Re: Strange S-60 more efficient than 8.75"?
[Re: Den300]
#2709091
10/22/19 08:15 AM
10/22/19 08:15 AM
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Joined: Feb 2005
Posts: 20,172 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,172
PA.
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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
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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
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Joined: Jan 2003
Posts: 13,362 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,362
Marion, South Carolina [><]
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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
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Re: Strange S-60 more efficient than 8.75"?
[Re: 340Cuda]
#2709225
10/22/19 03:28 PM
10/22/19 03:28 PM
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Joined: Jul 2019
Posts: 194 Springtown Pa
Ray408G3Hemi
member
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member
Joined: Jul 2019
Posts: 194
Springtown Pa
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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
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Re: Strange S-60 more efficient than 8.75"?
[Re: BradH]
#2709726
10/24/19 09:03 AM
10/24/19 09:03 AM
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Joined: Aug 2011
Posts: 2,856 Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,856
Pattison Texas
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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
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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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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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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.
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Re: Strange S-60 more efficient than 8.75"?
[Re: BradH]
#2709880
10/24/19 08:53 PM
10/24/19 08:53 PM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
pro stock
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pro stock
Joined: Jan 2008
Posts: 1,212
Minn
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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/ 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.
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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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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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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
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Re: Strange S-60 more efficient than 8.75"?
[Re: BradH]
#2709967
10/25/19 11:09 AM
10/25/19 11:09 AM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
OP
Taking time off to work on my car
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OP
Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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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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