JLBMERC

I just had the RENNtech ECU and pulley upgrade done on Monday. Given I am still in break in, I have not pushed the car hard for very long---but there is a noticeable difference--an improvement in acceleration--even at less than full throttle.

We were unable to dyno the car before and after despite attempting to do so. Apparently, according the installer, the car sensed the imbalance in speed btwn front and back tires and would not allow a full run. We attempted several go-arounds to no avail. Apparently , some piece of equipment is required to fool the computer that we did not have access to.

Despite not having hard numbers, there is no doubt of the improvement in acceleration.

The mod was farily easy---the ECU is easily accessible, however, the pulley took a little while to get off.

All in all, a more or less painless process and noticeable acceleration improvement. BTW, I also did the intake mod as described by Stephens---I used the s500 intake tube.

While the car was on the lift, we tried some RENNtech 19x10 rear wheels, it was obvious that these would not fit without a lot of work. I am currently leaning toward the Brabus Monoblock VI's.

I will post some pics shortly, have to clean them up.

kaneman

Where did you get the mods installed and how much did it run? I might get this done as Houston's only a very short drive away.

Poursha

Doesn't this void the MB warranty? I can't imagine wanting more power with my '03 E55 enough to risk that.

alz

It looks nice

Dr Chill

The warranty will likely still be valid for two reasons:

1) To determine the ECU was modified would take quite a bit of investigative work by the service dept and the pulley looks indistinguishable from the original except that it is slightly larger.

2) Many dealers offer Renntech mods as dealer installed options.

JLBMERC

Poursha,

You have a legit point, I run that risk---but it is one that I am comfortable with---for the reasons listed by Dr Chill---and the increase in power/boost is really not that extreme.

I look at this mod as well as the others I have done or will do-- as part of the fun of owning the car---and making it my "personal" car. But Hey, the car as stock is great--no doubt.

Kaneman,

I got it done at Memorial One on I-10--near the Wirt exit. I would recommend them--talk to Jergen.

Poursha

Pewter silver--love it!

Poursha

I've enjoyed making mods to my many cars over the years as well--to put my own personal mark on them--so I know what you mean. Call me chicken, but on these very expensive cars, I've always avoided anything that could void the warranty.

Dr Chill

I'd make the mods in a heartbeat-That is if I found a spare 5 grand sitting around.

blando

On the C32, we can put the car in DYNO mode - it completely shuts down BAS, ABS, and ESP. The procedure is probably not the same for the E55, but on the C32, you press the trip reset for about 40 seconds with the key in the number 1 position. That brings up an additional menu screen that gives you the dyno setting along with additional engine info. You can get a numeric reading on the oil level there as well - down to a tenth of a quart (useful for oil changes.)

Is Memorial One a MB dealer/service facility? Let us know if the dealer picks up on the enhancements if/when you go in for service...

Congrats on the upgrade!

vraa

You are soo kidding right?! You live in Houston too?! Man, we gotta hook up sometime!

btw: AWESOME CAR! Off the roof, or whatever us kids say these days.

blando

Good points Dr. Chill.

Do you think the black box will register the chip change?

Can't you change the pulley back if you ever had to go in for something major?

What's the downside to the pulley/chip mods? Poor fuel consumption? If the extra HP is this easy, why didn't AMG dial it in? Is it out of concern for the additional boost?

Dr Chill

I have no idea why AMG didn't do this in the first place but I suspect gas mileage is the reason. The pulley will never need to come off because unless you hold a stock one right next to the RENNtech pulley the two would look the same. $5000 is a lot of money for an ECU reprogramming and pulley-too much to make it worthwhile unless money is not an issue.

blando

I was thinking you might have to swap the pulley back or they'll see the additional boost when they look at the diagnostic data (OBD.)

Maybe I'm just paranoid...

JLBMERC

Some pics of the the pulleys--the new pulley on the left

JLBMERC

This is where the ECU is located---when facing the front of the car---on the upper right hand side. Note the cover and the ECU has been removed --the related connectors are visible

JLBMERC

This is the modified ECU about to be installed

JLBMERC

New performance air filters (Green) being installed

JLBMERC

I also purchased an S500 air inlet tube or intake tube--whatever the name is--Stephens discussed this earlier---note the difference--stock tube below S500 tube.

Bones

JLBMER : Do you know what Renntech quoted for the power gains for the ECU and the larger pulley. Also, how much for these upgrades.

Thank you

stephens

JLBMERC
Did you measure the two pulleys, to determine the amount of overdrive being produced?

JLBMERC

Stephens,

I did not measure the pulleys---just put them side by side for a comparison. Per RENNtech---the pulley change will increase the spin by approx 10% and boost in the 2 to 3 pound range. BTW, please post a pic of your F1 safety steering wheel when you get it. I am thinking about making this change as well.

Bones,

The RENNtech mods are supposed to put out 40 hp and 45 lbs/ft of torque--cost approx $5k. Sport exhaust is not yet available. Go to their website for more info--www.RENNtechmercedes.com

JAYCL600

PLEASE DYNO AND TRACK TEST!!!!!!!!!!!!!!!!!!!!!!!

JLBMERC

E55JAY,

I tried to dyno and could not get a full run --the car sensed an imbalance btwn the front and back wheels and shut down---the mechanic and dyno operators could not get around it. If I can figure out how to, I will. Nevertheless, my butt-o-meter tells me it was worth it.

blando

Did you ever find out if the E55 has a DYNO mode (like the C32) that will allow you to disable the ESP?

That would take care of the dyno problem.