SL55/63/65/R230 AMG: Performance Upgrade List



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
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



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
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.



500 hp is about perfect for the street, that’s according to my friend who lives next door to Richard Petty. His sweet spot I’m told is the 500-550 hp range depending on a few variables.
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.
Last edited by 57staff; Feb 2, 2019 at 07:30 PM.



I assume the improved hp and tq estimates are at the flywheel? Certainly significant improvement on the tq front either way (= quickness!).
How restricted are our cars in stock form as far as dealing with exhaust? Would you expect measurable gains to hp with say the mbh setup?
The lowering link idea makes perfect sense,get the mass lower to the ground. I read somewhere that the cars are already pretty low, any issues front end scrapping? Do you have any pics posted?
My first mod will be a paint correction and ceramic seal. I’m about to retire to FL and have plans to keep this car for the “duration”!
Thanks for all the help
Bill
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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.



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








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.




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.



