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Westfield SEiGHT Build

4 July 2009

Session 293 - throttle bracket

4 hours


Another month and a little more closer! So todays little project was to fabricate a throttle bracket. I had took some measurements in the week regarding how much the throttle cam moves compared to the throttle pedal. Total throttle pedal movement is 80mm, this translates to 40mm at the top of the pedal where the throttle cable attaches, this can be fettle a little bit by grinding away bits of metal. Unfortunately the throttle cam movement translates to 87mm. There is no way this is gonig to work directly. I need to design a bracket with a lever to match the movements.

Been spending a lot of time thinking about this and also numerous discussions on a number of forums and I have come up with a plan.



Photo showing the throttle cam. The cable on this design is rear facing.You can see my top mounted pedal box with a hole and slot to take the cable. The angle is a bit accute and would required the cable to snake around a bit, not ideal.

















An idea from another westfield owner is to use rodends and a bar. Here's one I made up earlier. Will attach to the throttle cam like this and angle downward slightly. I rodends are great, very useful. not cheap though! This will translate to linear movement of the throttle rather than the normal progressive type, could be interesting.
















This rodend will connect to a level which will then translate using the require ratio conversion to a standard throttle cable. This will move in the right direction and the cable will come into the pedal box pretty much straight on. This level will need a substantial bracket to mount it on. My idea is to mount under the second and third plenum chamber bolts from the left in the photo. This bracket will need to be bent and mounted under another bolt at 90 degrees to give stability. This is where the rocker cover bolt comes in which you can see in the lower middle of the photo.























So I went about designing a bracket and made a cardboard template for, as seen below.
























I then located a piece of 2mm stainless that has been in my garage for ages. By pure chance, maybe its a good omen, its the right length!





















So transferred the template onto the sheet ready for cutting.




















and a short time later, its cut out. Clamped between blocks of wood to form the 90 degree bend.




















Few blows of a rubber mallet later. Perfect 90 degree bend, old skool style.





















Now will it fit.


















Course it does!

But will the bonnet fit, erm, I hope so otherwise just wasted 4 hours!


















Phew, it does fit. If this bracket does not work out to be strong enough then i'll consider it a working proto-type and get it made up in steel.

That's all I have time for today. Tommorrow I'll set about making the lever to mount on the bracket. I might then have a fully functioning car, whoah!



5 July 2009

Session 294 - Throttle bracket part 2

5 hours

five more hours on this and still not finished, close.

Double checked the total linear movement of the throttle and the pedal and both are 40mm. So all I need is a lever with pivot in the middle. I am going to choose a length which equates to the distance between the throttle and the pedal to keep the rod, cable and bracket 90 degrees to each other. I am also going to set it so the bracket is at the 90 degree position when throttle at mid-point as suggested by a westfield forum member. So the bracket will be 100mm long by 25mm wide. I choose the width based on the size of repair washers that I will use to spread the load of the bolts that will connect the rod, cable and spindle.

Photo below showing the template for the lever and position to be installed on the bracket I made yesterday.

















Lever cut out and drilled ready for spindle and posts.



















A few hours later! Rod end post, rods and 6mm stud cut down to size and installed. For the cable I drilled a 2mm hole through a 6mm bolt, yes it was tricky. The cable was then inserted through the metal crimp on the end holding the cable in place. for the spindle I have used a number of bolts, metal and nylon washers. Spindle is held firmly in place and has penny washers spreading the load on the bracket. The nylon washer allows the bracket to spin quite nicely but with no lateral movement. The bolt holding the throttle cable has been installed so that it is allowed to spin this allows the cable to move as the angle changes.


Photo below showing the position of the lever with the throttle closed.
















Position of the bracket with the throttle fully open. Note the piece of angle bracket held on with masking tape. I considered using this has the outer cable stop but I am not 100% decided yet. I might just drill a 2mm hole through another bolt and use that as a stop.


















Whilst I was going through the full range of motion I noticed the the rod end on the throttle cam was fouling with the smaller outer cam spindle at closed throttle. So armed with a file I clearanced it.















Putting on the bonnet at the end of the day I checked clearance of the bracket, specially the posts. I noticed that the throttle cable post was quite close. I can drop the lever down by 3mm by using a different nut. I can also lower the post by 2mm. That sholud be enough, but that's for another day.




6 July 2009

Session 295 - Throttle bracket part 3!

3 hours

Yes another three hours on the throttle bracket, well perfection can take time!

So what did I do this evening. Well I made a post to form a stop for the outer throttle cable sheath, yes another 6mm bolt with a 2mm hole through the middle. I cut the throttle cable and sheath to size. I have temporarily clamped the cable on the end of the throttle pedal lever, well I cannot cope with drilling another 2mm hole through a bolt this evening. I had to cut a couple of millimetres of the rod amazing how much difference it makes when you clamp down the bracket so that it does not move. There's seems no slack in the system and the brackets or level do not flex from what I can see, this is looking like this is actually going to work.

Photo below showing everything connected and throttle closed.


















This photo showing throttle fully open as you see it just about hits the stop. There we have it, throttle pedal total movement from top to bottom matching exactly the throttle fully close and open.

















Whilst I was making this bracket I wondered a number of times what the throttle pedal feeling would be like, would it be heavy or light or just right? The spring on the throttle itself is quite strong when tuning by hand. Would the pedal feel stiffer at the bottom of the range? Well now it is all connected I can see it feels very light, too light with all the power! I am going to install a spring at the top of pedal level to give some more feeling. I can play about with different spring rates to get the feeling just right.


You may have noticed that the lever on the bracket is quite close to the bracket now, I changed this for two reasons, 1) if the lever does flex it will be stopped by the bracket and more importantly 2) it gives me some extra under bonnet clearance. I have also chosen to mount the bracket under the plenum chamber flange.


Photo showing under-bonnet clearance, close but not too close I hope!
















9 July 2009

Session 296 - Throttle pedal


3 hours

Decided to replace the bolt holding the throttle cable on the bracket for a large one so that I could drill a larger hole half way trhrough to hold the outer sheath more securely. I also inserted a piece of electrical wire outer sheath s othat the throttle cable is not making contact with the bolt. I'll replace this when I find something more suitable but for now it works well.

Connected the throttle cable to the pedal using an M6 bolt with you guessed it anohter drilled 2mm hole through the centre. I inventionally used a longer bolt that necessary so that I could anchor two springs to put more feeling into the pedal.




11 July 2009

Session 297 - Plenum chamber gasket

2 hours

Having done some tuning on the engine I had noticed that the manifold pressure at idle was a little unstable (varying by 2kpa) and suspected a small yair leak between the plenum chamer and inlet manifold. Pressing down on the plenum chamber whilst engine was idling did some to make a difference. So I removed the plenum chamber with the hope that the cork gasket would survive, of course it did not. So today's task was to source some cork sheeting (hobbycraft!) and set about making a new gasket.


So using the old gasket as a template along with the plenum chamber and the plenum base I made a paper template. When I intially installed the original gasket I noticed it was a litle close to some of the bolts that fix the plenum chamber base plate flange.My gasket will be a little different to clear this bolts.

Below is a photo showing the original gasket in the background and the paper template in the foreground.



















Cork sheet with the template carefully transferred and double checked against the plenum chamber.




















I then proceeded to cut this out with a surgical scapel. The holes where cut out with a hole press cutter (new tool from hobbycraft)

Photo below showing the gasket placed on plenum chamber.



















Photo showing the plenum chamber the right way up with gasket underneath.


















Holes all line up nicely, really happy with the result, it is better than the original one! I managed to speak to ACT performance today, the manufacturers of the Carbon fibre plenum chamber. I spoke about the gasket and the air leak. He recommended that I bond the gasket to the plenum chamber with the usual flange sealant but seal with blue hylomer on the plenum base. Sounds like a good idea as the plenum flange being CF is not completely smooth and you can feel the weave so a flange sealant would provide a better seal. The metal flange on the trunpet base is of course very smooth and straight so blue hylomer would be okay. This should then mean if I need to remove the chamber again, hopefully not, that it should peel of without wrecking the gasket.






12 July 2009

Session 298 - Plenum chamber fitted

2 hours

Sealed down the gasket to the trumpet base using blue hylomar as per ACT recommendation.

















I then applied a generous bead of flange sealant to the carbon fibre plenum chamber, messy stuff. Bolted down along with the throttle bracket.


















Made some minor tweaks to the throttle rod ends. I have also installed the rod end on the throttle cam with my purpose cut bolt, looking very slick no slack at all.

Below is a photo showing how I have attached the cable to the pedal along with the springs to give the pedal some feel at least.


















I had previously mentioned that I need to make some adjustments to ensure the throttle butterfly was not over extended. See photos below.

Photo showing the throttle almost closed, just open enough to sustain idle speed.I forgive if you cannot tell the difference!



















Photo showing throttle completely open with throttle pedal on the floor.












Gave it several hours for the silicon to dry. Started the car up with my PC connected to the ECU in logging mode. Analysing the logs show a manifold pressure variance of less than 1Kpa, result.

I could resist no more, took the car out of the garage, off the drive, down my cul-de-sac. To test the throttle, awesome.












17 July 2009

Session 299 - Dash calibration

Over the course of last week I continued calibrating my dash, what a pain this is turning out to be! The water temperature seems to be consistently 6 degrees hotter than the ECU temperature. I know the ECU is right as it reads 89 when the fan is switched on and 82 when fan is switched off. The fan is operated by a thermostat, on at 89 and off at 82. I tried plugging in formulas for the water sensor from Westfield and the orginal manufacturer and still it remains 6 degrees out. I therefore decided to change the formula myself and came up with:

Water temperature in celius y = 9.68x3 + 55.79x2 + 120.49x + 110.13


The fuel formula provides a fractional readout, i.e. full is 1, half full is 0.5. This looks better as fractions on old dials, but digitial seems foreign, ie, 0.1 ? So I decided that I wanted the read out in litres. I calculated the volume of my tank a while ago and it came out as 42 litres. So I transposed this formula so that 1.0 would become 42 and this 0.5 would be 21. This formula comes out at:

Fuel level in litres y = 51.9x + 0.853


Westfield formula for the oil pressure gives a read out in bar. I prefer PSI so I transposed the formula and arrived at:

Oil pressure in PSI y = -2.86x3 + 31.51x2 + 66.14x


We shall see how these settings compare.




18 July 2009

Session 300 - Car weight and its distribution

4 hours

Weight distribution below is car fully loaded with 20 litres of fuel but no driver:

Near Side Front 173kgs Front Left to Right distribution 49.7% Front to Rear distribution 48.5%
Off Side Front 175kgs Front Right to Left distribution 50.3%    
Near Side Rear 185kgs Rear Left to Right distribution 50.0% Rear to Front Distribution 51.5%
Off Side Rear 185kgs Rear Right to Left distribution 50.0%    
Total 718kgs        



Weight distribution below as above but with driver:

Near Side Front 173kgs Front Left to Right distribution 47.1% Front to Rear distribution 46.0%
Off Side Front 194kgs Front Right to Left distribution 52.9%    
Near Side Rear 208kgs Rear Left to Right distribution 48.3% Rear to Front Distribution 54.0%
Off Side Rear 223kgs Rear Right to Left distribution 51.7%    
Total 798kgs        






19 July 2009

Session 301 - Ride height

8 hours

I write my blog whilst setting in my car thinking of future blats out in the countryside on warm summer days. I've got to get that IVA booked soon. Anyway back on topic. Do not under estimate how long setting ride height takes. As you probably know I had set the ride height to the Westfield recommended values when all the body work and most of the drive train was in. Rear was 175mm and front 160mm. A word of warning, a flat surface such as a nice flat garage is a must be easily forgotten is to make sure the tyre pressures are correct. I thought my rideheight hadn't dropped too much until I remembered that I had pumped my tyres upto 36PSI so stop flat spots on the tyres where the car would be standing for a while. Suspension settings should be made at the correct tyre pressure of 18PSI! has it dropped, quite a bit. 10mm at the front and 5mm at the rear.

The ride height should ideally be set so with the driver installed and half a tank of petrol, slightly tricky. Tried getting my son to measure with me in the car was not going to work as he has not got as much patience as me and being taller finds it awkward trying to measure under the car in a cramped garage. So had a change of plan. We weighed and found that we were very similiar in weight closer enough not to worry about it. So he sat in the car for hours whilst I dialled in the ride heights. I would like to have the car quite a bit lower that the high settings that Westfield recommend but I have an under slung exhaust which needs clearance. Also my drive has the usual apex where it meets the pavement. So I am going to set my ride height so that it just clears this. This is higher than I wanted but not too bad.

So I adjusted all the suspension back to the base 160mm front and 175mm. double checked all measurements after pushing the car up and down and rolling it back and forth, important this, to settle the suspension. My son got in the car with his book. I then re-measured around again. Boy what a difference. Car had dropped 19mm at the driver side rear. 11mm passenger side rear. 2mm passenger side front and 7mm driver side front!

Don' think that adjusting the platform up the damper body by this drop is going to work because it doesn't. Depends on the spring rate, etc. Also important to make sure the dampers are set to their softest setting when doing this. Its trial and error and a bit of guess work and make small changes. Also when adjusting one corner it will affect the other three! So you quite literall have to make small adjustments and measure the other corners and adjust these as well. Each time having to lower the car off the jack and move bakc and forth. You can see why this takes a while.

Anyway to cut this story a little shorter, some 5 hours later I have it all level with the driver. final settings came out at 156mm at the front both sides. 169mm at the rear both sides.Big question does it clear the driver. Well just about, can hear the exhaust flange on the middle section just scrapping on the apex as I go over. Am I going to re-adjust, erm, its easier and less painful to go on a diet next week!!

I have now set all the dampers rate to six clicks from softest setting. These dampers have forty clicks!

A tip, when adjusting the suspension I found it very useful to have a piece of paper saying, well not this long but to clarify for reader:


clockwise from top of damper lowers ride height (ie front of car)

anti-clockwise from top of damper raises ride height (ie front of car)

clockwise from bottom of damper from bottom of damper raises ride height (ie. rear of car)

anti-clockwise from bottom of damper from bottom of damper lowers ride height (ie. rear of car)


I also re-installed my oil pressure sender which I had taken off in favour of a mechanic one when I had oil pressure problems. This is very cramped as mostly everything is on this car now. Oil pressure reads 43PSI when cold, well I say cold, its a warm day Warm it reads 38PSI at idle. So this seems to be reading slightly lower than the mechanic gauge but acceptable.

I also did a quite sound check of the exhaust. sound meter placed on an axle stand some 500mm away from the exaust tip at an angle of 45 to the side put level with the exhaust. Reading should be taken at the RPM which represents 2/3 of engine power not sure where this is on this engine but max RPM is 6000 and thats when the cam powerband ends so I thought I use this as the maximum power, probably lower but err on side of caution. So took engine upto 4000RPM, first time I have taken it this high, scary. It registered 97.8decibels lower than I thought, it sounds louder.




25 July 2009

Session 302 - Rear valance

8 Hours

Yes eight long hours! This is one of the hardest panels to get right I am sure. Have to cut holes for the exhausts and this is quite hard with the angles. I used a hole saw to cut out a best measured hole. Then trial fitted and worked out from the hole using a dremel .Cut holes on the underside to clear body rivets that were installed to hold the body on the chassis to ensure a flat install. Installed ali mesh which had to be sprayed black to match my color scheme. Installed chrome exhaust tips. The fit is okay could be better but looks a whoe lot better than before.





































26 July 2009

Session 303 - Speedo transducer

2 hours

When I bought the dash2 digital dash I was not informed that this would not work with the standard speedo sensor if the truth was known I think this not realized by the supplier until some people experienced problems. This is the problem with going leading edge! Today's job was to install the new transducer and wire into the dash.

The standard transducer reads the drive shaft bolts at the rear of the car. This sensor is to be installed at the front and read the bolts that hold the brake disc onto the hubs. This reads 4 bolts rather than 6 at the rear. The speedo will beed re-calibrating for this.

The old speedo transducer as two wires, one for +12v supply and the other one being the signal. The new sensor has three wires, Supply, Ground and Signal. The new sensor has a nice feature it illuminates as the bolt head passes it, nice! I set it at 2mm from the bolt head.

Westfield supply a small bracket to hold the sensor in position, this is clamped under one of the bolts that hold the steering control arm to the upright. See photo below. Then the task of routing the wire from the upright, to the wishbone, into the engine bay, missing the hot exhaust headers and through the scuttle, I literally just had enough cable to do this.

The wiring into the loom was accomplished by locating the speed connection block which plugs into the sub-loom of the dash2. I cut the yellow/white and soldered the black wire from the transducer to it, this is the signal. I cut the yellow/green wire, this wire is connected to ground through the dash2 connector so I solidered the blue wire from the transducer to it, this is ground. Remaining wire from the sensor is brown which is +12v so I tapped into the green wire on the connector, which in turn also supplies the dash2 with power.

I am a little concerned that this sensor is not particularily designed to cope with the environment in which it will be used, we shall see.

Next up calibrating the speedo. The unit is configured to how many pulses are received per mile from the sensor.This is calculated as 1609 divided by tyre circumference in metres multiplied by number of bolts. This works out as 1609 divded by 1.84 multiplied by 4 which equals 3498 pulses per mile.

I jacked the car up and rotated the front wheel as rapidly as possible, it registered 8mph. Could be right.




Photo showing the bracket and speedo transducer install.
















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