Cobra IRS Delrin control arm bushings

[ac427cobra]

but they did fit nice

Thanks, I just love hearing that!!! :bowdown:

The car is still on jackstands though so I can't comment on the performance of the bushing

If you haven't driven the car yet why don't you wait until you hear how loud the front diff bushings are before you decide how much effort and money you're going to spend on the material to help silence the noise? :shrug:

:thumbsup: :coolman: :beer:

 

[LargeOrangeFont]

Thanks, I just love hearing that!!! :bowdown:




If you haven't driven the car yet why don't you wait until you hear how loud the front diff bushings are before you decide how much effort and money you're going to spend on the material to help silence the noise? :shrug:

:thumbsup: :coolman: :beer:

The UHMW bushings for the front of the diff will be perfect for the street crowd.

BTW the fit on your bushings is great. Everyone that watched\helped with the cradle bushing install was truly impressed.

Ashley

 

[ac427cobra]

The UHMW bushings for the front of the diff will be perfect for the street crowd.

BTW the fit on your bushings is great. Everyone that watched\helped with the cradle bushing install was truly impressed.

Ashley

Ashley:

The UHMW pieces are what mount the cradle to the chassis. The front diff supports are aluminum and they are a tad on the loud side. But loud is a relative term. Loud to one person is not bad to another? If it cures their problem, they are willing to sacrifice a little.

Lots of people want those front diff mount pieces made out of another material besides aluminum to cut down on the noise. I'm uncomfortable going to any type of plastic given the heat that is generated in the diff.

If you're in a street driven vehicle, throw some AC/DC in the cd player and crank it!

:thumbsup: :coolman: :beer:

 

[hatsharpener]

\If you haven't driven the car yet why don't you wait until you hear how loud the front diff bushings are before you decide how much effort and money you're going to spend on the material to help silence the noise? :shrug:

I know myself; if I don't do it now, I will just tell myself that I'll live with the noise in the future because I won't have the desire to tear up the interior. At least now I can do it while I wait to accumulate parts for each of the bigger projects. Finishing up the rear suspension then I'll be moving to the front suspension. Then finally I'll be looking at redoing the motor

 

[LargeOrangeFont]

Ashley:

The UHMW pieces are what mount the cradle to the chassis. The front diff supports are aluminum and they are a tad on the loud side. But loud is a relative term. Loud to one person is not bad to another? If it cures their problem, they are willing to sacrifice a little.

Lots of people want those front diff mount pieces made out of another material besides aluminum to cut down on the noise. I'm uncomfortable going to any type of plastic given the heat that is generated in the diff.

:thumbsup: :coolman: :beer:

Bruce,

I can see your concern, but does anyone know at what temp the delrin or UHMW starts to get soft? I have used delrin in different applications under heat around 300 degrees and not had an issue.

I was talking to Ken offline about testing some shims or even bushings made out of either UHMW or Delrin and I was under the impression that he was going to make them to try out.

Does the front of the diff get that much hotter than the rear? I'm sure it does but I have no idea how much.


Ashley

 

[ac427cobra]

Bruce,

I can see your concern, but does anyone know at what temp the delrin or UHMW starts to get soft? I have used delrin in different applications under heat around 300 degrees and not had an issue.

I was talking to Ken offline about testing some shims or even bushings made out of either UHMW or Delrin and I was under the impression that he was going to make them to try out.

Does the front of the diff get that much hotter than the rear? I'm sure it does but I have no idea how much.


Ashley

A LOT of people OT their S/C Cobras without diff coolers. My diff runs over 250 degrees WITH a cooler. Granted, it has 4:10's and runs a tad hotter than your average diff but I would not be surprised if people saw 300 degrees on their uncooled diffs?

Now 300 degrees is not that outrageous for Delrin (forget PTFE or UHMW!!) but add in the pressure these parts are under and multiply it by numerous cycles and I (personally) am uncomfortable with it.

There is however a very expensive plastic called PEEK and I think it's a couple hundred dollars a foot? That MIGHT be an acceptable material but who's willing to spend that kind of ching on something that could possibly be just another bad experiment?

You can do and test whatever you want. If you want to test some Delrin pieces go right I ahead. I wish you luck. I hope it's successful? But keep a close eye on the torque specs for the front diff mount bolts. I don't necessarily think the Delrin will automatically fail? But I have personally tested our current configuration we are selling and I am VERY confident in the overall performance and durability of the components.

:thumbsup: :coolman: :beer:

 

[LargeOrangeFont]

A LOT of people OT their S/C Cobras without diff coolers. My diff runs over 250 degrees WITH a cooler. Granted, it has 4:10's and runs a tad hotter than your average diff but I would not be surprised if people saw 300 degrees on their uncooled diffs?

Now 300 degrees is not that outrageous for Delrin (forget PTFE or UHMW!!) but add in the pressure these parts are under and multiply it by numerous cycles and I (personally) am uncomfortable with it.

There is however a very expensive plastic called PEEK and I think it's a couple hundred dollars a foot? That MIGHT be an acceptable material but who's willing to spend that kind of ching on something that could possibly be just another bad experiment?

You can do and test whatever you want. If you want to test some Delrin pieces go right I ahead. I wish you luck. I hope it's successful? But keep a close eye on the torque specs for the front diff mount bolts. I don't necessarily think the Delrin will automatically fail? But I have personally tested our current configuration we are selling and I am VERY confident in the overall performance and durability of the components.

:thumbsup: :coolman: :beer:

I know you have a wealth more experience on this than I do Bruce. Thanks for the insight.

 

[BlackBolt9]

I don't know how well it would stand up to the vibration because I have not used it in that area but how about PVC? I know its pretty hard and from what I have seen I think it would handle heat fairly well. What about a glass (fiber or carbon) covered aluminum bushing?? Just some thoughts.

 

[NJ2000R]

I'm going to make up 2 UHMW bushings to test for street use only as they may not hold up to 300F (if the housing ever does get that hot) at the track without a cooler....mine, with a cooler (terry's design) never exceeds 200F, ok, maybe 210F, on a super-hot day....the white UHMW becomes clear and slimy in the upper 200's F....just keep an eye on it....

I dont think you would gain much from delrin, PEEK, PVC, or any other higher-temp alternatives, because they are all just as hard or nearly as hard as aluminum, and would transfer nearly the same harshness that we're trying to eliminate....

my 00R still has all of the stock stuff in it, except for the Paul's HP diff brace and polyurethane bushings, which have stood up fine so far, but, I'm sure there is some flexing going on at the track....I dont do burnouts, but I havent had any wheel hop since adding the Pauls brace and poly bushings....nothing beats a solid mount though, performance wise, so eventually I will go that route too....I made these bushings, and STILL havent installed them in my car? :shrug: kinda like the carpenter who has the crappiest house on the block! :lol:

 

[b4409]

my 00R still has all of the stock stuff in it, except for the Paul's HP diff brace and polyurethane bushings, which have stood up fine so far, but, I'm sure there is some flexing going on at the track....I dont do burnouts, but I havent had any wheel hop since adding the Pauls brace and poly bushings....nothing beats a solid mount though, performance wise, so eventually I will go that route too....I made these bushings, and STILL havent installed them in my car? :shrug: kinda like the carpenter who has the crappiest house on the block! :lol:

I can't believe I just read that!

 

[NJ2000R]

I can't believe I just read that!

:lol: :lol: yeah, i know? :shrug:

not enough time or space to tear the car down :rollseyes

I cant believe I actually have the 93R all ready for track duty....and there's a week and a half to go before my first event? thats a first! :lol:

oh well, bruce did all the R&D and grunt work on the bushings, I just made them :rolling:

 

[b4409]

:lol: :lol: yeah, i know? :shrug:

not enough time or space to tear the car down :rollseyes

I cant believe I actually have the 93R all ready for track duty....and there's a week and a half to go before my first event? thats a first! :lol:

oh well, bruce did all the R&D and grunt work on the bushings, I just made them :rolling:

But it's such a rewarding experience ;-)

It's good to have a spare track car - and one that's ready -- if they're ever really ready.

Btw, I meant to send the feedback form but haven't gotten around to it. The only issue I had was with the cradle bushing width on the forward (front) side. My car had more than 1/8" gap between the bushing and the torque box on the RH side - enough that I had to add a spacer on both sides. That's ford production tolerances, I suppose.

Bruce B

 

[Mr. Mysti]

Bruce,

I can see your concern, but does anyone know at what temp the delrin or UHMW starts to get soft?

Ashley

Delrin

UHMW

 

[magstang1]

what type of assembly lube are you guys using on the delrin and aluminum?

 

[ac427cobra]

what type of assembly lube are you guys using on the delrin and aluminum?

I'm recommending waterproof wheel bearing grease.

:thumbsup: :coolman: :beer:

 

[magstang1]

thank you

 

[moridin2004]

Yes it is. I used quite a bit to cover the rear of my car also. The Bassani cat back + MRT H pipe produced an unbearable drone. I used B-Quiet and Brown Bread.

Why not try http://www.lizardskin.com/?

After the aluminum diff bushing install on the family's 03 Cobra, I'm going to take a shot with it. Way lighter than the asphalt based stuff too from my understanding.

 

[johnny-longtors]

Well, this past weekend I finally had my IRS re-thrashed. Current work was performed by Terry Johnson of Street Lethal Performance of Edinburg, PA (don't look, he has no web presence) - while I am fully capable of a considerable amount of work I lack both the appropriate tools and the assistance to do things of this nature myself. I'm not going to have a relative come looking for me after a 10 day disappearance only to find me crushed under my car and my dog dead from starvation. If you've done this yourself you should be very proud of yourself, and please know that I am as well so no futher comment is required. I will gladly write a check to make this someone else's problem.

What's my goal with this car? The ultimate street driver, and possibly track car if I ever find time.

To recap where I was:

• IRS went into the GT in Nov. 2004 with FRPP 4.10 gears, full "Brand N" bushings (alum. front diff), Mathis braces, MM urethane cradle bushings, MM coil-over kit with Koni SAs & 550# springs, and BF brace.
• It was a pogo stick
• T56 install took place around December
• Car had a WICKED vibe over 95MPH (think "aftermarket gauges rotating in their sockets" vibe)
• Car made an unbelievable plethora of noises - squeaks when hitting bumps the size of 2 stacked nickles, major clunks over any rise or depression of note, weird grindings in tight low-speed turns, the unbelievable banshee howl of the gears/diff. bushings (yes, car had full interior; yes, gears were set properly and had been inspected by two qualified individuals), etc, etc.
• Spring 2005 the LCAs were pulled and replaced with another set that had reamed Brand N bushings. Car was tolerable for a month, then the LCAs started to squeek. A lot. A REAL lot.
• Combined with the noise from the 4.10s and the aluminum front diff. bushings I could no longer take it - and my impending turbo install gave me more additional reason to change things up yet again.

As a point of note - the car has the ginormous Hans Racecraft FLSCs


Here's what was done over the weekend:

• Based on comments on another board WRT coil-overs and the IRS and the stresses placed on the shock towers (the premise being that a rear STB is required) we thoroughly inspected the shock towers and chassis for any signs of fatigue or distortion. They were in fine shape (and I routinely see train tracks at full speed). We decided that the rear STB was not a requirement and we did not install it (meaning I can keep my Tarantula!!)
• As stated, the cradle had MM urethane bushings already. They were in fine shape, so for now they've been left in place. Once my turbo goes in we may swap in the UHMW units from the "Brand B" kit.
• The diff center section was pulled and replaced with a stock unit and a new BF brace. MM urethane front and rear bushings used (I will inspect them at the end of the summer to see how they've fared). Diff filled with Royal Purple.
• Both upper & lower control arms were replaced, the new units having "Brand B" bushings in place. The "Brand N" in the UCAs were absolutely wrecked. I could move the bushings 1/4" in any direction, and the centers had long ago rusted and frozen in place. I will post up video of me moving them. When we got the car off the ground we could grab a wheel and move it 3/4". Anyway - new control arms were zerked, and the LCA bushing received an additional pin opposite the zerk fitting as the zerk did not penetrate the delrin far enough for our liking. I know it is overkill - but I am not taking any chances - if it's not apparent I have no desire to be under the car once a month unless I choose to be. I had an off-line conversation with Bruce about the UCAs, and while he's not concerned about his design I will keep a close eye on them and if need be look at the next generation of bushing he's working on.
• MM bump-steer kit installed.
• MM end-links installed.
• End-link bars "fortified" as detailed here by a couple folks.
• MM urethane sway-bar bushings installed & fitted with zerks.
• Level 2 half-shafts installed (found them on closeout at Summit Racing!)

I took pics of much if this and will make a page once I get 5 minutes to spare.

Now, there's decidedly some tweaking yet to be done to dial all this in (and my Koni DAs are being rebuilt to IRS spec at the moment), but I can tell you that I am once again incredibly happy I installed an IRS. Once the turbo goes in (accompanied by a customized MM K-member, control arms, coil-overs, and Koni DAs rebuilt to FOX-III length) I'll to a total alignment and dial-in of the chassis - I can hardly wait!
There is no wheelhop - either from a standing start or dropping 2 gears & gunning it at speed.
There is not a squeak, groan, grind, or peep from the back. I can again hold a conversation in the cabin. I believe I have an exhaust leak - that's how quiet the back end is again.

Sadly, I am still running snow tires, but the rear is once again firmed up to the point that I can feel the comlpiance of the tires (I cannot wait to get my CompTAs back on) I never thought I'd be so happy to feel slop from the sidewall! The car drives like a friggin' Lotus - it's on rails!

Comments on the bushings -
Having worked on a set of "Brand N" myself, and having seen the installation of those from Bruce & co. I can say that the units from Bruce are superior. While I don't have a massive amount of "bushing experience", Terry has done many, and made the following 2 statements:
"I've never installed a set of bushings that fit this well out of the box"
and
"There's not many performance parts I'd say this about, but I don't really see anywhere for improvement with these bushings"

IMO - anyone reading this looking for an all-out handling IRS and considering bushings - don't waste time and money on anything else. Yes these are a bit spendy, but they are no compromise units and well worth the investment.



<shameless marketing>
I anyone is interested in the following PM me:

• Hans Racecraft rear Strut Tower Brace
• Complete IRS diff center section with FRPP 4.10s and (red) BilletFlow brace for sale if anyone is interested (~16k miles; properly broken in, fluid changed / gears inspected at 1K miles (Royal Purple) )
• Full set of Lower and Upper Control Arms - lowers have Brand "N" in place, uppers have trashed "Brand N" in place (would prefer to sell all 4 at once). IMO if the lowers are zerked the "Brand N" would be tolerable.
• Stock Axles (less inner CVs) - have them cryo'd and I'd bet they'd equal the Level 2s in strength - I have 2 sets - one with 1200 miles, one with 16k
• "Brand N" alum. diff bushings - one set used, one set new
• New set of "Brand N" UCA bushings

I also have a complete set of MM IRS tools - the control arm / subframe bushing removal tools AND the diff. bushing removal tool. PM me if you want to rent them.
</shameless marketing>

I would like to again say thanks to Bruce for the fine product, and the support here in the open forums as well as via numerous PMs, and also to say thanks to those that have posted up data here based on what they've done.

Don

 

[Mr. Mysti]

Great to hear you got your car back again Don! :beer:

I did try and say on the other board that the Brand "N" bushings were junk and the guy would not communicate after the purchase was made.

Nice write-up of all you went through. good luck with the parts sale.

-Vince

 

[LargeOrangeFont]

Having worked on a set of "Brand N" myself, and having seen the installation of those from Bruce & co. I can say that the units from Bruce are superior. While I don't have a massive amount of "bushing experience", Terry has done many, and made the following 2 statements:
"I've never installed a set of bushings that fit this well out of the box"
and
"There's not many performance parts I'd say this about, but I don't really see anywhere for improvement with these bushings"

IMO - anyone reading this looking for an all-out handling IRS and considering bushings - don't waste time and money on anything else. Yes these are a bit spendy, but they are no compromise units and well worth the investment.

+12345 I was suprised and a bit shocked that the bushing fit as well as they did.