Finally got around to building the IRS...

[70Maverick]

Holy Cow, what a difference. I know most people go with Bruce's stuff but I have had good luck with MM. I bought the WHOLE kit with A arm bushings, Diff bushings, IRS subframe etc. I also installed a BF diff brace. It is simply awesome now. I have the best of both worlds and recommend the full bushing upgrade. I know most people just do the 3 diff bushings but to me, if I was going to pull that out, why not yank the entire IRS and do it right.
Some people say the Delrin MM bushing don't last as long, I don't daily drive the car anyway and now, if they do end up wearing out, they are easy to change since those PITA stock rubber ones have been burned out. I believe the ones that wear are not the same ones they sell now anyway. The car already had MM full length subframes and a Kenny Brown strut tower brace. It is nasty now. :yes1:

 

[bleedingfordblu]

very nice! i wish there was a comparison someone could do between the two. How has it affected wheel hop?

 

[BlksvtCobra01]

Congrats I did the diff bushings and FRPP cover last year and could tell a huge difference. Eventually I wanna do all the bushings. Why didn't you go ahead and get a FRPP or LPW cover instead of the brace though?

 

[I'D WIN]

I think you are highly misinformed and yes, if you are gonna go thru the troubles, then why would you not upgrade the cover? It is one of the weakest points. We have seen a lot of those covers break, even with the differential brace.

 

[70Maverick]

Congrats I did the diff bushings and FRPP cover last year and could tell a huge difference. Eventually I wanna do all the bushings. Why didn't you go ahead and get a FRPP or LPW cover instead of the brace though?

I don't drag race the car at all. It is a convertible. Nobody serious about drag racing would have a convertible. It will never see a drag strip as long as I own it. The money it would have taken to purchase a cover paid for the labor to install all the bushings. I guess you chose the cover and no other bushings. Why didn't you replace all the bushings? The cover doesn't help wheel hop at all in any way, shape or form. Guess what breaks the cover? Wheel hop. I no longer have wheel hop.

It is 100% improved. Words can't describe the difference. It's funny that you say you went as far as to do the diff bushings but yet didn't install the rest of the bushings then ask why I didn't go further. Anyway, I am EXTREMELY happy with the results and I can play around at least now without massive hopping.

 

[BlksvtCobra01]

I don't drag race the car at all. It is a convertible. Nobody serious about drag racing would have a convertible. It will never see a drag strip as long as I own it. The money it would have taken to purchase a cover paid for the labor to install all the bushings. I guess you chose the cover and no other bushings. Why didn't you replace all the bushings? The cover doesn't help wheel hop at all in any way, shape or form. Guess what breaks the cover? Wheel hop. I no longer have wheel hop.

It is 100% improved. Words can't describe the difference. It's funny that you say you went as far as to do the diff bushings but yet didn't install the rest of the bushings then ask why I didn't go further. Anyway, I am EXTREMELY happy with the results and I can play around at least now without massive hopping.

I had a brace and sold it your cover may eventually leak it's thin. The brace is a band aid. There are plenty of people that drag race verts on here. I didn't drop the whole IRS I just dropped the pumpkin cause it was leaking and did the front and rear diff bushings. I have next to none wheel hop and the clunk is gone. You must of had the labor done cheap or picked up a used brace because it's only like a $40 difference if you buy the cover from autonation. At least your happy though.

 

[kramey24]

I have a question, I don't have a ton of knowledge about cars esp building so I'm looking for some information. I'm looking into to buying a 2003 Cobra. It has a GT 8.8 with 31 spline moser rear axle, does that mean it no longer has the IRS? What is your opinion on the GT 8.8 with 31 spline moser? TIA!

 

[P49Y-CY]

I guess you chose the cover and no other bushings. Why didn't you replace all the bushings? The cover doesn't help wheel hop at all in any way, shape or form. Guess what breaks the cover? Wheel hop. I no longer have wheel hop.

that is not true, but it is a common misconception. wheelhop does not break the cover, wheelhop breaks halfshafts.

what breaks the cover is the rearward/upward tilting movement of the pumpkin under hard acceleration with stock rubber differential bushings. that is why mjchip and billetflow designed the brace when these cars first came out.

so in effect, with solid diff bushings, which would not allow for any movement of the pumpkin whatsoever, there is no need for a cover upgrade (brace or replacement), at least from a breakage standpoint. but it is not always 100% so a cover or brace is good insurance. the stock cover is eggshell thin.

there are other nice benefits to an aftermarket cover though, including easy fluid changing, options for cooling, and bearing cap reinforcement.

congrats on your improved irs :beer:

 

[KyleSVT]

very nice! i wish there was a comparison someone could do between the two. How has it affected wheel hop?

There are many reasons to go with full tilt over anyone else. These are just a few reasons why.
[video=youtube;vqg6nLz7LpI]https://www.youtube.com/watch?v=vqg6nLz7LpI[/video]

[video=youtube;EQ2nAaA_t7g]https://www.youtube.com/watch?v=EQ2nAaA_t7g[/video]

[video=youtube;O_kZrNMsG34]https://www.youtube.com/watch?v=O_kZrNMsG34[/video]

 

[SlowSVT]

I think you are highly misinformed and yes, if you are gonna go thru the troubles, then why would you not upgrade the cover? It is one of the weakest points. We have seen a lot of those covers break, even with the differential brace.

For years the BilletFlow brace was the only option and it worked very well. A few serious drag racers still had problems but for the vast majority didn't have issues. I agree it's not the best option but for what the OP is doing he will be fine.

 

[JrSVT]

I had the MM bushings throughout my IRS with a brace and wouldn't you know...my diff cover still broke. It's not wheel hop that kills the diff cover like P49Y-CY stated...it's the movement of the differential and the torque/twisting of the differential under hard launches. I upgraded to the full FTBR kit with the FRPP cover and haven't had any issues since....and yes there is a difference between full MM bushings and the full FTBR kit with Bruce's products outshining the MM stuff.



Jr.

 

[03cobraracer]

I have the FTBR full kit in my car, everything he sells except the diff cover its a stock cover with a brace. I will eventually do the cover as well but I bought this whole IRS this way complete and didn't have any more money ha. But now it rides on rails and wheel hop is gone for good. I don't miss that crap ha