StephenK

I have given some consideration to Renntech Upgrades over the past year, but thru readings have not been able to be convinced about it. I emailed them this morning and here is what they provided me. Curuious about what you think.

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Good morning, this past weekend I took delivery of my 06 SL600 from Brumos in Jacksonville. I understand they are a Renntech representative. Thru various forums online, auto enthuisiats have given the Renntech upgrade mixed results. I am interested in finding out more details, and also some hard evidence of exactly what to expect from the upgrades, and what upgrades will produce what kind of results. Thanks for any information you can provide me.


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Their Reply:

First time I have ever heard our V12 upgrades getting mixed results. We have done hundreds of V12 in the US and in Germany and the performance is outstanding, no other tuner has been able to touch us especially on the track. Not only do we get more power from the engine, but we take the extra step of putting the AMG 65 transmission program in the transmission computer, this gives you faster shifting, 3 modes in the transmission and a top speed of 186. All you need to do is remove the engine computer and the transmission computer and send them to us, we need them for a day, full instructions are on our web site. The price is $6400 plus return shipping.

You might want to give Ben Traynor a call XXX-XXX-XXXX. His 2003 S600 stock did the 1/4 mile in 12.4 and after he modified it he did 11.7 with stock tires and 11.5 with drag radials, he has now moved up to a SL65 which we also modified for him.

The stock V12's have a bit more power than Mercedes calims, we constantly see between 440 and 460 HP at the wheels (drive train loss is about 19%), an SL55 only produces about 400.
The following is a dyno chart of a very strong V12.

Bob Brady

Chas Jr

I have to agree I have never heard of "Mixed Feelings" about the upgrade on a 600..Having done it personally to my car I still stand by the "Difference is Night and Day" description I said when I did it several months ago..Do it you will not be dissapointed..

StephenK

Do you mind telling me exactly what upgrades you did?

Also what differences do you actually notice?

Is it a real kick in the pants difference, say like driving a standard SL500 then driving a standard SL600?

v8plus4

Steven, would you mind asking them about their warranty, and whether their mods void the factory warranty?

StephenK

I actually just sent them an email about this.

StephenK

I think what I need to do is find someone with the car actually upgraded and make a comparison with mine. Anyone with this upgrade remotely near north/central florida that would consider this??

Chas Jr

I did pretty much the only thing they offer for the 600 the ECU and Tranny upgrade..You will feel a BIG kick in the pants difference..You will FEEL the difference..Just do it you will NOT be dissapointed..

StephenK

Bob at Renntechs reply about the warranty:

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As with any modification made to your car, as long as the modifications can not be traced to causing a problem, you will keep your warranty.

Our programming is not detectable by Mercedes and we can always put the computers back to stock at any time.

Over the past 3 years we have not had any problems with the V12's.

Bob

RadSteve

The ability to do this simple upgrade was one of the reasons I chose to purchase the SL600 in the first place, and I'm gonna do it as soon as there are about 500 more miles on the odometer...that shouldn't take long. Have not heard ONE complaint about the upgrade on any of the boards I monitor. I'd say GO FOR IT! (specially since they're in FL and you won't have to even do it yourself

NOTKTS

Here is what C&D thought about it when they tested in in the 04' Supercar Challange.....
Review: http://www.caranddriver.com/article....&page_number=5
Specs and Pricing: http://www.caranddriver.com/article....page_number=13
Complete Run Results: http://www.caranddriver.com/article....page_number=13

sillydriver

Perhaps some of my comments about the upgrade are included among the ‘mixed results,’ for example

https://mbworld.org/forums/showpost....7&postcount=45

Although I’ve tried to be honest about your having to be easy with your right foot as you drive the modified car, I want to be clear that I’m very happy with the upgrade and would do it all over again. I’ve driven my Renntech SL600 15,000 miles in a little over a year and have had no problems. My greatest reservation concerns do-it-yourself installation, but that concern goes away if you have a dealer do it.

StephenK

Bob with Renntech seems like a real dufus!

You can't get a straight answer out of him!

I am left with the feeling of "caveat emptor".

RadSteve

I should be up with the break-in period in a couple weeks, and I'll let you know how it all goes, even the do-it-yourself part.

NOTKTS

This is my personal experience with him...
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We only claim 625 HP, that would be about 500 HP at the wheels, we are very conservative, may of the cars we have done have gotten as high as 520 at the wheels and that would be over 640 HP. All the same programming but some car do a little better than others.

At present there is nothing on the engine that will indicate it has been modified.

We will have some time in the future an air box that will be carbon fiber and give about 15 HP, pricing when it is released will be about $4000.

Bob
----- Original Message ----- From: "Andrew XXXX"
<XXXXX@hotmail.com>
To: <bobb@renntechmercedes.com>
Sent: Saturday, May 21, 2005 6:51 PM
Subject: SL600 ECU and Trans Upgrade Question
Hello, I have recently come across one RennTech SL600 after a co-woker has asked me to look into 600s for him…. But this one claims to have 640HP. I have here the link to the auction http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW. …
My question comes from this your website only claims 625HP where are they getting this 15 extra Hp? I've asked them and it doesn't currently have any other mods like an exhaust.
Sincerely, Andrew

RennTechV12

I got the RennTech ECU upgrade and TransModule, as well as Eisenhaus exhaust for my '04 SL600. Pre RennTech Dyno (at the flywheel) was: 538hp/608lb/ft. After the upgrade it made 632hp & 782lb/ft. I run my car here at Firebird Raceway regularly and on drag radials with 100 octane fuel, my best 1/4 mile time was 11.78@119.45mph.

DO THE RENNTECH UPGRADE!!!!! My car is scary fast now. You won't be sorry!!

NOTKTS

I love the GR5s on a SL... Really nice car

StephenK

It will be good to hear your opinions on the upgrades.

craiglieberman

Guys.,...there's another option.

Jonari USA (www.jonari.com) sells the same ECU upgrade....for less.

I won't get into details, but call Jon Pek over at Jonari. I've known Jon for years, and you will NOT be disappointed.

Trimmer2

I have over 19k miles on my '04 SL600 and use it as my everyday driver. I also have the very first SL600 modified by RennTech and have had absolutely NO problems over the last 20 months. The throttle response is the first very obvious difference and in fact after driving the car for a while, you'll be so very, very dissapointed in anything else you put your foot into. What seems like just normal acceloration from a stop light, you'll have everyone in your rear mirror blocks behind. It only becomes lion when you step on it as other posts have described but, for everyday driving, it's an absolute dream. All other SL's including the 65 don't have the guts unless RennTech gets a hold of the 65 ala Treynor.

For me, it's a VERY BIG BANG for the BUCK...no brainer.

Just do it!

vraa

Never heard of it, I'd pass. Anyways, you can't have the same ECU upgrade as RENNtech, because that'd be stolen information which is illegal. Just like what some companies did with Powerchip's ECU software.

StephenK, I suggest you do it, if you need some help, just give me a PM, I have a friend who's really close to all the RENNtech guys and swears by them, he gets pretty good prices as well.

Can Drive 55

I have a question and if someone can please supply the answer, I would appreciate it. Let's say that someone has the ECU mod performed and sends the car to the dealer for service. MB has issued a service bulletin that requires the flashing of the ECU. The dealer service tech does the flash and the $6400 RennTech flash is gone. Is it going to cost another $6400 to have it done again? Thanks in advance.

StephenK

Good question, I would like to know the answer to that one too!

RennTechV12

The shop that I used, DynoComp will have me bring it to them before I go to the dealer and they flash it back to stock. When I'm done with the dealer I go back to DynoComp and they re-flash the RennTech upgrade, it takes about 5min to complete. A small price to pay for 782lb/ft of torque and 1/4 mile times in the mid 11's.

treynor

I've had RENNtech upgrade both my V12 Benzes. No "mixed results" - they both performed *exactly* as advertised - on the dyno and on the dragstrip. I'll use them again when I get my next Benz.

RennTechV12

BTW, that 65 of yours sounds like it's off the charts