Is aftermarket tuning to stock MB engines safe? - V12 Bi Turbo

[JC220]

Hi all,

My recently acquired 03 S600 V12 Bi-Turbo was bought in good condition but with the very common m275 misfire issues. To quote Vicktor of restore your Mercedes.com "Everyone has these misfire problems".

It is on one cylinder and is coil related so I have a coil pack to repair or rebuild.

Anyway - I was told by the PO the car was tuned. And eventually I got the details from the tuner in England.

Stock these cars are 500 HP and 800nm approx. The tune spec the car now has is rated for 578hp and 910nm. With improved throttle response etc.

When I asked the tuner about the implications of the reliability of this on the stock engine he said it is safe and nothing to worry about....

What are the thoughts on aftermarket tuning to stock MB engines? I now have a copy of the car's OE ECU file so I could have it put back to stock if I want.

MOT booked tomorrow so that will be the first time I'll drive it. Albeit I'll be taking it easy so as to avoid cylinder shutdown until the coil pack on the left bank is repaired or renewed.

So far I have only had it on my large driveway and gave it a little jab of gas, to which it responds with instantaneous tyre roasting Rear Tyres

 

[alabbasi]

It's pretty much a software tune so nothing has been done to injectors, coolers etc

If you're beating the snot out of it, it will likely grenade quicker. If not, you should be fine.

 

[JC220]

If you're beating the snot out of it, it will likely grenade quicker. If not, you should be fine.

This is not really reassuring "Gernade quicker" Oh dear. A grenade in a V12 is like a grenade in your bank account too.

But, yes I dont plan on tracking the car or driving WOT every day. I am generally a sensible driver and never even had a speeding ticket.

 

[TerryA]

This is not really reassuring "Gernade quicker" Oh dear. A grenade in a V12 is like a grenade in your bank account too.

I am generally a sensible driver and never even had a speeding ticket.

Geez, I thought you were an enthusiast. How could you possibly NOT have gotten a TICKET by now?

lol

 

[alabbasi]

They all wear out eventually. Come see me when if does. I have two spare engines

 

[maw1124]

I don’t have any experience, only years of second hand reading on this. The simple verdict is the tunes on these cars are a lot more reliable than the OE coil packs. This will not be your last time repairing a bank of coils. Up until the W222, it was the Achilles heel of the V12 cars — repeated coil pack failures. And when any failure means repairing or replacing the entire bank, that gets really old really quickly. What that means for you is, you’re not buying any more reliability by reverting the car to stock, so why bother? The forged engine internals can handle the extra boost. I’ve not heard of them grenading; hence, Alabbasi has spare engines because they outlive the rest of the car. But don’t quote me on that — it’s possible to break anything and the people who do tend to break things also tend to buy TTV12 Benzes. The extra force works harder on the transmissions than the engines from what I’ve seen, so of course tend to that. I’d say repair the coils and drive the car. People do pay attention to the gapping on the plugs, though... new plugs on S65 - MBWorld.org Forums

Cheers,

maw

P.S. you might also see post #28 here for a grocery list on your S600... Last post - getting rid of the POS - MBWorld.org Forums The rest of the thread is generalized complaining and theorizing about why V12s are buyer beware cars.

 

[gsxr]

I wouldn't worry about engine reliability with a "tune". They're just increasing boost, and tweaking fuel/ignition curves. MB builds their motors with plenty of safety margin... pushing from 500hp to 600hp is not a concern. Now, if you were at 800-900hp, yeah, I'd be nervous.

The coil pack / misfire issue will probably exist with either stock or "tuned" programs. I would be surprised if the misfire is in any way related to the tune, and would be cured by going back to stock program.

 

[JC220]

Ref the misfire I can describe a little better here.

This S600 I bought as "spares or repairs" due to the missfire issue. The seller had paid many hundreds of pounds diagnosis to supposed MB specialist shops and none could tell him what the issue was. I have one such report that cost him around 500 bucks and said: "slight misfire at idle. Possible intake leak" or something to that effect. Basically not mentioning ignition coil fault.

I did my homework on the car and actually found the older PO who had the car until October 2018. I contacted him on a forum as he was an enthusiast owner and he told me alot more about the car. And told me he had put a new coil pack on one bank prior to selling it. And all 24x spark plugs were new.

So when the car got here I checked and sure enough one coil pack is pretty new production date. On using my Star and the smooth running test (what the "specialist" clearly did not know to do) here are the results:

Only one cylinder on the older coil pack (cylinder 9) is misfiring. I did buy 2x new MB spark plugs and 12 new silicone insulator boots since the coil pack will be off anyway and it's worth making sure all is clean of oil or water, inspecting the coils, cleaning the springs inside, renewing the spark plugs on cylinder 9 and all boots before trying again. After that I have to deal with reparing the one coil pack myself or sending off to USA for rebuilding.

But a good result for my S600 purchase

 

[maw1124]

Joe, don't reinvent that wheel. These guys are basically the recognized experts on this, and they're a lot closer to you than to me.

V12icpack, Mercedes S600 ignition coil pack repair, ECU, misfires V12 engines - Home

V12icpack, Jamestown

www.v12icpack.com

Cheers,

maw

 

[JC220]

Joe, don't reinvent that wheel. These guys are basically the recognized experts on this, and they're a lot closer to you than to me.

V12icpack, Mercedes S600 ignition coil pack repair, ECU, misfires V12 engines - Home

V12icpack, Jamestown

www.v12icpack.com

Cheers,

maw

When I said I would send to USA they are who I was referring to.

They can also sell the coils for DIYers to install themselves if they feel up to the task. Which I do..... and I'm only dealing with one cylinder at present.

 

[alabbasi]

By the way, when you get this car running right, it's going to be a delight to drive. You're not far off my CL 65 which drives like silk until you put your foot in it. Then it scares the scrap out of you.

 

[maw1124]

When I said I would send to USA they are who I was referring to.

They can also sell the coils for DIYers to install themselves if they feel up to the task. Which I do..... and I'm only dealing with one cylinder at present.

Yeah that’s the way I’d go. Keep the tune; if you feel up to gapping the plugs, have at it; talk it over with them, whatever. But the car is ready after that. Join MBWorld, follow Wellnyck, etc., but Nick has done a lot for that community from the UK, and he and JohnLane specialize in these cars and are active in that forum (as am I). Enjoy!

Cheers,

maw

 

[JC220]

Yeah that’s the way I’d go. Keep then tune; if you feel up to gapping the plugs, have at it; talk it over with them, whatever. But the car is ready after that. Join MBWorld, follow Wellnyck, etc., but Nick has done a lot for that community from the UK, and he and JohnLane specialize in these cars and are active in that forum (as am I). Enjoy!

Cheers,

maw

Thanks! Funny you should mention Nick - this was his car until Oct 2018! He was the enthusiast PO I am taling about and as you know very knowledgable in these cars. He did want to buy this black car back actually but already has 2x V12TT again so for that reason he didn't. He had done alot of maintenance work to this car over his ownership which has made it a very nice example