9" Differential

[AUSTA]

Anyone fitted a 9" into an E body the Pinion centre looks lower than on the 8 3/4 do you have to change the pinion angle when welding on the perches TIA

 

[moparleo]

Pinion angle would need to be considered regardless of what rear end you installed, if the spring perches were being moved or changed.

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[Juan Veldez]

I would do a mock up installation, get your angle of the driveshaft set, tack the perches, remove the rear and do the permanent welding (or at least lower the springs out of the way). Or just use angle shims to set the angle if you decide to weld without the mock up installation.

 

[Chryco Psycho]

Do you already have the 9" ?
If you have ever been to the racetrack you will see 5 guys trying to push a car downhill with a 9" & 1 guy easily pushing a car with a Dana 60 , 9" have a ton of rolling resistance / parasitic drag .

 

[AUSTA]

Isn't the DANA 60 a lot heavier weight wise i have a Torsen in my 8 3/4 at the moment that adds a lot of rolling resistance it is almost impossible to move in reverse. I was mainly looking how much the lower pinion centre adds to the 8 3/4 angle .

 

[Chryco Psycho]

The newer Dana such as the Strange 60 is not a lot heavier even the original Dana is only about 50 lbs more .
they did a test years ago on a Dart & it was minimal difference in the 1/4 mile between the Dana 60 & 8 3/4 .

 

[Steve340]

Stick with your 9 inch idea - they are very easy to get parts for.
Just about every race car on earth has a 9 inch in it.

 

[AUSTA]

Called a few of the local builders & found there are good stocks of 9" parts available shipping DANA parts would be the deal breaker pushing 600 to 650 hp R3 SB .

 

[Chryco Psycho]

I find it funny we spend so much to get a few more HP , my dyno operator always factored in a 40 HP loss at the rear wheels if you had a 9 "

 

[Juan Veldez]

I find it funny we spend so much to get a few more HP , my dyno operator always factored in a 40 HP loss at the rear wheels if you had a 9 "

Spool or posi? Just curious.

 

[Steve340]

On the rolling road the one I use he has a factor of 27% loss in the transmission.
That would obviously mean the gearbox plus the diff.
No matter what you use you are going to lose quite a bit of power.

 

[AUSTA]

Mate just blew the arse out of his 8 3/4 adjusters & caps running 11's (Valiant VG 436 short deck )seen him do a lot of runs so I will see how the times change when he puts his new 9" in

 

[Chryco Psycho]

Not true , he factored in extra just using a 9" over other types of diffs as they have a ton of parasitic drag . The pinion sits lower & act like a screw winding the ring gear so there is more tooth surface area in contact at all times .
I used to build & narrow diffs for race cars . I personally destroyed a number of 8 3/4 diffs , never a Dana !

 

[AUSTA]

Was talking to a mate & mentioned the talk of increased effort with the 9" he said now that i mention it his daughter runs a blown charger at the drags & said it is impossible to move when in nuetral never new why.
Looks like DANA it is always Better to use the Mopar stuff where possible mates going to Calif next week to pack a 40 ft seatainer to bring back to Australia he picked up a fully rebuilt unit for $2200 but he is keeping that one so i will get a S60 Strange just have to devide on 4.1 or 4.56 ratio have a gear vendors O/D a 4.56 with a 3.20 in overdrive should be good for street work.