M. Requin

Mike Frye's comments about modifications have inspired me to post a project I've been working on to get some feedback from the group before I take the (moderately expensive) plunge and build this thing.

Others have commented about the dated look of the HVAC control head, but I have also been bothered by its design weak points: first, the well-documented relay problem, and second, the exposed wiper switch for air distribution control. I had to repair or replace my controller, so I borrowed on from a fellow RL'er (thanks, Chris!) will I did a PM on mine. Turned out it is still functional, but now I had the bit between my teeth, so onward...

First job was to figure out what I wanted to do. I read every post I could find, and after considering a number of functional mods, decided to replicate the stock unit, to make it as plug and play as possible.

Second job was to figure out a better airflow switch arrangement. That took a while, and then even more time to source what I was looking for. The temp control potentiometer was more difficult to source, because I wanted to incorporate limit switches to replace the microswitches in the stock controller. Finally found it. Neither of these components is cheap, and there is a minimum on the pots, which is why I am taking my time to be sure I have it right before I spend any bucks. The blower switch is different - I am retaining the stock unit (and will take out the mechanical numeric indicator), so no rewiring of the plug connector etc will be necessary.

Some other considerations including sourcing a better relay, figuring out lighting, and choosing component configuration. The design criteria became the following:

• Enclosed rotary switch for air distribution functions - no exposed wipers to corrode, get grunged up.
• Long-life cermet potentiometer with limit switches for temperature function, with led indication of minimum-maximum setting.
• Stock blower switch retained, minus mechanical setting indicator.
• All electronic components PC board mounted.
• EL back lighting with inverter circuit on PC board.
• Heavy duty 15A relay on PC board.
• Smaller form factor, more room behind console.
• Plug and play with only modification to stock blower switch required.

I'm working on the PC board design now, it's really pretty straightforward. Here's what my project looks like in terms of "user interface" at present. Please excuse my lack of skill with graphics programs, and those weird looking ***** might get changed, but I thought now would be a good time, as I said before, to get some feedback. The top illustration is daylit, the bottom at night:

I'll be interested in all feedback, good or bad!

Jim M.

I like it! Looks like you've covered all the problem areas. One question, the middle **** has two plain dots at 6 and 7 o-clock positions, what is the difference between position one and position two? On my GTS they are "OFF" and "Recirc." I assume yours are the same. I think these should be better identified.

M. Requin

I got lazy.

hans14914

PM sent!

Champagne

I guess that is one particular problem that will have many different solutions.

Hans and I have been working on a similar project for a few months now.
We didn't want to come out before it was ready.
I guess we will need to start our own thread since ours is pretty much done

Great minds think alike

Paul

hacker-pschorr

Very cool and good timing!!

I'm working on the details for installing a 7" screen and moving everything around. A newer more modern control head would be a nice addition.

Great work guys!

M. Requin

Thanks for the PM Hans, and comments, Paul. I'll just add that this is pretty much a personal project, and if it works ok it will be part of a total console redesign (gone whole hog). I look forward to seeing what you guys are doing, mine might be obsolete before being built! That would save me a bunch of work...

And BTW, I was also lazy on the defrost symbol, the "D" is a placemarker, for the sharp-eyed among you (like Jim).

auzivision

Both interesting approaches with night and day differences in design… rather ironic timing for two to be developed almost simultaneously.

Got to love the creative spirit around here!

Alan

Well I've commented on this before. I think you have addressed some of the key weak points functionally and a smaller size is always good. Plug & Play suits most best.

However ergonomically the only benefit is the ***** vs sliders - I'd be looking to do much more...
The orginal controls were really badly thought out - they basically replicate a typical cable operated flap system model of the 70's.

So what to change: some ideas - you can pick & choose - most can still be plug & play - just a few need additional connections.

- Variable speed fan AND HVAC on/off (+s ome auto features maybe)
- A recirc button that can be used at any time in any flap mode (its not a dist flap mode)
- Incorporate the AC on/off button (why is it dangling out there today on a seperate panel)
- Make the DEF function a dedicated override button - (its not a distinct flap mode)
- For the flap control ****:
.. - Relocate on/off it has nothing to do with air dist flaps
.. - Relocate Recirc it has nothing to do with air dist flaps
.. - Relocate DEF it does much more than air dist flaps and should be immediate
.. - Turns out there are only 4 real physical air distribution flap options on most 928s:
.... - Vents Only
.... - Vents + Footwell
.... - Vents + Defroster
.... - Vents + Defroster + Footwell
.. - On some older cars ('82-'83 I think) the console vent was controllable at 2 levels Open/Half Open/Closed.
.. - Ideally install one of these consoles for even more control... head unit connector has room.
- Incorporate the rear defroster switching & monitoring
- Modern cars woiuld incorporate seat heating/cooling also.

Alan

auzivision

Why stop there… I’d like to see one that displays various gauge functions like boost and air to fuel ratio plus one that doubles as an audio and GPS system.

DR

...heck don't stop there... don't forget SharkTuner software loaded for in-console Touchscreen "928 Tuning" on the fly!



OH, and Andrew requested built in WiFi Tethering to his 3G Smartphone for browsing **** sites on the web.

Alan

I stopped there because all these things are typically related to climate/passenger (temp) comfort systems. Mostly these are feasible with the existing equipment with different switching.

Unless the control system includes a giant touch sensitive LCD adding other features makes less sense. I think others are persuing those ideas wiht a big LCD etc and they make sense there - add flexible programmable guages like Louie Ott has done as well as Audio/Nav/Phone etc all as a seperate syste,

Personally I do prefer independant controls for some things eg: on/off/ac/fan/temp/fdef/rdef/volume - virtual controls for obscure functions make sense - for things you use a lot I think they just get in the way... So for climate control I would still want a seperate panel - just with different controls and features than what we have today - Rotary ***** - yes - same features - heck no...

Real life examples:

Maximum perceived effectiveness AC on a really hot day is vent only, fan max and recirc. This is impossible with the stock controls.

Cold day - nasty smell/smoke outside - switch to Recirc - I get AC on, different flaps and the temp changes...

It is important to understand how the current system works to see its limitations - many of these are only based on the control head implementation - not on the underlying equipment which can do much more...

Alan

auzivision

Okay, so I cheated... since I knew what Hans had up his sleeve already.

https://rennlist.com/forums/928-foru...h-windows.html

M. Requin

[QUOTE=auzivision;7505002]Okay, so I cheated... since I knew what Hans had up his sleeve already.

I wondered about that "both interesting approaches" comment! Actually, we are going in directions about 180 degrees apart. Hans and Paul are doing what should be done if you started with a blank sheet of paper today. The responses to the post Hans made show just how enthusiastic those responses to that approach are. I'm just trying to take the same old "tired" design and update it with modern parts.

And Alan's suggestions are right on, in terms of functionality, maybe I'll try a gen 2 with some of those ideas, but first, I want to get this project done.

And BTW, true to the RL spirit, I have had a conversation with Hans about our projects, and he has been extremely supportive. You just can't beat the spirit here.

pcar928fan

This just proves once again, that there has NEVER, EVER been a better time to own a 928 than RIGHT NOW!!! You couldn't get ANY of the cool tuning and High Performance stuff, or the Champagne interior gear, or the Kevin rear fender flares or any of this REALLY COOL center console gear 10 or 15 years ago when the cars were ACTUALLY BEING MADE...now look at all the cool stuff out here!

I LOVE IT!!!