S54 Build Decisions: Turbo vs. High-Revving NA – Seeking Experienced Opinions

[digger]

if you want to mess around with turbos you need something OE based otherwise IMO it going to be problematic non responsive aftermarket junk. i.e. you'd better off to start with B58/S58 based with Xdrive so you can actually put the power down properly

[maw1124]

I haven't done either and hate turbo cars. But I own a supercharged V8 and have spent significant time in supercharged M3, though not on track (E46M and E9XM). To my view the supercharging of these NA engines brings you everything you're looking for and none of what you're not.

So I'd say supercharge + weight loss + chassis improvements = where the money is. Turbo seems like a never ending science project, which is to say "buy a Porsche if you want a turbo car."

maw

[George Hill]

If I was in it solely for the RPM I would consider an S52 deal. The Rabid Racing Development guy and his crew are really pushing that package and turning those engines a bunch of RPM and making a lot of whp with them.

Not saying an S54 can't do it, but for the money the option is pretty intriguing.

[Nate047]

I have a turbo E36 M3 (stg1, 350whp) and a 3.4L stroked E46 M3 (390whp), and I used to have an S/C'd E46 M3 with over 600whp. If you want boost, just get an F8x. Seriously. Great car and you'll get way more out of it for far less than converting an n/a car into a turbo one. I've had fun with my E36 along the way but the S52 was pretty gutless to begin with and nowhere near as satisfying as the S54 out of the box. That being said, I am returning it back to stock if that tells you something... a big boosted M will not be the same car you first fell in love with, and at that point there are better platforms with less compromises to get 500hp.

To get 9500+ out of an S54 you'll have to destroke it and make up the power with other mods. In essence you'll be spending a bunch of money to go in a circle. The RPM 'gains' are pointless, all it does is give you bragging rights and wear the motor out faster. This sounds like a rainy day project/pipe dream at best so the ideal use-case is to leave the motor stock-ish, fortify it for track use and take weight out of the car. You have to ask yourself why are you trying to reinvent the wheel over what you already have? You're already in the sweet spot as far as N/A goes.

Why are you returning the S52 turbo to stock?

[Halftim3]

14th year of ownership with my e46 m3 and like some here we think about the potential of the 3.2L. To me M cars compared to other brands of the same generation reminds me of "The little engine that could"..... "no replacement for displacement" some go with boost.
I agree with if you want boost/big power go f8x.
If you want peak rpm NA hp I'd say build up the s65 IMO.

[jvit27]

I have a turbo E36 M3 (stg1, 350whp) and a 3.4L stroked E46 M3 (390whp), and I used to have an S/C'd E46 M3 with over 600whp. If you want boost, just get an F8x. Seriously. Great car and you'll get way more out of it for far less than converting an n/a car into a turbo one. I've had fun with my E36 along the way but the S52 was pretty gutless to begin with and nowhere near as satisfying as the S54 out of the box. That being said, I am returning it back to stock if that tells you something... a big boosted M will not be the same car you first fell in love with, and at that point there are better platforms with less compromises to get 500hp.

To get 9500+ out of an S54 you'll have to destroke it and make up the power with other mods. In essence you'll be spending a bunch of money to go in a circle. The RPM 'gains' are pointless, all it does is give you bragging rights and wear the motor out faster. This sounds like a rainy day project/pipe dream at best so the ideal use-case is to leave the motor stock-ish, fortify it for track use and take weight out of the car. You have to ask yourself why are you trying to reinvent the wheel over what you already have? You're already in the sweet spot as far as N/A goes.

[Cronenberged]

I’ve thought about this a lot over my 15 years of ownership. My two cents: if you're going N/A, choose whatever build is the most drivable. If you’re going turbo, based on conversations with several builders, I’d recommend a small turbo with 7-8 lbs of boost to avoid lag. This setup should produce around 450-500 hp.

[oceansize]

I'm supercharged but not a track guy so heat soak isn't really a day to day concern.

If I wanted to go turbo I'd sell the M3 and buy a Cayman 718 with the 2.0T. A shade over 3000lbs and with a few modifications it would be super fun, plus it isn't too terribly expensive.

[Grey Phox]

Don't screw with it if you are going to track it. The engine (and the car) doesn't need anything to be perfect at an HPDE. Its the driver that needs development.

Most people cannot out drive a stock e46 m3

Here are the 2 best answers.

Take the money refresh the suspension if it needs it and hit up an autocross.




That said i SC'd my E36 M3 but got bored of the power quick and wish I went turbo. Sold the SC setup after a couple years and went NA but left the Shricks, changed the injectors, and other minor stuff and as it sits now in its NA state is the most fun the car has ever been in the 17 years I've owned it and all the stages its gone through.

[Nate047]

Sell the S54 and do a turbocharged K series.

[CrisSilberGrau]

This question has been asked 329830 times here and answers are always kinda the same. You can't have a road car with road manners and great on track (depends what you deem as good road/track car).

NA imo is the way. To get the absolute best experience of the car, distill it all down to the chassis and engine. Rebuild the S54, I'd do 12:1 pistons, lighter rods, rebalanced crank, new OEM springs and retainers, PTB racing 9.5kg flywheel and clutch package, 550cc injectors, cams, KARB race box, SS v1 dual exhaust. All that is the heart and the catalyst of the emotion that comes from the car. I've done everything (some things twice) except the internal stuff. There are few engines that are as emotive as the S54.

To max it all you have to do chassis work. Rigidity improvements, look at SLON front bar, rear wall, Yurkan brace, raised subframe bushings. I want a cup car for the road with interior, so I'd get MRT engineering front race axle pack, rear bushings for geometry etc etc. Lighten everything within reason, lightness turns everything up to 11.

9,500 RPM has not been done by anyone, the only 9k rpm S54 I know of is in one of the Lebanese hill climb cars that was de-stroked to 3.0L and claimed 500bhp with VAC as a sponsor, think what you will of that ( X for doubt ).

TLDR - Do it

[01SG]

Is this a belated April fools post? Reliable 9.5k rpm S54? Turbochargers with the sharp, connected feel of the s54??

Most people cannot out drive a stock e46 m3, and making much more power on a NA s54 just isn't feasible anyway. Losing weight makes more sense.

If you really want to go fast, just go buy a Corvette. By the time you spend the easy 10k+ to do either of those things you suggest, you're well on your way to affording a C5 Z06 that will still blow any e46 away.

https://www.bimmerforums.com/forum/showthread.php?146984-How-does-Milner-squeeze-420-8200-rpm-and-300-lb-ft-6000-rpm-out-of-the-S54

Apparently the race cars didn't need that RPM to meet the power. But that's not reliable anyhow.

[9kracing]

NA is the expensive way to go slow.

To do it right, would require an entire rebuild of the engine, addressing all parts of the rotating assembly... lightening pistons, rods, and crank, forged internals, bigger cams, stronger valve springs, headwork, intake, exhaust... it's a lot.

Turbocharging will be far cheaper, with greater results.

That being said, I can't stand turbo charged cars, they have no soul. My E46 is supercharged, which I feel gives the best of both worlds... high revs and no turbo lag, but it pulls hard at high RPMs. (Some would argue that it's actually the worst of both worlds, but that's an argument for another day)


Ultimately it's up to you and your checkbook. If money was no option, I would love to build a fully built S54 with velocity stacks. Big cams, custom header, revs to 9K RPMS... The problem is the most I've ever seen is around 350whp, and you're talking big bucks to get there. I just don't think the juice is worth the squeeze.

[332]

Don't screw with it if you are going to track it. The engine (and the car) doesn't need anything to be perfect at an HPDE. Its the driver that needs development.

This, get pads, brake fluid upgrade, oil cooler, sway bars, e85 (for cooling).

[Estoril]

Don't screw with it if you are going to track it. The engine (and the car) doesn't need anything to be perfect at an HPDE. Its the driver that needs development.