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Phase IV ... The Dedicated Track Car

Commenced Nov 2006

Last Updated 3 Jun 07

Recent History. 

Its been a couple of years since I brought the 951 back to Australia and its spent most of its time in the garage not being used. There is no practical way to have the car road registered here and so its only realistic use is as a track car. After bringing the car back from the US I installed the Haltech E6X ECU in the car to give me some flexibility in tuning and to overcome the reliability problems that invariably develop with 20 year old wiring harnesses and electronics. After getting the Haltech installed I managed to knock 3 seconds off my best lap time at Mallala and had a blast in the process. The car had been off the road for quite some time while I sorted out the bugs in setting up the Haltech but one day at the track was enough to start a new itch. I blame that on a GT3 Cup car that blew past me and triggered a desire to take the 951  to a more serious level. That was enough to get me past the point of not wanting to strip the car that I had spent so much time restoring. Whilst the car had been a lot of fun on the track it was still a street/track compromise car at that point. It weighed 3000lbs and had suspension that was still on the soft side 300lbs springs & 29mm torsion bars and a mix of polyurethane and monoball bushings.

So the new plan became to turn the car into a dedicated track car.  With that in mind I had plenty of scope to start making changes. Clearly, losing weight was going to be a primary objective and replacing the existing dampers with more appropriate units was the second key aim. Thirdly I needed to add more front rubber for increased braking traction and cornering traction.

Since the car is to be dedicated for the track I also chose top eliminate every accessory that was not essential including lights and  wipers. I decided to remove all of the original wiring and replace it with new harnesses that provided just the basics that I needed for a track setup. This helps reduce the weight and complexity of the car and increases reliability.



In this first round of weight reduction I am not going with composite panels or lexan windows, instead I am just removing unnecessary gear and trimming unnecessary metal such as from the doors. I used a small digital kitchen scale to measure the weight of everything small so as to get a good idea of progress. The car already has a roll cage, fire system and race seats and on the bad side is also had a lot of dynamat sound deadener. Starting weight was thus 3000lbs. The goal I set for the initial round of weight reduction is 2500lbs. Naturally AC delete was a good starting point, as was a light weight battery which I have relocated to the area of the passenger seat so that it can help with centre of gravity as well as weight reduction.... May 07 I put the car on the scales (finally) 1160kg/2550lbs was the outcome. That was close to an empty tank.


Areas I simplified things were in electrics, vacuum plumbing and coolant plumbing (eliminated electric turbo coolant pump).


My previous paint work on the car had been exterior only and the interior was a mix of original blue and the red that the car was painted by a previous owner. Basically in stripped form it was going to annoy the hell out of me so I decided I would strip, scrape, scrub, dissolve, burn, sand and whatever else it would take to get all the old mess out and end up with a bare & clean interior. Then I planned to paint it basic white.

Nov 2006

Not being a fan of removing overspray I figure that masking is a lot easier than scrubbing.

I used generic primer surfacer primarily to minimise visible scratches that resulted from the use of a chisel which had proven the most effective method for removing the extensive dynamat which covered the floorpan.

The enamel I used, Wattyl Kill Rust, High Gloss Enamel, does not require a primer but I elected to use primer for the entire floorpan / roof for consistency.

Single coat of white enamel. The first coat was sprayed pretty light, using only 1 litre to do the entire floor sides and roof. This was left to dry for 24hrs (as were all subsequent coats)

2 coats enamel, some of the nooks & crannies and 90 degree corners looked a lightle darker than the main area's and so I eventually put a third coat in those corners to get them an even colour with the rest.

The paint/primer combo did an excellent job of covering minor scratches in the floorpan.

Issues: 1 Fisheye on the A pillar despite prepwashing. Solution: Left as is then sprayed over the following day with a fisheye eliminator additive. This worked fine. This paint seemed pretty forgiving and produced an excellent finish when sprayed properly.

Sat 25 Nov:

De-masking, Re-assembly begins

My son Alex had been observing the whole process and was keen as ever to assist with the unmasking.


The final finish worked out nicely, given the uneven nature of the floorpan and the fact that the car is now purely track, little effort was put into denibbing / sanding the paint, consequently it is not as smooth as would be expected of an exterior automotive finish. Having said that, it's smoother than I expected it would be.

I cut away the door internals to save weight and will prop the glass in place for transport and storage using a removable wooden prop.


The doors were sanded back to clean them up but otherwise painted without primer and the enamel still produced a consistent quality gloss finish. The sunroof was also painted without primer. At this stage the windows, hatch and trim is going back on the car.


I wanted to eliminate the stock dash in favour of a lighter alternative. The pics here show what may or may not be the final solution, its a simple folded piece of aluminium sheet (the folds cost more than the stock) which I trimmed to shape after using some cardboard to make a template. If I continue with this option I will fabricate some end plates to bolt up to the stock dash mounting bracket that can be seen in the middle pic. The main things I am aiming for with the dash  was low weight, simplicity and accessibility for the wiring and guages that will be mounted there.  Simple dashes already exist in the US for these purposes but shipping to Australia is a pain so this became a case of necessity becoming the mother of invention.

5 Dec I have added new pics with the gauge and accessory holes now cut into the dash. The gauges have ended up perfectly positioned for my view through the steering wheel. That was achieved by using some 52mm paper circles taped in place and repositioned until such time as I could see them clearly whilst seated. The warning and shift lights are also visible through the steering wheel thus being in my peripheral vision most of the time. The less important gauges are mounted to one side. The Apexi boost controller now gets a home in the dash and the Innovative LM-1 wideband controller will get a separate bracket under the dash. The pics show the dash with some black satin paint on it that looks nice and I have also put a textured white flecked paint on the upper surface of the dash to ensure that glare issues are minimised. The face has been left smooth plain black so that the gauge labels will adhere properly.

Good guts info:  I cut the holes for the 2 1/16th gauges as 51mm using a hole saw in a drill press and I have used a 101mm hole cut with a scroll blade jigsaw (rough cut) followed up by hand trimming to a scribed line with a crosshatch TCT bit in an air die grinder. Note: Straight fluted bits and grind stone bits will tend to bind up with aluminium, hence the crosshatch bits were most effective. The side bracket can be seen from the pic that is straight forwards. I also made a pair of 80mm x 50mm right angle brackets from some 25x3mm flat aluminium bar, these attach to the 8mm studs in the metalwork below the windscreen and secure the dash in its middle upper surface. Once the brackets are attached to the firewall area I put the dash in place and then drilled corresponding holes in the dash upper surface.


Sun 26 Nov: Roll Cage

The Autopower bolt-in roll cage went back in today. I decided that the bolt in cage will do the job (and stop me from holding up the job) until I can invest in a suitable pipe bender and TIG welder. The autopower cage was fairly painless to put back in once I remembered a few lessons from last time. That is to assemble the cage out of the car and label the location and orientation of every slider piece because they are all different and not every slider will allow the bolt holes to align at every joint. Hence pre assembly allows you to verify that bolt holes line up and generally they don't so a lot of swapping of sliders is involved until it can all be assembled. I am left with two holes that need to be enlarged slightly with a carbide bit and the die grinder. I had to drop the car back on the ground  before tightening up the mounting bolts so as to not introduce any chassis twist from being on the jack stands. Its been in the air for quite some time so it was nice to have her back on the ground and looking ready to roll again.

I was pleased to see that the dash and roll cage don't have any interference issues. I did figure that with a slight redesign I could probably make it so the dash can be removed with the roll cage in place. (as I'll need to do so I can put a non reflective coating on the dash.



3 Dec: Battery Disconnect:


Group 3D Sports Sedans require that a battery disconnect switch be installed within reach of the driver and whilst most install it near the A pillar I am not real keen on having all that heavy duty  battery cable running over such a long distance. I chose to mount the switch adjacent to the shifter because its in reach, its adjacent to the battery which I have relocated to the back of the passenger area and its between the starter and the battery. Of note I have also re routed the starter cable to go from the new battery location, along the torsion tube tunnel and then it penetrates the tunnel adjacent to the starter rather than having to go up and through the firewall and then double back to the starter. I like this routing as it minimises the unfused battery cable length. As it turns out my ICESHARK (RIP Dan) starter cable is plenty long enough to reach the battery in its new location. Also evident in this pic is the "tie rail" that is a simple aluminium flat bar formed to follow the tunnel. There is just enough clearance for me to use ziploc nylon ties along its full length, thus allowing me to keep the wiring, cable pulls and extinguisher tubing neat and tidy without having to drill  numerous holes for adel clamps (I like Adel clamps in some applications but they are not always the most flexible option where a multitude of items have to be secured.).


Seat back brace:

3 Dec 07



I did not previously have a seat back brace in the car and I noted some flexing in the seat when strapped in with the harness. I decided to alleviate that issue by fabricating a seat back brace which turned out to be a simple design since I did not need to make it adjustable. In the end I was surprised by how much more rigid the seat feels.


24 Dec 06 - Wiring Harness


With this build of the car I chose to relocate engine management sensors and electronics to the area previously occupied by the heater blower unit. This meant that I had to extensively rework the ECU harness - that basically meant cutting off all the existing terminations and splitting looms into new branches to suit the new layout. Internally all of the original wiring was removed so I had to build a new harness for dash functions, brakes, fuel pump, battery cut-off etc.


I ended up with 4 harnesses ECU, Dash LM-1 Wideband & Rear. Building the harnesses turned out to be a time consuming task - nearly 3 weeks worth. It could have taken less time but I chose to solder every single plug connection to ensure good electrical performance and minimise future electrical gremlins. The engine/ECU harness is protected in key areas by heat sheath and by woven fibreglass sheath in less critical/practical areas. The Injector harness also has an additional plug that allows me to insert a short harness for changing the way the injectors are wired to suit different batch injection strategies (this should have been done in the ECU software but that functionality is not supported). This approach also gives me an easy way to replace that section of injector harness if it does show signs of deterioration from heat.


On the dash side I have incorporated warning lights for Oil pressure, coolant temperature and the alternator indicator. The oil pressure light operates through a low pressure switch but does not come on unless the pressure is low AND the engine RPM is above 800. That's because the light is backed up by a warning buzzer that I don't want going off every time before I start the engine or when I turn it off. The function is controlled by one of the programmable outputs of the Haltech ECU. By the time all the gauges, switches and warning lamps were installed the dash wiring turned out to be fairly busy so I was glad that I had built a 'rail' into the dash which provides a means to secure all that wiring in an organised manner using simple nylon ties rather than Adel clamps. A soft 1" rubber strip between the rail and the wiring ensures that no inadvertent earthing can take place.


Radiator cooling is controlled by the radiator temp sensor as usual with power supplied via a general purpose relay and fused link to the 12V (off during cranking) terminal of the ignition switch. A turbo electric coolant pump is not utilised.


Fire Extinguisher Installed 26 Dec 06

Surprisingly I had a hard time finding 1/4" aluminium tubing locally so Summit Racing came to the party on that one. My setup takes one port from the bottle and splits that between outlets at the fuel tank and engine bay. The other port I routed to a 180 degree outlet facing the driver. It dumps halon towards the sides of the car as well as towards the driver position. The nozzle can be seen in the photo on the far left.



ECU Harness Installed  27 Dec 06



After bench testing the dashboard and ECU harness I was satisfied that there were no shorts or other unexpected issues so I made a mounting board for the ECU and installed the ECU and harness into the car. Using a few of the factory mounted nylon ties I was able to secure the harness into the footwell area in a tidy fashion. The remaining parts of the harness were secured to the previously installed 'rail' along the torsion tube tunnel.


Wiring Diagrams


These diagrams show/explain how various aspects of the wiring have been done.

The car has all non essential electrical items deleted including lights & indicators, wipers, turbo coolant pump. A Haltech E6X takes care of engine management and an Apexi AVCR manages boost. An innovative LM-1 provides wideband AFR to the ECU and its second channel is programmed to provide linear AFR output to the narrowband AFR gauge on the dash (ie true AFR indication)



Jan 8 2007

I deleted the turbo coolant pump and blocked off the heater outlet near the back of the head so that required some new coolant lines and adapters. A local radiator shop had a nice cap solution for the heater outlet on the waterpump. With the turbo coolant pump deleted I also had to reduce the 3/4 radiator hose to 19mm to go over to the coolant tank and that adapter had to be brazed up since it was not as easy to find one as may be expected.


I chose to relocate sensors to be centralised and close to vacuum ports and so ended up mounting the boost solenoid, boost pressure sensor, MAP sensor and ignition module all on one 'plate' that covers the heater blower hole. Also had to manufacture a new rubber seal for the harness to pass through the firewall. A trip down to Clarks rubber proved useful with some 10mmx40mm rubber strip proving ideal for this job. It turned out I could shape the rubber reasonably well with an aluminium oxide grinding wheel in my bench grinder. I ended up making the seal in two C shaped halves and used a hacksaw blade to cut a groove around the edge that retains the seal in place in the firewall.

Jan 13 2007

With the first track day getting near I had to make blanking plates for foglamps and side marker lenses and mount the headlight covers (which had nothing to mount to with the headlights removed). This was somewhat tricky considering there is not much to attach to but I ended up only having to drill two small 1/8th holes on the headlight cover flange. The headlight covers can then be removed using two readily accessible M6 bolts.


15 Jan 07

I have decided to retune the car for race gas at this stage and will initially be trying Martini Racing M102 (RON 102 MON 90) ie 96 Octane in (R+M)/2 US terminology. Elf race fuels are also available here with a very similar product. So it will be back to the dyno soon to re-tune and take advantage of the octane rating of this fuel. I expect to be doing a bit of data logging at the track so I made up a light weight aluminium rack for the laptop. It keeps things tidy and makes the tuning process a bit easier.

Race Fuel Specs

19 Jan 07

Some gear came in from Longacre today so I have been busy installing their 14" mirror. I ordered long brackets but cut them down to fit so short brackets may have been more suitable for my autopower roll cage. Anyway the visibility is excellent and a significant improvement over the stock mirror which had been partially obscured by the roll cage padding. The longacre mirror even provides a view through the rear quarter windows. Being a little closer than the stock position also seems to make the viewed scene 'bigger'. Also visible in that pic is the simple brackets I made to secure the sunroof in place.

Hood Pins

A minimum of 2 Hood pins are a requirement for the class I am interested in so these also went in today. I had planned to bolt up some brackets I made to the headlight bar brackets on the frame rails but I decided to rivet them in place in the end. In the location I put them, the pins go through the frame on the underside of the hood. Since I made the pins vertical the lower' hole ends up elongated to nearly 20mm to clearance between the hood and the pin. The upper hole ended up about 14mm (pin is 12.5mm) but the scuff plate hole is 13mm and covers up any excess gap nicely. I fashioned the brackets from 50x3mm aluminium bar stock and the brackets stand about 150mm tall - which has the pin at the end of its adjustment range... I could have made it about 170mm to put the pin in the middle of its range.

21 Jan 07 Splitter

I previously had this fiberglass splitter fixed to the car and found that it suffered stone chipping very quickly, particularly after tracking the car. I sanded back the splitter and applied a Sikkens rubber based body coat that is normally applied to the sill areas of a car. This should provide a greater resistance to stone chipping. I thought the texture might not look so good but the results are better than I expected and I would be happy to have a splitter prepared in this manner on a street car. I made a test piece which I subjected to various mistreatments and the results look encouraging.


29 Jan 07 Suspension

Today the Leda suspension arrived after a long slow boat ride from the US where I shipped it in October 06! Sadly this was just a few days too late for me to change it out with the existing Koni shocks & torsion bars because I am heading to the track this weekend and I do not have the time to do the change over and alignment before the weekend. This means I'll take the car to the track with the softer suspension and the 'high' ride height. On a positive note that means when I go to the track this weekend I will be able to get a feel for the effect of the weight reduction without the effect of the suspension.

Front Struts 2.5" x 7" hypercoils x 550lbs

Rear Coilovers 2.25" x 6" hypercoils x 700lbs & Torsion bar delete.


3 Feb 2007 1st Run at the Track

<<58MB Video

As per the plan we took the car out to Mallala for its first shakedown runs following the rebuild. It turned out to be a stinking hot 43 degrees C (110F), definitely not the best day to be rugged up in a race suit. Naturally everything was hot and it didn't take long to be reminded that with all the insulation gone from the car the sheet metal gets warm pretty quickly. Since I hadn't had time to fit the new suspension this day was used mainly to refine fuel mixtures under boost and that was pretty close to the mark by the last session. The pic of the data log shows the Spare AD channel recording AFR and under the cursor its reading 12.15 for example. Boost/MAP was run at a modest 13 PSI/90kpa. Not surprisingly braking was much improved and even at 13 PSI acceleration was much stronger than in street trim. Now the car definitely is in need of lowering with the new suspension and some extra down force has moved higher up the priorities list. The car ran every session and hung together pleasingly well.



12 May 2007 & 18 May 07

These two sessions were somewhat frustrating as I developed a boost leak which turned out to be a split intercooler hose - on the underside as always. This was eventually located by pumping compressed air into the intake and listening for escaping air. The throttle shaft also needs new seals but I am waiting on a kit for that. The other issue that had become apparent was a lean flat spot that was causing a hesitation as I opened the throttle when exiting corners. Only 10 PSI of boost and slow corner exits were not helping much in the lap times department.

26 May 07

The Adelaide weather was holding remarkably well for this time of year and 26 May turned out to be a cool, sunny, dry day. Perfect for turbos. I had also rectified the boost leak by this time and I had made some adjustments to the fuel map in the part throttle areas of the map. After the first run the boost was up (14 PSI) and the throttle response was showing a definite improvement compared to the 12/18 May. I made some more adjustments to the part throttle map and the 3rd run felt pretty good. The combination of normal boost and crisp throttle response in a 2550lb car was definitely enough to put a smile on my face. It also meant I was re-working my line around the track so it made for an interesting day. With all the changes to the car I have been keeping an eye on how things are going in the grip department and tyre wear in particular. My experience with Victoracers is that they go off at beyond 38PSI and 36PSI is fairly predictable. If I inflate them to 32 PSI I get 38 PSI hot. If I inflate to 31 PSI I get 35-36 PSI hot. Tyre wear is pretty even so far but I have had to dial in more camber than I have used previously, that is likely due to the fact that I am carrying more speed through the corners.

Overall the weekend worked well and I was able to do  a 1:21 lap compared with 1:25 previously.


I put a G-tech in the car as well to start to get some idea of what sort of lateral and braking G's I am achieving in the car.

Results are shown below (disregard RPM).




AFR Plot

The following AFR plot, when compared to the one from Feb 07 (above) shows that the width of the lean spike following throttle opening is only about 20% of what it was previously. Importantly the lean condition ceases as manifold pressure starts to rise. Next time out there I will put some additional effort into eliminating the transient lean condition that immediately follows the throttle opening... using the E6X throttle pump setting.

Click thumbnail to see AFR plot (AFR=red trace)



Video 26 May 07.

Mallala in-car Video (38Mb) 10 mins approx.

Click on picture to view video.






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