Thinking about converting to RWD; ECS center differential and axle plug delete

[thefleshrocket]

I have an APR stage 2 dual pulley '11 S4 6MT. It's my daily / beater. (140K miles on it, no rust but has its share of slight dings and paint chips, and I suspect that the hood has been repainted several times.) But I also have done a track day with it and plan to do a couple more, so it does get sporting usage. I came across ECS' center differential and axle plug delete which is surprisingly cheap ($413 before tax / shipping) and supposedly easy to install. https://www.ecstuning.com/b-ecs-parts/b8-c7-center-differential-and-axle-plug-delete-kit/012535lakt/

I am a big fan of RWD over AWD--everything else I own drives just the rear wheels, and I enjoy the occasional tail-out antics. I live in southern Illinois where the winters are mild--it only snows a few times each winter and it usually melts off in a few days. But the one thing I do appreciate about AWD is being able to go foot-to-the-floor in first gear pretty much any time and in any condition. My 613whp Mustang Cobra puts down the power pretty well with its summer Michelin Pilot Sport 4S tires but when I switch it over to all-seasons for the winter, it'll easily torch the tires in second gear. But my Cadillac CT5-V Blackwing, even when equipped with all-seasons, will still get out of the hole surprisingly well. That's probably due at least in part to the traction control and the chassis dynamics when compared to the Mustang, but those are two cars with 6MT, comparable power levels, and same-size tires.

I'm curious as to what would become of the S4 were it only to be driving its rear wheels. Will it still be relatively fleet-of-foot with half of the wheels putting down power, or am I going to be adding a second or more to the 0-60 time due to less traction?

[adm750]

interesting question 'rocket.

We have some guys on the BMW side that have bought xi vehicles (particularly if you find one uniquely appointed...) and turned them into RWD platforms by stripping them of the front drivetrain and transfer case equipment.

Evan's one of them.....https://www.bimmerforums.com/forum/showthread.php?2356672-DAS-VADR-Evan-s-E39-Touring-Build-Log&highlight=evan

[SwankPeRFection]

You’ll be asking for a lot of torque to be applied to that rear diff, something it was never designed to take by itself. Good luck. The x drive platform from BMW always started as a fully RWD capable rear diff with the addition of front linkage and transfer case. Something to consider.

[adm750]

^^^ good point. I never considered that angle as it relates to the Audis....

[fastboatster]

try it and report back to us. I wouldn't be worried to much about the rear diff, non-sport diffs are cheap (if you don;t have a sport diff, of course). Plus, as it was already brought up in some FB discussion, the stock diff already has to handle up to 80% of all the torque. My own 2c is that b8 s4 rear diff (non-sport diff) is similar in size to e90 335i rear diff, so shouldn't be much weaker if at all.

[f1torrents]

How this company is still operating is a mystery to me.
There are other much better options out there such as

https://www.fcpeuro.com
https://www.shopdap.com
https://germanparts.ca

Latest ECS horror story.

- Placed an order on Aug 12.

- No word from ECS until Oct 13. Email from ECS reads..
"There was an error processing your payment method. Please contact our Billing Department, do not resubmit your order. Simply reply to this email or call the Billing Department to resolve the issue"

- I replied and reissues the payment.

- Oct 16 I received another email from ECS...
"Hello,
Looks like we made an error, the Spyder Constant Full-Zip - Mens Small you ordered was missing from shelf when we went to pick your order. We will have to reorder a replacement and expect to have it by November 2
We're very sorry for the inconvenience. Please let us know if you have any questions. Talk to you soon. "

- Oct 31 I received another email from ECS...
"Hello,
I am reaching out about your past order for the audi pullover it looks like Audi has changed the price on this since we last ordered it the new price is linked below, let me know if you still wanted to order this item as the price has changed."

- They were requesting 4x what I had already paid for (twice).

- I did a live chat with them on Nov 3.

They said it was not there problem and I would have to pay 4x if I wanted the items. I was not happy and they refunded my order after refusing to allow a manager to review the order.

- At the end of the conversation was the worst of it though.

" sir this is over a sub 200 dollar order , i hope you find something in life that makes you happy because this is out of proportion to the situation , have a wonderful say and a great weekend this chat will be closing in 10 seconds
Kodey L. "

To say that because my order was not of a great value that I was not important enough to be brought to a managers attention is despicable.

ECS I am done with you and all of you should be done with them as well.

I will post the transcripts in the adjoining post as to not clutter the main one.

[Fresh.S4]

How this company is still operating is a mystery to me.
There are other much better options out there such as

https://www.fcpeuro.com
https://www.shopdap.com
https://germanparts.ca

Latest ECS horror story.

- Placed an order on Aug 12.

- No word from ECS until Oct 13. Email from ECS reads..
"There was an error processing your payment method. Please contact our Billing Department, do not resubmit your order. Simply reply to this email or call the Billing Department to resolve the issue"

- I replied and reissues the payment.

- Oct 16 I received another email from ECS...
"Hello,
Looks like we made an error, the Spyder Constant Full-Zip - Mens Small you ordered was missing from shelf when we went to pick your order. We will have to reorder a replacement and expect to have it by November 2
We're very sorry for the inconvenience. Please let us know if you have any questions. Talk to you soon. "

- Oct 31 I received another email from ECS...
"Hello,
I am reaching out about your past order for the audi pullover it looks like Audi has changed the price on this since we last ordered it the new price is linked below, let me know if you still wanted to order this item as the price has changed."

- They were requesting 4x what I had already paid for (twice).

- I did a live chat with them on Nov 3.

They said it was not there problem and I would have to pay 4x if I wanted the items. I was not happy and they refunded my order after refusing to allow a manager to review the order.

- At the end of the conversation was the worst of it though.

" sir this is over a sub 200 dollar order , i hope you find something in life that makes you happy because this is out of proportion to the situation , have a wonderful say and a great weekend this chat will be closing in 10 seconds
Kodey L. "

To say that because my order was not of a great value that I was not important enough to be brought to a managers attention is despicable.

ECS I am done with you and all of you should be done with them as well.

I will post the transcripts in the adjoining post as to not clutter the main one.

hater

ive never had anything negative with ECS, they've ALWAYS taken care of me.


for the OP, theirs a local guy with a RWD conversion thats fully modded and beats the heck out of it during burn out competitions.

[thefleshrocket]

You’ll be asking for a lot of torque to be applied to that rear diff, something it was never designed to take by itself. Good luck. The x drive platform from BMW always started as a fully RWD capable rear diff with the addition of front linkage and transfer case. Something to consider.

I'm not overly concerned about the rear diff. What's a new one cost? If it's $2K or less installed, well, that would suck, but I would just replace it and probably switch back to AWD. If it's a lot more than a couple thou, then I might need to reconsider.

[Nillious]

The only reason to do this is ability to do burnouts, drifting, ect. The car will be slower, handle snow and rain worse, and braking will be drastically decreased. Other than playing around there’s really nothing to gain. I don’t understand why anyone would do this.

[thefleshrocket]

The only reason to do this is ability to do burnouts, drifting, ect. The car will be slower, handle snow and rain worse, and braking will be drastically decreased. Other than playing around there’s really nothing to gain. I don’t understand why anyone would do this.

The car won't be able to launch as hard, but eliminating the front wheels as a driving force reduces drag and increases horsepower to the ground. https://www.motortrend.com/how-to/modp-1005-drivetrain-power-loss/ I would submit that a RWD S4 would be quicker from a second gear roll race than an identically-configured AWD S4.

Sure, acceleration in inclement weather will be reduced with RWD compared to AWD. But, I don't know where you are getting that braking would be worse on a RWD S4 as opposed to an AWD S4.

[Fresh.S4]

The car won't be able to launch as hard, but eliminating the front wheels as a driving force reduces drag and increases horsepower to the ground. https://www.motortrend.com/how-to/modp-1005-drivetrain-power-loss/ I would submit that a RWD S4 would be quicker from a second gear roll race than an identically-configured AWD S4.

Sure, acceleration in inclement weather will be reduced with RWD compared to AWD. But, I don't know where you are getting that braking would be worse on a RWD S4 as opposed to an AWD S4.

i agree...
ability to send power to 2 wheels is better than splitting between 4. (from a roll of course).