Rear End/Suspension Questions

[91TurboDave]

Just curious as to how you high HP guys (400+RWHP) keep your rear ends from grenading. Also how do you keep your rear sub assembly together under that type of strain. I am building a new 7MGTE and by my computer estimates I should have about 450RWHP after it is installed and tuned. This is down the road of course but I want to do a complete build of my car, not just build the motor to the moon and loose my drivability or break everything else. Any imput is appreciated.

-BTW My car is a 91 Turbo 5-speed with a sunroof. Currently all suspension and brakes are stock.

 

[suprabad]

First thing, use a LSD rearend.

Second make sure it's in proper working order (has oil in it, has proper oil, doesn't leak, no slop and clutches aren't toast).

If that's all up to snuff...at 450 hp, you should be fine.

 

[IJ.]

My way

 

[annoyingrob]

I hit the gas, and hope it stays in one piece


In all honesty, the rear-end will hold up to a lot in these cars. As for the subframe, I have heard of people snapping them, but have seen very few actually broken. I've seen even fewer that people actually took the time to beef up, so I wouldn't be able to tell you what's required. It looks like re-enforcing around the pumpkin's bolt holes is key though. Welding some piping around the bolts seems to work.

 

[suprahero]

I'm pretty sure they're bullet proof and until mine tears up I'm going to keep thinking that way. I know Duane has raced his alot and never broken any part of his rear end or axles and he's making alot of rwhp. My wimpy ass'd 1jz doesn't produce enough torque to bend anything, much less break something..........:biglaugh:

 

[IJ.]

Only failures I ever had with G series Diffs was accelerating over 150mph they tend to starve the pinion bearings and this trashes them in seconds.
(same failure on a T1 torsen and an LSD)

 

[91TurboDave]

First thing, use a LSD rearend.

Second make sure it's in proper working order (has oil in it, has proper oil, doesn't leak, no slop and clutches aren't toast).

If that's all up to snuff...at 450 hp, you should be fine.

As far as I know (and yes I am still learning) My car came with a LSD..I should check the Option codes but This was the "Flagship" 91 so...and if I get hard into the boost I leave a nice Dual footprint...:evil2: BTW I use Redline fluids everywhere I can. Thanks for the Tips

 

[91TurboDave]

My way

Ah the 9" cure all....NICE

 

[91TurboDave]

I'm pretty sure they're bullet proof and until mine tears up I'm going to keep thinking that way. I know Duane has raced his alot and never broken any part of his rear end or axles and he's making alot of rwhp. My wimpy ass'd 1jz doesn't produce enough torque to bend anything, much less break something..........:biglaugh:

Just break the bank on tire replacement...you cant fool me:biglaugh:

 

[Tun_x]

At 450 hp you should be fine as long as the the diff isn't screwed up allready

 

[91TurboDave]

Maybe I will give Nate a ring and see if I can snoop under his car...That Car is BAAAAAD! hence ROTY but then I got to listen to him try and convince me to sell. HEHEHE

 

[shaeff]

in all honesty, i would THOROUGHLY inspect the rear subframe before pushing any major power through it. my car lived it's life as an N/A until about 3 years ago when i swapped. at it's peak, the car made 289rwhp, 295rwtq @15psi on a blown stock turbo. - and i only had the car on the road for a total of about a year. i personally think that the crack was there all along!

here's what my subframe looked like when i dropped it to get it reinforced (because i wanted to be safe) please note the GIANT crack right through the front section above where the differential sits:

http://www.supramania.com/forums/showpost.php?p=834011&postcount=60

 

[buldozr]

in all honesty, i would THOROUGHLY inspect the rear subframe before pushing any major power through it. my car lived it's life as an N/A until about 3 years ago when i swapped. at it's peak, the car made 289rwhp, 295rwtq @15psi on a blown stock turbo. - and i only had the car on the road for a total of about a year. i personally think that the crack was there all along!

here's what my subframe looked like when i dropped it to get it reinforced (because i wanted to be safe) please note the GIANT crack right through the front section above where the differential sits:

http://www.supramania.com/forums/showpost.php?p=834011&postcount=60

By looking at those photos, that crack has been there for years, note the amount of rust buildup on the crack, that doesnt happen in a week. Personally, I would recommend replacement, but if you are atament about welding it up, do a good bevel with a dremel on both sides and tac the piss out of it, be careful not to get it too hot and take your time. Is he going to use stick, mig or tig?
EDIT: scratch the bevel idea, doesnt look like enough metal to do that, just take your time with it.

 

[IJ.]

There are reinforcements under the arch and behind it was well.

 

[shaeff]

By looking at those photos, that crack has been there for years, note the amount of rust buildup on the crack, that doesnt happen in a week. Personally, I would recommend replacement, but if you are atament about welding it up, do a good bevel with a dremel on both sides and tac the piss out of it, be careful not to get it too hot and take your time. Is he going to use stick, mig or tig?
EDIT: scratch the bevel idea, doesnt look like enough metal to do that, just take your time with it.

oh i know it. i'm pretty certain that's the clunk i had in the rear (the main reason i dropped the subframe- all u-joints are perfect, and the LSD is in good shape)

if i could find another subframe, i'd gladly purchase an '89+ unit and have bryan reinforce that for me, but supra parts around here are few, and VERY far between. (and ridiculously overpriced in junkyards, too )

bryan has a mig, and he might have a tig, but i'm not sure which he was planning to use. we were going to weld in plate steel, too, in order to help reinforce that whole area.

another thing, IJ pointed out to me that the '89+ subframes have extra braces in them that sort of cradle the differential (or around it)- maybe i can get bryan to hook me up with some of that, too. haha

edit: thanks for that pic, Ian!

 

[IJ.]

Chris:

You can see them going from front to back under where the CV's would be on the Diff.

 

[shaeff]

nice. i just came across this pic, too, in the for sale section:



edit: my god, Ian, i don't think i saw that pic before- that 9" look sweet in there! (and i'm sure it performs just as well as it looks!)

 

[IJ.]

For sale?

 

[shaeff]

yeah, i'm pretty sure that's where i saw it...? (unless you caught that post before i edited it- as i put the wrong pic in there, haha)

 

[IJ.]

Chris: LOL DOH (yep wrong pic)

Thanks it's works well and when installed you'd never know it was there!