240z diff upgrade advice

[aprophet13]

I have a 1973 240z with I'm assuming the stock r180 diff. The ultimate set up of the car will be an inline turbo motor with around 200-250whp. 

 

The car will mainly be a street car that will see occasional parking lot/empty street hooning. EG no super hard launches, no sticky tires (225 at the widest), and very rare clutch kicking/high revving.

 

With that set up in mind with those intended uses, is the r180 going to be a hinderance or major weak point? I've read that the spider gears are a common point of failure. Could a welded r180 remedy this situation?

 

TLDR- Could I get away with a welded r180 for essentially street use on a mid power (200-250whp) engine with skinny low grade tires?

 

If no, I'm assuming the r200 is the next logical step (or Subaru r180?)

 

Thanks in advance,

Adrian

[Hypertek]

welded diff on anything besides a drift car sucks imo. I hated it on my old rx7 (came with it), swapped it to a factory lsd.

 

But anyways, an obx helicol lsd might be something to look at.

[aprophet13]

My other car is a volvo 242 set up for drifting and has a welded- doesn't particularly bother me and I didn't notice drastic wear because of it. 

 

But you're saying even an OBX unit in an r180 case would be sufficient? Because at that point I think I'd just weld the r180 to make the spider gears more stout. I also read that the axles aren't as robust- but would this be noticeable at my desired power levels? It just seems that people here swap to the r200 on impulse but I'm wondering if its really necessary. 

 

I'm basically wondering if my power goals and intended use would make the r180 feel like an achilles heel. 

 

Thanks for the reply

[jhm]

OBX makes an LSD for the R200, but not the R180.  If you decide to go with a Subaru R180, you'll need different stub axles.  Some guys have fabbed their own; and they are available off the shelf from Wolf Creek Racing. 

 

Another option you might consider is an LSD R160, from either a Subaru or older Datsun (like a 510).  Very easy, and usually cheap, swap; which uses the 510 stub axles.  I think a few guys here are using a 160, and many of the 510 guys use the 160 with a lot of success....and many of them are putting out way more than your HP goals.  Search on it and you might find it's a good option for your application.

 

There's a bunch of info on this in the FAQs and the Drivetrain sub-forum.  Search and you should be able to find everything you need.  Good luck with it and be sure to post your results when you're done.

[Swami]

Hmmm, I've also been considering going with an R160 LSD for the same reasons. No plans to go turbo on this motor, so why am I so fixated on staying with an r-200? If the 160 is tough enough for my needs, it seems like the reduced weight would be a bonus too.

 

Beautiful car, Adrian! I love those wheels.

Edited March 9, 2015 by Swami

[seattlejester]

I wouldn't say way more hp, but there are indeed a few R160 LSD guys floating around.

 

I would build up honestly, especially if your end game is turbo. It's pretty easy to bump power in a turbo car if you build the peripherals to handle the power. You would be surprised how tempting it is to crank up the boost, or how affordable it is to buy a bigger turbo and injectors and turn that 200hp number into 250hp, then 300hp, and on and on.

 

I would say get an R200 with an LSD, cv axles, and 27 spline stub axles and not have to worry about the rear end for a while.

 

To answer your question though, yes you could get away with an R180 and skinny tires. The skinny tires will act like reliefs and protect you to a certain extent. I will warn you though, the bolts get real loose real fast with a welded diff, some lock tite and new hardware is probably in order.

[NewZed]

 

The car will mainly be a street car that will see occasional parking lot/empty street hooning.

 

TLDR- Could I get away with a welded r180 for essentially street use on a mid power (200-250whp) engine with skinny low grade tires?

 

Stick with the stock R180 open, and the skinny tires, and do lots of one-wheel smoke shows.  That way you'll be off the street as quickly as possible.

[aprophet13]

Hmmm, I've also been considering going with an R160 LSD for the same reasons. No plans to go turbo on this motor, so why am I so fixated on staying with an r-200? If the 160 is tough enough for my needs, it seems like the reduced weight would be a bonus too.

 

Beautiful car, Adrian! I love those wheels.

 

Its surprising that the r160 would be a better alternative than the r180- I was doing some reading in the drivetrain section and the feeling i got was r160<r180<r190 and then the subaru r180 and the r200 were good options. 

 

I wouldn't say way more hp, but there are indeed a few R160 LSD guys floating around.

 

I would build up honestly, especially if your end game is turbo. It's pretty easy to bump power in a turbo car if you build the peripherals to handle the power. You would be surprised how tempting it is to crank up the boost, or how affordable it is to buy a bigger turbo and injectors and turn that 200hp number into 250hp, then 300hp, and on and on.

 

I would say get an R200 with an LSD, cv axles, and 27 spline stub axles and not have to worry about the rear end for a while.

 

To answer your question though, yes you could get away with an R180 and skinny tires. The skinny tires will act like reliefs and protect you to a certain extent. I will warn you though, the bolts get real loose real fast with a welded diff, some lock tite and new hardware is probably in order.

 

I was mainly wondering if the r180 would hold up at it seems like a shaky yes, I'll probably end up going with either the r160 or r200. Thanks for the advice!