Which rear end with posi and BIG power?? - Lateral-g Forums

pano911 · #1 03-01-2007, 04:37 PM

69 Malibu with 509 all aluminum Twin turbo.....1100hp, 1100ft/lbs. Street car/ G-machine. Biggest posi combo in a 9" True Trac is with 31-spline axles....will be on street tires most of the time but on occasional will pump up the boost with race gas (1800hp) and go to the track with slicks....afraid I might break a 31-spline axle.

I could go 35-spline in a 9" with a Detroit Locker but I'm afraid of that on the street/in the twisties.

What about a Dana 60 with a True Trac/ 35 spline? Too bulky/heavy? Other options???

Definitely need a posi for the street....no spool...gonna have serious power and lots of weight (I'm guessing 3600-3800lbs)but I'm leery of a Detroit locker on the street... Help!!!!

Tom Welch · #2 03-01-2007, 07:19 PM

I would say that what you are currently discussing is very good. Its difficult to race a streetcar with that kind of power and not break things, like a driveshaft, axle, shred a tire or two, you know, normal race type stuff.

3kidsnotime · #3 03-02-2007, 09:15 AM

Why dont you leave the nine inch in and have a third member for the strip and one for the street....

Speedster · #4 03-02-2007, 09:26 AM

Don't get too hung up on a Locker. They were Ford factory issue for many of their street cars. If you are going to autocross, then that may be a problem.

nitrorocket · #5 03-02-2007, 09:30 AM

If you run slicks and go to the track, you will need a minimum of 35 spline axles and a spool. You have to draw the line somewhere. Most guys at that level are runninf a fabbed 9" with 40 spline axles and a spool with race gears. You will have to settle and be happy running on street tires if you want a g- machine so that you can use a nice limited slip diff. At speeds around 150 mph you will start to gain traction, and that is with only 1000 hp.

ProdigyCustoms · #6 03-03-2007, 05:48 AM

Your best option will be a 35 spline True Trac Moser 60. It will take your horsepower without having to use the dreaded locker! We can set you up with the killer deal on moser when your ready

Silver69Camaro · #7 04-04-2007, 08:03 AM

Quote:

Originally Posted by pano911

What about a Dana 60 with a True Trac/ 35 spline? Too bulky/heavy? Other options???

With 1800HP, are you really worried about the few extra pounds of a Dana 60?

dhondagod · #8 05-05-2008, 05:28 PM

ARB?

Open diff for street driving, flip a switch, instant spool for stoplight assaults on unsuspecting prey.

Chris

andrewmp6 · #9 05-05-2008, 07:43 PM

A air locker is nice its open tell you flip a switch have used 2 in my truck for 4 years they held up to me off road and towing a big trailer.

chicane · #10 05-08-2008, 09:32 PM

31 spline anything... no.

ARB ?? No way... not at that power level.

Limited slip... I dont think so. Not at your stated power level and chassis weight.

First off... at your suggested power level... you will never hook. Never. Not with slicks... or whatever else you can throw at it. 1400-1800HP in anything that goes anywhere but a straight line, crosses the line of shear stupidity. If you cant hook it up, turn it or stop it... your gonna wad the car up like a post-it-note in no time. And dont even think your gonna have a lot of fun with that much power in the "twisties" either.

You need to be looking at a 35 spline combination at the very minimum. I would NOT however, consider any axleshaft that is single point cut and that is not undersized below the minor diameter of the axle spline itself. So... that pretty much nixes MOSER, Currie, Strange... and most of the other barney bolt on, mass produced garbage.

If you keep the 9"... you will need a 3.812" thru bolt case, 4130 heavy wall tubes with the housing appropriately braced... and you may as well step up to 9.5" gears (but doubt that is going to work as the appropriate ratio isnt likely available... yet.) I would also suggest that you step up to Hy-Tuff or 300M axleshafts (preferably Hy-Tuff in my opinion) and at a minimum of 35 spline. Remember, not all axleshafts are created equal... and Moser, Currie or Strange dont cut it in this application... unless manufactured from a custom forging blank... and none of them do that. You can live with a 35 spline axleshaft, if... it is manufactured correctly... but if you skimp out... you may need a 40 spline axle from one of those other guys to equal the strength of a properly manufactured 35 spline axleshaft. Pretty much... your option's are going to be SummersBrothers Axle and Mark Williams.

I suggest that you call Bret at Mark Williams and discus this with him. I think you will be surprised at what you hear.

As for your idea of a differential... I dont believe that there is anything available on the current market that will put up to your power levels and use... other than that of a Detroit. I also... wouldnt even worry about utilizing a Detroit on the street. You have so much power... that you are going to be too busy working the wheel trying to keep it straight... than worrying about if it's going to reset on you or not. A Detroit just takes a little finess' and a different learning curve to get use to. I drive one everyday... and its a blast... but then again, I'm the exception to the rule... especially when it comes to differentials.

A DANA60, just as Frank brought to the table... is another consideration. It has native HD tubes, a 9.75" gear set and 35 spline axles... and EVERYONE make's parts for it. As for the axles... its the same as stated above... no single point cut splines and must be under minimum spline diameter. It also has about the only limited slip that will live under your stated parameters. It may not live forever... but it will take some damn hard abuse.

You do have one thing going for you in all of this... you make too much power for a short sidewall to hook up... and your most likely not going to brake anything just because of that alone.