Description:
RennTech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal. RennTech proprietary tuning module stores both the RennTech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose directly to the ECU. Programming takes only a few minutes and the vehicle can be reflashed at any time as many times as you wish.
RennTech intermediate level ECU upgrade for the Mercedes M278 engine still offers huge gains in performance across the entire RPM range, but with a slightly reduced peak HP and torque from our standard tune. This is ideal for customers who want increased performance in their daily driver without worry of extra strain on driveline components or for areas and countries with extreme altitudes, temperatures or fuel quality concerns.
RennTech intermediate ECU tune increases performance from 449 HP and 538 lb/ft torque up to 500 HP and 605 lb/ft at the crank! This is a slight reduction from our standard tune but still offers white knuckle performance at one of the most affordable price points in the tuning market.
Attention:
We have found the M278 engine stock performance numbers vary from the baseline figures claimed by Mercedes Benz. We typically see higher baseline numbers than claimed by the factory.
Power gains are calculated based on stock numbers measured by RENNtech.
Crank Performance Numbers are calculated with a 18% Drivetrain loss on 4MATIC SUVs.
Our numbers will be dependent on conditions and fuel quality. 91+ Octane gasoline is mandatory with this Performance Upgrade.
States known for poor fuel quality have to be supplied with a lower power setup
Features:
- Provides ability to switch between tuned and stock ECU programming
- Providing comfort or daily driver reliability
- Significant gains in horsepower
- Increases the performance
- Significant gains torqueÂ
- Gains: +26HP / +67LB-FT
Stock Performance:
- 449 HP @ 5,500rpm; 516 LB-FT @ 2,000-4,500rpm
- 474 HP @ 5,500rpm; 538 LB-FT @2,800-3,900rpm
Modified Performance:
- 500 HP @ 5,500rpm; 605 LB-FT @ 3,700rpm
- 410awhp @ 5,500rpm; 496awtq @ 3,700rpm
Vehicle Fitment:Â Â Â
- 2016Â Mercedes-Benz X166 GLS 550Â Biturbo
- 2017Â Mercedes-Benz X166 GLS 550Â Biturbo
- 2018Â Mercedes-Benz X166 GLS 550Â Biturbo
- 2019Â Mercedes-Benz X166Â GLS 550Â Biturbo
- 2020Â Mercedes-Benz X166Â GLS 550Â Biturbo
Note:
Images are for representation purpose only and may differ depending on application.
⚠️ California Proposition 65 Warning:
This product may expose you to chemicals known to the State of California
to cause cancer or reproductive harm.
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Avoid the headache of the wrong part. If you are unsure about compatibility, contact us first. If we verify the fitment for your vehicle via email and it doesn’t fit, we will handle the exchange at no cost to you.
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Direct Consultation:
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Secure Shipping:
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We offer FREE Ground Shipping within the 48 contiguous United States. Most in-stock orders process within 48 hours. For your security, high-value performance parts require a signature upon delivery to ensure they reach you safely.
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Please inspect your order immediately. Damage must be reported within 48 hours. For freight/LTL items, if you cannot inspect the contents immediately, please write "Subject to Inspection" on the delivery receipt before signing.
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Flexible Returns:
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Unused items in brand-new, original packaging can be returned within 30 days. While standard refunds incur a 25% restocking fee, we will waive this fee entirely if you choose store credit or an exchange for your next upgrade.
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Exclusions:
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To ensure every customer receives brand-new, untampered components, parts that have been installed, modified, or used are non-returnable. Custom builds, special orders, and wheel/tire packages are considered final sale.
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Need assistance? Reach out via our
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Fitment guides and tools are helpful—but your car is unique! Some trims and options aren’t always listed, so if you want 100% confidence that a part will fit, our team is happy to double-check for you. We take the guesswork out of your purchase by standing behind our expertise.
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Verify Your Build:
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If this product doesn't list your specific vehicle data, simply reach out to support@autohousesupply.com. We will manually verify compatibility for you.
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Our Promise:
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When we confirm a fitment in writing and it doesn’t work for your application, we cover the return shipping and exchange it at no cost to you.
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