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Re: Strange S-60 more efficient than 8.75"? [Re: Den300] #2709091
10/22/19 08:15 AM
10/22/19 08:15 AM
Joined: Feb 2005
Posts: 20,111
PA.
pittsburghracer Offline
"Little"John
pittsburghracer  Offline
"Little"John

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PA.
The set of 4.88 gears were in my Dana rearend when I bought the car in 2007 and I don’t know how many years before that. 1.25-1.29 sixty foot times so if it costs me .03 in elapses times I’m cool with it.


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: Strange S-60 more efficient than 8.75"? [Re: pittsburghracer] #2709098
10/22/19 08:49 AM
10/22/19 08:49 AM
Joined: May 2003
Posts: 13,171
aZLiViN
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J_BODY Offline
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My S60 in my Duster is 196lb. That includes axles, rotors, calipers. I do run a spool also. Prob up to 198 with the added sissy stick brackets

Re: Strange S-60 more efficient than 8.75"? [Re: J_BODY] #2709137
10/22/19 10:53 AM
10/22/19 10:53 AM
Joined: Jan 2003
Posts: 13,315
Marion, South Carolina [><]
an8sec70cuda Offline
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Marion, South Carolina [><]
I switched from an 8.75 w/ a spool to a dana w/ a spool. Saw no difference in performance running mid 10s, other than the Dana doesn't break.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Strange S-60 more efficient than 8.75"? [Re: an8sec70cuda] #2709201
10/22/19 01:50 PM
10/22/19 01:50 PM
Joined: Apr 2003
Posts: 3,492
Tulsa, Oklahoma
340Cuda Offline
master
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Posts: 3,492
Tulsa, Oklahoma
Like others here I switched to a Dana 60 from a 8.75 many years ago. Despite the additional weight the car did not slow down a bit.

Hundreds of runs on the original 5.56 as opposed to a few runs before breakage on the gears in the 8.75 before it came out.

If you want to change ratios a lot a Dana may not be for you. I think there are high efficiency models of the 9" but I am sure they are very pricey.

Re: Strange S-60 more efficient than 8.75"? [Re: 340Cuda] #2709225
10/22/19 03:28 PM
10/22/19 03:28 PM
Joined: Jul 2019
Posts: 194
Springtown Pa
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Ray408G3Hemi Offline
member
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Springtown Pa
My old 76 D100 went from knocking on the 9.99 door to 9.96 after the swap to a s60 , both rears had 4.88s don't remember what the weight difference was I don't think it was much the 8 3/4 had a back brace.
.


1963 Thunderbolt 496FE 10.80 (still a work in progress)
1968 Mustang slow a$$ 428 FE
1971 Boss 351 Mustang 11.20@115mph
1993 Lightning 10.61 @ 129mph 408Ci A3 headed NA
1996 Viper GTS
2001 Lightning 8.99 @ 155MPH 5.4 Mod Motor
2009 Ram 9.65@144MPH 463CI G3 NA
2010 Challenger 9.91 @ 139MPH 408CI G3ci NA
2019 F150 (local dealer's Lightning package) ..11.90s

Re: Strange S-60 more efficient than 8.75"? [Re: Ray408G3Hemi] #2709365
10/22/19 11:47 PM
10/22/19 11:47 PM
Joined: Jan 2003
Posts: 8,016
Polson, MT
DoctorDiff Offline
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Polson, MT
All else being equal, a 30 spline 8.75" rear equipped with a sure-grip is 50 lbs lighter than a 35 spline S-60 equipped with a sure-grip.

If both units are equipped with 35 spline axles and a spool, the weight difference is minimal.

Re: Strange S-60 more efficient than 8.75"? [Re: DoctorDiff] #2709381
10/23/19 06:32 AM
10/23/19 06:32 AM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
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Posts: 15,439
Val-haul-ass... eventually
OK, so it's basically 50#s minus the weight of the brace on the 8.75" housing... that's about what I expected. I still need to order a new driveshaft when the engine & trans are back in the car, too.

Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709633
10/23/19 07:41 PM
10/23/19 07:41 PM
Joined: Jul 2012
Posts: 424
Washington
skrews Offline
mopar
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mopar

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Washington
Went from 8.75 with 30 spline axles, spool, 4.56 gears, 10" brakes with cooling ribbed drums to S60 with 35 spline axles, spool, 4.56 gears, 10" brakes with smooth drums. Weight difference was just shy of 30#. No perceived difference in ET or MPH.

Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709691
10/23/19 11:28 PM
10/23/19 11:28 PM
Joined: Jan 2003
Posts: 30,934
Oregon
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AndyF Offline
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Oregon
I'd put the S60 in there just because it is better and it looks cool. I suppose it isn't a high priority although I'm not sure how long that 8.75 is going to last behind 700 hp. You can have Doctor Diff install some disc brakes on the S60 while you're at it and you can install a tone wheel on the pinion yoke just to be ready for the next upgrade.

DSC_2949 (Large).JPGDSC_2248 (Large).JPG
Re: Strange S-60 more efficient than 8.75"? [Re: AndyF] #2709706
10/24/19 06:34 AM
10/24/19 06:34 AM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
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Val-haul-ass... eventually
Just to be clear, the Dr. Diff-sourced S-60 is already installed.

20180902_114229.jpg
Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709726
10/24/19 09:03 AM
10/24/19 09:03 AM
Joined: Aug 2011
Posts: 2,837
Pattison Texas
CSK Offline
master
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Pattison Texas
The S trac works AWESOME !!!!!!!


1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5

Re: Strange S-60 more efficient than 8.75"? [Re: CSK] #2709761
10/24/19 11:55 AM
10/24/19 11:55 AM
Joined: Feb 2014
Posts: 1,693
central il.
S
second 70 Offline
top fuel
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top fuel
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Posts: 1,693
central il.
I changed from a weak trac lok dana to an S60 and it's wonderful. Good for 1000 HP instead of 400 HP and weighs a little less and a lot smoother.
Don't worry the factory dana is a rare 71 B-body dana and it made it back home to another members factory hemi car up north.
Mike

IMG_0906-1.jpg
Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709793
10/24/19 02:28 PM
10/24/19 02:28 PM
Joined: Jan 2008
Posts: 1,202
Minn
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SportF Offline
pro stock
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Minn
I really wish someone would do an actual scientific study on the efficiency of some rears. We have all heard this and that about various rears, and the "gained this much switching to this". But how about a real test? How could we talk HOTROD or some other mag to do this?

Re: Strange S-60 more efficient than 8.75"? [Re: SportF] #2709797
10/24/19 02:48 PM
10/24/19 02:48 PM
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Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
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One of the (few surviving) mags did a comparison of an aftermarket Furd 9", GeeEm 12-bolt and D-60 where they both gave all the general specs (weight, etc.) and put one of each into the same car -- a Chevelle, IIRC -- and ran it on a chassis dyno to see which lost the least power. Haven't Google'd it to see if it's available online, but it's possible.

I have attempted, unsuccessfully, searched online for the one comparison I remember w/ a D-60 vs 8.75".

EDIT: Here's the first one ==> https://www.hotrod.com/articles/ccrp-0806-chevy-chevelle-rear-axle-swap/

Last edited by BradH; 10/24/19 02:55 PM.
Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709880
10/24/19 08:53 PM
10/24/19 08:53 PM
Joined: Jan 2008
Posts: 1,202
Minn
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SportF Offline
pro stock
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Minn
Originally Posted by BradH
One of the (few surviving) mags did a comparison of an aftermarket Furd 9", GeeEm 12-bolt and D-60 where they both gave all the general specs (weight, etc.) and put one of each into the same car -- a Chevelle, IIRC -- and ran it on a chassis dyno to see which lost the least power. Haven't Google'd it to see if it's available online, but it's possible.

I have attempted, unsuccessfully, searched online for the one comparison I remember w/ a D-60 vs 8.75".

EDIT: Here's the first one ==> https://www.hotrod.com/articles/ccrp-0806-chevy-chevelle-rear-axle-swap/


I have read this test, and its so far removed from a scientific test, its hard to believe anything about it. For one, was any weather data adjusted from one test run to another? This entire test relied on the power output of the engine, which would vary from day to day, morning to afternoon. I am amazed that someone went to that much effort for unreliable results.

A real test would be just the rear, measure the bearing pre load, then measure the force (load cell on the pinion) it takes to lift a weight placed on one axle. Subtract the bearing preload and compare that effort to another rear. And make sure temps are all the same as well.

Re: Strange S-60 more efficient than 8.75"? [Re: SportF] #2709884
10/24/19 09:17 PM
10/24/19 09:17 PM
Joined: Oct 2003
Posts: 11,677
W. Kentucky
justinp61 Offline
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W. Kentucky
Unless you're running a scienced out stocker I don't think most here (me included) could tell a nickels worth of difference between a 12 bolt, 9", 8 3/4 or a Dana. After I broke my 8 3/4 I replaced it with a S60, if I were doing it again most likely it would be a 9".

Re: Strange S-60 more efficient than 8.75"? [Re: justinp61] #2709887
10/24/19 09:26 PM
10/24/19 09:26 PM
Joined: Jul 2012
Posts: 424
Washington
skrews Offline
mopar
skrews  Offline
mopar

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Posts: 424
Washington
^^^ THAT X 1,000,000

Re: Strange S-60 more efficient than 8.75"? [Re: SportF] #2709888
10/24/19 09:28 PM
10/24/19 09:28 PM
Joined: Jan 2003
Posts: 30,934
Oregon
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AndyF Offline
I Win
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Posts: 30,934
Oregon
I'm sure someone somewhere has a rear axle dyno and that would be the way to answer the question. I've never seen a rear axle dyno but if someone asked me to build one I'd use an electric motor to turn the pinion. Then I could tell how much power it takes to spin the axle at X RPM. It would be fairly easy to test different rearends since all you would need to do is attach a driveshaft to the yoke and flip the switch.

Re: Strange S-60 more efficient than 8.75"? [Re: skrews] #2709898
10/24/19 10:07 PM
10/24/19 10:07 PM
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Washington
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madscientist Offline
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Washington
Originally Posted by skrews
^^^ THAT X 1,000,000



Very true. But the real test of HP loss has to calculated based on gear ratio. When I had to decide what axle to use under my race car, the entire world consensus was the 9 inch Ford. Until they found out I needed a 5.57 gear. The ford would have ate up a bunch of power at that ratio.

Of I was doing something like everyone wants to build today, and I was going to end up running a 3.55 gear or taller, I'd do the ford.

Ratio has a ton to do with it.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Strange S-60 more efficient than 8.75"? [Re: BradH] #2709967
10/25/19 11:09 AM
10/25/19 11:09 AM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
BradH  Offline OP
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Posts: 15,439
Val-haul-ass... eventually
Originally Posted by BradH

I have attempted, unsuccessfully, searched online for the one comparison I remember w/ a D-60 vs 8.75".

FWIW after looking for the other article I mentioned, I found an old thread on another forum that discussed the article, although I couldn't find a copy of the actual article:
- It was the Jan 2001 issue of Hot Rod (in case anyone has a copy sitting around)
- The test car was a Hemi Dart, but I couldn't find out how fast the car was
- Nobody said if they both had spools or both had some type of limited-slip diff
- "Like for like" testing w/ no mention of weight adjustment, the D60 was .05 slower, but the car supposedly launched straighter w/ the D60

The same old thread also had some posts by Jack Zimmerman, who has (had?) a B/SA 440 Six Pack Challenger running low-to-mid 10s at the time:
- He mentioned having tried 8.75 and D60 (both w/ spools) looking for ET improvements
- W/o adding ballast to make the car weigh the class min at the time (about 3600 w/ driver), the lighter 8.75 was worth .03
- When the weight was equalized since the car was below the min required w/ the 8.75, the ET difference was a wash

Chew on it, spit on it, whatever... It sounds like there really isn't much difference in "efficiency" and the weight difference may be as much a factor as anything else.

So, for my ET estimates, I'll consider the weight difference is about 40#, and a$$ume no offsetting benefit from the change in diff types.

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