RX8 Project – Part 11, Turbo’s #2 – Wastegates

So now the project is going in the turbo direction I need to be a bit wary with how I do it. The GT1549 turbo’s I chose had positives and negatives. They looked to be exactly the right size for the engine I had, they were fairly common in one form or another and importantly the price was spot on! I still don’t understand quite how but I managed to find someone on eBay with a matching pair of these turbos fully cleaned and rebuilt for £65 each delivered! So that’s the positives, now the negatives, firstly rather than the normal bracket bolted to rear of the compressor housing to hold the wastegate actuator. On these turbos it is actually cast into the housing and so it would make rotating the housing to fit the application considerably more difficult. The second problem is they have a factory fitted actuator which isn’t adjustable more than a small amount and I really didn’t want to start tweaking a completely untested engine with no idea what was going to happen with no way of keeping the boost below the 18 psi wastegate pressure!

So getting over these problems. Having looked at the rotation problem I came to the conclusion I should be able to make them both fit with no rotation changes needed. The backup plan here was to grind off the cast in mount and custom make a bracket using a bit of steel plate if it turned out I needed to later on. This takes us to the wastegate problem. I looked at a number of ways of providing a reduction in the actuator pressure including adding springs to the rod side of the actuator and even bolting the internal wastegate solid and fitting external wastegates to the manifolds I came to the conclusion the only real way of giving a wide but reliable range of adjustment while keeping the package as small as possible would be to replace the stock actuator with an aftermarket adjustable one.

Now this is where the plan goes a bit wrong about – after looking about for ages to find a sensible option at a half sensible price the best I could come up with was this : Kinugawa Actuator 

Kinugawa Actuator

I’m under no illusions here, this is a a cheapo unit! But I strongly object to spending the cost of the car on each wastegate. The problem is even though I got these for £68 each which really is very cheap they actually cost more then the pair of turbos! Considering all this it’s still a pretty good option because it is a ‘universal’ version. It comes with a range of springs for different pressures so I can start at just a few psi and swap the springs out as needed and also comes supplied with four different actuator rods.

So here we are – actuators!

Kinugawa Package

So at first glance they look ideal, but don’t let that fool you! There’s a couple engineering problems to overcome.

Actuator Flap clash

The first problem is this; the hole in the supplied rod end isn’t large enough for the flap actuator on the turbo. The solution is simply to drill this out to fit. I didn’t note the sizes, but it was a standard drill size.

Next up was that this ‘universal’ actuator was never really intended for a turbo this small and as such the shortest actuator rod is too long to allow the wastegate flapper to close so I had to modify that as well. The rods are nominally 6mm diameter but the end the rod end has a fine pitch thread meaning modifying that would need me to buy a fine pitch die to extend the thread. Luckily the end that goes into the actuator is a standard M6x1mm metric thread so that was the easier option.

Modified Actuator Rod

I measured how much I needed to shorten the rod to allow the flapper to just close at one end of the rod ends adjustment. The opening pressure of the actuator is set by preload so the more it is tightened greater the boost pressure. I then simply cut the thread down to the required point and then trimmed off the excess. The good news is if I made the rod too short I three more tries for each one!

Modified Actuator Rod

And here is the difference – it’s actually about 25mm less than it started out! Reassemble the whole thing and magically it now fits where it needs to!

GT15 Kinugawa actuator

The other thing you will need to do potentially at this point is change the spring. Once the actuator rod is in the actuator this is actually not too bad but be a bit fiddly. First of position the actuator so the rod is sticking downward between the jaws of a vice. Tighened the vice to hold the rod in place then undo all the housing screws. Lift off the top housing and carefully remove the diaphragm underneath. Next you need to carefully release the rod to take the load off the spring. then you just unscrew the rod and take the aluminium piston and the spring underneath out the housing. Reassembly is just the reverse but the key is to put tension on the rod again and clamp it in place again before refitting the diaphragm and cap otherwise it’s very difficult to get the diaphragm correctly positioned without any wrinkles that could cause damage or leakage.

So now we have two turbos with adjustable wastegate actuators with a potential working range covering something like 3-30psi!

 

RX8 Project – Part 9, Flywheels Part 3

So just to finish of the flywheel section here are the the finished custom parts :

Flywheel spacer on the crank, you can see the black dust seal in the centre covering the new pilot bearing underneath.Duratec V6 Crank Spacer

A wider shot showing the spacer in position among the currently disassembled state of the engine.Duratec v6 Flywheel spacer

And finally the flywheel itself.

Custom Duratec v6/RX8 Flywheel

In this photo the ring gear and location dowels for the clutch basket have been fitted.

The ring gear was actually a lot easier to fit than it was to remove because you can just put the ring gear in the oven (at maximum, in my case 250°C+ off the end of the scale!) and put the flywheel in the freezer for an hour or so as well – this may not actually be necessary but you want the most possible room between the parts when you fit them together. If the ring gear snags on the way down it because there isn’t quite enough space it can be a real pain to get it off again. Before installing the ring make sure it is the correct way round – all the teeth should have a bevel on one side to help the starter engage cleanly this goes towards the position of the starter motor! Take the hot ring out the oven, check it and drop it into place as quickly as possible but make sure it’s right and fully seated to the shoulder of the flywheel. Once touching the flywheel the ring will cool rapidly and lock in place.

The dowels in question turned out to be the wrong size, I specified them as 1/4″ diameter (6.35mm) and this is what is still shown on the drawing but it turns out the ones I measured had more rust than I thought and the holes in the clutch basket are actually designed to locate on 6mm dowels – something I really should have checked! From what I have since found out this is likely one of the many Ford engines which have special dowels which are  (from what I can find out) 8mm on the flywheel side but only 6mm on the clutch side. The correct dowels are actually 6.30mm on the smaller diameter so my original measurement wasn’t actually too far off, I just shouldn’t make daft assumptions! Larger end is 7.97mm diameter by 6.5mm long on the ones I have, overall length is 18mm. Tolerances and fits are not my strong point but I’ll probably start with a 7.9mm drill and hope to press fit them.

For simplicity I recommend buying something like this available via eBay as Cosworth clutch dowels by x-power engines:Xpower Flywheel Dowels

I’m planning to modify the appropriate holes on the flywheel to use the correct dowels I just haven’t quite got round to it yet!

I should probably also take a moment here to mention flywheel bolts. The Duratec crank has a slightly unusual thread which is M10x1.0mm (M10 Extra fine). This is as it happens the same thread commonly used on brake hydraulic components like bleed screws. Needless to say the stock bolts are far too short as the engine originally just had a thin flex plate so longer bolts were needed. Now various companies will sell flywheel bolts for almost any engine but not for something like this and they rarely specify the actual sizes of the bolts in a kit so I can’t just buy one for something else that will fit very easily. My solution was find the best standard bolt I could and so I am using some 12.9 high tensile socket cap bolts which I managed to find from a bolt supplier on eBay with the right thread. For anyone who doesn’t know 12.9 rated bolts are the highest rating before getting into one off special items (usually using exotic materials) and they really are very strong. As a comparison ARP gives their flywheel bolts as having a tensile strength of 180,000 PSI. The 12.9 bolts are rated to have a minimum tensile strength of 176,900 PSI – a number close enough it makes me think they are likely the same material! The strength figures for these bolts mean at the size I will be using each bolt can be safely loaded to in excess of 7000kg of tensile load indefinitely with no deformation. Their failure point being somewhere north of 9500kg each! Some time in the future I will do a full write up of nuts bolts and other fixtures it’s worth knowing about.

So that’s my shiny custom flywheel, next time you see it it should be bolted to a rebuild engine with a whole host of custom or cobbled bits on it!

RX8 Project – Part 8, Flywheels Part 2

Apologies for the long delay since my last post (more than a month!), life has been getting in the way of having time to do anything on blog of late. The good news is that the RX8 project has made some progress and this blog is still no-where near the current status so there’s still plenty to come!

In flywheels part one I mentioned how I ended up in a situation where I didn’t really think the cast flywheel was save to modify and how a chance encounter led me to a solution. The problem it presented is I’m primarily an electrical/electronic engineer, while I dabble fairly extensively in mechanical things designing a flywheel isn’t exactly something that comes up every day and the precision was critical so I spent a lot of time making sure I got it right!

Critical aspects as I saw them were the bolt pattern to match the crank, bolt points for a suitable clutch and and very accurate outer diameter to allow fitment of the RX8 starter ring gear.

Looking at these criteria one at a time the bolt pattern is an interesting one. At first glance all the 8 bolts appear to be evenly spaced around the crank on a PCD (Pitch Circle Diameter – this means the centre of each of the holes is placed on a circle). After checking my early flywheel model drawings against the real flywheel I noticed that all the bolts lined up except one which was just slightly wrong; ok, approximately 2mm, enough to be considered very wrong! Duratec V6 Crank Alignment

This suggested the pattern wasn’t exactly what I thought so I started checking exactly what the error was in different directions to figure out what was going on. After extensive measurement I managed to work out what was wrong, the bolts were indeed on a PCD they just weren’t evenly spaced. For even spacing the bolts would be at 45° intervals but one hole was shifted 4° round the PCD so it was 41° and 49° to the two nearest holes. Combined with a 76mm PCD this made the bolt pattern line up perfectly. This is actually quite useful because it means when the crank/flywheel are balanced they cannot be reassembled in the wrong alignment.

The crank also features a location register to make sure the centre of the flywheel is perfectly centred on the crank. The register is a raised lip accurately machined to a specific outer diameter so there is no lateral slop between the parts, in this case I measured this to be 44.40mm in diameter. when I trial fitted this it needed some emery on the crank to fit but this seemed due to surface rust where the engine had been stored in a damp room for a long time. Your mileage may vary!

Next up we had the clutch, I initially planned on using the RX8 clutch as I thought it would be stronger and have more options later but on further research it turned out RX8 clutches are very expensive indeed and anything other than a stock one gets very expensive very quickly and largely need to be imported so I started looking at other options. This took me back to the idea of using a Mondeo 240mm clutch, they’re cheap, readily available and the stock ones will handle a fair amount of power. Admittedly a stock kit is highly unlikely to last long with the amount of power this project could get to but there are readily available uprated covers and plates that could be used. Plus £50 on a project that may never really work isn’t too bad, £300 for a new RX8 stock clutch is more than the car cost! I also already head the factory Mondeo flywheel to take all the appropriate dimensions from which kept the process fairly simple.

The last issue was the ring gear, this is critical because the RX8 has its starter motor on the gearbox side and when because of this the options are either re-use the RX8 starter or butcher the RX8 bellhousing to allow an engine side starter to fit. For simplicity I figured I’d go with the RX8 starter since I was getting the flywheel made anyway. Starter ring gears are whats called an interference fit on the flywheel. In essence the ring gear is intentionally slightly smaller than the flywheel it is designed to fit onto and when the two parts are either pressed or heat fitted (heating up the ring so it expands and can be slipped into place) together. It is a tiny change in size when fitted and just the friction between the two parts that prevents the ring gear slipping when the engine is started hence why this is rather critical. To simplify this I modelled a nominal 290mm for the diameter of the lip this mounts on but supplied the ring gear to the machine shop and asked them to machine to an interference fit. This led to the following design:

RX8 Flywheel V6 – Machining Drawing

After a lot of double checking with these base measurements I needed to get the correct offset from the crank to make sure the clutch plate is in the correct position to be fully engaged with the gearbox splines. This led to me modelling everything to make sure it would all fit where it needed to:

RX8-V6 Clutch AssemblyHere you can see how everything stacks up. Between the bell housing and engine there is a 10mm spacer (grey) this represents the adaptor plate thickness. Clearly the bell housing has been simplified but the overall length is correct and the position of the splines (a little hard to see in the picture) and pilot bearing diameter (the reduced diameter) on the gearbox input shaft are correct.

Unfortunately having got all of this looking right and sent it over to the machinist and work starting on it I realised a couple minor mistakes, one was that I’d not offset the flywheel to match the spacing of the bell housing caused by the adaptor plate (shown above but this picture is from a later version) but related to that I hadn’t checked the offset to make sure the starter ring gear was actually in the right position to engage with the starter!

Turned out it was a little off and actually needed more offset but unfortunately the raw material for the flywheel had been delivered and machining had already begun and sadly it wasn’t big enough to allow for this extra thickness so I needed a new plan. The best I could come up with was to add a small spacer to correct this. Luckily this also allowed an opportunity to include a new pilot bearing location. This is a bearing that locates into the end of the crank to support the engine side of the gearbox input shaft and due to the gearbox adaptor plate thickness and the fact of it being a mismatched engine and gearbox the standard bearing was now too far away to support the shaft.

RX8 V6 Crank Spacer V1

This spacer corrects the problems above and still includes the correct bolt pattern, location diameters to keep everything centred. The 35mm internal diameter is the exact size of the bearing I used. This allowed a suitable bearing and a dust seal to be pressed into place and likely stay there, that said there’s a lip in the spacer to hold the bearing up and once the gearbox shaft is in place it physically can’t fall out. It’s probably worth pointing out here that this bearing only actually moves in use when the clutch is pressed, when driving along in a gear the clutch locks the crank and input shaft together and so the bearing is rotating overall but the inside and outside are rotating at the same speed so the vast majority of the time it shouldn’t experience any wear.

The final product to be coming in part 3!

 

 

 

 

 

 

 

RX8 Project – Part 6, Canbus #2

So now we have a powered up RX8 cluster and some Canbus hardware that we can talk to we can start doing a few interesting things with our new setup.

Fire up the Arduino IDE and we can start writing our basic controller code. Canbus devices have a device address and a memory location for all the required data so we need to work all of these out. This is a lot easier for digital IO than the more complicated analog values because digital IO are just either set bit on or off whereas analog values can have funny scaling and things going on. I initially used a canbus demo program which worked because I basically cloned the Arduino Canbus shield. Plenty of starter guides and information can be found here : https://learn.sparkfun.com/tutorials/can-bus-shield-hookup-guide

My initial approach involved setting the target address for the Canbus transmission and sending patterns of bits high and low and see what happens. Google told me that the cluster Canbus interface operates on 500 kHz clock so with that information we should get a connection.

#include <Arduino.h>
#include <mcp_can.h>
#include <mcp_can_dfs.h>

#define CANint 2
#define LED2 8
#define LED3 7

MCP_CAN CAN0(10); // Set CS to pin 10

void setup() {
 // put your setup code here, to run once:
 Serial.begin(115200);
 Serial.println("Init…");

Serial.println("Setup pins");
 pinMode(LED2, OUTPUT);
 pinMode(LED3, OUTPUT);
 pinMode(CANint, INPUT);

Serial.println("Enable pullups");
 digitalWrite(LED2, LOW);
 Serial.println("CAN init:");
 
 if (CAN0.begin(CAN_500KBPS) == CAN_OK) 
 {
 Serial.println("OK!");
 } 
 else 
 {
 Serial.println("fail :-(");
 while (1) 
 {
 Serial.print("Zzz… ");
 delay(1000);
 }
 }

Serial.println("Good to go!");
}

unsigned char offarray[8] = {0, 0, 0, 0, 0, 0, 0, 0}; // Always Off Array
unsigned char onarray[8] = {255,255,255,255,255,255,255,255}; // Always On Array

void loop() {
 // put your main code here, to run repeatedly:

for (int i=0; i <= 512; i++){ 
  for (int l=0; l <= 10; l++){  
    for (int j=0; j <= 100; j++){
       CAN0.sendMsgBuf(i, 0, 8,offarray);
       delay(10);
     }

     for (int k=0; k <= 100; k++){
     CAN0.sendMsgBuf(i, 0, 8,onarray);
     delay(10);
     }
   }
  }
}

So this loop will iterate through 512 addresses strobing all 8 bytes high and low on 1 second intervals. The trick here is that canbus needs regular packets to stay active, so we can’t just send a value once. In this case each value (high or low) is send 100 times at 10ms intervals so the cluster should stay active long enough to see if anything is happening. Each address will get 10 cycles of high and low before moving onto the next address. In concept this would work and provided ‘i’ is set to increment high enough you would cover all the addresses. Bear in mind at this rate you’d have to watch it for about 90 mins…

Thankfully around the time I started running though this trying to find any useful addresses I came across this :

https://www.cantanko.com/rx-8/reverse-engineering-the-rx-8s-instrument-cluster-part-one/

This nicely tied in with the hardware I was working on and so the code and information is all exceedingly useful and saved me a lot of time. Specifically it gives the address locations for most of the indicators on the cluster which is what we really need.

After lots of trial and error I managed to come up with a block of code that can control the cluster but easily allow me to set any warning light I need on the dash, or more accurately also to turn off all the warning lights. Something that will be essential come MOT time as a warning light that stays on is an MOT fail and since most of the systems that control them will no longer be in the car (primarily the original ECU).

#include <Arduino.h>
#include <mcp_can.h>
#include <mcp_can_dfs.h>


#define COMMAND 0xFE
#define CLEAR 0x01
#define LINE0 0x80
#define LINE1 0xC0

#define CANint 2
#define LED2 8
#define LED3 7

#define NOP __asm__ ("nop\n\t")

// Variables for StatusMIL
bool checkEngineMIL;
bool checkEngineBL;
byte engTemp;
byte odo;
bool oilPressure;
bool lowWaterMIL;
bool batChargeMIL;
bool oilPressureMIL;

// Variables for PCM
byte engRPM;
byte vehicleSpeed;

// Variables for DSC
bool dscOff;
bool absMIL;
bool brakeFailMIL;
bool etcActiveBL;
bool etcDisabled;


MCP_CAN CAN0(10); // Set CS to pin 10

void setup() 
{
    
    //Serial.begin(115200);
    //Serial.println("Init…");
    //Serial.println("Setup pins");
    
    pinMode(LED2, OUTPUT);
    pinMode(LED3, OUTPUT);
    pinMode(CANint, INPUT);

    //Serial.println("Enable pullups");
    digitalWrite(LED2, LOW);
    //Serial.println("CAN init:");
    
    if (CAN0.begin(CAN_500KBPS) == CAN_OK) 
    {
        //Serial.println("OK!");
    } 
    else 
    {
        //Serial.println("fail :-(");
        while (1) 
        {
            //Serial.print("Zzz… ");
            delay(1000);
        }
     }

Serial.println("Good to go!");
}

unsigned char stmp[8]       = {0, 0, 0, 0, 0, 0, 0, 0};                         // Always Off Array
unsigned char otmp[8]       = {255,255,255,255,255,255,255,255};                // Always On Array

unsigned char statusPCM[8]  = {125,0,0,0,156,0,0,0};                            // Write to 201
unsigned char statusMIL[8]  = {140,0,0,0,0,0,0,0};                              // Write to 420
unsigned char statusDSC[8]  = {0,0,0,0,0,0,0,0};                                // Write to 212

unsigned char statusEPS1[8] = {0x00,0x00,0xFF,0xFF,0x00,0x32,0x06,0x81};        // Write to 200 0x00 00 FF FF 00 32 06 81
unsigned char statusEPS2[8] = {0x89,0x89,0x89,0x19,0x34,0x1F,0xC8,0xFF};        // Write to 202 0x89 89 89 19 34 1F C8 FF

unsigned char statusECU1[8] = {0x02,0x2D,0x02,0x2D,0x02,0x2A,0x06,0x81};        // Write to 215 - Unknown
unsigned char statusECU2[8] = {0x0F,0x00,0xFF,0xFF,0x02,0x2D,0x06,0x81};        // Write to 231 - Unknown
unsigned char statusECU3[8] = {0x04,0x00,0x28,0x00,0x02,0x37,0x06,0x81};        // Write to 240 - Unknown
unsigned char statusECU4[8] = {0x00,0x00,0xCF,0x87,0x7F,0x83,0x00,0x00};        // Write to 250 - Unknown


/*

215 02 2D 02 2D 02 2A 06 81 // Some ECU status

231 0F 00 FF FF 02 2D 06 81 // Some ECU status

240 04 00 28 00 02 37 06 81 // Some ECU status

250 00 00 CF 87 7F 83 00 00 // Some ECU status

*/


void updateMIL()
{
    statusMIL[0] = engTemp;
    statusMIL[1] = odo;
    statusMIL[4] = oilPressure;
    
  if (checkEngineMIL == 1)
  {
    statusMIL[5] = statusMIL[5] | 0b01000000;
  }
  else
  {
    statusMIL[5] = statusMIL[5] & 0b10111111;
  }
   
    if (checkEngineBL == 1)
  {
    statusMIL[5] = statusMIL[5] | 0b10000000;
  }
  else
  {
    statusMIL[5] = statusMIL[5] & 0b01111111;
  }

   if (lowWaterMIL == 1)
  {
    statusMIL[6] = statusMIL[6] | 0b00000010;
  }
  else
  {
    statusMIL[6] = statusMIL[6] & 0b11111101;
  }

     if (batChargeMIL == 1)
  {
    statusMIL[6] = statusMIL[6] | 0b01000000;
  }
  else
  {
    statusMIL[6] = statusMIL[6] & 0b10111111;
  }

       if (oilPressureMIL == 1)
  {
    statusMIL[6] = statusMIL[6] | 0b10000000;
  }
  else
  {
    statusMIL[6] = statusMIL[6] & 0b01111111;
  }
}

void updatePCM()
{
    statusPCM[0] = engRPM;
    statusPCM[4] = vehicleSpeed;
}

void updateDSC()
{       
  if (dscOff == 1)
  {
    statusDSC[3] = statusDSC[3] | 0b00000100;
  }
  else
  {
    statusDSC[3] = statusDSC[3] & 0b01111011;
  }

    if (absMIL == 1)
  {
    statusDSC[4] = statusDSC[4] | 0b00001000;
  }
  else
  {
    statusDSC[4] = statusDSC[4] & 0b11110111;
  }

      if (brakeFailMIL == 1)
  {
    statusDSC[4] = statusDSC[4] | 0b01000000;
  }
  else
  {
    statusDSC[4] = statusDSC[4] & 0b10111111;
  }

     if (etcActiveBL == 1)
  {
     statusDSC[5] = statusDSC[5] | 0b00100000;
  }
  else
  {
    statusDSC[5] = statusDSC[5] & 0b11011111;
  }

    if (etcDisabled == 1)
  {
    statusDSC[5] = statusDSC[5] | 0b00010000;
  }
  else
  {
    statusDSC[5] = statusDSC[5] & 0b11101111;
  }
 

}

void loop() 
{
    // StatusMIL
    engTemp         = 145;
    odo             = 0;
    oilPressure     = 1;    // Either 0 (fault) or >=1 (Ok)
    checkEngineMIL  = 0;
    checkEngineBL   = 0;
    lowWaterMIL     = 0;
    batChargeMIL    = 0;
    oilPressureMIL  = 0;

    updateMIL();
    CAN0.sendMsgBuf(0x420, 0, 8, statusMIL);
    delay(10);


    // StatusPCM
    engRPM          = 60;    // RPM  Value*67 gives 8500 RPM Reading Redline is 127
    vehicleSpeed    = 93;    // Speed  Value=0.63*(Speed)+38.5

    updatePCM();
    CAN0.sendMsgBuf(0x201, 0, 8, statusPCM);          //CAN0.sendMsgBuf(CAN_ID, Data Type (normally 0), length of data, Data
    delay(10);

    // StatusDSC
    dscOff          = 0;
    absMIL          = 0;
    brakeFailMIL    = 0;
    etcActiveBL     = 0;    // Only works with dscOff set
    etcDisabled     = 0;    // Only works with dscOff set

    updateDSC();
    CAN0.sendMsgBuf(0x212, 0, 8, statusDSC);
    delay(10);

/*
    CAN0.sendMsgBuf(0x200, 0, 8, statusEPS1);
    delay(10);            

    CAN0.sendMsgBuf(0x202, 0, 8, statusEPS2);
    delay(10);    
           
    
    CAN0.sendMsgBuf(0x215, 0, 8, statusECU1);
    delay(10);  

    CAN0.sendMsgBuf(0x231, 0, 8, statusECU2);
    delay(10);  

    CAN0.sendMsgBuf(0x240, 0, 8, statusECU3);
    delay(10);  
    CAN0.sendMsgBuf(0x250, 0, 8, statusECU4);
    delay(10);  

*/
            
 }

This is the current latest version of the code I have, the serial comms section at the start is handy for checking you have a working connection but if you don’t have the serial monitor open it will cause the Arduino to hang at the transmit instruction and not get as far as updating the canbus so I recommend enabling these initially but once you get a working connection comment them back out as above. There are also sections above taken directly from the Cantanko page to deal with the power steering controller and some other bits, I haven’t tried these yes as the cluster isn’t in a car but I plan do so at some stage.

This code has some limitations in this form, basically the warning lights etc are set in the code as static values so this code will just set everything normal and all the lights I have addresses for to off. One particular curiosity is the way the cluster treats the oil pressure value. The data space actually has a whole byte for a value here but the cluster only only has two values despite having an actual gauge, a value of 0 drops the needle to the bottom, a value of 1 or more sets the gauge to normal. My feeling on this is the car was originally intended to have a proper oil pressure transmitter but someone decided it was too expensive and a normal pressure switch was used instead and rather than redesign the cluster they just changed the scaling in the on board microcontroller to behave as described. long term I’d love to mod the cluster to add the analog functionality back in but without the code for the controller this would probably involve disconnecting the original drive to that gauge and adding another Arduino inside the cluster just for driving that gauge. It seems like a lot of work to know oil pressure on a scale of low to high!

The code also sets a speed and RPM however the ODO and trip meters will not increment as it stands – I purposefully left this bit of code out because it’s only really applicable if you’re on an actual car otherwise your cluster will just keep clocking up. The ODO and trips seemed to be the one bit no-one else had managed to do or identify but after quite a few hours of testing  random blocks will various combinations of high and low as well as sending incrementing / decrementing values I noticed my trip meter had actually moved up by 0.1 miles which meant something was working. I eventually managed to trace it to the address listed above. The trick to actually making it work is that the value in the byte is irrelevant to what the cluster displays, so no this doesn’t let you clock it back! What it appears to do is counts the changes to the value so I made it work by setting up a loop of code that keeps changing this value up to a certain number to give a specific distance. Turns out the cluster needs to see 4140 changes per mile. Eventually I plan to tie this in to the speedometer value so only one value needs to be set, by knowing the pulses per mile and the speed we can work out the time delay between each change. As an example at 100mph we need to send 115 changes per second, this is one every 8.7ms which is obviously faster than the loops above and so for speed and accuracy would have to be hardware timed with an interrupt to do the update at the right speed. I’ll probably do an updated version at a later date.

There’s a couple other things I need to sort out, the airbag warning light being the prime one because this is an outright MOT fail. Now in theory when it’s back on the car it should work just fine as the airbag wiring is all there but I figured it was worth working out anyway. So after working through all of the RX8 cluster wiring diagrams (1)(2)(3)(4) I pieced this together :RX8 Cluster Pinout

This covers the majority of everything someone might need to use the cluster on a simulator apart from the fuel gauge. The RX8 fuel gauge is a bit of an oddity because the car uses a saddle shaped fuel tank to allow it to clear the driveshaft and so it has two senders denoted as ‘main’ and ‘sub’.

RX8 Fuel System Senders

Each of these apparently has a resistance value of between about 325Ω at the bottom and 10Ω at the top. There seems to be some questions about how this system works out what to display based on the two sender values and whether it expects to see one remain full while the other empties or something similar. Unfortunately I’ve not played with it much because I’ve don’t actually need to make this work off the car (since the car will have the senders but I can say putting 100Ω a resistor between both 2R-2P and 2R-2T gives a value of about 1/3 of a tank and 9Ω (because I just added a 10Ω on along side the existing 100Ω) across these connections gives a full tank reading  (actually a little above full) so as long as you move both together it works fine, this is ok if all you want to do is get the fuel warning light off for a driving simulator but not that helpful for a single fuel sender conversion which is why most people are interested. If I get chance I’ll investigate further. Also for some reason it takes an absolute age to move up the scale which is a bit unfortunate but I suspect is as intended. At least it should be stable!

All of that leaved us with just one light I can’t get to turn of, the warning light for the electronic power steering. This is controlled via canbus by the look of the circuit diagram but as yet I’ve not found the address for it. If anyone knows the address please leave a comment! Else I will have to go back to either trial and error or the really dodgy backup plan which involves cutting the tracks in the cluster and doubling up on another warning light which isn’t used much! Maybe I should just add another controller in the cluster!

So hopefully that gives you (almost) everything you need to know about making the cluster work! We might get back to mechanical things in the next update…

Old Houses!

So having started putting information on here there has been something of a gap in progress to to various other projects getting in the way, a problem I’m sure others will sympathise with!

On thing that’s been keeping us all busy of late is our house (which is a very old ex pub) appeared to have something of a woodworm, nothing too serious but a problem we wanted to rectify while we still had as little stuff as possible to do any harm to! Anyway the outcome of this was we needed to treat the entire attic and first floor meaning we had to remove all of the floorboards on the first floor and clear all the attic space, in total something like 200m², so let the chaos begin!

So the story begins with dust, not just any dust but the sort of residue you get after a building has been left for upwards of 200 years, this stuff is awful, if you have have to deal with it you’ll understand what I mean! It WILL get everywhere, I’ve previously used those cheapo disposable masks and have found that while they more or less work as soon as you start moving about a bit they either fall off or lift away from your face enough to leak and not do anything. My feeling on this is if you ever have to do anything like this it’s worth splashing the cash a bit on a half decent one. Personally I bought 3 of these : http://www.screwfix.com/p/site-reliance-28-day-half-mask-respirator-ffp2/1232j
T
hey seemed to fit well as they are flexible rubber and have replaceable filter elements. There are plenty of other options that should also be fine, out of preference I would just avoid the cheapo ones. This was around the time we realised the better masks were a good idea.

dust
Dust!

Adding to the above, safety goggles! When you start ripping apart a building things will start flying, be they intentional or not! In our case we had to add a new loft hatch to one end of the building to allow access. the building being rather old and actually still has old style plaster and lath. This is where lots of small sticks are nailed onto the beams and the plaster would be pressed through between the sticks where it will curl round the back of them and set holding the plaster in place. This works very well if left untouched but sadly it’s rather fragile if it is ever disturbed the back half separates from the front and the plaster peels off the ceiling! The problem here being if you start cutting through it you will get covered in an torrent of plaster, horrible black dust, splinters, nails and anything else that’s previously been left all over the attic. We had big lumps plaster, concrete and even daub (as in wattle and daub)! Goggles are not just a good idea in this case, I rank them as essential! This is a chunk of daub we found in the attic, it’s about a foot wide…Admittedly if this fell on you goggles would only help to a limited degree!

Daub
Daub

So now next up we had two old galvanised steel water tanks up there that were long since taken out of use. Somehow, I’m not sure how, the tanks were about double the size of the hatch we had to get them through. The obvious answer to this was to make the tanks half the size! So knowing this I got tooled up and got to it. First off I tried a 4.5″ angle grinder, while it kind of worked sparks flew everywhere as expected and after cutting 6 inches or so the first cutting disk was gone. If you ever try this I recommend having a second person to hand with a fire extinguisher. you will also need plenty of cutting disks, or ideally a larger diameter grinder may work better! After my first disk I abandoned the grinder and went for a reciprocating saw, specifically this one. These are a very aggressive tool but highly effective. To be honest on these it was like a (very noisy!) hot knife through butter. In total for the two tanks I wore out one already part used blade, bent a second one that it turned out I had previously ruined and had to do the last couple inches with a new one – In hindsight I should’ve just started with the new blade!

So back to ripping up the floor, just as a quick example of what chaos we’re talking about here, so this is the master bedroom as :

Is it still the first floor if it doesn't actually have a floor?
Floor-less bedroom

And here’s another bedroom, after insulation was installed in the floor. In most houses this really isn’t necessary but in this case it has quite a few benefits. Firstly being an old building it has a lot of drafts from pretty well everywhere, there are large gaps around sections of the floor allowing all the warm air from the ground floor to escape upstairs, plus any noise passes right through.

Bedroom 1 Floor
Bedroom 1 Floor

Hopefully that will solve a lot of these problems, we also packed felt sleeving (I bought some of this, it comes as a tube which isn’t ideal but it can be cut open or if the pipes are really close just wedged between them pressed flat as a double layer between to stop them clanking as they change temperature.

Anyone looking at this and thinking  there’s a lot of pipes and cables in there, you’re right! Being an ex-pub everything is wired separately so we have quite a lot of individual sockets which have their own circuit breakers and other related things which would be excessive in a house but in a business where you don’t want one faulty appliance to trip out all the power it becomes worth the additional cost and effort!

The other thing we’re working on is adding a networking cupboard to tidy up all of our wiring and to add a number of wireless access points to have internet all over the building. Being old and stone construction wifi doesn’t exactly travel far so we need to do something a little more serious than the average wifi router! I suspect that’ll be another blog another day!

Hello world!

Welcome to my blog, this is where I plan to record all the projects I do primarily for my own benefit but also with the home that someone else might find some aspect of it useful.

Projects will cover a huge range things, from quite simple to very involved and technical and will cover electrical. mechnical, DIY and anything else that comes along.

I don’t try to claim the way I do everything is necessarily the right way to do things but where there’s failure I plan to record that as well – failure is just another way to learn!