Tell me about the various Z IRS's

[Guest Anonymous]

This is sort of off topic, but I'd appreciate the advice. I'm building a 302 powered Triumph Spitfire, and I need a good IRS that can handle ~250 HP. The rear ends off 280 or 300 ZX's has been suggested to me. Questions:

 

1. When you guys hop up your Z's, do you have to do anything to the rear ends, or can they handle the power just fine in stock form?

 

2. Are any years/models IRS better than any others in terms of strength, performance, ease of mounting etc.?

 

3. Anything else you can tell me about these rear ends that will help me in my quest?

 

Thanks.

[Tim240z]

If you want something really stout, the R230 diff from an Infinity Q45, or 300ZXTT will hold up to just about anything and comes with OEM VLSD.

Otherwise, most guys go with the R200 from the later 280Zs or ZXs. Those will take a good bit of punishment, but to be honest, if you will only have 250hp or so, in such a light car without slicks at the 1/4 mile (traction kills diffs, not hp), then just about any of them will be ok, including the smaller R180 from the earlier Zs. There is a picture side by side of the R180 and R230 on my website.

Hope this helps,

Tim

[Guest Anonymous]

Here is a side by side comparison of the of the R180 and R200 diff which are usually 3.54 to 1 web page

[DavyZ]

I am amazed at you guys that are able to fab a big V8 small car...oh wait, I'm doing the same..never mind.

 

Seriously, that Spitfire sounds cool. The Nissan rear end parts will be stronger then the Triumph parts, and much cheaper too. The R200 will work fine and put up with most of the punishment you can give it. I think you will be pleased

 

Look for R200's in almost any 280Z with 5 speed. Pay close attention to the pictures and you won't go wrong at the wrecking yard.

 

Davy

[CruxGNZ]

Welcome! If you go to this thread here , you will see the side by side photo's of the R180 and the R200, also if you scroll about 3/4 of the way down on that thread, you will see my post that shows what rear end ratios came in what car. Hope this helps you.

 

!M!

[Guest Anonymous]

Thanks guys! Pretty cool forum you've got going here. Quick responses and great answers. I will now fearlessly embark on a quest for an R200 rear end for Project Warm Spit.

 

By the way, I'm elbow deep in the engine buildup now. My goal is a <400 lb 302. With creative use of aluminum I think I'm almost there. My next challenge is an intake system flat enough to not require hood mods.

 

Thanks again everybody!

[David K]

66, may i suggest you take a look in our for buy/sell/trade forum? Often there are sellers with r200's.

[johnc]

An R180 with ANY kind of 4 pinion LSD can handle 300 ft. lbs. of torque (unless you're a drag racer) and its lighter, smaller, and cheaper then a comparable LSD R200.

[Guest xrotaryguy]

I am sorry to bring back such an old thread. I'm also doing a motor swap into a Spitfire and I have just one more question. I can see from the pictures on the linked web site that the 510 and early Z diff is narrower than the later 240SX, 280/300ZX diff. I believe that a 510 diff is 9 inches (23cm) wide from flange to flange if you measure from one mating surface to the other. Do any of you know exactly how wide the 240SX diff is?