:tapemouth how much horsepower can a stock z car rearend take?

I have heard R180=300+ and R200=600+. Remember: HEARD!

steve77

r 180? r 200? what is mine? how do i find out?

You can go to ZHOME and it will direct you to a Geocities site with all the STOCK diffy's listed with years and models. That is as start. But do you have the original diffy? The 200 is a lot bigger, but without them side-by-side, you have to be pretty clear on the concept....Look at the two bolt stubs poking out the rear. If they are as fat as your thumb, it is a R200. If they are more like, say, your index finger, it is a R180.

OK, I have small hands!

steve77

How did this end up in Funnybone? but while on topic, did the R180 come as LSD or only the R200?

R.

The R-200 was the only rear that came from the factory with a LSD in the US, 87 was the first year it was available.

Here's a close guess on the years available.

70-74 R-180

75-76 R-200

77-78 R-180

79 and up all had R-200's

Don't ask me why they had both R-180's and R-200's in the 280Z's.

Nissan Competition had units available for all the rear diffs, not usr eif they are still available or not. If they are, they will be rather expensive. They used to be over 700 last I knew.

Just about every diff. that Nissan ever made was offered with an LSD option for the Japanese "Home" market. There are still some areas of Japan that have unmade roads ( especially up in the mountains ) and in the northern areas they have a lot of snowfall which they tend to drive ON TOP OF, with studless snow tyres or snowchains ( banned in many areas ). In this kind of environment, an LSD-equipped diff ( albeit with quite a low initial ) is a godsend.

I regularly holiday in Hokkaido ( northern island of Japan ) and noticed that even the Nissan Cedric and Gloria taxis ( running on LPG ) are still fitted with versions of the R180 diff, and have LSD's in them!

Additionally, Nissan always offered LSD units for just about any diff or axle that they made, in their Sports Option Catalogue.

At the risk of disappointing you dohc, almost any S-30 or S-130 series Z ( whether R180 or R200 equipped ) would be very unlikely to have an LSD unit fitted by the factory, except in the Japanese market.

Putting "max BHP" figures against any diff is a fool's game. It will depend not only HOW that BHP ( or more importantly, torque ) is transmitted through the diff, but also the traction of the tyres on the other relevant interface ( ie. between the tyre and the road ). Not only that, the actual ratio of the diff. will have a bearing on how easy to break it is ( especially the amount of teeth on the pinion ). Its "easier" to break an LSD-equipped diff too........

Also, don't forget that we are quite often talking about diffs that have been together for 25 years or more! You would have to take into account the condition that it started in.

Here in Europe, the Historic Rally guys who run S-30 series Z cars have almost all changed over to R200's with LSD, and either 3.9, 4.1, 4.3 or 4.6 ratios - depending on the trans ratios. These are pretty hard to break, even on tarmac - but they do quite often need re-shimming of the clutch packs to stop them slipping too easy. They set the initial quite high.

Its not that difficult to break an LSD-equipped R180, even with just 220 to 250 HP ( I know, I've done it..... ). The design of the R200 is far superior to the R180, so its not just a case of bigger is better.

Alan T.

2manyPosts...The Geocities site and myself must quibble a bit on those years. I have a 77 with a 200 and just dismantled a 79 with a 180. Neither of these were transplant situations. Hey, YOU were the one who sent me that link several months ago!

steve77

I did? Hmm, must be geezing again.

I did say it was a close guess didn't I? I know they went to the R-200 then changed back and forth for some reason. I find it odd they would go back to the R-180 at all after they started outfitting the 280's with the R-200's in the first place.

Maybe someone can shed a little light on the reason behind this. I don't think I've ever seen anything in print that explains why they changed back and forth between the R-180 and the R-200.

I found it out by accident when I was racing and looking through FSM's and saw that the 280's were available with both during their model run.

YEah, I always found that pretty interesting too...."Hey, I just found 8 boxcars full of 3.4 R180's out behind the factory! We gotta use these things up!".....

Maybe they felt they had to go to the heavier diffy because the 280 motor was putting out SO MUCH MORE POWER THAN THE 240!!!!!

That'll get'em going!

steve77