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RennTech ECU+ Upgrade for the 2015-2017 S 550 BiTurbo: grey RennTech HHT tuner showing the OBD2 plug end

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RennTech HHT hand-held tuner graphic with the grey OBD2 module - RennTech ECU+ Upgrade for the 2015-2017 S 550 BiTurbo

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Compact black power module - RennTech ECU+ Upgrade for the 2015-2017 S 550 BiTurbo

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Back of the RennTech HHT tuner with its USB port and status lights - RennTech ECU+ Upgrade for the 2015-2017 S 550 BiTurbo

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RennTech HHT tuner seen from the connector end - RennTech ECU+ Upgrade for the 2015-2017 S 550 BiTurbo

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RennTech ECU+ Upgrade 2015-2017 Mercedes-Benz S 550 BiTurbo C217

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Regular price: $2,405.60
Regular price: ~~$2,480.00~~
Sale price: $2,405.60
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RennTech ECU+ Upgrade 2015-2017 Mercedes-Benz S 550 BiTurbo C217

Subtotal: $2,405.60

Not sure it fits? Text us your VINSee all fitment

Vendor: RennTech

SKU: 54.217.S550BT

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Overview

If you want more from the 2015-2017 S 550 BiTurbo without touching the hardware, this RennTech ECU+ Upgrade is the cleanest way to get it. RennTech revises the factory calibration for the 4.7L M278 twin-turbo V8, raising power and torque through the full band and keeping the smooth manners the car left the factory with. RennTech rates the S 550 BiTurbo at up to 540 hp and 705 lb-ft with this upgrade, a gain of 66 hp and 139 lb-ft.

Watch it explained

Features

Loaded through the RennTech HHT hand-held tuner via the OBD2 port, no ECU removal
The HHT stores the tuned and the factory file, so you can switch back to stock any time
Revised ignition timing, throttle mapping, air-fuel ratios and boost control
Gains across the entire rev range, not just at peak
Developed on RennTech's own dyno and road tested
Keeps factory-like drivability and reliability for daily use
93 octane or better recommended for the full calibration

What is included

RennTech calibration for your car
Delivery as listed by RennTech for this model (HHT tuner or ECU flash)

Specs

Part number	54.217.S550BT
Engine	4.7L M278 twin-turbo V8
RennTech rated output	540 hp / 705 lb-ft
Gain (RennTech)	+66 hp / +139 lb-ft

Fitment notes

For the S 550 BiTurbo (C217), 2015-2017 as listed by RennTech. Please include your VIN with the order so RennTech can confirm the exact application. The full calibration needs 93 octane or better fuel. Check the fitment table before ordering, and contact us if your car differs.

Fitment

Make	Model	Chassis	Year	Engine
Mercedes-Benz	S 550 BiTurbo	C217	2015-2017	4.7L M278 twin-turbo V8

Fitment

Year	Make	Model
2015–2017	Mercedes-Benz	S550

Not sure? Text us your VIN and we’ll confirm.

Shipping & returns

Shipping: Orders ship via UPS, FedEx or USPS, from our facility near Los Angeles or directly from the manufacturer. Rates for many items are weight-based and shown at checkout. If you need it by a certain date, text us before you order.

Returns: Unused items in brand-new condition and original packaging can be returned within 30 days of the invoice date, with a 25% restocking fee unless otherwise specified. In some cases we can offer a lower fee with the balance as store credit. Shipping charges aren't refundable in either direction unless approved by AutoTalent.

Not returnable: special-order or custom items, and anything that has been installed, modified or altered.

Cancellations: free if the item is out of stock or we miss the ETA you agreed to. Other cancellations carry a 5% processing fee to cover card fees we can't recover. Special-order items can't be cancelled.

Damaged in transit? Report it to the carrier and to us within 48 hours, keep all packaging, and don't send anything back without our written approval.

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