Posi rear end

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paintdudeluke

Posi rear end

Post by paintdudeluke »

Anyone here ever seen one of these welded up solid axle in the rear? I know guys that have done it on various cars and of course they pinch on tight turns like going into a parking spot etc, I can live with the bad behavior. Question is this, are these rear ends really whimpy or would they take the abuse with a pretty stock motor? The ass end is pretty light so I think it might slide before it snapped, but I really have no idea how strong these rear ends are. If not, whats the best rear end swap candidate? explorer 8.8?

Opinions?
Last edited by paintdudeluke on Mon Feb 17, 2014 11:15 pm, edited 1 time in total.
Tobi

Re: Posi rear end

Post by Tobi »

I shaved of a few teeth by doing 90 degree turns into side streets or drifting around corners.
These rear ends don't like abuse :roll:
vandor
Posts: 3996
Joined: Sat May 23, 2009 1:23 pm
Your car is a: 1971 124 Spider
Location: Texas, USA

Re: Posi rear end

Post by vandor »

'Posi' and welded rear ends are completely different things. You should not use a welded rear on the street.

These rear ends are not that strong, welding them will likely find the weakest link...
Csaba
'71 124 Spider, much modified
'17 124 Abarth, silver
http://italiancarclub.com/csaba/
Co-owner of the best dang Fiat parts place in town
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v6spider
Posts: 1035
Joined: Tue Feb 28, 2006 6:57 pm
Your car is a: 4.3L V6 Powered 1972 124 FIAT Spider
Location: Mount Vernon WA

Re: Posi rear end

Post by v6spider »

I'm using a limited slip(posi) differential from a 1983 rx7 gsl . Gear ratio is 3.90 ...don't use welded rear end on a street vehicle...they corner horribly and the fiat rear end is very weak. It is highly unlikely that it would survive. My 300+ hp v6 tore up a stock rear end in a few short months. I highly recommend the rear end I mentioned . It's a strong piece and there are some here that are using them in their race cars. Any who my two bits..

Rob
http://www.v6spider.com
4.3L V6 Powered 1972 124 FIAT Spider
Daniel

Re: Posi rear end

Post by Daniel »

Just out of curiosity how many ponies are you turning that you feel the need for posi? I've had some beefy engines
and didn't really feel i needed posi maybe you could adjust your driving style some to solve the traction issue if your
even having one?
paintdudeluke

Re: Posi rear end

Post by paintdudeluke »

It's more about the fact that the last mile and a half of my road is dirt and when it rains sometimes it gets really crappy and one banana peel is barely enough to keep it rolling.
Daniel

Re: Posi rear end

Post by Daniel »

you will have more issues with posi then gains for street driving the car will be more likely to break loose in turns so
when it rains it's not going to be so fun...
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engineerted
Posts: 531
Joined: Tue Feb 21, 2006 9:57 pm
Your car is a: 1974 124 spider
Location: Farmington Hills, MI

Re: Posi rear end

Post by engineerted »

First off, poor attention to maintaince is the cause of broken rear ends. The early style axle is plenty strong, been racing with the same welded diff for over five years with 10" wide racing slicks and twice the stock HP. Never broke a tooth.

Now if you have the early pumpkin diff you can get a ATB diff from a lada that will drop right in. Look up ladaworld.com on the web, I think they are about $650.
Ted
1978 124 Spider, Complete Restoration
1974 Fiat 124 F Production Race car
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divace73
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Your car is a: 1980 Fiat 124 Spider Silver
Location: Sydney, Australia

Re: Posi rear end

Post by divace73 »

engineerted wrote:First off, poor attention to maintaince is the cause of broken rear ends. The early style axle is plenty strong, been racing with the same welded diff for over five years with 10" wide racing slicks and twice the stock HP. Never broke a tooth.

Now if you have the early pumpkin diff you can get a ATB diff from a lada that will drop right in. Look up ladaworld.com on the web, I think they are about $650.
I've got one of these in my car and am real happy with it
Cheers David
-=1980 silver Fiat 124 Spider=-
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v6spider
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Joined: Tue Feb 28, 2006 6:57 pm
Your car is a: 4.3L V6 Powered 1972 124 FIAT Spider
Location: Mount Vernon WA

Re: Posi rear end

Post by v6spider »

Hi Ted,

Glad you have had great success with your stock welded rear end. I wasn't so lucky.. and there was plenty of gear oil in it when it died..However, I put over three times the torque and 3 times the rated horse power into mine... is the lada unit a locker or limited slip?

Thanks!
Rob
http://www.v6spider.com
4.3L V6 Powered 1972 124 FIAT Spider
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v6spider
Posts: 1035
Joined: Tue Feb 28, 2006 6:57 pm
Your car is a: 4.3L V6 Powered 1972 124 FIAT Spider
Location: Mount Vernon WA

Re: Posi rear end

Post by v6spider »

http://www.ladaworld.com/product_info.p ... ucts_id=47

Pretty cool... expensive but looks like it is plug and play.

Rob
http://www.v6spider.com
4.3L V6 Powered 1972 124 FIAT Spider
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engineerted
Posts: 531
Joined: Tue Feb 21, 2006 9:57 pm
Your car is a: 1974 124 spider
Location: Farmington Hills, MI

Re: Posi rear end

Post by engineerted »

DARN IT! Forgot to say "Knock on Wood" If it breaks this summer it is all you guys fault!
Ted
1978 124 Spider, Complete Restoration
1974 Fiat 124 F Production Race car
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v6spider
Posts: 1035
Joined: Tue Feb 28, 2006 6:57 pm
Your car is a: 4.3L V6 Powered 1972 124 FIAT Spider
Location: Mount Vernon WA

Re: Posi rear end

Post by v6spider »

engineerted wrote:DARN IT! Forgot to say "Knock on Wood" If it breaks this summer it is all you guys fault!
Tell you what Ted... we'll hook her up to v6spider 2.0 and she survives a three shift burnout and the complete shredding of your racing slicks, then I think it will be safe to say it'll survive! :mrgreen: :mrgreen: :mrgreen: 8)

Rob
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