decent job of 'matting was done for cradle vibrations that you'd have added more 'mat than you would for quieting exhaust-driven vibrations.

But I think OP's car is more of a competition car, for which a lot of added weight wouldn't be desired (and some amount more NVH at least tolerated).


Norm

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