I really didn’t expect heat wrapping to play such a profound role in the spooling of a remote turbo, I thought it would maybe give me an extra 1psi boost, however people are claiming they can net an extra 5-7psi boost with heat wrap on the exhaust

more fine tuning/optimization updates-

I spent a lot of time inspecting the breather and evap system of the car, and realized I was losing some boost pressure through the valve cover breather hoses... slightly pressurizing the crankcase (which isn’t good). I used some testing cap plugs and jb weld to remove the evap and breather ports on the throttle body

instead of the evap and valve cover breathers feeding into the throttle body, they go to a small catch can, and then are inhaled through the intake manifold during vacuum. During boost there is a one-way check valve (pcv valve basically) to keep the positive pressure out of the evap and breather systems.

the evap purge valve seems to have a one way check valve, when I blew into it I did not have any flow. However I’m not sure I trust the evap purge valve to withstand 7-8 psi, let alone if I experienced a boost spike to 10-11 psi... in which case I would be pressurizing the fuel tank, which isn’t a good idea

After the evap and breather mods, the boost comes on sooner and smoother now.. in fact the boost was pulling strong enough to blow off a silicone elbow on the intake pipe that hadn’t blown off before. Afterwards the car had really ****ty afr... I thought I killed yet another maf sensor however I later discovered it was just a massive intake piping leak

I’m still not getting much, if any boost in first gear... Some will say this is normal but as I’ve stated, I’d like to get some quicker boost despite this massive turbo mounted 10’ away from the engine. Before I heat wrap the exhaust, I’ve decided to remove the factory X pipe in the exhaust and go for a Y design instead for better airflow. I want to ensure I have no exhaust manifold/exhaust clamp leaks as well. The factory exhaust clamp system seems OK but I don’t think they are designed to withstand the high pressures that can exist on the hot side of a turbo setup...I might have to go through the trouble of installing real v-band clamps instead. Then I will work on some exhaust heat wrap, and maybe a tighter spring to have the VGT system on the turbo get faster spool through simulating a smaller exhaust turbine housing

I’m having trouble sourcing the correct vacuum hoses for the eboost2 controller I bought, so that is still on the to-do list... fcpeuro has been good about honoring their lifetime replacement policy on the maf sensors I cooked during trial and error sessions

which brings me to my next point about maf voltage clamps

I’ve done some research on the topic and found the simple resistor on the maf signal doesn’t always work for idling, low and part throttle situations. I had a feeling this was the case, but everyone said that Kleeman setups often would use a 550ohm resistor, perhaps the Kleeman blower provides a lot of extra airflow at idle as well? But I don’t think that’s how superchargers work..at idle and cruise I am willing to bet the intake is in vacuum...

Another thing I knew is that some people used expensive “voltage clamp” devices, to let the voltage signal remain unchanged in all situations besides when the engine is under boost.

the answer to this situation is a little trick called zener diodes

zener diodes are a $1 method to clamp voltage...

it seems the oem maf will cut fuel/throttle once it sees over 4.85 volts (which I guesstimate to be equivalent to maybe 5-6psi of boost, the voltage raises as the airflow raises for example...)

so I’ve ordered a few 4.7 watt zener diodes, which should leave the maf signal untouched until the car is into boost. So it should behave/daily drive very nicely with no funny overly rich/lean afr or anything like that.

I got the idea after reading about some guys doing this with their map sensor on newer c63 models for tricking the engine into more boost. And later found this method has been used quite a bit in the past by Audi and Volkswagen guys

just keep in mind you should install a resistor between the ground and zener diode or the ground will burn out the maf sensor. I learned this the hard way while trying to use a chassis ground as a ground for testing voltage output on an older maf I burned out

i think ultimately I can get some more usable boost out of this existing system that can be utilized in daily driving and not just heavy throttle/racing usage... and now that I know the system works, I can one day upgrade to a really nice turbocharger, etc

edit: I also tried running the system with no cone air filter on the turbo, it delightfully made the turbo noises louder, more woosh and gobble noises, however I don’t think the boost pressure was too majorly affected. I’ll test it again soon. This experiment did however make me realize I should develop an extension on the turbo compressor inlet, so it can inhale cooler air rather than the warmer air immediately surrounding the turbo Itself

No boost in first gears means your turbo is too large or you or losing boost pressure. I believe you need to ditch the turbo you have and get one that is properly sized for the application. It will cost some money but would also keep you from chasing your tail.

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Here’s how the engine bay looks now without the engine covers
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Here is an overview of the engine bay layout. Here you can see the Volvo intake valve at the top left, the routing of the catch can/pcv system and how the evap system ties in. The catch can now returns to the manifold where the egr valve used to tie in
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Here’s how the engine normally looks with the covers re installed
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Here’s a closeup if the evap purge valve routing, instead of the unreliable(under boost that is) port on the throttle body, instead it is routed alongside the valve cover breathers, through a check valve and then sucked back into the manifold under vacuum. The purge valve has a check valve but furthermore the entirely new catch can/pcv/evap grouping has a master check valve to keep boost out of unwanted place
https://cimg1.ibsrv.net/gimg/www.mbw...083757fde.jpeg
Here’s the oil catch can routing and mounting(with check valve), for only $20 the can was a good value and makes it easy to add separation between the intake manifold and the evap/valve cover breathers


i think I would like to work on maybe removing all of the secondary air injection stuff, because I believe eventually this will only lead to boost leaks, etc. I have already had the secondary air pump disabled so it is just filling space really.


Next im getting some of the exhaust work smoothed out and optimized for reducing back pressure, etc. and then heat wrap. then I will be able to show more finalized pictures such as the photos of the engine bay here

Did some welding on the exhaust, turned the factory X pipe into a Y pipe for enhanced flow on the hot side of the turbo. I still need to install some heat wrap but I’ve had a lot of expenses lately, the home plumbing became clogged, the ac system stopped working, and the garage door spring broke... so I’m making the most of what I have currently with this project

I’ve temporarily left off the wastegate as this setup has not had much of a tendency to overboost yet anyways, (the wastegate is sealed shut in other words) I’ll just keep an eye on boost pressures and afr readings in the meantime

but one thing that has helped a lot was a stronger spring controlling the vgt system on the turbine. Spool is noticeably louder and quicker now, and I’m currently sorting some maf circuitry issues(And a vacuum leak it seems), but it seems I’m finally able to build some useful boost pressure in first gear now.

Before, it was a bit difficult to attain positive air pressure in first gear, the boost seemed to mostly kick in once the increased engine load presented by shifting to 2nd gear happened. Now I’m able to start seeing boost at the top of first gear, which is going to help the 0-60 times, and give me a stronger presence of boost in second gear onwards.

looks like the heat wrap is going to be one of the final pieces to this puzzle for a nice, powerful setup capable of reliable daily driving on a budget.

in other news it seems my accelerator pedal is failing. The accelerator pedal is a common failure on the w215/220 cars. I checked my vehicle history through Mercedes and it says my pedal was once replaced under warranty about 14 years ago. So I guess a 14-15 year lifespan isn’t too terrible. Not sure if I’ll be buying a new unit, or hopefully I can be allowed to pull an accelerator pedal from one of the unused w220’s sitting at my work so my funds can go more towards things like heat wrap and tying off the finishing touches of this turbo setup

Accelerator pedal fixed
Replaced the accelerator pedal with one from a 2003 s500, surprisingly it lacks the extra plug for the kickdown switch but it works fine. I’ve not gotten anymore p0221 codes

recent developments/changes and testing
as I recently mentioned I have removed the factory x pipe, and installed a Y pipe instead, I’ve also removed the wastegate for time being. This turbo is so massive I do not have much worry in regards to overboosting at the moment.

the biggest improvement in spool/boost response was installing a tighter spring to control the vgt system on the turbo. I recently found out this turbo can often provide 50psi of boost in its OEM configuration so I am starting to believe I will only ever use the first 50% of the capability of the vgt system anyways

Here’s a video of some clips taken recently, the first and third clips are the most recent, I decided to use zip ties to keep the vgt system entirely closed and the boost response, low end torque and spool have noticeably improved. This tells me I need to use an even stronger spring to control the vgt normally, maybe two strong springs!

first gear boost achieved
in the third clip you can see (and hear) I’m finally getting some good boost at the top end of my first gear, and then once second gear engages the boost snaps up to about 7 or 8psi boost pressure which is exactly where I wanted this car to be

current drawbacks!
keep in mind the exhaust still has not been heat wrapped (which has a reputation to greatly improve rear mount turbo performance), I also have discovered a small new exhaust leak(which means my drive pressure driving the turbo is weakened) and I also have been chasing down an intake/boost leak, which surely does not help performance

n/a variable intake manifold system problem-
im also starting to wonder if the entire “n/a variable intake manifold” system found on Mercedes n/a cars is prohibiting flow, not too mention I think my pre existing secondary air injection non sense may be a large boost leak in itself as well. I think the system can reliably withstand some intake vacuum pressure, but this system was not designed to withstand 7-8psi of boost pressure in the intake manifold

Some argue the variable intake runners are helpful for both low end and top end power, some argue that it’s merely to quiet down the manifold for “luxury”.

Regardless, it’s easily realized this system was never really used on any Mercedes cars with turbos or superchargers from the factory. So it seems Mercedes has already done the homework in regards to this system being useless on a forced induction car

id like to get another intake manifold, and completely remove all the variable intake stuff inside and see how the boost behaves.

overall-
So far it seems promising even with a used semi truck turbo, and parts from eBay. Being my first turbo build, the car not suffering in reliability or daily driving aspects I consider the project a success and only improving as things are further tweaked and perfected. I still have yet to install the fuel pump voltage booster, I have noticed under prolonged boost applications the air fuel ratio does start to get into a lean afr territory. However it’s not a problem for me at the moment. By the time you are running out of fuel supply in these prolonged boost situations, the car is already well over 120mph and you are running out of road...

I believe I could get better early acceleration with a different rear differential, I believe my differential has 2.82 gearing which is great for highway driving but there are better options for quicker acceleration off the line. I’m also not sure how a 3.15 or 4.10 rear differential setup would affect boost ... some say the gears I have are good for building engine load and subsequently good for building boost. I’m just not sure this 5.5 liter v8 will have much problem building boost either way once everything is perfected...

The intake is fine. If it worries you, disconnect the variable intake flap actuator. The problem is most likely the turbo size and possibly exhaust leak. An exhaust wrap would help slightly but it will not overcome the fact the turbo is too large for a rear turbo application. It's probably sized for an 10 L diesel engine and is mounted right next to the manifold.

it spools much better with the vgt system held shut. i could make it work with some really strong springs or utilizing the pneumatic vgt controller that came with the turbo. in theory this could be achieved with a simple hobbs switch.. around 1 or 2 psi a hobbs switch can send a signal to an air relief valve to allow the vgt to open the turbine...but would require an air compressor to be installed in the car and a reservoir. before i even really consider twin turbos i need to dyno test this current setup and see what is really happening in the data

in other news i am having some trouble diagnosing a rough idle situation with the car, and i believe the car to be down on power to maybe 80%. it seems with all the boost pressure i've been building ive busted open a vaccum leak in the intake system, somewhere around the intake manifold or the throttle body. a smoke test is in order

but even with this apparent vacuum leak (it has an audible whistle sound, that's why i know its a vacuum leak) the car was still running very strong with the whistle/vacuum leak. but sometimes the car would read lean after coming to a stop

seems the lean problem is gone but now the engine has a noticeable stumble while parked/sitting at stoplights. i noticed this first happening after a cold start in the morning, car ran strong the day before, next day the car had a stumble during idle...

it's a fairly annoying diagnosis as no real fault codes are present in the diagnostic system

using the Star diagnostic scanner i was able to test for "smooth cylinder running", a sort of detail oriented monitoring of the firing of the engine

the test revealed cylinder one was the one having issues, and cylinder one is furthest from the fuel supply line. which led me to worry that the engine was running lean under boost and tearing up engine internals

i tried swapping with an extra fuel injector, swapping an ignition coil, swapping spark plugs and no change. i tested the resistance of the spark plug wires and they seem OK. i really started to believe the valves or piston rings were bad

i used a boroscope/endoscope tool through the spark plug hole to see the piston, the piston looked good however there was some sort of fuel/oil sitting on top of the piston off to one side ..

i rented a compression tester expecting to find less than 90psi on this cylinder one, however the compression was healthy on this cylinder. i tested the engine cold with no throttle pedal applied, and after two cranks of the ignition, the cylinder was already reading 160psi....

ill take another look at the spark plugs and the ignition wires... otherwise i may have to more seriously investigate the vacuum leak in the intake manifold, im just not sure why the issues would only register on cylinder one... the tune i have been running lately does run fairly rich so i wouldn't be entirely suprised if i just need new spark plugs...i just would normally expect a check engine light with a spark plug or ignition coil/wire problem

Would think changing the plugs, wires, and coils should have been the first thing to do before installing the turbo system. It's not terribly expensive and is an easy DIY. You may also want to run tighter pug gaps since you are now forced induction.

yes the plan was to get the system running on the original plugs and ignition coils, that way I am not changing too many things at one time and can pinpoint diagnostic issues more efficiently

the plan was to install 03-06 cl55 spark plugs, the train of thought was the m113k plugs would be a more suitable spark plug for this engine when run with boost. However these m113k spark plugs are longer and the n/a 55 piston/rod has longer stroke so the m113k plugs do not fit, otherwise they would hit the piston. The other idea, was just a one step colder set of plugs but the one step colder plugs from ngk also have this same extra length. In fact they seem to be the same plugs found in the m113k motors

so now I have a bunch of m113k spark plugs for a future project. And yes I was paying extra attention to spark gap now that we are running boost

more interestingly it seems my latest tune was preventing me from seeing which cylinder was misfiring. Only under advanced tests was I able to see cylinder one had faults

well I uploaded one of my old n/a tunes and immediately upon startup the engine has a more pronounced misfire and immediately gives me a check engine light for cylinder 6 rather

it seems something about the old tune not only made the engine run stronger at idle, but had a sort of raised threshold for triggering misfire faults

I switched ignition coils between cylinder 5 and 6 but there is still a fault on 6. I have new spark plugs arriving Wednesday, and will likely check the compression on cylinder 6 once I can get to my tools tomorrow . Looks like a spark plug/injector issue if I had to guess, but can’t rule out valve, head gasket or ring issues trying to run 8 psi of boost on an engine with over 100k miles

Wanted to report back and close out this thread

overall this project was a lot of fun. I learned a lot about what works and doesn’t work when building a turbo system from the ground up

and in the process got to experience what these n/a 55 amg engines feel like when they are fed 7-8psi of boost and nothing compares. Even the new 2017 s63 coupes (new CL) don’t give the same feeling of “holy ****.. how are we able to accelerate this fast when we are already traveling 70mph”. Ultimately I believe it is very possible to reliably turbo these cars for under $4,000USD but you mustn’t become greedy or reckless in your testing/tuning/etc

but seems in the process I have found the weak link in my motor, the same weak link many others seem to be stumbling upon I’ve noticed. Cylinder 6 is down on compression, seems to be only making around 60psi compression and I believe it to be the exhaust valve, I do not think I’ve blown a hole in the piston or destroyed the rings or cylinder. Ultimately I believe the car needed a more optimized tune for the abuse I put this motor through, before and after the turbo. This car was seeing multiple WOT pulls daily to and from work if that gives you any idea

lately I’ve been reading about a lot of these engines having a cylinder 6 failure in particular for some reason, even without any turbo setup or anything.

the newest tune I had on the car for some reason did not register any misfires, so while the cylinder 6 was slowly failing. There wasn’t as much as a check engine light or any weird noises or anything, the only thing I noticed was a rough idle the next day upon startup and there is still a very slight rough idle

who knows if the cylinder 6 was already on its way out, or if all of the damage happened recently

it’s a shame I never got the chance to dyno this setup, I believe at peak power I may have been over 500whp, nearly double the stock output

the good news is I’ve since bought a low mileage m113k motor, and have started the tear down process for a complete rebuild. I’ll be using the best parts from each motor (the n/a 55 is known to have better flowing cylinder heads, while the m113k has stronger pistons etc) and using my Mercedes employee discount to help the rebuild along. Piston rings alone on this motor can cost up to $1000 without a discount

I also have decided I will be doing two smaller twin turbos on this car because I want some instant boost daily driving purposes.

this whole process was a bit of a “quick and dirty” turbo 55 project, and I’ve before this I’ve never built or installed a turbo system.

this rebuild will likely take a bit of time with the new engine and turbo. And for that reason I am going to wrap up this thread and start a new thread for the next stage

I believe the current n/a 55 motor can be repaired with some cylinder head/valve work. But I’d rather build up a m113k motor for longevity sake

the old goal was 450-500whp. The new goal will be more like 650whp+ with the m113k motor and twin turbos

im at the crossroads now of wondering if I should do the sleeved cylinders for a monster of a m113k, or stick with the oem Mercedes parts knowing these engines can handle 650whp reliably anyways.

thanks for those who have been following and offering advice, stay tuned for the next phase. Hopefully by late summer/early fall I will have the new motor and turbos ready for testing, and more attention paid to the tune and not abusing the new motor as much
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Yes, sleeve the engine so you can run custom pistons. Don't waste your time with the aluminum bore. Just too many variables with the pistons and the cost is high for those that are compatible. Also, to double the power of an engine with no other mods to improve flow, you need to run 1 bar of pressure. Of course, that assumes you have cool air via an intercooler and not hot air.

Assuming your car makes around 250 RWHP stock, you will need to run around 24 psi to produce 650 RWHP. You can improve the ratio by better flowing heads, cams, exhaust, ETC. It's hard and expensive to do that work so let's assume you will be running stock heads and cams.

Running two smaller turbos will help your low end but don't go too small if you want to make big power up top. It's a balancing act. You found out what running a turbo that was too large does, in that, it is hard to make low end boost and struggles to make much boost. Keep up the work and thanks for sharing.

I'd just like to say thank you for all of your experimentation and knowledge given on turboing these cars. I work at an mb dealer in ohio and have always wanted to do something like this but im not a tech but i have tech experience with LS swaps and other non MB cars.

i'd like to clarify for my own experiment i may be trying in the future.
to turbo this car aside from the obvious turbo components you used:
rising fuel pressure regulator
tricked the maf with your diode thing to stop at 4.7ish volts
and that seems about it to me from what i gather, a stock tune might have worked just fine cuz you're bypassing everything else. in hindsight your performance tune might have added more timing to the top end and resulted in the misfiring with too much boost/timing combo, no way to tell now i guess like you said.
anyways i have eyes on an s55 thats a salvage title car, but i would like an r class with that engine in it so im wondering if i can use everything out of the s55 to make it work in the r class or i can just get a r500 and add a supercharger to it from the s55 and do the few mods you did to trick the maf and add fuel and be good. Interested what your thoughts are. Thanks!

yes and no

according to Kleeman, if you install their supercharger while aiming for 7.5psi of boost, all you need is a rising rate regulator, a maf clamp(diode or resistor also works) and I believe they also recommend bigger injectors

and a lot of those cars ran fine for years. I did hear about some having problems, I think I also heard of an engine blowing because of the Kleeman setup paired with a bad maf. A lot of those folks were drag racing and driving the car hard

I would additionally recommend either higher flowing injectors or to install a stronger fuel pump. I did notice the car wanting to lean out after prolonged boost, AKA 20-120mph pulls for example. I was just going to install a fuel pump voltage booster to help that but didn’t find much time to be going faster than 120mph anyways

keep a close eye on your maf voltage readings, and your fuel pressure. I think the oem tune may be safer as you say, I think my piston rings on cylinder 6 were destroyed because of too much fueling. An air/fuel meter is essential as well. I used to think too much fueling would not be too bad on these engines but now I agree it’s important to not go overboard with the fueling

I would highly recommend an experienced tuner to tune the car on a dyno rather than trying to manipulate the maf, timing and fuel sensors, if possible. You may just end up spending more on tricks to manipulate the sensors rather than paying a tuner one time for a proper tune

just take your time and yes I think this can be accomplished fairly easily. I would aim to maintain an Afr no lower than 12.5 and no higher than about 14 if i did this same setup again

if you wanted to install a supercharged engine I can refer you to a shop who can convert an M113K ecu to work in your car, the cost is $800+ supplying a M113K ecu and your current ecu.

edit: I highly recommend reading the installation manual for the Kleeman setup, and taking notes on how they approach the testing and all that. The Kleeman manual was a good bit of reassurance for me a few times while setting up a turbo on a 2000’s Benz

I'm familiar with proper tunes as I own hptuners for my ls swap tunes I do, but I dont know of a comparable software for mb cars of this era as hptuners does newer mbs but not these . I'd feel comfortable tuning it myself if I had a way to do it and would definitely feel better about the finished product rather than bandaiding everything with bypass items lol. Are you aware of anything that can do such tuning yourself ?

I wasn’t aware there were more user friendly tuning options for newer models, that’s good to know!

but on that note, there really aren’t many good alternatives to someone who has the capability to dyno tune these cars.

I know of one guy who recently made a thread about his piggyback ecu system on his w211, check the w211 section for more info

otherwise the next best alternative is a standalone ecu such as megasquirt, the possibilities for tweaking, special alarms and settings is endless if you have the patience for the learning curve

one thing I forgot to mention about the home brew Mercedes turbo setup, it’s imperative to have a good blowoff valve in my opinion when working with boosting a maf-based system. Between gear changes, the throttle will snap closed and you’ll have an “overload” of air pressure, at least according to the maf sensor. If a blowoff valve was able to relieve this pressure more suitably, you’ll have less issues to sort out

I just wonder what programs these dyno tuners are using for these cars lol. i dont know of anyone around me that does it, at least reasonably anyway. i could street tune my own car if i had the software. I've had a megasquirt on a car before, i put a ford edis ignition setup on a small block chevy engine with one. that would definitely be a way to control any engine really but the problem comes with the transmission control unless you have a manual you're out of luck.

Also where did you put the oil feed and drain on these engines? I missed that part if you posted it.

i have a self contained (divorced)oil system to avoid running long oil lines from front to rear of the car and risk running the engine low of oil. It’s just a turbowerx exapump, steel oil reservoir I welded together with stuff I found in the garage, An oil temp sensor, -8an hydraulic lines and a Moroso oil filter. With the turbo(s) being mounted higher than the reservoir there is a natural gravity drain to bring the oil back to the reservoir, so the system only needs one pump

others usually tend to tap the oil filter housing on the motor for oil pressure, and return to the upper oil pan or valve cover. I think I saw one person even install an oil fill cap with a turbo oil return hose for a very quick setup

I found myself back here again, because I finally picked up an R500 haha. Going to be tinkering soon I'm sure, would love to single turbo nothing crazy just a reliable family hauler that makes turbo noise. may start my own thread once i get things going.

500 engine will be nice with 6-7psi of boost. Anything past that and I think you could be asking for trouble without further mods