VirtualRain

Hi there, I have a 2016 CLS with M278 engine with a couple of years of warranty left and I'm interested in getting a tune to improve throttle response, and performance, but don't want to overly stress my drive-train or impact reliability so I'm thinking the RENNtech intermediate tune is ideal for me... about 50HP/150LB-FT that will work with normal 91-octane pump gas. Here's the link:
https://www.renntechmercedes.com/ind...e550-fl-detail

I'm thinking it should give me a nice boost in performance, maintain reliability, and I like the trust and reputation they have, even though they are more expensive, I'm willing to pay more for some peace-of-mind and hopefully reducing my chances of having a bad experience. Apparently they can also disable the Eco mode default at startup and I can later upgrade to the full tune for the difference in price if I choose to.

I'm wondering if anyone else has gone this route? Or what others think of my approach to this.

KEY08

VirtualRain

I never really understood this kind of warranty thinking. It assumes that you're going to have an expensive engine failure before your warranty expires while completely stock - and best not to invalidate your warranty so you don't have to pay for this repair. While I agree that's a remote possibility, the far more likely failure scenario is you find some weak coils, plugs or other drive train components that don't reveal themselves until after the tune is applied. In which case, waiting to reveal this until after your factory warranty has run out makes no sense to me. You may as well get this weak part identified as soon as possible, and perhaps you'll get it replaced under warranty, even with the tune. You certainly won't get it replaced under warranty after your warranty has expired. And applying a *****-out tune that is going to push everything to the absolute limits, is almost a guarantee to have an expensive failure... hence my interest in a modest tune that will likely not "break" anything.

bob2011

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bob2011

I think the 2015 and up CLS models have the 9 speed right? Which is more than capable of handling the torque and HP put out by stronger tune, the intermediate tune won't be stressing anything. But your warranty will be shot on powertrain related things, so just a heads up.

bob2011

[quote=bob2011] double post

KEY08

VirtualRain

LemonSqueezy

This doesn't really answer your question above but I have 2 ecu's for my 14 e550.. one for stock and one with a eurocharged tune.. dealer also knows i have this.. Recently went in with my stock ecu for a CEL, they gave me 8 new spark plugs and a new battery under warranty.

bob2011

God forbid this happens, but let's say in a worst case scenario, something catastrophic happens with the drivetrain components, would having a second stock ECU forgo warranty denial?

VirtualRain

KEY08

VirtualRain

Warranty situation aside, I think having a 2nd ECU with stock tune would be ideal for troubleshooting if you had a problem. For example, you could immediately determine if the problem only occurs when the tune is applied?

LemonSqueezy

My SA tells me I need to 'revert' back to stock because anything aftermarket not from oem prohibits them from diagnosing and doing warranty repairs, if related to the ecu. He was okay with me getting a 2nd ecu. Now if my engine or tranny blows.. that's a chance i guess I'm willing to take. But with a stage 1 tune, highly doubt anything will ever go wrong.

I bought my 2nd ecu off ebay for some $300 or so. Ecu's are Vin coded I believe so i had my tuning company clone my stock file over to the new ecu. You just need to make sure it comes off a v8. The ecu has a little MED number and it needs to be 17.7.1 or med 17.7.3.

cocobeex

I also have 2 ECUs...
Our 2014 E550 ECU Part# A278 900 1300 thats all you need.
but my whole car is modded. I can't really think of anything thats stock. No warranty anymore for sure....lol
God Blesssss me till next new car

LemonSqueezy

If cocobeex's heavily modified dream machine is still up and running, then I really should have nothing to worry about 😂👍

Leonardick

I got my 2013 E550 M278 4Matic done by Weistec, I luv it. There's differences tuning for RWD and 4MATIC, this link is for the RWD 2012 M278 to present http://weistec.com/all/mercedes-benz...u-upgrade.html

VirtualRain

Leonardick

In normal driving it would perform just like any other Tune, the power change once your floored the pedal. I think you should go with the Race Chip people, no alter on your ECU at all.
https://www.racechip.us/shop/mercede...-443lb-ft.html