need to beef up rear end 700hp on stock diff/axle

[Mach1Junkie]

hey guys My car is all built up to take 1000 hp except the axles and diff (and chassis brace). I have a t56 magnum xl with mcleod clutch. I want to get moser 31 splines so I just need a 31 spline diff right? I see I can get a factory traction lok for under $300, a torsen design (not quite sure what that is but im assuming more durable and sends tourque to outside wheel) for $500, a fr500 torsen t2R for 700, eatons for between 400-700 and lastly an auburn posi traction that locks electronicly via a push button or at WOT. I figure I can keep replacing/rebuilding the cheaper one but everything else ign my caR is over built and I wouldnt mind spending the 700 on the t2R fr500 torsen or on the auburn electronic locker (sounds pretty cool) or if the regular torsen is all I need thats fine too I jusgt know nothing about differentials and I have a lot of power that will be going through mosers and nitto drag radials and id like to go WOT and have the car go straight and if it does burn the tires burn both every time. What would you guys chose? If anybody could explain the differences to me that would be amazing.

Thanks as always
Pete

[Mach1Junkie]

also I was thinking iof upgrading the 3.55's to 3.90's I was told 3.73 is not much of a difference. Will that be too much gearing? does anybody on this board have 5 or 600 hp and use 4.10's ? I wanna stay in the meat of the powerband of my centrifugal blower and I figure my t56mag is geared a lot taller that the t5's we had stock.

[slojunk91]

i went with 31 spline Strange c clip axles& 31 spline FRPP cobra diff with lightened 4.30 gears. It works fine for me. the only weak link is the spider gears with drag strip abuse with a stickytire.

[devildogmach]

Originally Posted by Mach1Junkie

also I was thinking iof upgrading the 3.55's to 3.90's I was told 3.73 is not much of a difference. Will that be too much gearing? does anybody on this board have 5 or 600 hp and use 4.10's ? I wanna stay in the meat of the powerband of my centrifugal blower and I figure my t56mag is geared a lot taller that the t5's we had stock.

Um, tr3650 you mean?

[Mach828]

Detroit truetrac or locker is my vote

Sent with a shot of DROID go fast

[Mach1Junkie]

my bad I thought the stock tranny was t-5. So what is a premium diff company? I'm guessing the torsen t2r from ford racing isnt worth it what about the auburn ected elctroinic limited slip that locks at the push of a button or at WOT? it's 700 bucks. Or do you think ill be fine wiith one of those ford racing ones with the rebuildable carbon plates for 275 bucks ? also anybody here have the 3.90 gears in a high horsepower application?

[littlemags]

for diff....you can go with a cobra diff and be fine at 500-600 hp. I did it for 3 years no problems at all...
As for gearing...I ran a 4.30 with my p1...
Iam over 800hp at the wheels and run a 4.10 with my t56...with the t56 you will need gearing. Even with the closest ratio magnum t56...anything lower and you can will feel like a pig

[Mach1Junkie]

thanks a lot guys so you think the 3.90's will be ok with the t56 for some reason 4.10's scare me (in the sense that I will have too much gear) so you think a 31 spling cobra diff is fine I dont have to send 500-700 on a torsen design?

[linus2004]

Originally Posted by littlemags

for diff....you can go with a cobra diff and be fine at 500-600 hp. I did it for 3 years no problems at all...
As for gearing...I ran a 4.30 with my p1...
Iam over 800hp at the wheels and run a 4.10 with my t56...with the t56 you will need gearing. Even with the closest ratio magnum t56...anything lower and you can will feel like a pig

what size tires did you run with this set up?

[DSG2003Mach1]

i make over 700 on E85 (procharged), I have the wide ratio T56 Magnum and 4.10s, Im very happy with them.

also while doing all this rear end work you need to weld the axle tubes and do something about re-enforcing your torque plates

[linus2004]

what size tire do you run?

[DSG2003Mach1]

Originally Posted by linus2004

what size tire do you run?

Im not running anything ideal..Ive got some MT ET street IIs on 17x10.5 wheels which looks like I would end up in 5th by the end of the 1/4 if I ever get it down the track properly (havent taken it out yet, need to drop the rear and get axle tubes welded)

[linus2004]

i was going to make the switch to 4.10, i have a d1 making approx 800hp. alittle torn on what size tire go with 27 or 28 in tall. what you think?

[DSG2003Mach1]

really not sure, i just found a calculator and put in my tire size and gearing and saw that what I think I would trap would put me in 5th so Id imagine that would be a start

[lcaptmorg]

T2, t2r, true track, wave track are are all worm gear driven torque bias sensing diffys. . T2 and t2r not designed for drag racing . They are far better for open track cars.

True track is a great diff and we have had great luck with it behind plenty of high hp cars for many years. Problem is when it breaks it's done. The wave trac is a newer unit . I have run it for a year with 60 or so 6k + launches and it has held up. Moser warranties it but it's $1k .

Plennty of hight hp cars using the ford tlock with extra clutch pack.

I have no personal experience with the electronic auburn posi unit but do have one buddy with it in his 700hp gt500 and seem quite content with it.

4.10s with a stardard ratio t56 is in no way to much gear.

[lcaptmorg]

Originally Posted by linus2004

i was going to make the switch to 4.10, i have a d1 making approx 800hp. alittle torn on what size tire go with 27 or 28 in tall. what you think?

What does the car weigh? Where is peak power? What 27 or 28 are you looking at? Huge difference between 28 radial or slick.?