Launch control for Motronic

[prj]

you should try with a k24 7400...

I will as soon as I get it attached.
Won't be long now.

[S2central.net]

Results of 1st back to back tests of VLC versus stock ECU. Remember that the ONLY change in code is the addition of VLC - Variable Launch Control.

I was expecting an improvemnt of 0.1 - 0.2s in 60ft times but ended up with 0.3s

More tests to come. Dmitri & I have cooked another little refinement for adjustment at higher revs but nobody else need worry about that.

Now - I am no drag queen - ooops that came out wrong... I dont get it perfect every time - but with VLC enabled it is a LOT easier to get a clean get away with a good swirl of wheelspin and then the G-force hits your guts.

Running uprated chips with VLC will come next - my poor old car is an R&D shed now

[Rocco]

nice Paul¡¡

[Ross]

I'd like to see this on the RS2, must admit it's pretty brutal as-is if you do a 4k launch. I've only ever done one, too much drivetrain sympathy

[Sonic]

If you can keep this thread on topic gents, it would be most appreciated

You know who you are!

[Dan]

Depends, the topic is now Dinosaurs, right? I like dinosaurs...

Okay, srsly. Nice to see some preliminary results, thanks Paul.

[prj]

While Paul was looking once again at the pages and pages of Excel spreadsheets gone into this, he realized that because of the way the RPM limiter is calculated in Motronic we have a small problem.

Namely the fact, that our variable resistor adjustment does not have a linear change.
It is finer at the low-end and then gets more and more progressive at the higher-end.
So this means that while you have adjustments as fine as 10 rpm in the lower end, in the upper end even a single touch of the knob will adjust the limiter by 120 rpm and more.

This wasn't really acceptable, so I came up with a way of linearizing the adjustment, so that it is always a 36 RPM change. No matter where in the range.

This is illustrated by the following graph.
The blue line is the delta for each little change in the adjusting knob's resistance without linearization.
The red line is the same delta, but with proper linearization applied using some assembly coding inside the ECU:



This means we are getting closer to the final version.

[S2central.net]

@sonic - thanks for restoring sanity here. I go out for one night and missed all the 'fun' it seems.

[Rocco]

I'd like to see this on the RS2, must admit it's pretty brutal as-is if you do a 4k launch. I've only ever done one, too much drivetrain sympathy

only 4K rev launch?? i was doing a 6/7K launchs in one friendly drag race in spaIN,and no problems

[Dan]

one friendly drag race in space

[S2central.net]

Pmsl

[S2central.net]

So I have source some nice compact pots that will fit in either the centre console near the ciggy lighter or in an unused upper console switch.

the problem with the console switches is attached - lots of plastic needs to be neatly removed in a switch blank to add the pot... Does anyone know of alternative types of blank - or suggest something better than ~20 mins of fun with captain dremel to remove the extra material ?

[Rocco]

edited...

i did not knew in WTF i was thinking in the writing moment

[S2central.net]

So... I took the plunge with the dremel and carved up the rear of the blank switch... bit of a phaff but not too bad - addition of an 8mm hole allows the pot control to poke through. I think its a bit of a blatent location though - especially without a nice black knob (can I say that ?) fitted to make it look prettier. I've ordered up enough parts for the 1st ten kits.

Anyone wants me to modify a switch blank as part of the service is fine as well as long as it is sent with the ECU for minor surgery - or you can do your own thing with regards personal preference for the pot location - the supplied cable will be long enough for most locations near the driver - and easy to extend for the more bizarre suggestions.

[andy10v]

suggest something better than ~20 mins of fun with captain dremel to remove the extra material ?

Recruit Madwolf?

Good progress guys, think I need a new clutch first though, flat foot shifting sounds interesting though.