Sorry if there is a write up on these topics already but I can't seem to find anything can anybody please post a link?

- how would one go about removing exhausts ?

-is a cat delete on a sl65 going to bring extra Hp? My exhaust shop says they help spool up the turbos and doing so will make it go slower.

I am no expert on these cars exhausts systems any valuable information much appreciated on this topic

 

Would removal be from the top and bottom? Or just bottom? Could it be done using a jack under car or will it need to go much higher ?

 

So from what I'm hearing correct me if I'm wrong unbolt from the top first then exhaust drops? I think I may have worded the question wrong, I didn't mean to remove exhaust from top, I meant to access the bolts of turbo and sensors , does one begin unbolting and accessing it from engine bay everybody waiting to have a cheap shot at me really , why ? Because in other posts I've proven a lot of people wrong on a certain issue ? Honesty grow a set

 

Down pipes.

 

something I've always wanted to know whats the difference between just removing the cat and the downpipes I know its stainless steel and will last for ever but these metal exhausts do last plenty too. I might sound silly posting this but, really if you look at the pipe and the actual "downpipes" there is not much or a very noticeable curve, why would someone pay thousands for a half metre piece of pipe?

 

See attachment for exhaust system removal. Everything comes off from the bottom.

There are several other models that use the V12TT besides your SL. You could poke around in those forums for performance enhancements here as well as Benzworld.

Good luck,

Bob

 

thanks heaps , do you know anything in regards to removing the cats would it help in performance , also are they ceramic or metal ?

 

You probably need to check with the experts at Speedriven. They should be able to point you into the right direction for what ever level of performance you are looking for. They are sponsors here and have ongoing projects that they share.

Help will be scarce as there are not many of us mortals in that lofty V12TT world!

Bob

 

Checking with experts doesn't seem to be working out so well for him.

Might want to emphasize LISTENING to them, not just checking with them.

I might suggest not tearing the rest of the car apart until he gets it running right from the last fiasco. 'course, I'm probably not an expert.

 

The exhaust system is made of five sections, so you could remove individually or in one piece.

The are four lambda sensors, so first disconnect two above and two below.

The catalysts and downpipes are one and the same thing.

You need E-torx sockets to remove the forward clamps (they're awkward to access) and there are clamps at the rear.

The procedure sounds straightforward, but its never that easy, everything is always corroded and seized.

Obviously, you'll make no friends by claiming to have proved other people wrong in other threads.

Nick

 

im not trying to prove anybody wrong if something is true and correct I give credit when due, but if something is wrong I will engage into a discussion to explain why I believe so, but people refer to this as "proving others wrong" I call it " a learning process"

 

Sorry what do you mean " it doesn't seem to be working out for him ?"

 

Srsly?

Got your plugs and coils worked out yet?

 

soon man , just working with EC to get it sorted. It may be a combination of bad coils/ plug gap too big/ tune demand

I better start apologising now I suppose

 

Can you give us an example of that?

 

Well when it came to one of the guys I cant recall exactly whom , it may have been you! he did testing on IC pumps and came up with a huge writeup on different pumps, there flow, the best option to cool down etc, I said kudos to you and "gave credit", but when other people came on telling me that I have not serviced my car appropriately, and thats why my car is misfiring, and they tried to tell me that the coils were on the way and it was in no way any of the tuners fault, I couldn't and still cant accept that totally....meaning maybe it was a combination of conditions created , but when asked the tuner "would any upgrades be needed and would this in anyway affect or damage anything" they could of told me , "have you got new plugs on it?, if not there is a chance it might put stress on them and its better you upgrade now and remove the others , selling them of". I may have gone overboard to blame the tuner completely for everything , but even now I'm not so sure if it is the tuners fault or not, but from my understanding it happened right after I tuned my car anybody in my position would have immediately also assumed what I did at the time.

Another example is with the coil heat shield designs I dont agree to the custom ones you made nor do I have to this is the whole beauty of discussion it expands ones ideas and learning process as to why someone would "agree" or "disagree" , simply put I believe them sheilds are designed to allow a rubber hose to pass over and also to keep the heat of the intercooler piping shielded, and until otherwise proven wrong or shown otherwise I will maintain this idea. Doesn't mean if someone agrees or disagrees they are your friend or not. Its okay to have differing opinons on matters and still respect one another.

Did you end up getting them ohm readings and how you did it on the coils

 

I know you don't agree with my coil heat shields, but I don't think you have any basis for that.

I did before and after temperature measurements, and the custom heat shields reduced the peak operating temperature of the coil packs by 10 deg F.

Therefore they're doing their job, and its not a matter of agreeing or disagreeing.

Nick

 

do you believe 10F is negligible ? I see you did not bother to address my last question. That fine I'm sure Ill figure it out, dont be upset I agreed or disagreed , respect people for being real in the end.

 

I've answered the coil measurements question several times. They measure 300 milliohms on each leg, and good and bad coils were both the same.

10 F may be a small improvement, but it is an improvement, its not worse, and its not negligible. The coil packs run at close to the engine coolant temperature, and electronics become very unreliable when run continuously at much over 200 F. They're unreliable enough as they are, so any extra margin is welcome.

Any of the Mercedes V12TT are difficult to maintain, and I think many of the problems are caused by engine heat. I've tried many different heat management techniques, as you can see in my signature threads. Not all of them were successful - such as insulating the intercoolers, which I don't recommend to anyone. On the other hand, insulating the ABC hoses is a huge win, and I think everyone should do it, and stop winging about the unreliability of ABC when they can do something about it.

Coil pack heat shields are probably a modest win. Although they run cooler, I don't think they will help the real cause of the unreliability. This appears to be overheating of the coils, caused by heat generated by the coils themselves, rather than what's radiated by the turbos. This heat comes from the power needed to generate the sparks, and this increases with engine load, engine speed, and the spark plug gap, but lets not go there again.

Mercedes' problem seems to be that there's nowhere else for them to put the coils. Much has been written about coil packs, but I'm not aware anyone has dug this deep before. Rather than complain about all the common problems, I've tried to find sensible, robust DIY solutions. Aside from the transmission selector, I've had EVERY common fault on my first TT, and found a solution to every one. The problems you've had have been a drop in the ocean.

respectfully, Nick

 

I got it was 300 mill ohms , but the "procedure to test the coils" was never gone into, were the coils removed from the electrical boards then tested? also on which pin was the measure , and where did the probes take the measurements from? i.e was it inside where the plug sits on the coil and a pin on the actual board or the coils themselves ??

 

I'm getting abnormal readings on 6 out of the 12 coils completely unstable going from 1.50 ohms to 20.0 ohms , the coils were tested whilst disconnected from the PCB boards (procedure on ohms test middle pin of coil to inside where spring connects to spark plug) , on the other 6 coils I'm getting steady readings of 1.96 ohms instead of 3.0 ohms ?, any suggestions??