I am quite sure this has been discussed in the past, but not recently. I have noticed more SL55's in the 10's recently (all motor). Here is a video of a SL55 walking a modified SL65 at the speedway.


Then again an SL55 pulling a 10.7 in the quarter.


About 10 years ago, this wasn't the case. Just curious because I have owned both r230's fully built, but unfortunately not at the same time. The 2006 SL65 I had was fully tuned, custom intakes, turbo downpipes, and no exhaust, and it pulls like a freight train. My 2006 SL55 with LT headers, larger intercooler/pump, Kleeman crank pulley 168, and smaller supercharger pulley, 82mm tb, belt rap kit, colder plugs, custom exhaust, cat delete, etc.. rips your head off. It's so hard to tell which one is quicker. Anyways, I have the chance to get another SL65 and was just curious of other members thoughts on these vids, and if the platform for the SL55 has been somewhat underrated for years. Owning both cars fully modified, it seems the SL55 is slightly faster. I just prefer the SL55 for it's bank vault reliable M113 engine and 722.6 trans, and it's just seems like more and more mods have come to the forefront for these engines, 90mm tb, smaller supercharger pulley. I was always worried with the 65, that if the Turbo's went it would be a $10k plus fix, then you have the coil packs etc.. Anyways any input is appreciated.

 

My answer is above lol,you forgot to mention the nightmare of putting in motor mounts in the 65

 

Yeah, motor mounts are stupid on the 65, my daily ML55 with 170k miles is on original motor mounts. It's strange not many video's of 65's vs 55's. The only other mod I wan't is a 90mm tb, have you done one?

 

Problem is, fully modified SL65 (bigger Turbos) are very rare and don't post much results. Assuming you can get more than 900 HP Crank HP out of the 65, which has been achieved, the 65 should be a LOT faster if there is enough road for a comparison.

Also keep in mind that 55K has approx.80-100 HP parasitic losses from the blower and INMO the 55K is maxed out a lot before 900 Crank-HP.

 

I completely agree once larger turbo's are put on, the ceiling is raised, but until that point I think they are pretty even when both modified. Larger turbo's pretty much require dropping the engine for install and a nice chunk of change over $16k. I guess it's apple's to oranges, but the value of the SL55 seems to outweigh the potential benefit of the top end speed of the SL65. Both are such formidable powerhouses, and I don't think most ever saw the SL55 as competition for the SL65. I wonder since, it's been 10 years for the SL65 and about 12 years for the SL55, which one has proven more reliable?

 

I'm sure it has to do with the combined factors of:

There are more SL55's out there to begin with

SL55's are generally less expensive to buy than 65's

SL55's are *generally* considered less expensive to maintain (IE motor mounts, coil packs, etc) I'm not saying it's gospel but, it's a general belief that likely holds true

SL65's are capable of amazing power but, turbo upgrades are a big dollar item. It's less expensive to modify a SL55 **not to the limit of a fully modified 65 but, to get it close the 55 is quite a bit less expensive*

Let's say worse case I grenade my 55 engine. I see them on Ebay and they seem quite reasonably priced (IIRC $6,000 or so, maybe a bit less depending on miles). The 55 engine seems relatively common considering what it is.

A 65 engine? that's a whole other league.
I'm sure each of these factors come into play.

 

They have both proven to be incredibly robust engines. Both A+ reliability. I don't think someone could say one is more reliable than the other as neither has any inherent weaknesses (internals).

 

That's kind of what I have been hearing, m113, m275 are pretty bank vault reliable. I think I am getting talked out of getting another 65, lol . It's kind of what I kept replaying in my head, but it's nice to hear it from others. I would probably jump right on this 65, if it where not for the pending doom of motor mounts, and coil packs. My E55 was reliable for 5 years, and I think the SL55 will continue this streak, and I love that I can use the same oil filters from my ML55's and the tranni service is identical. I just got done installing a HPS supercharger kit on my ML55, and it feels like a stock E55. I just love having coil overs and the same combo in a truck form. I really think the m113 and 722.6 are the best combo ever to come out of Mercedes. Like those late 80's model diesels, you can't break them. Warranties after factory are ridiculous, and I DIY most everything myself(except motor mounts). If I wanted a car with a reliability issues I would go back to BMW.

On a side note VTVette your procedure for ABC is spot on, I think a lot less people would have problems if they did this every 20-40k miles. Valve blockage and dirty oil lead to these expensive repairs, it only cost about a $100.00 in fluid, and takes no more than 20 minutes. It saved me huge money, when I first got my SL600 and then 65 I had red dash lights, performed this procedure and never had a problem again. I read your post over 2 years ago and it was invaluable to say the least. So thanks .

 

All this sounds great until you add up the costs of all these mods and unfortunately one can quickly run up a bill that costs more than the car and ends up decreasing the value of the car over a bone stock or slightly modified car.

 

It's very expensive to get the 55 to the level of the bi-turbo v12's. A simple and relatively inexpensive ECU tune will get you to over 500 RWHP on a 600 and around 550 RWHP on a 65. To get to that level on a 55k motor, you are going to need to drop much more money than a simple ECU tune. If you spend the amount of money it will take to get a 55k to 500+ RWHP, you can take that money and get a 65k to 600+ RHWP.

 

There is also the factor of how fast does one really need to get to coffee with the guys. I've had allot of very fast cars and frankly, for all intents and purposes (except for bragging rights), these cars are more than fast enough right out of the box.

From my perspective, I just wanted to get rid of the speed limiter. That lead me to create an ECU tuning business. I've had my 55 in various states of tune over the years (from stock to well over 600hp) and I've always settled on around 550 being more than adequate.... but with no limiter. Even with free reign, I've only Vmaxed it twice in 13 years... and it will do 200+!

For me it's more about the corners, and the 55 handles surprisingly well for what it is. I've been out with a fellow instructors and run similar lap times to a Z06... until the brakes gave up the ghost, which is a testament to what AMG was able to do with what is essentially a fast cruiser.

Over on another forum I always hear how 'slow' the Challenge Stradale is. Well, I'm faster around a track with it than my old F40 and has no problem outrunning the 55 in a straight line. As an instructor, I heard all the, "I need more power" over the years. Based on that, I would have figured that talent and ability (not reliance on computer nannies) would have increased...... but sadly, it hasn't!

 

I have owned both the SL55 and an SL65 even at the same time for a very short period.

There is absolutely NO comparison between the two cars. The effortless Torque generated by the M275 V12 engine is amazing! Even after ECU tunes and upgrades in both cars the SL65 is soooo much faster.

The SL65 broke the tires loose at over 60 MPH while starting to fishtail... Roll on just a tiny bit too much throttle and the rear tires light up like a Top Fuel Dragster. Definitely Fun but not safe. I actually asked to have the ECU tune dialed DOWN just a bit to make the car more drivable. I never had too much power in the SL55 nor have I heard anyone ever mention this.

Plus the suspension and brakes on the SL65 are radically better! (unless you have the ultra rare 030 SL55 package)

I thought the SL55 was under braked for doing high speed canyon runs... I experienced severe brake fade in the 55 several times!! Never happens with the huge 8 piston Brembo Calipers and 390mm Rotors on the SL65.

I few years ago I had access to the online MB parts data base. I spent several hours just checking to see what parts were specific to the SL65. I was amazed to learn that there are 50-100 chassis and driveline parts that are SL65 ONLY! Not Black Series just standard R230 SL65...

AMG upgraded things on the SL65 like Hubs,Bearings and lots of other parts. Although things in the suspension look the same between the 55 and 65 the part numbers are different.


The SL65 does have a few issues!

Motor Mounts are a total BYTCH! But luckily they last 35,000-40,000 miles+/- so it is not a constant problem... The Coil Packs are a problem at the same milage and the replacements have been upgraded (Supposedly) by Mercedes so they might no longer be a problem?? I have not heard about failures in the Coil Packs ending with 07 and 08.

I have also not heard about Turbos failing and the SL65. Turbos have been around since the 1970s in diesels and those engines can go 300,000 miles. Also the SL65 has the same motor as in the CL65/S65 so there are a few wrecked 65s around. I did buy a pair of spare 65 turbos for $500 just in case but doubt I will ever need them.

All the ABC and other R230 issues are common between the cars!

So with the SL65 as they say... You want to Play?... You have to Pay!

 

I have had a SL55 and 2 SL65's. There isn't much between them really,
a little more power in the 65 but then you can tune a SL55, but then
you can also tune the 65. The 55 feels more nimble and the 65 feels
heavy, and what let's it down is the 65 gearbox. It needs a MCT box,
then it would fly. 65's are getting cheap so why spend the dosh.
S8

 

In my opinion, stock SL65 if way faster then a stock SL55, I owned a 06 E55 with a tune and smaller S/C pulley and I pulled away from every SL55 I raced. E55 was lighter and more hp. Once I bought my SL65 I noticed how underpowered 55K engine was unless you did a lot of mods. SL65 just takes my breath away every time a step on it little harder. I didn't feel that way in my E55.

 

Sl65 just went 9s so ya they are fast

 

I know an SL600 went 9's but I didn't see where an SL65 did?

 

Sorry, yes sl600

 

 

Yes, that was noted in a few spirited posts with the guy working for Speedriven trying to sell his wares and pass the car off as the greatest MB tuner achievement ever. I wanted to get the upgraded turbos on my car but they seemed sketchy and the guy working for them was intolerable. Looking back and reading about cars sitting for years and then the guy who paid a fortune for his plagued CL65 big turbo build cemented my decision not to send them my car.