S54 drop in, good, bad and ugly

Markos said:
I wouldn’t go in to a project like this with $20K reserved for labor. The car needs a new subframe and new steering and front suspension, brakes. Trans tunnel work, custom driveshaft. Speedometer fix. I know nothing about this swap other than $20K labor doesn’t seem feasible.

It would be far easier to swap in an s38 with a factory harness. Personally wouldn’t do that either unless it was a low mileage motor.

What performance problem are you trying to solve?
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hello and thanks' for sharing your information with me, It is something that he offer me to do and to me 20K labor is kind of low for project like that that's why I start questioning to see what I am getting in to before he touch my car all I know if project goes wrong my car is destroyed and todays day it is not cheap to buy another E9
 
I would talk to Jeff Tighe of Jeff Tighe Productions. He has done the swap you are thinking about. I spoke to him when I was interested in going the S54 route. He is an advocate of the S52 into the E9 as he feels it is more suited to the coupe. His quote was very reasonable from what I remember, but this was years ago. Ultimately, I’ve decided to keep it simple and upgrade with a M30B35 and remove weight where I can.
 
e30strube said:
The 5 speed is smaller, cheaper and lighter. The 6 speed gives you an overdrive gear, but given you would be putting a 300 hp motor into an older car, gas mileage probably isn't a big concern The 6 speeds are about $1000 versus the $300ish 5 speeds.
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oops - old post
 
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WALTER said:
I would talk to Jeff Tighe of Jeff Tighe Productions. He has done the swap you are thinking about. I spoke to him when I was interested in going the S54 route. He is an advocate of the S52 into the E9 as he feels it is more suited to the coupe. His quote was very reasonable from what I remember, but this was years ago. Ultimately, I’ve decided to keep it simple and upgrade with a M30B35 and remove weight where I can.
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Hello,
where is he located and what was his price with parts or without parts.
thank you for sharing your experience with me
 
I don’t have his contact info anymore but it looks like he is active on LinkedIn and Instagram via a quick google search. I hesitate to post what he quoted because it was so long ago that it may well not be relevant today, but it was under the $25K cost for labor you mentioned (S52 engine).
 
I have been going down this rabbit hole myself lately since my M30 decided to get all smoky on me, and the performance has always been 'underwhelming'. I'll put it this way, I was dusted by an '83 US 633 auto. So, something is clearly off with my setup.

As a result, I've been looking carefully at four options:
0. Fix the existing setup
1. Warm over the M30
2. Install a S38
3. Install a S54

For option 0, I've had the car in with a few different shops that specialize in 80s german cars, and most of them haven't found anything with the engine setup. I ended up fixing more by careful observation and fiddling. Replaced the spark plug wiring (torn boot), adjusted the TPS sensor, checking plugs, etc. without putting it on the dyno, I don't know if this is as good as it gets, as I've never driven any other M30 car to know if it's 'right'. I do know it's running better than it has in a very long time. Then it decided to start smoking on me. </table flip>

For option 1, the M30 (NA) seems to be limited by the head design, as even a base S38B35 outperforms a heavily modified M30 on dynos. Ergo FI is the way to go. Parts are rapidly becoming NLA. (like oil pumps, coolant hoses, FI components and sensors, etc.) A warmed over NA M30B35 seems to top out around ~200-230 rwhp (cams, 10:1, porting, MS, headers, etc.) and costs around 10k, to say nothing of install. So, total, we're talking about 15k. Turbocharging, end to end, would likely be in the 10k range for a kit + install, and yield ~300 rwhp.

For option 2, there's quite a bit of work involved, with very expensive parts. The going rate for a S38 seems to be 10k+ for just a used, dressed, long block right now. After that there's all the usual swap stuff to worry about, like oil pan, front subframe, thermostat housing, brake booster clearance, firewall modifications, etc. Also parts are rapidly becoming NLA and are dreadfully expensive. On the plus side, the stock M30 transmissions will work. Total is probably in the 20-30k range, and will make ~260-320 rwhp depending on S38 version and if it is improved prior to install.

For option 3, I also looked into Jeff, Castro, and spoke with the seller on Stan's E9. They went to Castro to actually get it working properly. Castro verbally quoted me ~25-40k to convert to a S54, depending on the work on the S54 prior to install. As others have said, this is substantially more radical because there's subframe work to clear the hood. That opens up huge cans of worms since now we're talking about suspension and steering redesigns as well. S54s seem to end up around 300 rwhp without other work. Cams + head work get to ~340 rwhp.

So, now we're all looking at multiple seriously expensive options. Based on the M30 Motronic phase out (~25 years) and the S54's last build date, I estimate we have ~10-12 years of good parts availability remaining for the S54. The S38 is already on the way out the door, as can be seen by trying to find good MAF/ICV/TPS etc for something less than a king's ransom. Most of the M30 and S38 FI system components are very mechanical in nature and don't have a lot of integrated circuits. This means dedicated aftermarket systems / sensors can be adapted and implemented. (Like Megasquirt!) The S54, on the other hand, is fully IC'd, so long-term support will be challenging.

If the goal is to setup the car for long-term use and serviceability, while heating it up a bit, I see 3 ways to go about this: update it as BMW drops things, bite the bullet and go aftermarket for the FI system, or keep the car as original as possible. Going aftermarket can be great (just as sfdon!) but it also opens up issues with someone new supporting the car, as the only person that actually knows how to maintain it is the owner, because they are the only one that knows what it truly 'is' at the moment. Updating the car with new BMW powertrains causes the same problem. None of the original parts will suddenly work, then you're referencing 10 different tabs on realoem to figure out which hose should work. Keeping the car original eliminates this uncertainty, but then you're at the whim of BMW to keep making parts for a 50+ year old car.

I have no idea which option is best, but I would love to hear if others have different ideas.
 
A coupe with 300 hp would be fun for a few months, until the strut towers crack or the transmission tunnel tears or the dif mount starts to break. Our cars were not built to support 300hp engines, and would need structural work to do so.

I know several coupe owners who are happy with well sorted m30b35s, because of the low end torque. And they seem to find the hp to be just about right.
 
Ohmess said:
A coupe with 300 hp would be fun for a few months, until the strut towers crack or the transmission tunnel tears or the dif mount starts to break. Our cars were not built to support 300hp engines, and would need structural work to do so.

I know several coupe owners who are happy with well sorted m30b35s, because of the low end torque. And they seem to find the hp to be just about right.
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That begs the question of whether what breaks the coupe is the extra power or the extra torque...
 
I‘m very sure that torque put stress on the chassis, will create flex and can probably destroy spotwelds or permanently bend something. But in my opinion it highly depends how you will use it.

I will strengthen the chassis as much as I can without welding in a full cage. But I think, i will also limit torque over the software, because I will have maybe a bit to much torque then.
37A0BCDB-CAFE-4220-B6FA-6D254496A709.jpeg
 
It's been my experience that if you have it, you'll use it. Limit torque through software? You're going to have enough work just getting it running well without the additional sorcery.
 
Here’s my two cents worth. I have every possible engine option at my shop because I’m a hoarding fool. I have an s50 (Usa), s52, s38 (x2), s54, and every m30 ever built. I’ve considered every one of them at length for my silver coupe. My final decision is that I’m going to a warmed over m30 4.0. I happened to come along this engine this past year so it’s the one. Before this engine it was going to be a b35 Frankenstein variant. The m30 makes great power and the torque is perfect for our cars. Don’t waste your $ on a cam without some head work. This is the part that really lets the engine shine. The simplicity and fit and period correctness are all spot on. I’ve found these engines to be readily available if you are willing to buy an entire car like an old (throw away) 7 series. I’ve purchased every single one of my engines complete with a car. You get everything at one time.
 
tferrer said:
It's been my experience that if you have it, you'll use it. Limit torque through software? You're going to have enough work just getting it running well without the additional sorcery.
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Yes, This is also my experience. But this is my main concern to limit the torque.

Bits and bytes are my daily bread, so Software and get it running is really no problem, wiring also. This is thankfully a very simple engine compared to modern day engines. Did a couple of s54 swap in various chassis, some standalone programming and wirings with M54,S54,S65 etc.
The most heavy and hard work for me is all the mechanical fitting, welding, custom work with e28 rear end etc. Most modifications are already done, steering calculations&fabrication for r&p and new rear strut tower are the last big things at the moment. Cluster gauge is already converted to digital signals, because of no mechanical speedo drive.
Anyway car will be anything that purist will hate. Engine will get some ITB‘s and therefore a modern engine management, (Race)abs and some other restomod goodies.
 
Nice. Throw a nice tight rollbar and tie-in to the rear end. That'll help with the rear bits at least. Helped mine a good bit
 
I think that all the chatter about coupes not handling the power is mostly anecdotal. Where are all the pictures of the cracks and failures from the multitude of 250hp+ swaps? There are numerous 260 - 280hp s38 swaps with no chassis modifications. If you can swap in an S54, you can stitch weld the chassis and/or install a simple roll bar and front/rear strut bars.

This “chassis can’t handle the HP” anecdote spans every forum and every sub 250hp make an model. The people stating this have rarely done the discussed modification.

I recongize that a longitudinal motor will want to twist a chassis, and the e9 has no b-pillar. It does however have rockers that are on par with a convertible from a reinforcement perspective. I don’t think it would take much to tighten up the chassis enough to handle the extra power. My opinion isn’t based on hard data either, and is therefore equally uninformed.
 
maxxfish said:
Guys,

Tyler from The Arc Asylum and I designed an S54-to-E9 front subframe. It uses E30 suspension and steering pickup points. He should have the jig to make more, and he can also modify your oil pan. Does beautiful work.
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Any idea where to find access to this subframe you designed? Sorry to bother on this old thread. Looking to do an S54 in my E9.
 
it is a lot of work to put an s54 into a coupe. its been done successfully a couple of times ... but you need to reinforce the crap out of the chassis and if i remember correctly, its an e39 subframe. but you have to change everything to make it work. you might want to touch base with @bdigel as he did the work on one of the ones that i know.
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