31 Splines Question

[chefcaleb]

So I am having my rear end upgraded. Some issues with the car point to the need of a new posi unit. Since I am considering going with a supercharger some time down the road, the garage that I am using suggested making my rear end "bulletproof" as he put it. Meaning that it will accommodate the added power of the supercharger and be upgradeable in the future, should I choose to do so. Anyway, we were discussing a 31 spline upgrade vs the stock 28 spline. He was saying that it isn't completely necessary to go up to the 31 splines so I chose to stick with a Detroit locker diff for a 28 spline to keep the cost down. He is also doing a reinforced cover with the upgrade bolt kit and c clip eliminators.


So my question is, are 31 splines completely necessary? If you feel they are, what are the reasons? Is the Detroit locker a good choice. I want to be able to have good turning capabilities as this is my daily driver but have the added benefit of locking the tires for the torque as I am wanting to do some weekend racing with the local circuits, in the future. Just want to make sure I made the right choice. The guy at the garage assured me the 28 splines are very capable and it was refreshing not to have someone try and push a more expensive product on me. Anyway, thanks for any input.

[sailsmen]

Are you going to Drag Race with slicks or drag radials?

Are you keeping the stock torque converter?

What RWHP&TQ are you anticipating?

[MOTOWN]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.

[crownvic05]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.

Said by a pro.

[chefcaleb]

Are you going to Drag Race with slicks or drag radials?

Are you keeping the stock torque converter?

What RWHP&TQ are you anticipating?

I will be keeping street tires. I know drag radials would be best, but bear in mind I am not wanting to go full on race mode with this car.


My anticipation for the RWHP would be in the mid 500s. He says he could get me to the mid 600s but I like to remain conservative.


I'm not sure about the torque converter at the moment.

[RubberCtyRauder]

you will need a built motor and a large centri or a twin screw to get to mid 500rwhp. stock motor generally can handle 425 range. A true Detroit locker will chirp and hop on turns

[chefcaleb]

The Axle package your looking to build is going to be nothing short of a nightmare for DD use , a Detroit locker is the worst choice for a DD (other than a spool) C clip eliminators are not meant for street use and leak consistently , all you need if you want a strong 8.8 are 31 spline axles an Auburn pro series diff and whatever gearing your going to run , don't overthink it with a Bunch of unneeded parts.

I think the reason he showed me the Detroit locker was because I specifically told him I wanted a happy medium between the stock diff and a spool. Seems Detroit locker fits the bill. But from what I am seeing you all say, that may not be a good choice. Does the Auburn pro series offer good torque management like the locker is known for? I've seen many people say they love their locker for daily driving, then there are others saying they don't. Seems the one that love the locker are on 4wd Jeeps and what not. Perhaps that is the difference?


Yeah, I am reading about how the c clip eliminators leak. Some say they haven't had issues, some say they do. I will talk to him about it. I know he was saying that it offers more safety so the c clip "nub" doesn't wear down and the axle fall off from the extra torque. But I don't want the leaking issues either as this is my DD. Anyway, thanks for the input.

[Blown3.8]

Well here are my thoughts. If you are replacing the diff you might as well upgrade the axles too. They aren't that expensive. Especially if you want 600 hp someday. And I would not go with the Detroit Locker if you are planning on driving thru twisties. Instead go with the Detroit Tru Trac. That is a slick diff and no clutches to wear out.

[Gryphonzus]

I ran for several years pushing 480HP to the wheels on a stock block stock rear end. I finally broke the carrier so I upgraded to a Mustang carrier and 31 spline axles. I looked at it this way if they are going to be working on the rear end I am going to upgrade everything. If you cannot afford to upgrade everything why not drive it as is until you need to fix it? Just my two cents.

[chefcaleb]

So other than being capable of handling the more horsepower, does 31 spline offer any other benefits?

[Gryphonzus]

No they are just more capable of handling the horsepower.

[chefcaleb]

I ran for several years pushing 480HP to the wheels on a stock block stock rear end. I finally broke the carrier so I upgraded to a Mustang carrier and 31 spline axles. I looked at it this way if they are going to be working on the rear end I am going to upgrade everything. If you cannot afford to upgrade everything why not drive it as is until you need to fix it? Just my two cents.

Yeah good point. The axles aren't that much more... maybe a couple hundred. I posi for a 31 spline though is also more. But I agree, why not do everything. I just want to make sure I'm not going to a 31 spline needlessly. That's my concern. I also want to make sure I get the best diff for my needs. I want the extra grip on the road, but I also am tired of sliding out of control when I turn... wet roads make it even worse. That's why I looked into this to begin with now, rather than later. I am hearing a whine/grind sound when I turn and I am skidding a lot when I turn and barely hit the gas. What's funny is I am already driving like I would have to with a locker. I already have to take turns rather slow due to the slipping. Anyway, I am talking with him about redoing my order.

[Lowndex]

you will need a built motor and a large centri or a twin screw to get to mid 500rwhp. stock motor generally can handle 425 range. A true Detroit locker will chirp and hop on turns

Will the Auburn unit not chirp and hop on turns?

[RubberCtyRauder]

Will the Auburn unit not chirp and hop on turns?

no, it is a limited slip

[RubberCtyRauder]

if you hear noise then possible axle bearing going bad and your clutches in trac lok could be worn, so its good you are going thru rear and looking at upgrades