W124 Performance Thread

[mcbear]

I have had about eight different PMs and email asking the different ways to get more power for W124 cars. I decided to put up a sticky to give us one single performance resource to expound on our different methods and results. What I would like to see is all the folks that have put together big POWER projects for any of the W124 variants please write up a detailed post that gives details, the good, bad and ugly of the modifications. Also post up dyno results if you have them and hours/costs so folks can understand what all is involved with tuning up a M103/104 and M119.

To start the known methods of bumping power [but not all witnessed yet] I have put together this little list which will be the second post. As time goes on, I will enhance the POST2 list which will become the index of theoretical, hopeful, practical, and whimsical project ideas.

Let’s keep this thread technical, without any namecalling discussions intermixed. Obviously we want really good conversation but anything that would keep the thread from being enjoyed by all might be edited down so please keep everything fun.



...

[mcbear]

Turbocharging
The most tried and true method of gaining horsepower from the M103/104 motor is by adding a twinturbo system from either one of the two aftermarket suppliers [neither of which are supplying units any longer] or a “roll your own” approach. Several examples of completed systems are written up on the forum and owners are requested to write up a “white paper” to document the process. 300+BHP can be a realistic goal from this application.

Supercharging
Supercharging the M103 and M119 series have both been talked about and there are currently folks poking around at doing something but so far I have not seen a operational system. Hopefully I can update this paragraph soon.

Transplant
The two major transplant options appear to be either dropping in a General Motors Small Block [350ci] or installing a Nissan or Toyota 3L powerplant that is designed around twin turbos.

The GM option is usually the easiest to buy as there are so many variants and suppliers available by mailorder and breaker yard. Aftermarket industries are built around this motor so there is no shortage of parts available to make the car go up in horsepower. 350BHP is a starting point with a myriad of options to take a LSx motor to over 700BHP. The motors can be bought for as little at $300 and up to $7500 and the rest is manhours required to fabricate the fitments. NOT for the faint of heart

The Japanese option is a bit less brute force and more elegant but has the same potential. Again, motors are available [along with 5 speed manual trannies] with stock turbo packages that can start with 300BHP and go to 1000BHP [I don’t think I would try that one]. The motors can be bought for $2500 and the rest is manhours required to fabricate the fitments. NOT for the faint of heart.



Breath In, Breath Out Grasshopper
The quickest way to a bit more power [although not the 100-300BHP gains other options give is simply to increase the airflow in [a cold air induction system] and increase the airflow out [a more freeflow exhaust, new high performance Catalytic Converter and ditch the Resonator. It can be worth about 10%.

Trade UP
The last option, if you love the W124 body but hate the slow M103 is to find a good 400E [275BHP] or really go all out and get a 500E and your base HP is now at 320. For the money you spend on buying a transplant motor and fabricating all the fitments, UNLESS you are planning to go toward 500HP, your best bet is just find a 400E. You will same time, money and enjoy the engineering that Mercedes put into the very nice M119 motor.

[greasy_benz]

Hey what happen to the OM603??

That one is easy but still $$$

Send out your injection pump to myna diesel in finland to be upgraded.

Upgrade your turbo+up the boost, holset hx35 is supposed to plug and play with your stock exhaust manifold on the 603.

Add an intercooler

Upgrade the Rear differential from the stock 185mm to the 210mm differential. Any W124 that had a M104 or M119 engine will have a 210mm differential that will suit the extra HP

Stock transmissions cant hold up the tremendous amount of torque that moddified diesels put out. Which is why the stock 722.3 transmission moddified with the SL600 clutch pack will handle the extra power. Early 600SL/SL600 use the 722.362 transmission that have to deal with 389hp and 421 lb-ft. So they should be able to handle the extra power from the diesel.

Most of this was discussed on the Schuman Automotive forum in the 'super turbo' section.

DIESEL'S RULE!

[RBYCC]

Earlier this year installed one of the few remaining TurboTechnics UK twin turbo kits on a 63K mile M103-12V with 190-200PSI compression readings in all cylinders.
Kit included cast manifolds, chassis rail mounted intercooler, and twin Garrett T2 turbos set at a fixed 7LB boost.

Kit was a "bolt on" in many respects.
Modification and modernization to a kit built in 1992 produced a much better install.

Suspension was modified to accept the additional power.
Mods include H&R lowering springs ( about 1.5" drop ), Bilstein HD struts/shocks, Sportline front/rear swaybars, new motor mounts, Zimmerman cast drilled rotors/Textar pads, 18x8 ET35 AMG replica rims with 225/40-18 Falken FK452 rubber.

The main "additional power mod" was replacing the supplied piggy back fuel enrichment control with a stand alone 3D mappable computer programmed control by Split Second.
This controller allowed 12.5 AFR through boost.

The other significant mod was to replace the intake and boost coil hose with aluminum tube and smooth silicone hose and replacing the supplied Fram panel filter with a free flowing K&N panel filter.
A true cold air intake was obtained by drawing air from the intercooler plenum opening in the Wald EX spoiler, approximately where the stock tow hook cover is located.

Air in must equal exhaust out, so the exhaust system comprised of two x 2.5" down pipes to two inline Magnaflow spun metal cats ( #59954 ) then 2 x 2.5" pipes back to the supplied TurboTechnics rear silencer ( 2 x 2.5" in and 2 tips out )

Base line dyno ( Mustang load dyno ) was 136HP/146Torque against a published 177HP/188Torque.
This indicated a 30% drive train loss on the load dyno.
Keep in mind a load dyno reads typically about 18% lower then an inertia type dyno.

The basic kit install with the Split Second control produced 197HP/221Torque with the torque peak moved to 4250RPM from 4500RPM with HP peak remaining at 5500RPM.

The intake/boost/filter change was significant raising the numbers to 208HP@ 5200RPM and 239Torque @ 4000RPM.

Dyno pulls were done in 85 degree + ambient.
Cooler temps produce much more power.

To calculate flywheel HP we add back the 30% and factor in the 18% dyno difference as most tuners use inertia type dynos.
208HP x 1.3 x 1.18 = 320HP
239Torque x 1.3 x 1.18 = 367Torque.

The figures published by TurboTechnics in 1992 were 300HP/300Torque for the M103-12V.

Best 0-60 mph ( using G-Tech 3 axis accelerometer ) was 5.49 seconds in 90deg F ambient, pre intake/boost mod.
After intake/boost mod times were in the 5.2 second range.

This almost confirms the HP/torque readings based on a 3700 lb vehicle.

Failed to get to a 1/4 mile this year, but will do some runs when the track opens.
Estimating with 60deg F ambient, 0-60mph around 5.0 seconds and a 13.5-13.7 1/4 @ 100-104MPH.

Not inexpensive, professionally installed by one of the few tuners who is still familiar with the CIS-KE Bosch Ke-Jetronic III injection system.

Total cost including suspension, exhaust, TT kit install, motor mounts etc. was around $15K.
Manhours ran at 110.
This including a good bit of time figuring out mismatched parts and resolving issues in the supplied kit.
Could probably save 20-30 hours if done again.

Added 143HP and 179 torque which equates to about $100/HP.

Vehicle still is stock as far as settings of the CIS-KE unit and only change is under boost with enrichment via two additional injectors mounted between the air valve and throttle body.

I'm sure more HP can be produced from a M103-12V by converting to fully electronic injection and using larger turbos with higher boost.

This is not for me as I wanted a "period" install with a result of performance equal to a NA AMG V8, exceeding the 500E/E500 and the earlier Hammer and approaching the 6.0 Hammer.

Not bad for a 3.0L SOHC motor !!!

ORIGINAL INTAKE/BOOST PIPING



MODERNIZED PIPING





AIR FILTER COMPARISON



COLD AIR INTAKE PIPING



INTERCOOLER



SPLIT SECOND ADDITIONAL INJECTOR CONTROLLER



FINISHED PRODUCT !

[mcbear]

Nice writeup and thanks. Looks great also.

I did fail to mention the Diesel motor. I will stick that in the Post2 list in a bit.

[EvoGuy]

For the past couple of months I've been looking for a bolt on exhaust. I looked in Europe too, just no luck yet. My V8 sounds lame right now, I want to change that really bad!!! I looked on ebay.de and various websites but still nothing that's bolt on. There's tone of stuff for the 4 and 6 cilinders.

[RBYCC]

Originally Posted by EvoGuy

For the past couple of months I've been looking for a bolt on exhaust. I looked in Europe too, just no luck yet. My V8 sounds lame right now, I want to change that really bad!!! I looked on ebay.de and various websites but still nothing that's bolt on. There's tone of stuff for the 4 and 6 cilinders.

Check out local muffler shops who do custom work.
You might end up with a great exhaust system at a price much lower then you think.

Would suggest a true dual exhaust and using as I did on my M103-12V individual inline Magnaflow spun metal cats.
My system was semi custom, a combo of bolt on and TIG welded sections.

Consider 2" - 2.5" individual down pipes to the inline cats, then an x-pipe cross over to individual rear silencers.

Would take some layout based on routing and chassis clearance, but if you can do it on American iron, then it will work on a Merc.

[EvoGuy]

I here you, unfortunatelly I don't have the time to go and plan all this stuff. I just want to buy it and install it myself on a sunday morning! Plus I don't know if I can trust any muffler shop to do this! I would like to find one that has some history in building exhaust systems for Mercs.

[mcbear]

As I sent a note to EvoGuy, I am working on a CAT and back setup that is incorporating one of two exhausts at this point [Borla and MagnaFlow]. I have looked at the various euro exhausts and frankly they do not offer any value add to the mix. All they are is a XXXXX stock exhaust box with model specific fitments welded on the front and back to make installation easy to a specific form factor. Any of the aftermarket manufacturers [euro or domestic] have sufficient model sizes to provide a competent person with the ability to size up their car.

Once I get this system mounted up and dyno'ed again I will post model numbers of the "stock" parts. The big bogie is the bent pipe in the middle from the CAT to the EXHAUST if you remove the resonator [which I find makes a better sound, less restriction and saves some weight]. I will be making up about two dozen of those pipes, mandrel bent in stainless steel to make fitment easier for folks to either DIY or take to a shop.

I dyno tested a 3" diameter connector pipe with the high performance CATS and Borla EXHAUST and, while got a great growl, was disappointed with the torque band. I am recutting/bending a 2.5" pipe in the next couple of weeks to retest the car. I expect that the low end torque will increase across the band [picking up earlier]. For those wanting to run Bonneville and need the 175MPH top end, the 3" pipe would be YOUR better choice

Updates, recommended part numbers [borla v magnaflow] and availability of connector pipe as soon as they become available.

[RBYCC]

McBear

The main point of restriction is in the stock cat.

The Magnaflow spun metal cats as we have discussed for a while seem to give the most flow and still maintain emission control.

Many of the Euro kits just address the silencers, which over stock may sound better but provide no additional horsepower.

Agree that larger then a 2.5" pipe would be counter productive.

Best setup is just the individual high flow cats and a rear silencer ( two in the case of a V8)

Are you looking at an x-pipe in your system for balancing and scavenging ?

Ed A.