Advice/Input for S54 swap

Hi all,

Some background on my car - intention is a primarily daily drive with the odd track day or two every year. I intend to S54 swap it eventually, and am trying to decide on direction for certain areas, and thoughts on what I should do. It was originally a stock 325i auto. It has had some changes over the years, and as it stands it is as follows:

GS6-37BZ Manual Swapped
M-Factory 1.5 way LSD in 3.46 gearing with completely new bearings and seals

I would prefer to keep the GS637BZ and the diff as is, and I believe the measly torque out of an S54 is perfectly manageable for the non-M drivetrain to some degree. All the anecdotal evidence I have seen doesn't move the needle from the 'No evidence which way' part of the scale.

My questions to you all:
Will the rear end hold up? The diff is rebuilt, gears were good, the LSD centre is used with 335s/135s autos/DCTs (one of them)
Will the axles hold up? Anecdotal evidence with people running ESS TS2s and so forth suggest the possibility.

I have three ideas:
Upgrade to M3 rear end, and having to replace all the bushings I have just put in the car.
Upgrade to 330/ZHP RTAs + manual axles if possible, but autos if nothing else. (I can reuse all the bushings in the car.
Custom axles.

I want to avoid the M3 rear end as long as possible. I don't want to have a custom driveshaft and have to sell my LSD for otherwise unknown condition parts.

the 330 axles seem to be the logical option if/when the 325 axles break.

Custom axles is a likely good option too, but probably the most cost inhibitive.

Thoughts?

The S54 puts out decent torque...more than an auto 325i for sure. You should have a set of 330 axles on hand for when you pretzel the 325 axles especially if you have sticky tires and are attacking corners. The rear gears should be ok

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Get ahold of Shawn and ask him. He has done the S54 swap a few times and understands exactly what needs to be done. In fact I think he has his project thread on this forum for when he did his M3 sedan project. I would contact Shawn....

Quote:

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Originally Posted by DeathTrap

The S54 puts out decent torque...more than an auto 325i for sure. You should have a set of 330 axles on hand for when you pretzel the 325 axles especially if you have sticky tires and are attacking corners. The rear gears should be ok

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Yeah, that's the plan at the moment. I mean I could buy an M3, but I want the four doors and I think I'm a bit too attached at this point.

Quote:

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Originally Posted by cakM3

Get ahold of Shawn and ask him. He has done the S54 swap a few times and understands exactly what needs to be done. In fact I think he has his project thread on this forum for when he did his M3 sedan project. I would contact Shawn....

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What's his username? I'll message him privately. Cheers!

transfer over the ZHP M54 flywheel, clutch and transmission over to the S54. all bolts up just fine. reuse the ZHP 6 speed transmission cross member, drive shaft and you get to retain your current subframe and diff setup. change out to the 330 larger axles and you should be good to go just fine.

Coolio. Sounds like the plan. Forgot to mention I'm already running a UUC Twin Plate, though I'll probably go to a Clutch Masters FX250/350 setup when the S54 comes.

Woo child make sure you do your research on those Clutchmaster kits!

I test drove an M3 with an FX250 kit recently and it was unbearable for the street. It was difficult to modulate and get a smooth shift and the rattling was LOUD - car sounded broken. It was enough to turn me off from the car completely.

Perfect kit for violent launches though...