Performance Upgrade List
 

New MB owner with 08 SL 55. Looking to put together punchlist of mods. Value ( ie $ spent for benefit derrived) and reliability impacts are my main keys. Not looking to improve handling at this point.

For those who have experience, what would be your top 3 mod elements to implement and in what order? Additionally, as I'm located in NC, I'd appreciate tuner recommendations as I'm not a DIY individual.

Thanks in advance for your input. I appreciate it

Bill

Hi Bill, here is my take on what you want to do:

1. Make sure engine is maintained with fluids/plugs/original parts and working properly.
2. Leave it stock.
3. Enjoy.

I can tell you that I went through the same exercise that you are wanting to do with mods. The 2008 SL55 runs pretty dang good as it came from the factory. Sorry to the aftermarket companies as they all help us get what we want, but my feeling is leave it stock. It is an incredible car as it came from the factory.

I performed a pulley swap, tune, additional HE, colder plugs, etc. For me, the performance increase was negligible for my use of the car - see stock and tuned dyno charts. My car is well sorted and the tune is very safe. I spent a lot of time researching and spending money - which is what us hot rodders like to do. I gained knowledge from this which is probably the most benefit that I gained from this work. You can't learn anything unless you experience the process. I'm sure I could tweak my car to make more power with these mods to make a better performance impact. The tune is critical and you have to spend time with the tuning process to achieve this.

If you want to make mods here are my three items:

1. Do a baseline dyno and then after tune, do a dyno on the same machine with same conditions (temp, humidity, fuel, etc.).
2. Pulley upgrade will get you the most bang for your buck - make sure that you modify the intercooler system to effectively deal with added boost pressures.
3. Item #2 coupled with a good tune from a reputable company is key.

Best Regards - Greg

https://cimg0.ibsrv.net/gimg/www.mbw...b978bae19c.jpg
https://cimg3.ibsrv.net/gimg/www.mbw...5fa8493549.jpg

Thanks for that feedback Greg, I appreciate it.

I've got a Holden Commodore SSV, has the 6.2L LS3( NA). With a CAI, tune and headers I picked up almost 60 HP and 65ft lbs TQ, both now 400 at the rear wheel.

I was hoping to get 15-20% improvement with the 5.4L SC engine doing similar tweaks. Perhaps that's not the right approach and that's why I'm asking.

Thanks again.

Bill

The after tune results showed gains of 38 HP & 100 TQ over the stock Mercedes Benz quoted engine output, figuring 15% drivetrain loss at rear wheels. The baseline dyno showed a little more HP and a lot more TQ than advertised by MB (again using 15% drivetrain loss) - which is why I suggested running on the same dyno before and after to more accurately discern differences. I used two different dynos at different times of the year for base line and after tune results.

I did achieve over 500 RWHP on a pull, but subsequently tuned more safe at the same dyno session. I think 500 RWHP is about max before you start changing things substantially.

Another item that will enable more power is headers. A lot of people say to do this first.

Bill,

When I got my SL55 I had a new 83MM pulley, IC pump, RaceIQ tune, and lowering links upgrades done. The pump was just the Bosch upgrade of the stock pump - no separate IC cooling circuit added. This got me up to about 530 HP and 610 Tq - that's just an estimate as I never bothered to get it dynoed. This is about the max you can do without having to upgrade the IC cooling.

Pulley was $500 plus $240 for R&R. Tune was $300.

IC Pump $145 plus $120 for R&R. I also had the coolant flushed at the same time.

Lowering links are a cheap and easy mod and I think improves the look and handling. Lowering links are about $100 off eBay plus a front and rear alignment for another $360 in labor.

I also put a modified front grill on for a 1-slat look over the stock 4-slat grill.

From what I understand the exhaust itself is not very restrictive. The biggest bang for the buck exhaust wise is long-tube headers. Definitely not cheap but a good mod (~$5k). Helps with heat in the engine bay, too.

Best bang for the buck mods are pulley(83 or 78mm) and tune. Then upgrade the cooling(especially if your going 78mm). 83MM is usually fine stock cooling.

If you got a little cash long tube headers do wonders on these cars. MBH your looking at a solid 45HP gain and helps your cooling out also. Your looking at about $2800 for the headers and probably another $1500 for install and exhaust work to hook it all up. So it isn't cheap. Eurosport makes some mid headers for around $700 but I think the installer may need to bend them slightly(could be wrong maybe I'm thinking of a different model). If you don't want to mess with all that have a shop cut the resonators out for about $200 if not less and it will create a nice sound without being that loud. Think about a 3 to 4 decibels higher than stock with a little more rumble in it.

So guys, I'm finally ready to pull the trigger on headers. My goal is to improve the sound of my 08 55 plus enjoy the hp and tq gaines that come from improving exhaust gas flow. I have had my car dyno'd so I know the car's
starting point (see attached).

My dilema is determining if long tube vs. mid length headers are worth the added cost. The MBH product looks beautiful but costs 3X that of mid length options sold by Companies like Eurocharged.

Does anyone out there have experience with both product types, and if so, what was your experience?

Thanks!

Bill

You will not be sorry going with the full length headers if power is what you are after. It will support the flow of the additional mods if you decide to do any. Your best bet is to review the W211 E55 section since all of this has been posted and that section is an excellent source of nodding information for the M113k.

If I ever got headers for my SL55 - they would be MBH, hands down.

Loving the talk here, is there a long tube option for the V12? I guess you could cut out resonators but I would rather work to keep the engine cooler (show vs. function). A quick search lead me to that one guy who added headers to his S600 in Japan but I don't want to ship my car halfway across the world haha

You have a 2005 SL65? If so, you have turbo manifolds a d not headers. You would need to make turbo manifolds but you would not want to move them far from the heads

Because it is not naturally aspirated, I got it (rookie mechanic at best learning as I go here)

So the only "noise gains" would be from modifying the exhaust on a V12TT? Turbos keep the engine pretty quiet I have noticed. I was hoping to be able to achieve that Pagani Zonda sound from my engine but alas maybe not possible.

Downpipes, 200 cell metal cats, and straight pipes back to the exhaust tips. Also, do the Racehorse intake. You will love the new sound.

oppps wrong forum

looked the list on what you done, Did not se anything about bigger trottle body ?