FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: retroboy on January 14, 2015, 02:47:21 PM
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Howdy.
I’m just about finished my build and it will be the first time I’ve been down a track in 25 or more years but I’m already thinking about building my next car. Next time I would like to use a diff with a higher pinion than a 9” so I can run the engine nose down a little rather than the current set up that is level. Any suggestions for a diff that has a higher pinion height ?
Cheers
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Of the ones that are practical the 8 3/4 Mopar and the 12 bolt conversion for the 9" housing are probably the best bets.
Roo
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Anyone ever use a dana 60? or is it just an expense thing?
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Just to add a note on Mopars I have done them for many years
There are three carrier casting numbers--Folks always say use the "489" case as it has thickest pinion shaft diameter--well.big deal--it is tapered, used a crush sleeve to set preload and so it is a PIA or you use a machined spacer to take place of the crush sleeve but..
Best bet is the "742" housing --Plenty big pinion , easy shims to set up, lots of gear selection
Easiest to set up and plenty strong
The "741" housing is the one to avoid--poor gear selection, small pinion diameter
8 3/4's are a very tough!
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Anyone ever use a dana 60? or is it just an expense thing?
Have to pull the entire RE to do gear change and also heavy
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Fan of the 8 3/4 here, light, good parts availability (maybe not as much as a 9"), and traditional.
The Dana is heavy, and with the cast center I think it would be terribly uncomfortable to drape your legs over.
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Anyone ever use a dana 60? or is it just an expense thing?
Have to pull the entire RE to do gear change and also heavy
I built my car using a Dana 60 It's without question the strongest, cheapest rear to put in anything. I have easily changed gear sets without removing it, in fact it was very easy. I do not find it uncomfortable at all. Heavy yes, I do have a Mag housing but I did not use it. If I build another car it will have a Dana 60
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Hi Retro:
The 12 bolt has about a 3/4 inch less Hypoid then a 9". A Dana 60 is about another 1/4 inch + or- less then the 12 bolt. Not sure on the 8 3/4.
So they would give you a little easier dump.
As Roo states there's a 12 bolt carrier that fits into a 9 " 8)
http://www.strangeengineering.net/dragrace/center-sections-components/complete-aluminum-center-sections/12-blt-drop-out-u-l-steel-spool-standard-gear-yoke.html
Luke
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I found the Mopar 742 setup to be strong enough for my injected combo but the blower power with a trans brake and well prepped track took it beyond its limits. The only Pro gear set currently available is the 4.86. We removed the Mopar unit a couple months ago in favor of the Ford. The entire 8 3/4 is for sale brake to brake. It is listed in the for sale section with details. George
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Anyone ever use a dana 60? or is it just an expense thing?
Have to pull the entire RE to do gear change and also heavy
I built my car using a Dana 60 It's without question the strongest, cheapest rear to put in anything. I have easily changed gear sets without removing it, in fact it was very easy. I do not find it uncomfortable at all. Heavy yes, I do have a Mag housing but I did not use it. If I build another car it will have a Dana 60
Here is the pic of how easy it is to change gears in the Dana 60
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There is always an exception, and if you are running a Dana, and have the tools and knowlage to change out a Dana R&P in the car and in the pits---Cheers to you--- but most of us find that changing the center faster and eaiser to do with minimal amount tools and stripping the car down. Moving the motor back towards the rear end does more for angle than raising the pinion up .500
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Thanks was just interested in opnions on a dana. Have a dana housing and thought about using it over a 9". It is indeed heavy.
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I found the Mopar 742 setup to be strong enough for my injected combo but the blower power with a trans brake and well prepped track took it beyond its limits. The only Pro gear set currently available is the 4.86. We removed the Mopar unit a couple months ago in favor of the Ford. The entire 8 3/4 is for sale brake to brake. It is listed in the for sale section with details. George
Thanks George sound great but I'm just thinking a head at the moment.
Cheers
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I found the Mopar 742 setup to be strong enough for my injected combo but the blower power with a trans brake and well prepped track took it beyond its limits. The only Pro gear set currently available is the 4.86. We removed the Mopar unit a couple months ago in favor of the Ford. The entire 8 3/4 is for sale brake to brake. It is listed in the for sale section with details. George
Thanks George sound great but I'm just thinking a head at the moment.
Cheers
Cheers to you too! I thought I would throw a comment out there on the Mopar 8.75. It served us well for a time. George
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Thought I’d throw in one more option for a raised pinion position. Winters make a non-quick change that mounts the pinion centerline directly in line with the ring gear centerline. Whole thing is like ‘32-’48 Ford rear with a center banjo and side bells. My dragster has one of these units in it and it appears to have worked for the last 10 years in a junior fuel car. With its spiral bevel ring and pinion, it's more efficient, uses less power to operate, and runs cooler compared to a typical hypoid rear-end. The centerline of a 12 bolt is 1 ½” lower and the centerline of a 9” is 2 ¼” lower than the non-quick change. Down side, it’s more time consuming to change the gear ratio. You must split apart the rear-end to make a gear change. Went 7.40s @ 180mph on the left coast, first race out for me last October ran 8.40s @162 with a mild tune-up. Have pictures but are to large to post here, sorry.
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Pictures, I hope!
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That looks like it would be uncomfortable on the legs.
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Uncomfortable but Stout.
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Thought I’d throw in one more option for a raised pinion position. Winters make a non-quick change that mounts the pinion centerline directly in line with the ring gear centerline. Whole thing is like ‘32-’48 Ford rear with a center banjo and side bells. My dragster has one of these units in it and it appears to have worked for the last 10 years in a junior fuel car. With its spiral bevel ring and pinion, it's more efficient, uses less power to operate, and runs cooler compared to a typical hypoid rear-end. The centerline of a 12 bolt is 1 ½” lower and the centerline of a 9” is 2 ¼” lower than the non-quick change. Down side, it’s more time consuming to change the gear ratio. You must split apart the rear-end to make a gear change. Went 7.40s @ 180mph on the left coast, first race out for me last October ran 8.40s @162 with a mild tune-up. Have pictures but are to large to post here, sorry.
Had a look at the winters web site and saw them . Super nice looking in a slingshot. They seem to have a 10" or 8 1/8" crown wheel aand 31s spline axles wonder what they cost?? Hmm but by far the best option I've seen otherwise.