So who has solid mounted their subframes?

[spiller]

Im in the process of building my JZA70 for track work. Id still like to use the car on the streets for occasional meets and the odd weekend drive but the priority is to make it handle as well as possible. I have some alloy subframe spacers here for the front and the rear (and also a bunch of wesbeech heim arms) but i'm not sure if fitting the spacers is worth the effort?

My main concern is the rear subframe is notoriously week and I know it will require bracing and reinforcement to prevent cracking if I am going to solid mount it.

So my question is, who has done this? How is it holding up and most importantly was the change worth the improvement in terms of handling and stiffness?

 

[emericaskater285]

I have mine done. I havent lowered my car back to the ground yet tho, as I am waiting fr my new rotors to come in. I will let you know how it is once I get it back on the ground.
They really arent that bad to do. All you have to do is take out the back drive shaft, and unbolt the two 14mm bolts and the six bolts that hold the subframe up, lower it a little bit and put the bushings on.
Although it could be that easy, if you want to do it without that much hassle, you could disconnect the rear drive shaft remove that. Take your ebrake cables off from the connector above that rear drive shaft, undo the brake lines or take the calipers off then you can lower it to the ground, clean, and even disassemble and reinforce it while your at it. Then put it back in.

I took the second more through route, but I did not reinforce mine. I have a second subframe I am going to reinforce, and put traction arms, bushings, and all new suspension components on when I get done with my engine. I also plan to strip it and powdercoat it, and do a lsd locking kit while I am at it.

 

[IJ.]

I used Red Poly's last time and it was noticably harsher in street driving.

 

[spiller]

emerica: if I fit the spacers, I will probably just let the subframe hang there and slip them in between it and the body. thats the easiest way to do it. but that's obviously fitting them and hoping they dont crack it in the process. i could obviously always pull it out and have it re-enforced later. my subframe is in good nick as its spent most of its life in an automatic transmission car (but now sits with a locked diff and R154).

IJ: im not fussed at all with harshness, just dont want to crack my subframe going over a pothole etc. Was yours braced at all? Which poly's did you use, actual bushes like ronny k's or just spacers that go between the body and the subframe? If you are talking spacers, im keen to see where you got them as they would be better than billet alloy that I have and much easier to fit than actual bushes inside the subframe...

 

[IJ.]

Mine were Ronnie K ones, Yeah I'd braced the crap out of my SubFrame when I did the 9" conversion, I think the broken Subframe issue is more people not torquing the Diff bolts correctly than a mount problem.

 

[emericaskater285]

I am going to be upgrading to the Ronnie K ones when I do my other subframe. There is actually a guy selling the poly spacers (not alum, or the Ronnie K's) on the for sale section ither on here or SF just to help you out a bit.

 

[spiller]

oh yeah? what's his username or do you have a link to the thread?

 

[spiller]

Mine were Ronnie K ones, Yeah I'd braced the crap out of my SubFrame when I did the 9" conversion, I think the broken Subframe issue is more people not torquing the Diff bolts correctly than a mount problem.

that's interesting, you are referring to them being under-torqued I guess? I wonder what the torque settings are. I'm sure the TRSM has them...

Ian do you have any pics of your subframe bracing?

 

[IJ.]

Have seen plenty where they've had missing bolts or undertorqued, yes there's a Spec in the TRSM.

 

[emericaskater285]

Shoot. They sold already. They would have been a good deal tho. They were for 50. Sorry I got your hopes up.

IJ can you post some pics of how you reinforced? or was the enforcement in those ones above?
I want to get an idea of how I am going to do it when I do.

Edit: I think I can see where you enforced it. Would putting a brace from the front to the back be necessary too? I was thinking of that, but I don't know if it would be required.

BTW your 9" is sick.

 

[spiller]

Emerica, no probs mate thanks for letting me know anyway. Bracing the subframe from front to back with an X would increase the stiffness but wont solve the cracking issue. To fix that, you have to do what you see in Ian's pics. They usually crack at the front diff mounts and usually on the right hand side (if im not mistaken). The rest of it is pretty beefy as you can see.

Ian, thanks for those pics. neat job too. Well maybe ill just cross my fingers, do up my diff bolts properly with a torque wrench (although I did them pretty damn tight) and hope for the best. As I mentioned, my subframe has been subjected to an auto for most of its life so its already in good shape.

 

[IJ.]

That one came from an JDM JZA70 Auto car and had the additional factory braces under the axles so was about as good a starting point as you can get

 

[k20maniac]

BTW your 9" is sick.

Thats what she said.. :eek3dance

 

[roadboy]

Haha funny, I was planning to brace and put subframe bushings. But i decided not to.

 

[Mr Bojangles]

I will be doing this same thing in the next few weeks before I put the TRD diff in. The pics are much appreciated.