mantylar

Taking delivery May 8th from Barrier Mercedes in Bellevue, WA . Silver/Charcoal with Sport Package and all options except Distronic. I spoke to George at RENNTech today regarding their software upgrades. For $6,400 the upgrades seem like a "no brainer". I loved my CL55, but I really wanted a convertible.

theboogers

if you just want chipping try oliver at speedtuningusa.com. they have been great for sl55 owners.

mantylar

I appreciate your input. After reading the comments from Treynor on the S Class Forum about his RENNtech S600, and the article that was published in Car and Drive about the RENNtech chip results, I am pretty sold on their product. Also, RENNtech offers a software upgrade for the tranny, which George at RENNtech is quite insistent should be purchased with the ECU upgrade. He said that the tranny software is for safety reasons only and does not change the shift patterns. He said it protects the transmission from the excess torque that is created with the engine ECU upgrade. Treynor indicates that he has had the RENNtech upgrades for over a year with zero problems. If anyone has any experience with ECU upgrades offered by companies other then RENNtech for the new 600's, I would like to hear about them.

WhiteTrash

congratulations on the purchase.
please post pics as soon as you can.

sillydriver

My experience is that it does change the shift pattern -- it improves it. Shifts are quicker, it downshifts on braking and it downshifts from 4th or 5th at higher speeds than stock.

northbenz

Were the guys at "Cal Worthington" Mercedes in Anchorage agreeable to having the car drop shipped and if so how much do they charge compared to shipping it up yourself on Tote?

benznut

Pardon me for being a skepticist, but in order for the transmission to be protected, one needs hardware, not merely software, in my opinion. If the logic behind the software is to change/perfect the shift timing or load, then, I do not see how this can be achieved without affecting performance.

WayneE

On a modern, electronically controlled transmission, upping the line pressure can be done using software. This would firm up the shifts, make the shifts occur faster and therefore protect the transmission.

sillydriver

WayneE’s theory about raising hydraulic pressure is interesting. I assume that would speed the engagement of clutches within the transmission at the cost of making shifts a little less smooth. I wasn’t very precise when I said “shifts are quicker” – what I meant was not that the shifting process itself was that much quicker (although it might be a little) but that when you squeeze power at the throttle the transmission downshifts sooner: the shift is initiated more quickly, so less time passes between engaging the throttle and getting hard acceleration.

mantylar

Northbenz, I tried to do business with Worthington, who recently purchased Mercedes Benz of Anchorage. They have an SL600 on their floor that has the same color and options as the one I just bought from Barrier. I offered full MSRP and they turned me down. They never came up with a price, but they hinted that they wanted $20,000 over MSRP. The fact that I have purchased 5 new Mercedes from that dealership since 1999 didn't matter. Barrier had one coming in that they were willing to sell me at MSRP. Saturday May 8th I am picking my new car up in Bellevue and spending 5 days in Seattle before shipping it to Anchorage.

ano0oj

CONGRATS ON THE CAR MAN! Can't wait to see what the result will be!

Twinturbo

Excuse me if im wrong, but wouldnt speeding up the gear changes and increasing the pressure but more strain and wear on the gearbox. I mean wouldnt the more sudden torque shock make it worse.

From what I thought, and what is logical, is that the software simply makes the shifts faster but less comfortable, for sportiness and acceleration, and alters the timing of the gear changes for more sporty driving. The response of the electronic throttle is also enhanced, making it more responsive and so on. I would be interested to see where you got the information from regarding new software to protect the gearbox. THis is the sole purpose of the upgaded software from what I know. The SL600 trannies can take 1000nm, so this also appeard to confirm this.

WayneE

By speeding up the shifts you're putting less strain on the wear items (clutches, drums, bands, etc). The faster, harder shifts will cause more strain on the other drivetrain components (driveshafts, ujoints, diff, etc), but it will prolong the life of the transmission.