Definative thread on how to convert your S4 (and most Audi vehicles) to RWD!

[JaredVL]

This process can also be done to achieve FWD, you would just mod the rear axles and not the fronts.

This is in response to this THREAD, it comes up about once a month so it gets its own thread now. This is the last time I should need to post about it. (key words for future searches: RWD conversion weld welded differential torsen rear wheel drive)

#1 You need to remove your center diff. If you go to the STaSIS website ( www.stasisengineering.com ) and go to the diff section on parts for sale, there are instructions for their awesome 4:1 diff. Follow them.

#2 Clean the diff very well with degrease, then hit with alcohol or brake cleaner and let dry. If possible pre heat the diff in a oven or on a hot plate. This will prevent warpage, although not very likely it is possble.

#3 Weld the central gears to the side of the case, you cannot mess this up. There is really only one way that makes sense to do it. Also weld the gears together on the ends. Make it so that those gears in the middle can no longer turn. Try to do even amounts of welding on all sides to maintain balance. YOU DO NOT NEED TO GO CRAZY WITH THE WELDS!

Reference pic #1, weld high lighted areas:


#4 Reinstall diff using the STaSIS instructions once again. Fill trans.

#5 Remove your front axles, first unbolt them at the transmission output. You will need a triple square in order to do this. Stick a screw driver in the vents of each rotor and bind against the caliper to keep them from spinning as you break them free. Once those are totally disconnected drop the car back to the ground and break the through hub to axle bolt loose. Jack car back up and compress suspension, slide entire axle assemblies out.

#6 you need to disassemble the outer CV, all you will still be using is the bell that normally would house the balls, cage and star. It's the part that has the splines to the outer hub and ABS tone ring (area around the axle end with little notches) on it. You need this there to hold the hub together, do not ever attempt to drive or even put the car on the ground without it in place, you will break stuff and probably get hurt. It also is what the ABS uses for wheel speed. ABS is good, you need it.

Reference pic #2, you only keep high lighted area:


#7 Once you have that part free and all cleaned up just reinstall it through the hub and bolt in place. You don't need the boot or anything. Also clean all the grease off the trans outputs.

Now to answer some specific questions I know will arise or already have...

The rear axles are weak, if you try and drag race or launch like this on sticky tires you will break rear axles. If you haven't realized that I have tried all of this and want to argue, I will not entertain you.

Yes the car will roast the tires off like crazy if you want, it will also drift like crazy. If you have a LSD hang the F on

I ran my car like this off and on many times, I also set a few people up with it, everyone had fun.

No I didn't try FWD, that would be really lame.

Braking feels exactly the same as normal.

No I will not build you a "kit" for this. Not only am I not an advertiser but the cost of a diff is insane, good luck finding extras or bad ones. Just do it yourself if you really want. If you needed to pay someone to weld it, figure 50 bucks and thats getting raped.

Time to do all of this for an average skill level shad tree mechanic who has a welder should be no more that 2-3 hours.

Yes Quattro is awesome, yes I agree it is better than RWD, so dont preach to me.

Happy drifting and stuff, dont hit a tree!

-Jared

[Audi S4 Turbo]

Any vid of the rwd S4? I want to see how it launches, drives in 1st under wot, shifts into 2nd and 3rd fast, drifting, etc...

[JaredVL]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

[Boris]

DRIFT!!

[AMC]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

not at stasis no more?

p.s. lol

[Audi S4 Turbo]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

Oh, since being a smart ass really shows you made this thread to help out. It was not a ridiculous question as everything I wanted to see is important to justify doing this mod. You go through the hassle to create this thread but don't care to host a video?

[JaredVL]

Oh, since being a smart ass really shows you made this thread to help out. It was not a ridiculous question as everything I wanted to see is important to justify doing this mod. You go through the hassle to create this thread but don't care to host a video?

Oh c'mon I mean really. You have been here since '05 and you are going to act shocked?

First off what you asked for was a little over the top. Typing a thread in some spare time is different than going out and making a video. A video that would need at least 2 people.

All those things you asked for are also going to vary from car to car. Have you ever driven a RWD car? I am not here to spoon feed you, so sorry if you now view this thread as me not posting it to help, totally makes sense. I owe you a video!

[JaredVL]

not at stasis no more?

p.s. lol

Nope, moved back to Truckee. Got sick of the bay area. Miss STaSIS though, best job ever.

[Audi S4 Turbo]

I clearly did not state that you should create a video, but perhaps, just maybe you had one stored that you did not post up. Usually, when someone does a unique mod, they make a video.

If you look at my sig, I have driven rwd cars, as it says my last car was an E46 M3.

[AMC]

Nope, moved back to Truckee. Got sick of the bay area. Miss STaSIS though, best job ever.

i would imagine, workin on cars and doing what u love, makes me hate my job! lol time to open up a stasis shop located near u

[FrimmelNoJerz]

i has my snowtrooper back?

[JaredVL]

i has my snowtrooper back?

u can haz

[saucys4]

is the B5 A4 center diff the same as the S4?

[JaredVL]

is the B5 A4 center diff the same as the S4?

exact same, no. but the process would be the same

[Matt@JHM]

Nice information

[BurnAll4S4]

034's RWD CQ is cooler than a RWD S4

[saucys4]

exact same, no. but the process would be the same

So could I go down to a salvage yard, find an A4 center differential, weld it, and throw it into the S4? I would love to swap between the two but when it comes to shelling out a few hundred for a center differential I have better things to spend my money on

[GetAwayFromMe]

Does the exhaust need to be removed? I cant remember if it covers the center diff or not.

[JaredVL]

So could I go down to a salvage yard, find an A4 center differential, weld it, and throw it into the S4? I would love to swap between the two but when it comes to shelling out a few hundred for a center differential I have better things to spend my money on

Like I said, the a4 diff is not the same.

[Das General]

Anyone in the s4 world running a rwd setup already?

[Boris]

Anyone in the s4 world running a rwd setup already?

I think Reza does, but he only drift in yemen.

[onemoremile]

You can pick up a spare S4 center diff with housing, modify it, and swap them in a half hour.

If you need to run on a 2WD dyno you can swap the diffs and drop the rear driveshaft. This is much quicker and easier than going near the axles and is a temporary mod. I've considered doing this to get cheap FWD dyno time.

[goohead]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

LMAO LOL

but seriously i dont see why someone want to do this, i dont see anything appealing about a 3600lb rwd audi there are many better and cheaper rwd platforms that are lighter and funner to drive and produce more power

[Auburnsky1287]

LMAO LOL

but seriously i dont see why someone want to do this, i dont see anything appealing about a 3600lb rwd audi there are many better and cheaper rwd platforms that are lighter and funner to drive and produce more power

Agreed, go freaking buy a supra!

[CruzS4]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

that's the most hilarious bit of sarcasm i've come across in awhile... kudos

[Jung]

Agreed, go freaking buy a supra!

oh yeah just like that? Since I can just go out and buy a supra with the snap of my finger. I like to work with what I have. I'll take the S.

[saucys4]

Agreed, go freaking buy a supra!

i actually would buy a freakin supra in a heartbeat over an s4.

[RolledMySTi]

People need to remember the rear diff and axles were only meant for half the power. If you are stg 1 or 2 this might work, but if you are trying to go stg 3 and rwd my money is on a blown up rear diff.

[Jung]

so are there any beefed up rear axles out there? would cryogenically freezing the axle and diff (dont laugh it actually makes metal stronger) help much?

[JaredVL]

cryo treating the ring and pinion wouldnt make a difference. that is done to actually lower the rockwell hardness of the material to resist shattering. I have used it a lot with off road applications where loading is different.

your diff will be fine, most failures out there you ever hear of are from people jacking their car up by the rear diff and not having the pad in the right spot, it puts cracks in the housing and then its done when it sees a big load.

the axles will be fine on street tires and normal driving. yet if you have tires that are sticky at all and you try to get crazy with a launch you will break one.

you can source beefed up axles, if you are seriously interested PM me and i will pass along the contact info, they arent cheap

[lrg8683]

if this made the car weigh 400 lbs. less, i'd do it..

[Four Play]

Sounds like fun!

Where is the widescreen hd movie though?

[gmann]

Oh c'mon I mean really. You have been here since '05 and you are going to act shocked?

First off what you asked for was a little over the top. Typing a thread in some spare time is different than going out and making a video. A video that would need at least 2 people.

All those things you asked for are also going to vary from car to car. Have you ever driven a RWD car? I am not here to spoon feed you, so sorry if you now view this thread as me not posting it to help, totally makes sense. I owe you a video!

Pshhh, Tripod.

[slingshot]

How much does this improve acceleration? Seems like it would make the car significantly quicker by shedding all that extra driveline...

[fdation]

If i wanted a rwd i would have kept my is300 and why would i do that it was a deathtrap when i modded it it just would spin everywhere...s4 is dope the way it is because its awd and has controlled power go somewhere with that bullshit get a old m5 and drift all u want

[Number54]

Old thread, but I have a question....

Is this what STaSIS did to their B5 S4 race car(s) or did they run AWD?

Thanks.

[slingshot]

If i wanted a rwd i would have kept my is300 and why would i do that it was a deathtrap when i modded it it just would spin everywhere...s4 is dope the way it is because its awd and has controlled power go somewhere with that bullshit get a old m5 and drift all u want

Take it easy big fella.
First of all, it's not necessarily for drifting. Some of us just want a car that doesn't understeer or torque steer like a fwd/awd car does. I'm planning on doing this to improve handling and hopefully free up some extra power as well.
A RWD car doesn't have to be a deathtrap. You just have to know how to drive it. Not all of us need to awd training wheels to keep us on the pavement

[lonestar22]

why is there always 'that guy' in the thread that has to tell everyone the reason why you shouldnt do something. everyone knows AWD>RWD in some applications and the OP already made it clear that he understands the benefits of AWD

[CTS Turbo]

Let me go get my production team. Do you want CAD drawings and maybe a 3D animated video of the process also?

I hope Widescreen HD works for you, thats all I can do.

jared rules hands down x infinity lol

[Shomegrown]

How much does this improve acceleration? Seems like it would make the car significantly quicker by shedding all that extra driveline...

All you're "shedding" is the front halfshafts. That's not much difference in weight or driveline drag.

Old thread, but I have a question....

Is this what STaSIS did to their B5 S4 race car(s) or did they run AWD?

Thanks.

The Stasis cars are/were AWD.

Take it easy big fella.
First of all, it's not necessarily for drifting. Some of us just want a car that doesn't understeer or torque steer like a fwd/awd car does. I'm planning on doing this to improve handling and hopefully free up some extra power as well.
A RWD car doesn't have to be a deathtrap. You just have to know how to drive it. Not all of us need to awd training wheels to keep us on the pavement

I don't know what's wrong with your car, but I've never been in an S4 that torque steered...and I've been in 1000+ hp S4's before.

We have equal length halfshafts. That means you really shouldn't be getting torque steer.