apg231

Back in the early 90's when I had a Buick Grand National we added bigger turbos, intercoolers, cams, heads, fuel pumps, injectors, wastegates and computer chips to boost horsepower. Now we flash forward to today and I keep hearing/seeing "Tune" in posts and threads. I assume this is where a company (like Renntech) modifes the ECU. What exactly are they modifying? Fuel curve? boost levels? timing? I see one kit for the W212 E550 that puts out 540hp, that's 138 hp over stock. Is that correct? All from modifications to the ECU? Nothing else?

Please explain this to me,

PatrixUSA

Here's a start re what a "tune" is:
https://en.wikipedia.org/wiki/Chip_tuning

Advisory, Wikipedia is a free encyclopedia, written collaboratively by the people who use it, so trust but verify.

PatrixUSA

Correct.

That's likely highly proprietary information that we may never know.

According to their website, yes, yes and yes.
http://www.renntechmercedes.com/inde...l-e-550-detail

apg231

So again, back in my early GN days, we could remove 2 screws, take an access cover off the ECU and replace the chip in the ECU. Kinda like changing RAM modules on motherboard. Later on we could take a laptop and connect to a diagnostic port and adjust timing and fuel curves. This saved time having to swaping out chips. Do tuners now in days swap out the whole ECU? Do they send you one with a core chsrge and you send them yours?

Still trying to catch up with today's car technology

PatrixUSA

ECUs of today are much more sophisticated and secretive. Nowadays, the programming and software on today's ECUs are locked down so most users cannot break in to make adjustments, this would be where RENNtech comes in. In fact, car makers tried to claim car owners do not own the ECU or the software that runs today's cars, their claim is that owners are in fact merely licensing the software that runs a car (ECU) for use, and therefore have no right to access.
http://www.autoblog.com/2016/10/31/c...ners-fix-cars/

All that aside, bottom line, things are much more complicated now.

Depends on the company doing the tune. Most, you send in your ECU, they plug in and make purchased programming adjustments and send it back to you. Some can send ECU tune via software package that can then be on-boarded via the OBD port with appropriate tools.

Nofreee

You're spot on. They are adjusting fuel, timing, boost, valve timing etc. With motors like the M278 that are used in various other chassis at higher power levels, MB has simple de-tuned the motor via the ECU. Modern turbocharged/supercharged motors are extremely efficient straight from the factory, but have been held back for emissions, reliability or to not overshadow other cars in a manufacturers lineup. By simply adjusting those parameters mentioned earlier, you can get incredible gains without touching any other parts.

Now this is not exclusive to MB obviously. Nearly every single factory boosted car will get ridiculous gains from just a tune. The greater the displacement and cylinder count, the more power over stock you'll generally see. You can get 40-60hp from a tune in the latest 2 liter motors from Ford, Subaru, Mitsu, MB, etc..

The amount of parameters can be tuned are limited by how much of the ECU the actual tuners have "unlocked". Nearly all ECU's have some sort of encryption to prevent stuff like this, but if there is a need, someone will crack it eventually. The more popular the car, the more people are willing to invest time into figuring it out. Subaru is a great example. With the factory ECU, they can tune it now to run on E85, 93 or any mix in between. Using an ethanol content reader on the fuel return line, the ECU is aware of exactly what mix the car is running and will adjust timing, boost, etc to always run at the max safe power. Hell on my old STI, just going from 91 to full E85 would get me 50hp and 100ftlbs at the wheels. All with zero user intervention, just fill up with whatever fuel you have available and the ECU does the rest, no switching maps or whatnot.

RENNtechHQ

Hey,

most of your questions have already been answered, and we can confirm what has been said before.

On our ECU upgrades we do not install any additional chips or modify the hardware of the ECU. We open the ECU, download the software, modify the software and re-flash it onto your OEM ECU.

And you are also correct with the power numbers on the 550/M278 engine.
With our software the engine goes up to 540 HP and 705 LB-FT @crank. And that's just with the software upgrade, nothing else needed.

Your RENNtech Social Media Team