Monday 21 November 2016

Smiths Gauges - out for repair

The decals in my Smiths Flight clocks had de-laminated; It started about 12 months in after the car was on the road and just looks untidy, all the dials are affected - speedo the worst.

The weather is nasty at the moment - so the dials are all out, about a month ago, and off to Caigauge in South Wales who makes them. The initial feedback is it was a bad batch of materials - so hopefully I get them back soon and can get the Zero back on the black stuff!

Looking pretty empty...

Update - Phone message today (25th) from a nice welsh lady at Caerbont Automotive - clocks should be on their way back to me by next Tuesday. Its taken a few weeks - but if they are right when they come back that is a result!

Sunday 20 November 2016

Wideband Lambda - 14Point7 Spartan2

Time to upgrade the old narrowband sensor with wideband. This is partly due to continued challenges getting emissions correct for MOT, partly because its something new to play with, and significantly because I was made aware of a wideband setup with an in-build calibration mode to null out some variables caused by the install.

I'm chasing the holy grail of calibrated emissions using home/garage equipment without a full blown rolling road remap.

Installation

I'm using a Spartan2 setup from 14Point7 supplied by ExtraEfi.

I don't need a dashboard indicator - so went for the simple sealed unit.
The processing box was installed in the engine bay next to the gearbox - which should be reasonably protected from both the road and away from the hottest parts of the engine bay.

The sensor must not be detached from its cable or plug - due to built in calibration - meaning a hole in the car side panel large enough for the whole sensor to pass through. A small marine clamshell covers the hole, riveted in place for simplicity - if I ever need to replace the sensor its easy enough to drill out the rivets.


Wiring

The unit has simple wiring requirements - 12v, Main and Signal Grounds, optional LED output and a couple of Lambda outputs for wideband and simulated narrowband. Sensor ground and wideband feeding into the Emerald on pins 30 and 34 currently. Best advice from Emerald is use pin 10 as the input - however its working fine on 34 so I'm not changing just yet.
I wired in another circuit for it through the main fusebox to avoid having a trailing inline fuse on the loom, while everything was open I unsheathed and re-bound this part of the loom.

The Spartan2 takes its power from the ECU relay via its own 5 Amp fuse so starts up and shuts down when the ECU does.

Calibration

The interesting part of the Spartan2 is the calibration mode.
As soon as the wide-band module starts up it sends 2x known voltages/AFR readings, 5 seconds each, to the ECU. 

This permits correction for linear shifts and angle of the AFR graph, not the shape of the graph, but should factor out differences/voltage drops in installation wiring and even differences in Emerald's voltage measurement.

14Point7 supplies a spreadsheet which converts the calibration AFR outputs to two corrected points which can be input to Megasquirt ECU.

Emerald has a single decimal place on AFR, but shows and allows entry up to 3 places on voltage - so I re-worked the OEM spreadsheet to input voltages and calculate voltages from known AFR values.

Entering the calibration readings in volts, 1.642 and 3.314, in the top green boxes and the desired AFR points the sheet works out the voltages which correspond exactly to those AFR values.

Emerald does not allow selection of every voltage so the error column works out the potential error due to data entry - negligible and well inside the wide-band units accuracy.

.. Just needs copying in to the ECU settings and job's a goodun.
I suspect the wide-band has enough damping built in - so reduced the emerald signal smoothing to 0.

Gotcha - the only issue I found was by the time the ECU had powered up and connected to my laptop the wide-band had already gone through its calibration steps. The resolution was to power everything up with the wide-band fuse out, open the right Emerald Lambda screen then plug in the wide-band fuse, only needs doing once to calibrate.

Minor tweaking to restore the original powermap target AFR, and adjust the closed loop gain to get a stable idle. The idle zone used to have a lower AFR on the 500 revs column - meaning, as the ECU interpolates, its getting mixed messages - I flattened that out to 14.7 to try and give it an easier time of finding a stable tick over.

The only way to prove this is correct is a garage/MOT testing equipment - but it should be getting close & now have the controls to find the right emissions settings and have the ECU reproduce them using active feedback. I'm planning to try with a friendly garage pre MOT (next June) and if that fails a rolling road.

Saturday 19 November 2016

Radio noise suppression & bluetooth headset

Ground Loop isolation

Testing the new bluetooth output from the radio I had some ground loop noise.
Two options:
   - Isolate the 5v feed to the bluetooth board
   - Isolate the audio connection from the radio to the bluetooth board

I went for the second with a cheap off the shelf component which installs between the radio cable and the bluetooth card. No power required - inside are a couple of audio 1:1 transformers for left & right channels.

Does the job - audio is now crystal clear. 

Headset Mod

I bought a pair of Sena SMH5 intercom units, designed for installation inside a motorcycle helmet. Selection of SMH5 vs 10 is a combination of price, due to being an older model, nice prominent rotary volume control and physical size. They will also work when charging via a 5v USB cable which means my pet hate of flat batteries is not a problem.

SMH5's can pair to each other - for standard intercom functionality as well as mobile phones and receive a bluetooth audio input. I think although have not tested they should be able to also share the bluetooth signal - so the single transmitter installed in the radio should provide audio to both passengers.

The first one is installed on a Howard Leight L0f earmuff. Selection being a combination of price and quality - they are thinner than my existing wired earmuffs but perfect for modding. The SMH5 sticks to the outside and cables routed over and sewn to the headband, speakers stick inside to the earmuff padding.
I didn't want to detach the speaker cable, it is very flexible and thin & dont fancy re-soldering the stereo wiring inside - hence routing it outside the headband, this approach also means I have not damaged the SMH5 in any way - warranty FWIW intact.

The loose cable is for the microphone arm to be installed later.

Update - completed these headsets much later,  sometimes life just happens and the car takes second place!

Saturday 12 November 2016

AC Ace - head turner

A visit to the Haynes Motor Museum as part of a Birthday weekend away, and - my head was turned by something rather nice.

The AC Ace, the predecessor to the AC Cobra - but to my eye with nicer lines - high grille and a subtlety about its shape. Originally I chose the Zero because it wasn't trying to be anything but itself - straightforward and to the point - not a reproduction. (I know its a Seven - but you can't really say its a copy/repro/trying to be a Caterham)

However - the shape of this thing... hmmm....



No problem at all - an astronomically expensive and rare sports-car.... 

except...  

There is a firm, Hawk Cars, that makes a replica kit, and they are less than an hour down the road from where I live... synchronicity?

No, I'm not 'familiar with the works of Jung' - I've just read/seen The Eagle has Landed too many times. 😀

I do miss the build process...

Just a little daydreaming, for now :)