Best 280z rear end for lots of torque

[280cummins]

Hi All, I’m new here and recently purchased a 1976 280z with a 5.9L Cummins Turbo diesel in it. Car drives but has the stock 280z rear end which will be the first weak link. I’ve been doing a ton of research but I just want to see if there are any guys out there with tried and tested systems running roughly 1000 foot pounds of torque. From what I can see the kit from Techno Toy Tuning looks pretty stout but I was hoping to spend less than $7k! Any other options you have seen work well? This will just be a weekend warrior car and possibly drag raced a few times a year. Thanks for any help provided. 

[walkerbk]

Good luck with finding a rear end setup... if I were you I would switch to a solid rear axle setup. You will be hard pressed to find any IRS that can handle the torque.

[AydinZ71]

Doood... 1000ft-lbs. only guy on here I know who has that kind of experience for a rear end is @Invincibleextremes. 
 

I don’t have drag racing experience, but from an engineering perspective this is a challenge. I would be looking into a driveshaft designed a built by a shop that works on off-road vehicles. They snap axles and shafts like twigs, so they should have a good handle on what will last. 
 

I would Be tearing that car apart and reinforcing the chassis throughout. That’s way too much torque for a stock chassis, especially if you are launching and have grip. I’d also get a full weld-in roll cage and read-up on drag racing safety systems like a chute etc. What transmission are you using? These torque beasts often have a ton of inertia, so there could be a lag between “oh shit” and the torque letting off (auto trans). 

 

The Apex Engineered or Techno (T3) stuff won’t work for you. You are in a whole different league. None of their systems have been stress tested to my knowledge, and I have not seen any published data. 

[jhm]

If you want to see what other folks are running, I'd check out the "Swapped S30 Owners Group" on FB.  That's where I've seen all the craziest builds imaginable.  

 

As Aydin suggested, a Ford 8.8 would probably hold up well.  Whatever differential you decide to go with, you will need to do something about the stock stub axles....these are the outboard stub axles that reside in the lower rear strut assemblies.   Time and time again, the stub axles have shown to be the weakest link in the stock driveline.  Please be sure to post some follow-up, because I'm sure we'd all be interested to see what route you decide to go and how it works out for you.

[AydinZ71]

14 hours ago, jhm said:

If you want to see what other folks are running, I'd check out the "Swapped S30 Owners Group" on FB.  That's where I've seen all the craziest builds imaginable.  

 

As Aydin suggested, a Ford 8.8 would probably hold up well.  Whatever differential you decide to go with, you will need to do something about the stock stub axles....these are the outboard stub axles that reside in the lower rear strut assemblies.   Time and time again, the stub axles have shown to be the weakest link in the stock driveline.  Please be sure to post some follow-up, because I'm sure we'd all be interested to see what route you decide to go and how it works out for you.

 

+1 100%

 

If you go with @Invincibleextremes kit, I'm pretty sure you can install the mustang stub axles into his uprights. That will also give you a 5-lug wheel hub. That is what I will be doing with my L28et car. 

[grannyknot]

invincibleextremes  setup is going to be the easiest and most cost effective by far, he's done all the engineering for you.

[rturbo 930]

IMO the rear end is the least of your concerns here, that amount of torque is going to destroy your chassis if you don't reinforce it thoroughly. Honestly, I think that engine is totally inappropriate for a Z to begin with. It weights, what, 1200lbs? A 280Z weighs only about 2600lbs. I can't imagine it drives well. 

[clarkspeed]

Hmmm, the perfect question for this forum. Gotta love that conversion. Reminds me when a guy ask me to recommend a clutch for his 1000HP 2JZ. There is just not a cheap solution for that.

 

If you want to do it on the cheap, go with a live axle conversion. If you just want to do a lot of skinny tire smokey burnouts, you can probably keep the IRS with some upgrades. If you want to put that power down at a drag strip with sticky tires, and keep the IRS, you have a mountain to climb with every step built on a roll of cash.

 

 

[Invincibleextremes]

On 6/13/2021 at 1:16 PM, 280cummins said:

Hi All, I’m new here and recently purchased a 1976 280z with a 5.9L Cummins Turbo diesel in it. Car drives but has the stock 280z rear end which will be the first weak link. I’ve been doing a ton of research but I just want to see if there are any guys out there with tried and tested systems running roughly 1000 foot pounds of torque. From what I can see the kit from Techno Toy Tuning looks pretty stout but I was hoping to spend less than $7k! Any other options you have seen work well? This will just be a weekend warrior car and possibly drag raced a few times a year. Thanks for any help provided. 

Tried and true at 900hp so far with no limit in sight is the 34 spline super 8.8 swap.  It's held up at power levels where others have failed in various ways.

 

Honestly don't bother with t3 for this application, I have a few customers who broke those setups at much much less hp.  And I've seen explorer 8.8 setups fail as well.

 

Keep in mind dss sells 2,000hp axles for a 2015 mustang.  So if it's durability you're looking for, that's honestly the only way to go.

 

Also, to be able to actually drive the car, the 3.15 or 3.31 ratio would definitely be a plus....