silver65

I have an 03 S600 that has the ECU/TCU upgrade by RENNtech.

I've only had this car for about 3 or 4 weeks, so I decided to do some testing. I stopped on a desolate road, turned off the ESP, left the tranny in sport mode and nailed it from almost a dead stop. This is the first time I've ever done this in this car. Well, the car started to roll, the turbo's kicked in, the tires let loose, she quickly went to red-line before she started to shift to second gear, so I let off,...and then,...there was no tranny. Like it was in neutral. I thought, Great!, There goes the transmission. I let her roll to a stop, put it in park, turned it off, and then restarted her. Seems to be fine now. What happened? What did I do?

StephenK

Call Renntech, I am sure them will have something to blame it on other than their tune.

OBXTucker

Now that's a helpful comment....

silver65

Geez guy, seek some inner peace. Somethings eating you up inside.

StephenK

Being so close to BLAMEtech, why not just go by there and get their advice??

Personally I have found them to be less than reputable,

Performance WITH Compromise!

silver65

I'm seeking advice from several sources including RENNtech.

This is not my first car with them. My SL65 was a real beast thanks to them. My S600 now feels almost like the 65 did when it was stock. Not bad for a large sedan. I have had nothing but positive experiences with RENNtech.

Now let me say that RENNtech did not build my car. Mercedes Benz did.

StephenK, I can accept the way that you feel about RENNtech. Everyone is entitled to their own feelings. And, I'm not here to debate Good RENNtech, Bad RENNtech. I just want to know if this has happened to anyones car before. So do me a favor, unless you have some helpful information with this particular problem, please don't respond. Thank you.

NZ_Benz

Sometimes these types of cars just hit a brick wall and like a computer you just shut it down and start over. If your really worried I guess you could disconnect the battery to clear any memory that the car may be holding.

silver65

That's along the lines of what I was thinking. The car definitely has some extra power since the tuning. With the added power, I may have stretched the paramaters of the computer, and it shut it down as a safety precaution. Does this sound reasonable? Or am I just trying to placate myself. It looks to be working good now. I've done some full throttle runs from about 35 mph and everything seems fine. I'm still not ready to do a dead stop run yet. I'm going to try and bring it to RENNtech on Tuesday and ask them to read any codes in memory before I do that. I also need to do a dyno run.

BigBody6

I haven't had a problem like that. THe guys over at Renntech will do anything in their power to help their customers. I think its messed up for StephenK to badmouth them everytime their name or product is brought up because of one bad experience. If you didn't like it to f-en bad buddy. get over it. There are plenty of Renntech cars that make the power and performance increases maybe you just got a Lemon.

StephenK

Renntech Is Great!!!!!!


You feel better???

StephenK

Who have you spoke to at RENNTECH about your problem????

silver65

Nobody yet. I emailed Bob, but I'll probably stop by there on Monday or Tuesday depending on my schedule.

StephenK

I spoke with Bob in the past.

When you find out anything via the dealer or Renntech please post, I would be curious to see what the problem was.

silver65

I am also curious. I certainly will post.

11.9 in the 1/4 mile is very good for a 4500 lb car. Doesn't seem like anything's wrong with your car. Why all the hubhub about RENNtech?

StephenK

My problem with Renntech is for the upgrade, my car has never produced the numbers as advertised. I drove all the way to their shop and after several hours, two people came out to my car and within two minutes said my intercooler pump was bad, this surprised me, since the owner in an email to me told me it was not an easy thing to determine and would take considerable time for the mechanic to determine if there is a problem with the intercooler pump. So I could drive all the way back to Tallahassee and replace it and get nowhere or have them replace it. I opted to PAY them to get the part which was supposed to be a NEW and Improved pump, but was the same part number that was originally in the car. I have had two different shops dyno the car, both of which work on lots of performance vehicles with way more power than the 600 and was told since they didn't get the numbers, they probably didn't know what they were doing. I have talked to them about bringing the car back to them after I get a SERVICE B done on it this next week, and asked them to tell me what they would be looking at as a problem with the vehicle so I can get the dealer to check and see if there is a problem before I go to them.

I CANNOT get any specifics at all as to what the dealer should check, the only thing mentioned was "SENSORS", which means nothing to me.

If I travel all the way there and there is a problem with the car, it is a meaningless trip, if they are going to be looking at things, I don't see why they can't tell me what they are and I can get the dealer to check them for me.

They do not like to get specific.

silver65

I have found that every tuner, on every car I have ever dealt with, has always inflated their numbers. They just have to get it on one freak engine, or they'll lean one out for a dyno run, and those will be the numbers they will publish. I'm not saying that RENNtech did that. But it wouldn't be a big surprise if it was something like that. It's just the nature of the business. It also makes a difference what type of dyno is used.

What kind of dyno numbers is your car producing? I'm very curious. I think we have the same engine, Right?

I'm going to bring mine in Monday or Tuesday for a dyno. I'll let you know what kind of numbers I get. My car in stock form is supposed to be 493 at the flywheel. RENNtech says 620 with the ecu/tcu upgrade. That's an increase of 127 flywheel HP. That's a hell of a lot. I seriously doubt it's that much, but we'll find out. OK, now if it's 620 at the flywheel, then it should be around 496 at the wheels with a 20% drivetrain loss. I'll be happy if it's anywhere close to that. I'll post what happens.

whoover

It does sound like the new TCU program has a glitch. The TCU electronically protects the transmission from exceeding its torque rating, 738 ft-lbs, which the Renntech ECU tuning can exceed. So they must alter the protection programming, and it sounds like that where the problem is. I don't know if they leave some torque limitation in the TCU (I would hope so), but maybe it's set too low.

If the shift wasn't fast enough and the engine hit the rev limiter (which in itself sounds like a TCU calibration problem), I can see a TCU torque limitation cutting in at the same time. In the S65 it has the ECU reduce boost to stay in the transmission's safe area. The S600 might not have the capability for that so Renntech might just do a brute-force disconnect if things get too torquey.

But it does sound like their issue.

silver65

Thank you. Much appreciated! I'll ask them to take a look.

silver65

Well, the codes showed a failure of some solenoid in the transmission, which explains what happened.

Dyno run @85 degrees turned out 500.68 RWHP and 582.49 Max Torque. Car was hot when I got it to the dyno. We could have had a better run if the car and air was cooler. But I'm still very happy with the numbers. This would put it at about 625 at the flywheel. RENNtech advertises 620. So the numbers are better than they advertise.

StephenK

Do you have your dyno graph, I would be interested in seeing it.

thebigsicilion

In a yrs time with my 03 s600 Renntech I have had the same tranny situation 2 times and I drive it to the floor everywhere. Good to know its a solinoid issue.

Steve

silver65

Yes I do. I'll try to see if I can scan and post it later today.

silver65

RENNtech printed the codes for me, but I forgot to take a copy with me. I'll see if I can stop by to get them, then post the exact failure.

silver65

Dyno Chart

Clickable thumbnail:

StephenK

Found this DYNO from RENNTECH: