SLKV12TT

Hello Forum Members! Any help here would be appreciated.

I've just aquired a complete Twin Turbo/Intercooled V12 Merc motor with the intention of installing it in the current SLK. After taking many measurements of both the car and motor I believe fitment is possible.

Anyone know how robust the six speed manual transmission is from the 350?

Anyone try this conversion before?

Anyone familiar with the ECU programming of installing this OBD2 motor in another Merc OBD2 vehicle?

Thanks in advance for your help!

Militant-Grunt

I would imagine that your would need a very powerful flywheel and clutch inorder for the tranny to handle that torque. Im pretty sure you'd need a ECU out of a SL65 or CL65 or S65(assuming thats where the motor is from). Im pretty sure you'd be the first, a SLR motor was fit into a SLK before.

MercedesFTW

Post some pics of the engine please!

cantdriveonly55

That would be incredible!! With a Renntech ECU and custom exhaust you might be pushing 900 lb/ft(!) Make sure to keep us posted and get it out to the drag strip with some drag radials for a pass asap. The only manual that is easily available to handle the torque would be something like the Tremec T56 or whatever the newer version is used, a la Z06 and Viper. I suggest finding a MB 5 speed auto tranny from a 600/55/65 car to handle it instead. Can't imagine the 6 speed for a V6 to handle a TT V12. good luck and make sure to get some pictures up asap. get bigger brakes too

Shinigami

I know the 7G box takes about 700nm of continuous torque stress, and it's been said the manual can take something like 400nm or more...

SLKV12TT

Thanks! Definitely want to use a manual six speed: if not by Merc then the Viper T56 transmission. Would like to tune the motor for hp not so much torque given the SLK weighs at least a thousand pounds less than the SL65 and putting power down will not be easy. Pics of motor as soon as I get it in a place accessible for photos.

SLKV12TT

It's the "or more..." that I'm wondering about)

SLK55R

well it certainly will be an interesting project ... Good luck.

cantdriveonly55

Thing is the V12TT engine puts down more like 1000nm or more than twice the capacity of the 350's stick. I believe T56s are available from a lot of hot rod tuning companies for a couple thousand $s and can handle that kind of power and torque. Search around for them. In general, look into places that sell crate engines and crate trannies and you should find a suitable one. This is going to be one crazy SLK, might one up the SLR engined one.(!) Where are you located, I might want to pay you a visit sometime

HLG600

Sounds like an incredible project! Did you purchase the MB V12 motor or the AMG V12 motor?

In either case, you absolutely need to install a bulletproof LSD rear end to handle the massive power input.

Good luck.

FishtailnZ

The T-56 is a strong piece, but it's a BIG b@stard! You say the V12 can fit, but you might want to check on how much room you got left to fit a transmission like that! My previous car was an LS1 F-body (with a T-56) and there are several companies out there that specialize in making that unit even stronger - I know a few f-body owners that were putting down close to 1000hp on nitrous with a T-56, so it is strong enough. You just need the space to fit it!

P.S. Best of luck with the project - I'd LOVE to see the numbers such a car would put down!

Yellow R1

I believe that SLK will be too front end heavy & will be significantly traction "challenged" due to the balance disparity between the front & rear of the car. The problem will be exacerbated due to the car already being undertired - especially in the rear (I don't think anything larger than a 275 can be accomodated unless the sheetmetal is altered).

In any case, good luck! It will likely be a huge & time consuming project.

-Matt

SLKV12TT

I've already purchased a new T56 transmission. It is tad large but not that big. E.g. not much bigger or heavier than say an E46 M3 transmission and it will handle the power of a twin turbo V10 Viper motor so all should be good here! As for nose heavy you'd be surprised: First, Merc puts their motors too far forward to begin with IMO. As such there's several inches to move the standard motor backward. Second, the V12 is actually the lightest production 12 in the world. If I recall correctly only the Ferrari F50 motor weighs less, but not by much, and the Merc 12 is significantly shorter. I put this motor on a scale and with all accessories, minus the massive alternator (which will be replaced and weighs a ton!) the engine, exhaust, turbos, intercoolers, wiring harness, computer, etc, weighs just 520 pounds. My guess that's roughly what a fully dressed V8 weighs. Now move that back a few inches in the chassis and balance won't be as much of an issue as it may first appear. Tire size with stock flares would be limited to 275 to maybe 285 (rubbing). Fact is there's only about 285 mm of space inside the well itself. The Black series SLK has widened front flares so of course I intend to widen the rather wimpy looking rear flares to accomodate a bigger tire. (Pirelli makes a 355/25 19 )

I'm in LA. Anyone with expertise that wants to chime in with some advice please do so! Thanks in advance!

dinko

I'm in LA every now and then, would love to see the engine in the car! Keep us updated, this sounds really interesting.

Dinko

BoBcanada

Was it the engine from the ebay?

pshek

You will need a new ECU and a good programmer. You will definitely need an LSD, but you should wait til the engine and transmission is working first. Good luck. Who's doing the swap for you? I hope they know what they are doing and what they're getting into.

Marktini

Pictures!!!

SteveL

Hmmm... the 6.3 litre motor won't fit so I'd be shocked if the V12 will fit but good luck.

cantdriveonly55

You seriously rock with your courage and commitment. 355s might be overkill, but why the heck not? HRE will probably be the only way to go in order to get offset, bolt pattern, etc. and still lightness for the car. For my T56 suggestion, do I at least get a ride in the finished project? With a custom exhaust from the headers back for: (you name it) fit in the SLK, sound, lightness, etc should gain you power and lose some weight if it is well done and doesnt have as many millions of mufflers as a normal 600/maybach would have these days. Good shops should be able to do that for you. Custom fabricated for sound and power. Get some groovy big fat tips and youll be set! Keep us posted with pictures and news.

SL BRABUS

No way it can be done......!! If it could be done.....Brabus would already done it... ... Just my 2 cent....... Good luck.........

blackbenzz

Wow, this will be a monster project. Good luck though and I really hope you get it to work.

Shinigami

I'm thinking that cooling would be the biggest challenge with this... Apparently many of the larger engined MB's already need a bit more elaborate work to keep the engines from overheating. But good luck and do get it done, that would be quite funky

SLKV12TT

Hmmm... the 6.3 litre motor won't fit so I'd be shocked if the V12 will fit but good luck.

A 60 degree V12 is a bit narrower than a 90 V8! Cooling shouldn't be too much of an issue given this is a front engine car with front mounted radiator. May need larger water and oil coolers though and perhaps larger fan but will cross that bridge when I get there.

Thanks for words of support! As for exhaust, V12s really rule. There sound is so sweet and smooth you don't need as much muffling as say you would with a V8 or 4. I'm thinking a set of high flow metal based cats and seeing how she sounds! My Ferrari V8 with just cats is loud but not as bad as one might think. Here's my experience with high tech cats: They are lighter than mufflers (2.5-3.5 pounds), drop noise levels like a good performance muffler and they pass Cali emissions. Green and fast!

cantdriveonly55

I agree completely. With a nice exhaust it should sound purrrfect. (V12s do purr/growl) Anyways, are you getting a Brabus/AMG/Kleemann/etc body kit to spice up the look of the SLK, along with the big fat wheel/tire setup? What's your time frame?

AndrewAZ

Sounds like a good idea... But you are going to kill yourself.. Whats wrong with the SLK 55 with a supercharger on it? Just thinking about the cost you could probably buy an SLR.