I just bought a 2008 CPO ML350 and have done searches on the web for performance chips. There are a few which promise a boost in horsepower and gas mileage. I'm pretty happy with the performance of the stock ML350 but it would be nice to have just slightly quicker acceleration and especially better gas mileage. Anyone have experience with any of these chips? Thanks

 

Oh dear, here we go again with "performance" chips...

When a manufacturer builds an engine, he builds in a safety factor so that the thing lasts a long time and doesn't self destruct if the owner abuses it or puts in bad gasoline. All that so-called performance chips do is reprogram the engine management computer to eat into this safety margin. In the early days of computer-controlled engines, the chips (and back then they really were replacement chips) ocasionally made a noticeable difference. Not often, but occasionally. But today's engines are so precisely controlled that there is absolutely no way any after-market reprogramming could improve engine efficiency. No chance. None. Zip. Nada. Zilch. The 'chips' are typically sold to younger owners who will swear they can notice a difference. It is a well-known psychological phenomenon, which the vendors rely on to keep making sales. My son once chipped his Golf GTI. He swore it made a difference. So one day we spent the whole day doing instrumented runs, averaged over both directions, discarding both the best and worst of each and averaging all other results. We used electronic timers throughout. The outcome? The car was fractionally slower with the performance chip than when running factory specs.

It is a different story with turbocharged engines, as they can be reprogrammed to increase boost which can make a noticeable difference to performance. It is a stupid, dumb thing to do because if the engine ever suffers from damage, most manufacturers today can tell if the ECU has been reprogrammed even if you revert back to manufacturer specs before reporting the trouble. And good luck then with your warranty claim.

So my apologies for not answering your question, but whatever you hear -- save your money!

 

OK here's another viewpoint on a tune:
The mfr tunes a car for a wide range of climates, and fuels, and driving conditions, emissions, and warranty issues.

A good tuner can dyno-tune your car and squeeze out a few HP/tq in the rpm curve, but you will hard pressed to get more than 5-10 hp on a M113 engine for instance. (ML500, or CLK55, or equiv). Because the motors are tuned so well from the factory, there just is not much left on the table. This is NOT the case for all mfr's...... some models respond to tuning very well...... examples would be Turbo Charged Diesel p/u trucks, and the new TT 3 series bmw gains sig hp/tq from just a tune like 70hp!!!

Back to mb - now things get a little more interesting IF you start changing some hardware on your MB...... highflow intake system, headers, catback, port/polish heads /intake, cams... then you will want a custom tune to take full advantage of the mods, and also to ensure the engine is operating properly with the hardware changes.

The other cool thing about modern fuel injection systems is that they have advaptive learning...... which means they have a range of operating parameters that are continually adapted to actual engine conditions based on amb temp, demand, driving style, fuel quality, etc...... this adaptive aspect allows people to simply bolt-on some simple mods and the computer will learn/adapt the afr to the new mods (within a reasonable range) and all is fine with no tune.

When you bolt-on major mods a tune will be necessary.

You can buy a wide-band o2 sensor to datalog engine afr/rpm, this is helpful when tuning a car, particularly if you have any type of boost adder.

Agreed - though most mail-order tunes are crap..... your best bet is a pro-dyno-tune on your actual car when doing major mods.


If you want more performance from your ML350 do a search. I asked my local mb tuner about playing with my ml500 and he said even after bolting on a Kleemann blower on an ML500 it was not a big an improvement because the ML is such a heavy car. You'd be better off selling the ML350 and getting a used ML63..... the prices on these "performance" suv's is dropping fast...... local dealship has an 08ml63 for upper 50's with 20k miles...... not cheap, but less than 50% of the price new..... and very very fast in stock form.

 

If you consider yourself a boy racer or have a need for extra speed go for it.

I would leave things standard as the manufactuer has spent many milions of bucks getting it right. So why would yer tamper with it. Perhaps only to make the aftermarket guys who reckon they know more than the manufacturer, come up with something to sell- to make bucks for themselves. It's a bit like the bling bling stuff people are peddling on EBay.

But some people can't help themselves. They do silly things like this, abuse their vehicles and end up on sites like this winging about things going wrong.

Smile and live gently.

 

betrezra: I don't disagree with your comments, although the OP was just asking about 'chips'. Regarding the addition of a supercharger: I had an '02 X5 4.4i and I added a 6 psi ESS supercharger. The improvement was dramatic, with HP going from 285 to 405, allowing me to quite easily outrun the 4.6is and 4.8is models that BMW sold. So I am a little surprised that you were told there wouldn't be much of an improvement in an ML500 after a supercharger was added "because it is a heavy vehicle". Personally, I wouldn't mess with the engine in my ML550 because it is already powerful and sweet, but an increase in power is an increase in power regardless of whether the vehicle is a Lotus or a tank. The problem is that so many after-market tuners and vendors of add-ons don't really test their stuff thoroughly and almost never offer any kind of guarantee if you blow your very, very expensive engine.