I have installed my Renntech ECU flash (530 HP, 606 TQ) and completed a fair amount of performance testing. There is no doubt the car makes more power, but regretfully the car is consistently slower due to traction issues as shown in both my 0 - 60 and 1/8 mile times.

Conditions:
All the testing has taken place on the exact same stretch of flat road at night with just me in the car.
I am using a Solo DL timer ($700) which uses multiple satellites (looks like 13) to measure performance.
I previously tested the car by selecting the Sport transmission setting, turning off ECO, pointing the car in a straight line, AC off and smashing the gas. Using this method I have NOT been able to post as quick of times in either 0 - 60 or 1/8 mile (basically 0 - 90) tests even after many (15+) attempts.

The car definitely make more power as shown by the traction light coming on much more easily and frequently and it feels like stronger acceleration when it is getting traction.

O - 60
BEFORE: 4.27, 4.28, 4.27 as my best times, but also 4.51. I threw out a few times which were just bad runs due to traction or hesitation for whatever reason. I was consistently getting upper 4.2x as my fastest times. Back to back 4.27, 4.28, 4.27.

AFTER: 4.24, 4.4, 4.38, 4.45 I notice that the traction light keeps coming on significantly more both from the start and especially between 1st and 2nd gears. No acceleration times in 4.2x until after numerous attempts of trying to progressively press the accelerator until in 2nd gear and then smashing it to the floor. Using this technique, I was FINALLY one time able to post a quicker time of 4.24. I just started trying this acceleration technique and not very proficient at it yet. However, I do believe I will be able to take time off my now best 0 - 60 run of 4.24 with a little practice. This technique is not easy to do whereas before I could just smash the accelerator to get my best times.

1/8 mile
BEFORE 8.41, 8.42, 8.42
AFTER 8.46, 8.57, 8.6 I have not yet run that many 1/8 mile tests post flash. I have not tried my new progressively accelerating technique on any 1/8 miles runs. I ran these test with the same method I used pre-flash mentioned above - straight line, slash the gas. I expected on a run where I reached 90 mph, the loss of traction from the start would more than be made up for and it would show in quicker acceleration times however that has not been the case. I have yet to come close to beating my pre-flash 1/8 miles acceleration times. Probably eight or so post flash 1/8 mile runs attempted and the above three are my best post-flash times to date. I will try a few progressively accelerating trying to avoid wheel spin and suspect that my times will improve.

Overall impression
It really does not drive that much differently. If anything it pulled a little harder pre-flash off the line 0 - 30 since much less wheel spin. Post flash, when I hit the gas going 30+ it pulls harder. It definitely makes more power however I do not believe it is usable power and would not recommend the flash unless your goal is faster 60 - 130 mph times.

 

 

Thank you very much for the detail. I wondered about that. You might have to upgrade the tires to get the benefit. One of my friends upped his Z06 to 700 hp and was unable to put it to the ground without proper tires.

Again, thanks for the feedback.

 

You're welcome Centexhokie, glad to help.

 

Thank you, you just saved me some money. I was thinking about doing this but wanted to see your results.

 

After another week or so of driving the car post-flash, I have made another eight attempts at 0 - 60 and regretfully nothing in the 4.2x range. I tried using a progressive accelerating technique but it's difficult to not hit the gas so hard that you lose traction yet hard enough to get your best time.

 

What tires do you have? My friend with the Z06 had to go to a drag slick to take advantage of his hp, but I would think that a softer compound might allow you to hook up the car.

 

I am probably not going to put slicks on my SL550.

 

Yeah, I wouldn't either, but I would think there might be some non-slick with a softer compound that could help ericnaustin with his new hp without having to go to a drag slick. Just a thought since he has been so helpfult to us in testing this out.

Maybe something like this

http://www.michelinman.com/US/en/tir...ort-cup-2.html

if you can get them in the right size.

 

Sounds like you would have been better to spend the money on a proper LSD and some Michelin pilot sport cup 2 tyres.

Good to have this kind of feedback. Well done on the tests.

 

Not sure what an LSD is?
Yes, planning to go with the Michelin Pilot Sport Cup 2.
I will re-test after tire change and and post results.

 

Limited Slip Diff, I think the R231 only comes with an electronic diff. It enables the power to be distributed properly between the two rear wheels to get better traction.

 

LSD's are available (standard) only on the R231 AMG models. A good set of tires will be a great improvement in runflats are used. I use Michelin Pilot Super Sports and love them

 

So I spoke with Renntech about a LSD and it is approximately $5500. Suspect another $1000 minimum to remove and then reinstall. Plus this would not be something I could return to stock should I have transmission issues down the road. The car is a little more fun to drive post flash, but I rarely accelerate hard enough to spin the tires. Just not interested in turning what I believed to be a quick and easy 3K improvement into a 10K project. Next time I will just buy the SL63.

When it's time to replace my rear tires, I will go with the Michelin Pilot Sports and re-test.

 

Smart call. I have an employee who bought a 2005 Z06 and he has been chasing upgrades now for a year. He has upped it to 800+ hp and gone to drag slicks for the strip. Every upgrade seems to require another upgrade to take full advantage of the last upgrade. I know it is over $10K, but I don't want to ask him how much as I know it has gone from fun to a frustration.

I look forward to seeing what the Michelin Pilot Sports do for you.

 

You can get a quaife LSD for 1/3 of that price and is probably a superior unit.

 

I just ordered Renntech stainless mufflers. Although I am doing it strictly for the great sound, Renntech states a performance increase +15 HP and +20 TQ. We will see if that actually translates into quicker acceleration or not.....
I am working with a reputable local performance shop and will see what else they recommended after installing mufflers. Planning to have them dyno the car and I will re-test 0 - 60 and 1/8 miles times and post my results.

 

Does the SL63 comes with a LSD?

 

I believe so.

 

Getting Renntech mufflers installed tomorrow by Moorespeed here in Austin, TX. Will have them dyno my SL as well. With ECU, filters and mufflers, according to the marketing materials from Renntech, I should be at between 530 - 545 HP.
I will start a new thread and post dyno graph and notes on how it drives. Will also talk with Moorespeed about my issues hooking up and what the recommend.

 

Mufflers really sound nice! Not too loud just a good tone. Very high quality construction.
Guys at Moorespeed drove my SL and believe it is making big HP vs stock. They pointed out a very obvious traction control switch on the dash that I overlooked. Recommended that I re-try my 0 - 60 times with the traction control off and feathering the throttle. I will re-run and post times. Also recommended that I go with wider Michelin Pilot Super Sport 305 30 in back and 265 30 front.

Their dyno waiting on a city permit, so no testing yet.

 

The wider front tyre is more important than the rear as the SL is set up for massive understeer.

 

I have done the Renntech high performance ecu update as well, but went with GTHAUS - Meisterschaft Performance Exhaust Systems for the SL. (what a sound, I luv it, it sounds a lot better than my S63 with same setup...)

Never did the testing like you did and don't have a friend that I could borrow the solo dl, but can definitely tell the big HP gain, and wheel spin, especially, when you are at red light when green is on try to give little gas i get the wheel spin, ooh well, comes with the territory....definitely will change the tires to Michelins, softer compound, when it's time, did it on S63, i like it alot....

I did ordered the K&N filters for both cars but changed my mind & returned them, i read some reviews that they do let more air in, but they also may let small particles come thru as well, just didnt wanna take that small risk.

GREAT REVIEW, KEEP IT UP, THNX.

HAPPY NEW YEAR TO ALL...

 

Any updates, Eric?

If you haven't put a softer tire on yet, you aren't going to net any benefit in 0-60 times, as you have meticulously documented.

The thing to measure would be 60-130 times pre/post mods, or a full 1/4 mile ET/MPH.

Frankly, there's really no point in trying to shave a few 10ths off your 0-60 in a car like that. My wife has a '13 SL as well, and it's plenty entertaining, but if you want rocket like acceleration off the line in a comfy daily driver, you need a Tesla P85D.

 

Updates:
Renntech has changed the ECU upgrade program for the M278 and it's now producing 540 HP and 705 TQ. This is 10 HP and 99 LB-FT more than the previous version.

I emailed Renntech and they allow for free upgrades for three years from the date of initial purchased. I sent in my ECU and just received it back today.

I have also just replaced the tires on my car with Michelin Pilot Super Sports.
Modifications now include: Renntech mufflers, ECU flash and BMC air filters.

I will be re-running my 0 - 60 and standing 1/8 miles tests this week in the same location with the same meter and will post the results.