E30 engine swaps compared: M50, S52, S54 and LS

The M50 is the easy upgrade, the S54 is the dream, and the LS is the shortcut to big torque. All three bolt into an E30 with off-the-shelf parts. They just ask very different amounts of your money and patience.

This guide compares factory figures, the parts each swap needs and the prices kit makers list today. It doesn't cover the cost of the donor engine or labor, which vary too much to pin down.

The baseline: the stock M20B25

The 325i's 2.5-liter M20 makes 168 hp and 164 lb-ft in US form (Hagerty). It's a smooth, cheap, belt-driven six. It also has an interference design, so a neglected timing belt can wreck it.

That's the bar every swap has to clear. If your M20 is healthy, a fresh belt and cooling system may be all you need. Our E30 buying guide covers those checks.

The four swaps at a glance

The S54 and LS roughly double the stock output. The M50 is a mild step, and the S52 sits in between.

Grouped bar chart of horsepower and torque: M20B25 168 hp and 164 lb-ft, M50B25 189 and 180, S52B32 240 and 236, S54B32 333 and 262, LS1 345 and 350 — The LS wins on torque; the S54 nearly matches it on power

Engine	Donor cars	Power	Torque	Block	Key E30 parts
M20B25 (stock)	E30 325i	168 hp	164 lb-ft	n/a	None
M50B25	E36 325i, E34 525i	189 hp	180 lb-ft	Iron, aluminum head	24-valve mounts, E34 oil pan, gearbox brace, rewired loom
S52B32 (US)	E36 M3	240 hp	236 lb-ft	Iron (US)	As M50, plus coolant adapter
S54B32 (US)	E46 M3, Z3 M, Z4 M	333 hp	262 lb-ft	Iron	24-valve mounts, M50 oil pump conversion, standalone ECU, headers
LS1	C5 Corvette, from 1997	345 hp	350 lb-ft	Aluminum	LS mounts, T56 or similar gearbox, headers, GM wiring

Power and torque are factory ratings from Jalopnik (M50), the E30 Zone wiki (S52), Wikipedia (S54) and GM's 1997 Corvette release (LS1). The S52 figure is 177 kW, which BMW rounded to 240 hp in the US.

M50 and M52: the easy 24-valve swap

It's the most common swap for a reason. The M50B25 makes 189 hp and about 180 lb-ft, and it was built from 1990 to 1996 (Jalopnik). A 1992 update added single VANOS on the intake cam, which helped low-end torque.

The gain over a healthy M20 is modest, about 21 hp. The real appeal is a free-revving twin-cam six that bolts to the E30's own gearbox.

Here is what the swap needs:

Mounts. E30-specific 24-valve mounts move the stud locations without changing the angle. Condor Speed Shop's set covers M50, M52, S50, S52, M54 and S54 (Hack Engineering). Garagistic sells polyurethane bushings for the same swap at $195.
Oil pan. Builders use the E34 525i M50 pan. Achilles Motorsports sells a weld-in baffle for it at $154.99 (Turner Motorsport).
Gearbox. The E30's Getrag 260 stays, but it needs a swap brace. Garagistic's brace and selector-rod combo is $209.10 (Garagistic).
Wiring. You cut and rewire the donor's loom to the E30's C101 engine plug. The E30 Zone wiki has pin tables for the M50B25 and M52B28 (E30 Zone).

One quirk: the economy gauge and trip computer read wrong afterward, because the injectors pulse differently. A small correction unit fixes it.

S52: more torque, same recipe

The S52 is the US E36 M3 engine. It makes 177 kW, about 240 hp, and 320 Nm, which is 236 lb-ft (E30 Zone). That's 72 lb-ft more than the M20.

The parts list is almost identical to the M50's. Add an OBD1-to-OBD2 coolant hose adapter, $54.99 from Achilles, if your engine is the later OBD2 type. US S52s have iron blocks, so don't expect to save weight.

S54: the big one

The S54 is the strongest of the three BMW engines here. In US form it makes 333 hp at 7,900 rpm and 262 lb-ft, and revs to 8,000 rpm (Wikipedia). It's also the most work.

The E30 Zone wiki calls the S5x family "one of the most powerful (and challenging) engine swaps." The challenges are concrete:

Oil supply. S54 swaps use an M50 oil pump. Achilles sells an upgraded pump shaft kit for that conversion at $305.99.
Electronics. The S54 has electronic throttle control. BimmerWorld and Epic Motorsports offer a standalone conversion for $1,497, including the ECU modification and a drive-by-wire pedal cable (BimmerWorld). BimmerWorld lists it for racing vehicles only, and you supply the ECU.
Exhaust. Supersprint makes stepped stainless headers for S54-swapped E30s. IND Distribution lists them at $3,946.05 (IND Distribution).

Comparison card of the M50B25 and S54B32: displacement, power, torque, block, years built, donor cars and the extra parts each needs in an E30 — The S54 adds 144 hp and a much longer parts list

LS: the V8 option

An LS gives the most torque for the money. The 1997 Corvette's 5.7-liter LS1 made 345 hp and 350 lb-ft. GM said its all-aluminum block was lighter and stiffer than the old iron designs (Corvette Action Center).

It's a different kind of swap. The engine, gearbox and wiring are all GM, so very little of the original drivetrain carries over.

Mounts. SLR Speed's E30 LS kit includes two engine mounts and a transmission mount, at $603.99 (SLR Speed). It lists T56, TR6060 and Colorado AR5 gearbox options.
Headers. Sikky's E30 LS headers cost $1,343.99. They are designed for Sikky's own LSX kit with a T-56 gearbox (Evasive Motorsports).
Emissions. Those headers are not CARB legal. Check your state's swap rules before you buy anything.

What the parts cost

The engine-specific hardware is cheap for an M50 and expensive for an S54. The prices below are list prices from October 2026 and cover only the parts named.

Range chart of swap-specific parts priced: M50/M52 $404 to $559, S52 $459 to $614, S54 $710 to $6,153, LS $604 to $1,948 — The S54's ECU and headers cost more than the other swaps' parts combined

Part	Swap	Price	Seller
Polyurethane 24v mount bushings	M50, M52, S50, S52, S54	$195.00	Garagistic
Getrag 260 brace and selector rod combo	M50, M52, S50, S52	$209.10	Garagistic
E34 M50 oil pan baffle kit	24-valve swaps	$154.99	Achilles Motorsports
OBD1-to-OBD2 coolant hose adapter	M52, S52	$54.99	Achilles Motorsports
Upgraded oil pump shaft kit	S54 with M50 pump	$305.99	Achilles Motorsports
S54 standalone conversion	S54	$1,497.00	BimmerWorld / Epic Motorsports
Supersprint stepped headers	S54	$3,946.05	IND Distribution
E30 LS engine and transmission mounts	LS	$603.99	SLR Speed
Sikky E30 LS headers	LS	$1,343.99	Evasive Motorsports

The donor engine is the big variable. So are the gearbox (for the LS), driveshaft, exhaust, cooling and fuel parts, and labor. We didn't find a published, like-for-like total from a reputable source, so we haven't guessed one.

What about weight?

The M50, US S52 and S54 all have iron blocks, so none of the BMW swaps is a big weight-saver. The LS1's aluminum block is the exception. The E30 Zone wiki lists the S52 at 141 kg and the S54 at 148.5 kg, but we couldn't cross-check those against factory data.

Which swap for which owner

The daily driver: M50. Cheapest parts, keeps the Getrag 260, and still feels like a BMW.
The torque fan on a budget: S52. Same recipe as the M50, with 72 lb-ft more than stock.
The no-compromise BMW build: S54. Expect to spend real money on the ECU and headers before the car moves.
The straight-line or drift build: LS. The most torque per dollar, but a new gearbox and a very different character.

Whatever you pick, start with a rust-free shell. Our E30 restomod guide covers the chassis upgrades that should come with more power.

Common questions

What is the easiest engine swap for an E30?

The M50. It uses E30-specific 24-valve mounts, an E34 oil pan, a Getrag 260 brace and the donor's rewired loom, and every part is off the shelf.

How much horsepower does an M50 swap add?

About 21 hp over a stock 325i: 189 hp versus 168 hp, with roughly 16 lb-ft more torque.

Can you put an S54 in an E30?

Yes. It needs 24-valve mounts, an M50 oil pump conversion and a way to run its electronic throttle, such as BimmerWorld's $1,497 standalone kit.

Is an LS swap cheaper than an S54?

The swap-specific parts we priced were cheaper: $604 to $1,948 for LS mounts and headers, against $710 to $6,153 for the S54. The LS also needs a different gearbox, which we didn't price.

Sources

Featured image: BMW E30 Meeting 2014 by krysiaman, CC BY 2.0. Source