Custom rear for ERA?

[puppster]

I was wondering is anyone has designed and built a custom rear end for an ERA. It seems plausible that one could buy an ERA without the rear carrier, and then create their own for either a Jag rear, or some other more readily available IRS.

[Gunner]

It would seem to be very much a case of reinventing the wheel. The original Jag IRS is superb; the ERA-reengineered rear is at least as good, 50 pounds lighter, repositions the brakes for cooling and serviceability, and is highly tweakable.

I doubt you could save very much money by building your own or adapting something else, and I strongly doubt you could do better in performance.

But I suppose you could adapt a Vette or BMW rear setup if you really wanted to.

[1985 CCX]

If you want a trick set up go for their outboard brake upgrade.
Very nice!

[*13*]

The rear assembly is one thing I left for ERA to do. I don't know Jag Rear's all too well. By the time I bought the right parts, Had them rebuilt & assembled to the correct specs I probably would have spent nearly as much money & lost a big chunk of "Piece Of Mind". ERA have been building these units for a long time now & know why & how they need to be built for their cars. If you really know what you are doing with Jag Rears, go for it. Please start a thread so we can see the process also. I for one would love to see it. If not, hand over the money & let them do it correctly. Piece of mind is worth way more than Pulling the rear out every couple of weeks to fix it. My 2cents

[Grubby]

#178 had a mid 80's Vette rear in it when I bought it. It was shortened some, but not enough. To shorten it enough the bat wing on the rear cover would have had to be removed and come up with a better mounting system. I seriously considered this approach.

The car only had about 2" suspension travel when I got it. The wheels could not come in any further without comming in contact with the bat wing. I looked at the mess and determined the best fix was to put in the "correct" ERA set up in. ERA fixed me up with the parts and it is now right.

I could have done some modification and made the Vette rear work. The big problem was, I got the car at a great price because of the rear. It scared many buyers. It made no sense to put a bunch of time and more money into a Rube Goldberg setup. Then I would have trouble selling a modified ERA. I sold the Vette rear for $1500 on ebay with Koni coil overs and then spent about $4500 with ERA, Reider racing and a Jag core.

Now my ERA is right and will be no problem to sell at normal ERA prices.

Don't do it.

John

[ZOERA-SC7XX]

ERA has done their homework with both rears they offer. I did the build up of mine with their shortened Jag halfshafts, lowers and sub frame. Yes, I saved a few bucks and learned a lot, but I'm a glutton for punishment. Their cars work best with their rears, and I doubt you can improve on it. You can save some bucks elsewhere.

[puppster]

All good, sound advice. Resale would be a big one. Thank you everyone for the input.

[Jim Holden]

Scrounge for a Jag XJ "posi" rear. They are out there. (Whenever I come across them I buy them up, even if I don't have a project, at the moment, for them).

Order up ERA's cage and ERA will shorten the half shafts and lower arms for you. Assuming that you do not have to go into the differential to repair/replace anything, everything else is readily available and "do-able" by a "shadtree" mechanic.

Take it from someone who has been dealing with ERAs for over 25 years; DON'T TRY TO REINVENT ERAs ENGINEERING. YOU WILL NEVER GET YOUR MONEY BACK AND IT WILL NOT BE (PERCEIVED AS BEING) BETTER.

Jim

[jschiller]

The average XJ will have a 2.88 open diff, no posi. Look for an XJ-S rear, or possibly a XJ-12, those are the posi's. And make sure its a Salisbury (with a drainplug) not a Dana (no drainplug and hard to get parts for if you want to change ratios).

John

[Jim Holden]

John:

Generally, the early XJ rears may have posi and have better ratios than the later ones which as you say are generally "long" ratios and open rears. I have used 2.88 and 3.08 rears with a Richmond 4+1 (5th is 1:1) and found it, for my purposes, to be a good setup. The most recent rear that I scrounged was out of a late XJS V12. It had posi, but a 2:88 ratio which I had swapped out for a 3.77. This is behind a Tremec TKO.

Jim

[Gunner]

I'd bet that you'd end up paying as much for a 3.xx posi Salisbury as you would for a 2.88 open plus the rebuild and add-in parts. Barring the part-out gem where the seller doesn't know what he has. Unless you're going to try and penny-pinch the rebuild, the overall condition of the rear unit and its completeness are probably more important than what guts it happens to have.

And I concur, the 2.88 is just fine with the Richmond gearing ahead of it. I have to remember to go into 5th on highway cruise.