SL55 AMG, SL63 AMG, SL65 AMG (R230) 2002 - 2011 (2003 US for SL55 and 2004 for the SL65)

SL55/63/65/R230 AMG: RennTech Lowering fitted, not happy...

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Old Nov 26, 2014 | 03:05 PM
  #1  
sound 8's Avatar
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RennTech Lowering fitted, not happy...

Right, after several recommendations to take my lowering links off, I have
done so, and fitted a RennTech lowering module. I knew nothing about
how it worked, but now it is in I am very unhappy. I thought it would have
buttons or something to adjust, no, it is just set up to a lowered height
and that's it. You can adjust it but you have to plug in your computer and
go through it again. Also it feels very light on the steering and pulls to
the right with your foot down and then back to the left with your foot off.
At 100 mph it doesn't feel on the road and you want to instantly slow
down. All the suspension and alignment has been checked, I even e mailed
RennTech but no reply. What the hell do I do now..
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Old Nov 26, 2014 | 03:32 PM
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Assume you must have the V3 Lowering Module which means you adjust it either by pc or smart phone. I have the V2 with the dedicated remote control which I prefer. I really dont understand all the problems you seem to be suffering. Who installed it for you and are they a Mercedes specialist? I recommend you only let a Merc specialist touch your car as these SLs are very complex and it is very easy for someone not used to working on them to screw them up. Where abouts are you based in the UK?
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Old Nov 26, 2014 | 07:44 PM
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Why don't you start three more posts on the same subject ????
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Old Nov 27, 2014 | 08:35 AM
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Originally Posted by cnterline
Why don't you start three more posts on the same subject ????
If you don't succeed , try,try...... getting answers is sometimes like
pulling teeth,
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Old Nov 27, 2014 | 08:42 AM
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Got an e mail from RennTech, suggesting my trouble could be rear bushes
so I guess it's back to MB.
By the way , the RennTech makes it look pretty easy to fit. I thought it
came with control buttons inside the car instead of being fixed, same as
links.
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Old Nov 27, 2014 | 04:41 PM
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Originally Posted by sound 8
Got an e mail from RennTech, suggesting my trouble could be rear bushes
so I guess it's back to MB.
By the way , the RennTech makes it look pretty easy to fit. I thought it
came with control buttons inside the car instead of being fixed, same as
links.
Could have purchased the LOMO M1 or Lorinser to use the steering wheel controls for adjustments. I think Carlson uses the iPhone/iPad.
Just run the USB cable for the Renntech into the glove compartment and put an Android tablet there. There are multiple saved settings you can use for different pre-set ride heights.

That said, if you car pulls or feels funky at 100mph, something on the install is wrong. Also, if you had proper alignment when using the links, your alignment will be off at any speed over 30mph since the module set the car to stock height.
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Old Nov 28, 2014 | 03:03 PM
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Yes, I don't understand, the guy said, with the RennTech installed the car
would raise at 30 mph and then drop at 50 mph, why does it do that.
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Old Nov 28, 2014 | 05:10 PM
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He means raise at 30mph up to the normal running height( stock ) on the comfort setting then at 50mph will lower down to the sport setting for less drag and more stability the reason it does this is so your stock suspension settings can be maintained and you will not get uneven tire ware or reduced ride comfort. Then when slowing down elbow 30mph it will lower to your desired low look for the aesthetics.
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Old Nov 28, 2014 | 09:11 PM
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Originally Posted by F1BHP
He means raise at 30mph up to the normal running height( stock ) on the comfort setting then at 50mph will lower down to the sport setting for less drag and more stability the reason it does this is so your stock suspension settings can be maintained and you will not get uneven tire ware or reduced ride comfort. Then when slowing down elbow 30mph it will lower to your desired low look for the aesthetics.
The Renntech module raises the car to stock height at 30mph. That's it for Renntech.
Any MB with ABC has automatic lowering at speeds but it lowers the car just a bit (12mm for the SL). Can't be considered lowering in a sense like the module.
Given that model year I believe the lowering is on either comfort/sport setting as the ride height is the same on both. Newer versions differentiate between comfort/sport when lowering.
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Old Dec 1, 2014 | 08:47 AM
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Well thanks guys, but I am totally confused.
Who the hell is making the decisions Is it the RennTech, or does the cars own ecu, and where do I come in. When I bought this, I expected a
button to lower and raise it which turns off the cars ecu.
Instead I have a set height which I cannot change, only with the aid of a
computer, and this is then over ridden by the cars ecu.
At least with links it was fixed, then I could just raise it when need be.
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Old Dec 1, 2014 | 10:48 AM
  #11  
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This how mine works. Set up so the lowest level of ABC (no light on) is the way I want it to look when it is parked up but too low to drive around on. Use the middle setting of ABC (one light) for normal driving and use high setting (two lights) when I need it raised up as high as possible. Not really changed the Renntech setting from when initially set up and just use ABC to raise and lower. Works for me!!
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Old Dec 1, 2014 | 09:17 PM
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Before lowering your car you need to figure how the ABC works. First off, the car will lower itself at speed no matter what ride height you set the car at. I wrote that the lowering will always end up at the same height no matter if you raised the car or not, but not quite. the max difference is 12mm.

For example at 80mph, the car drives at 12mm below standard level, if raised via buttons it drives at standard level. Raising the car one or two levels only works at low speeds and cancels itself out as one speeds up.

That's ABC.
When using lowering links, the car follows the same process thinking it sits taller than it is. Since many lower their car aggressively, the car is typically out of camber alignment when standing still but even more so when the car lowers itself more over 50mph. I suppose at that time you are really eating through the inner edge of your tires.

Lowering modules try to offset that by looking cool when parked or city driving but returning the car to stock when hitting the highway, thus putting the same stress on wheels/tires as the manufacturer intended.

Regarding how fast the ride height can be adjusted depends on the module. If a tablet is used on the Renntech V3, there are multiple presets than can be selected in seconds. But you need a tablet.
The Lomo M1 can use the steering wheel controls but I don't think there are presets which would mean adjusting each wheel individually. That's slow.

Given the costs of wheels and performance tires I find the lowering module a bargain. Plus the ride quality is better is installed correctly.

Last edited by Wolfman; Dec 1, 2014 at 09:43 PM.
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Old Dec 2, 2014 | 11:31 AM
  #13  
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Toe angles been done, drive great now, still light on the steering but not
as light as my SL63 bi-turbo.
Thanks guys for your help.
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Old Dec 2, 2014 | 12:19 PM
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Glad you got it fixed and glad you made sure we'd see it with all 13 threads.....
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Old Dec 2, 2014 | 04:00 PM
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Why suffer alone, when there are all you guys to spill your problems too.

And of course, the more lines you cast, the more fish you catch.

It's great having all you guys, like owning your own MB garage.

Sorry if I go on a bit, but problems really get me depressed, not to mention
winter nearly here.
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Old Dec 2, 2014 | 04:44 PM
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Originally Posted by sound 8
Sorry, it's my English humour ..


But I was agreeing with you regarding wheels/tyres on a F1 car.
I don't understand your remark " ive done wasting my time w/you "
What did you do for me ?:
I've tried to & helped you multiple times..

Now you've figured out I was right about the lowering module too, imagine that

Originally Posted by sound 8
Toe angles been done, drive great now, still light on the steering but not
as light as my SL63 bi-turbo.
Thanks guys for your help.
Try getting more informed on what you're tying to fix, & high possibility your 10 yr old car may need a lot of maintenance in order to work in concert w/perf mods.... Before you go off making multi threads complaing this mod/that mod didn't/doesn't work etc

Last edited by Thericker; Dec 2, 2014 at 04:47 PM.
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Old Dec 3, 2014 | 09:46 AM
  #17  
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Heh TheRicker I always thank members for info given when I need help,
I expect there are quite a few members who will gain info and help from
your replies, that is what the forum is for.
Having a lot of Knowledge on this subject means you will always be in demand for help, if you can't be bothered to answer them all I understand,
A big part of my life is to do with cars, so there are times I get carried
away with threads, especially when I have done, or are doing something
to my car

If you need to know something about sound, I can help..
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Old Dec 3, 2014 | 10:30 AM
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Hey sound8 I have the H/K system in my sl600 and I am upgrading to a Alpine touchscreen with car play. I am also considering upgrading the speakers and sub. What would you recommend?
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Old Dec 4, 2014 | 10:35 AM
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Hi I don't have much to do with car audio, but unless you drive a car
like an S class with double glazing and sound damping your wasting
your money. The background noise in a normal family car is around 80 DB,
this obviously gets higher with speed. Also big wheels and tyres generate
a lot of low frequencies which will cancel out your bass. You will need
a huge amplifier, I am not sure what you can get from 12 volts, with
transformer boost to 110V I still think your amps will be low. Have you ever
notice as you slow down suddenly you hear more bass, lowering the speed
lowers the bass anti phase meaning sound improves. The Bose system
im my S and SL is perfectly adequate, but you can't listen seriously when driving 70 and above. It's like buying a high end system for your house,
then having a Harley ticking over whilst your listening. Other things like
speaker placement will affect the accuracy rather like wearing headphones.
Hope this helps, all car audio amps will sound similar, so go for power, the
speakers will be the thing to listen to, then when you have decided on your
system, and it sounds great, all will be ruined when you start the engine,
and with the roof down forget it,
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