Damn Poly Bushings :/

[Scott8583]

Heading to the track in the morning... Took the car out on the street for a couple test hits on some shock adjustments. Just launching the car and running it thru 1st & 2nd. Car felt funny (squirlly) so I put it up on ramps to check it out. This is an AUTO car and should not be finding this. Top hole in the relocation brackets and a Roush upper control arm. These bushings have less then 1000 miles on them. This is what I found :/ Grrrr

 

[JTS_7]

Did you use the correct grease? I know certain types will soften the bushing, which leads to pre-mature failure. Happened to a few people I know for that exact reason.

PM Kelly he backs his products.

 

[Scott8583]

Synthetic green grease. I know it's not Red Line, but it is synthetic.

 

[CPRsm]

I tell my customers if you track it, no poly bobos!!!! It's just the wrong part for the job. A street car w some power, sure. Won't see the shock like it will at the track.

 

[vortecd]

I have used poly bushings for 20 years on Mustangs and never seen one do that

 

[Scott8583]

I tell my customers if you track it, no poly bobos!!!! It's just the wrong part for the job. A street car w some power, sure. Won't see the shock like it will at the track.

Now you tell me! I swore I've seen post from Kelly about customers running 8's with poly lowers...

Stock lowers are back on now. Took the relocation brackets off too. I'll see how it goes at the track tomorrow.

 

[el jefe 302]

Are you sure you didn't hydro the bushing?

I.E. applying too much grease to cause hydraulic force to split the bushing.

 

[Scott8583]

I've seen post that said not to over grease... I only put a couple pumps in on the install. I've made about 15 hard launches at the track ( 1.4 60' times ) and probably 15 not so hard launches on the street.

 

[50blackout]

I remember reading that if you have the Roush upper control arm you are NOT suppose to use relocation brackets. Kelly will confirm this.

 

[Scott8583]

I thought I seen Kelly mention the Roush upper lowers the front mounting point. That's why I had my lowers on the top hole, but that has nothing to do with a cracked bushing. My car was still squatting so I know the anti squat wasn't too aggressive...

I guess this was a blessing in disguise... Took off the relocation brackets (even with a 1" drop in rear) and put stock lower rubber control arms back on. 2 hits at the track today resulted in back to back 1.39 60' times! (Stock converter still)

 

[slow306stang]

Thanks for the heads up and man you just keep on chopping that et down. My prediction of 9.40s this fall is looking better.

 

[cjd223]

Should have listened to Lidio.

 

[Scott8583]

Yep...

 

[Shaun@AED]

That's my go-to setup.
Roush upper and stock lowers. We've plotted the geometry with this setup and it's damn near perfect for stock to 1.5" lowered cars.
For serious cars we go straight to spherical bearings.
Poly has it's place, but IMO not in a suspension piece that sees huge loads on one side of the bushing.

Congrats on the new best.

 

[Scott8583]

^^^^ that's good to know... Thanks Shaun!

 

[SilverCoyote]

Thanks for posting.... wtf... how are you supposed to know if you can use these or not...!!! lol..... NOVI 2200 with Tremec T56 Magnum XL, 555R's 305 40 18 on back.... sooooo. Mostly drive on street but have been at flashlight drags, etc. I'm about to get into some suspension mods, was looking forward to poly bushings... ??

 

[cjd223]

Roush upper control arms or just the mounts?

 

[ziggity]

Same thing happened to me after one day at the track ( 6 speed ) , if I was going to buy them again id go with spherical bearings for sure.

 

[Scott8583]

Roush upper control arms or just the mounts?

The Roush upper comes with a bracket. It's like the stock upper, just less rubber.

 

[vortecd]

Same thing happened to me after one day at the track ( 6 speed ) , if I was going to buy them again id go with spherical bearings for sure.

Same control arms?