SHOP ›EXHAUST ›EVOLUTION RACEWERKS COMPETITION SERIES 4.5" CAT...
Evolution Racewerks 4.5 inch catless competition downpipe for BMW B58

Evolution Racewerks Competition Series 4.5" Catless Downpipe — B58

$675.00

Evolution Racewerks 4.5" Competition Series catless downpipe for the B58 inline-six. Three finish options. The B58 makes meaningfully more exhaust mass-flow than the B48 at the same boost level — 4.5" is the size ER engineered specifically to match the B58's 4.5" turbine housing outlet without creating a "step" transition that causes back-pressure.

Why 4.5" specifically

ER's note from their own product page: "The new turbochargers on the B58 engines utilize a much larger 4.5" outlet compared to the 4" outlet on the older N55 engines. If we ran a 4" downpipe flange inlet so we can use 4" tubing, a 'step' would be formed between the turbocharger outlet and downpipe inlet. Exhaust gas would hit this step and turbulence would form, causing back-pressure close to the turbocharger." ER had to source 4.5" stainless tubing specifically — not commonly available — to keep the inlet seamless.

Three finish options

Brush Finish (standard): ER's default. Matte stainless appearance, ages cleanly under engine bay heat cycling.

Polish Finish: mirror-polished stainless. Shows in the engine bay; preferred by show-build customers.

SwainTech White Lightning: our signature white ceramic thermal coating — details below.

Catless reality

All three finish variants are catless construction (no catalytic material). Race use only. Triggers CEL on stock calibration — Esse Werks Stage 2 / 3 calibrations clear rear O2 monitoring. The catted variant from ER's catalog is a separate ER product (the Sports Series 4" catted, which uses 4" tubing rather than 4.5") — contact us for catted B58 sourcing.

What Evolution Racewerks builds in

  • 100% 304-grade stainless steel construction
  • Mandrel-bent piping — smooth transitions, no flow restrictions at the bends
  • 100% TIG-welded by ER's in-house fabricators
  • Precision CNC-machined flanges (billet 304 stainless)
  • Made in the USA — manufactured in-house at ER's California facility
  • Limited Lifetime Warranty against manufacturing defects
  • Free shipping in the continental US on orders over $100 from Evolution Racewerks (we pass that through — no shipping markup from us)

EGT bung included — standard on every Esse Werks ER order

Evolution Racewerks offers the EGT (Exhaust Gas Temperature) sensor bung as an optional add-on on their direct catalog. We include it on every ER downpipe / mid pipe we ship — no upcharge. Comes pre-installed with a 1/8" NPT plug so you don't need to run the EGT sensor immediately. When you're ready to add EGT monitoring to your build (recommended at Stage 2 and above for any sustained-load driving), the bung is already there.

SwainTech White Lightning — our signature coating

When we coat a part, we use one coating: SwainTech White Lightning — a true ceramic thermal barrier applied about 0.015" thick (versus roughly 0.002" for paint-style "ceramic" finishes) and sprayed molten so it bonds to the metal instead of sitting on top. It cuts radiant heat off the exhaust by roughly 35–55%, dropping underhood and intake temperatures, and keeps heat inside the pipe where it sustains exhaust velocity and scavenging. And it's white — a deliberate signature in a market that otherwise all looks the same in black. Select it above.

California restriction

This product is not for sale, installation, or use on licensed vehicles in the State of California. 49-state product. Vehicle Compliance Waiver signed at order intake. International orders ship without restriction.

Install

~3-4 hours at a competent shop. Reuses OEM hardware where applicable. Includes all hardware for complete installation.

Fitment

All B58 BMW applications — M240i, M340i (incl. Touring), M440i, Z4 M40i, X3 M40i, X4 M40i, X5 40i, X6 40i, X7 40i, 540i (incl. Touring), 740i, 840i, plus legacy F-chassis M235i (B58), 340i, 440i.

This part is the downpipe-side Core of every B58 Stage 2 build. The Stage 2 Kit — B58 packages the matched parts + calibration for 8% under à la carte.

Fits engine B58
Fits chassis F22 · F23 · F30 · F31 · F32 · F33 · F36 · G01 · G02 · G05 · G06 · G07 · G11 · G14 · G20 · G21 · G22 · G23 · G26 · G29 · G30 · G31 · G42
Category Exhaust
Manufacturer Evolution Racewerks
Install effort ~3.5 hours
What this is

A Part Recalibration is one focused revision built around the part you just bought. We take logs on your car as it runs now, on your current tune, then make a single full revision so this specific part delivers what it should. Hardware only does its job with a calibration shaped around it.

We bundle that tuning with the part right here, whatever brand the hardware is. If you want a fresh start across all your hardware, a Full Tune is the step up: a new base map, three revisions, and a written report.

This is a bootmod3 calibration. We tune through your own active BM3 license, so you'll need bootmod3 active on your car to load it.

Ships freight from Boca Raton, FL — additional fees may apply at checkout.

Step up to a Full Tune?

You've added a Part Recalibration to more than one part. At that point a complete tune does more for you: a Full Tune lays down a fresh base map and three revisions so all of your new hardware is dialed in together, with a written report at the end. We can roll your recalibrations into one Full Tune for $395 — below our standalone Full Tune, which starts at $495 for a four-cylinder and $595 for a six.

The Full Tune is a bootmod3 calibration — it loads through your active BM3 license, the same one you confirmed for the recalibration.
WHY WE SHIP EVOLUTION RACEWERKS
Cooling is the first thing to run out on a boosted BMW, and Evolution Racewerks builds the charge coolers and intercoolers that buy back the headroom. The bar-and-plate cores carry more thermal mass than the factory units, which is what keeps intake temps from climbing into timing-pull territory on a back-to-back pull. Their charge pipes also delete the factory plastic coupler that is a known weak point under boost. When a Stage 1 or Stage 2 car is heat-soaking on the second hard pull, a competition cooler from Evolution Racewerks is usually the fix that holds the tune's numbers session after session.