In the 420 when you click it over to the right you can hear the solenoid engage the whole time unless you click back out, if you take off quickly it will stay in first a while, if you keep the shifter engaged over to the right it will take 1st to redline....not sure if it will just stay there or if it will shift on its own....never tried it, don't intend to either. :eek: Highest I've gone with it in that slot is about 4500rpm....and it shifted to 2nd as soon as I released it.

$250 is a bit more than I was going to charge for the device I came up with and that device does a bit more than mine is going to.

My original intent with this was to build it for Hit Man X in exchange for some parts.

I suppose I could come up with an interface for setting the shift speed as well. That's not that difficult at all considering the controller has a USB interface. At that a 0-60 time device would be easy too but largely not useful for core functionality.

As 97 SL320 mentioned my biggest issues so far are:
1) investigating solenoid life and duty cycle.etc.
2) filtering, attenuating speedometer input signal for the controller.

Function List
-First Gear Downshift/Up-shift at Preset/User Determined Speed
-Disable Switch to resume second gear starting
- ?

I have a euro V8 trans computer for use with the E/S switch that in effect does exactly what you're intending to do-- it shifts at exactly 7 mph without a spirited push of the pedal form a stand still. I dunno if it's easier to start from scratch or check out the innards of an older trans 'computer'. Any euro V8 W126 should have it.

You could always reverse-engineer the PCB on a BergWerks unit, if you could get your hands on one ... ;)

Back in 2008, I posted about doing this on my 500SEL. Do an advanced search on my name 'pmckechnie' and 'first gear start' and and you should be able to fine it. This is using a controller from a 500SEL and 1 wire and 1 switch. It gives switchable first gear start for almost nothing. Look and see if it helps. By the way, It still works great after 4 years.

Paul

Well since we were looking into this for the I6 cars AND the component cost is about $30, it makes some since in this instance to 'reinvent the wheel'.



I have the ECE V8 box around my house somewhere if you want it Kris. I think it is only about five wires. I have no clue why no one built a kit for the I6 cars. Hell, maybe it is not possible or no one felt there was a market.



http://www.peachparts.com/shopforum/1670746-post6.html