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After modifying and racing a GSR Lancer for many years I found that when it came to weight reduction (which is my favorite mod) the majority of weight reductions came from the rear of the vehicle. This resulted in unfavorable weight distribution causing increased understeer which is not good for any form of Motorsport but particularly for the tight turns encountered in Hillclimbs and Street Sprints. This was solved by “band aid” fixes in suspension setup. Wanting to retain the AWD advantage but not happy with the engine and gearbox being located transversely ahead of the front axle centre line I decided the next vehicle will require the engine and gearbox to be repositioned to a mid-mounted location in front of the rear wheel centre line as per Fiat X19s and Toyota MR2s. As I like getting value for money out of a vehicle, the car had to be road legal and competitive on the track - so had to be an ICV (Individually Constructed Vehicle). I was disappointed to find out what the average time for building an ICV was while surveying builders of Lotus 7 type cars during a couple of runs in a friends Locost (home built) Clubbie. This was only half the story as the worst cases were scratch built cars which were built using the readily available plans, so with such a unique drivetrain, chassis and body work design I would easily have doubled this time. With such a busy work life and not wanting to be off the track for too long I decided to find a suitable kit car as a basis for the build.
Sylva Autokits, owned and run by Jeremey Phillips, was selected as the supplier for the basis of this build due to Jeremy’s vast experience and his flexibility of supply suited my requirement of only needing the fibreglass components and enough chassis to support the body work and thereby deleting the pedal assembly/supports, centre tunnel (which was too narrow for the tail shaft), all of the front end bracing to allow room for the diff and of course engine and gearbox mounts. Suspension wishbones and rear uprights were supplied but not used as the track was to be widened to suit the GSR track to reduce machining and the ease of sourcing spares. To accommodate the standard GSR half shafts I custom-made rear uprights and for the front I modified Mirage front uprights which were chosen due to their suitability of the steering arm to be machined to get correct Ackerman angle with a front mounted Escort steering rack, thus allowing room for the upside down GSR differential.
The mechanical trickery required to get drive to the front of the vehicle was accomplished by machining an aluminium adaptor plate to change the orientation of the transfer case (Mitsubishi call it a transfer case but in the early Evo, GSR and VR4 this is just a right angle drive to send power to the rear differential) from pointing to the rear of the car to the front. To account for the thickness of the adaptor plate I machined from EN36A - a new longer gearbox output shaft which was splined and heat treated by Gear Concern in Acacia Ridge, Brisbane. To get enough clearance the engine inclination needed to be altered requiring me to modify the sump and pickup which I thought while I was about it I’d improve the baffling and increase capacity. The flipping of the diff and transfer case required changes to the drain and fill points and some custom breathers.
To confirm that the chassis would pass the torsional and beaming test, it would be painful to make changes once painted and the structural aluminium panels riveted on, Gazza, a Structural Engineer (and good friend) and I did a FEA model to confirm all the structural modifications I intended to do would pass the approval torsional and beaming tests, while also providing a consistent torsional rigidity along the length of the chassis. As anticipated, the toes up channel profile in the location of the occupants would have been the weakest location. Triangulated side bar work resolved this issue with the bonus of some added side impact protection. So along various other additional bracing and gussets the chassis passed with the result being within a few percent of the FEA model.
In order to get such an old modified engine to meet the current emissions standards my approving Engineer, Earl of Autotechnica in Capalaba, Brisbane, suggested running on straight LPG. With some research on LPG I was sold on a Vapour Injection system and promptly went off to TAFE to become qualified to do the installation.
I started with a Manchester 34L end fill tank mounted behind the seats pretty close to the vehicles centre of gravity. Regarding the choice of liquid vs vapour LPG injection I chose the vapour system as these systems have been out for a lot longer and are well developed with good reputation and at the time of purchase more technical information was available to design a custom system. Not to mention these systems were significantly cheaper which reflects the philosophy of the build. However, I would say that the significant intercooling effect provided by liquid to vapour state change was tempting.
BRC was chosen as the LPG component supplier due to their high quality components which are used by Australian auto manufactures. A V8 system was initially purchased due to the small injector flow rate available with vapour injections. This kit was supplied with the largest flowing yellow Super Max injectors rated at 56hp each. After consultation with the guys at BRC Impco Technologies the large single Genius Max reducer (rated at 322hp) was swapped for two smaller Genius MB 1500 reducers (rated at 213hp) each with its own ET98 Super gas lock mounted on the liquid side and a FJ1 HE filters on the vapour side feeding either side of the eight injector fuel rail bank, thus removing all restrictions with the goal to achieve 400hp at the flywheel.
In order to keep the costs down I recycled the Microtech LT10s with on-board logging and 3bar map sensor used in the GSR. This unit has 4 low impedance injector drivers which were supposed to run two 2ohm injectors per driver. I sent a couple of injectors to Microtech where the guys tested the injectors and found that even though the LPG vapour measured 2ohm the current draw was too great for their highest spec driver, however with a bit of internet searching, revealed that the best injector driver option was a Microtech INJ-8 which uses 8 high spec low impedance injector drivers which I am controlling by splitting the 4 signals from the ECU into 8 inputs of the INJ-8.
While on the topic of ECUs, the Microtech has been configured to accept a 0-5volt signal from Tech Edge 3B1 wideband unit which has been recycled twice, originally used on my Stanza drag car. Yet another great affordable Australian product. All tuning has been done on the road using the wideband and G-tech which have data logged 0-100 kph in 2.8 sec of which 0.4 seconds are consumed by two gear changes using the old fashioned syncro manual gearbox, no fancy dual clutch gearboxes here. With no dyno results the 0-100 time and a weighbridge weight (740kg with a full tank of gas) indicates approximately 400 flywheel hp.
In order to reduce costs and allow for easily obtainable replacement parts as much of the GSR components were utilised including the gauge cluster (wound back to represent distance traveled in the new car), modified shifter to allow the use of standard cables, handbrake cables, steering column and the wiring harness, with all the obsolete wires removed and the lengths altered.
A second hand Wilwood brake, balance bar and clutch pedal assembly with cylinders was installed along with my custom made accelerator pedal assembly and a longer accelerator cable manufactured by Control Connections at Sandgate, Brisbane, who also made an extension cable to lengthen the speedo cable.
The minimalistic interior is furnished with seats which follow the original Riot design philosophy in that they are simply cushions tightly fitted into the chassis with Velcro to provide additional security. Bob at B&L Upholstery (Slacks Creek, Brisbane) made the cushions to my design using marine grade vinyl in a retro diamond stitch pattern.
Many locations for the intercooler and radiator were considered, the Sylva Riot has the radiator mounted at the front of the vehicle with the cooling pipes running down the centre of the car, which now houses the tail shaft, and in an effort to achieve a 40/60 front to rear weight distribution the radiator and intercooler were mounted to the side of the chassis behind the front wheels. This location provides good access to airflow which is then fully utilized by the sheet aluminium diffuser ducting and attention to detail of the duct sealing and side pod exit layout. In order to maintain good throttle response calculations confirmed that using 2 ¼ inch intercooler tubing will maintain good throttle response by minimizing volume and yet still support 400 hp with minimal pressure drop. After mounting the aluminium VW Polo radiator and my own fabricated intercooler using a PWR core, which spent well over a decade of use in the GSR, I welded up aluminium tubing for both.
You may recall the reasoning for the purchasing of the Riot kit was to reduce build time by not having to do body work, however, with the significant vehicle layout changes dictating that I either farm out this portion of work or learn another skill, so you guessed it time to learn another skill! At the time of supplying the Riot kit, Jeremy informed me that the chassis could be widened by 80mm, but the nose and scuttle would need to be widened by me. The scuttle also required a raised section above the steering column to house the GSR instrument gauge cluster. I also made a two piece engine cover with built-in vents to replace the supplied one piece unit. A symmetrical mould was made to allow side pods to be produced for both the intercooler and radiator. When it came to sanding and polishing these components a deal was struck with a friend (Keith) that he would do this job for me, and that I would gladly do some fibreglass work for his Locost. The final part of the body work was the cycle guards, which after selling the originally supplied fibreglass ones, as they would not fit over GSRs 15x7 wearing 205/50/15 tyres and chosen due to this size having one of the largest range of tread compounds. The replacements, which ended up giving me some spare cash, were trimmed aluminium trailer guards supplied by Mudguards.com.au.
This vehicle was built for spirited driving on the twisty roads of the hinterland and competing in Hillclimb and Street Sprints in street trim.
It took about 5 years (although 2 of those were not productive) and about 25K if parts were counted as new, however, the majority of the parts coming from the GSR Lancer which I had been racing for about 5 years and probably depreciated to very little.
I have obtained the sole rights to manufacture and sell the Sylva J15 Kit in Australia which I will redesign to allow it to use the majority components from a locally available vehicle. I hope to be going through the type approval process at the end of this year.
Specs
The engine is a 1990 VR4 4G63T stroked to 2.3lt using a $100 L300 Van Crank.
Blue printing and assembly by me, with engine machining by Bryant Engineering, Brisbane.
The sump and pick up modified (by me) for change of engine inclination angle, increased depth, bigger volume and better baffling.
The LPG consists of 2 BRC 1500 Genius MB Reducer (213hp each) and 8 BRC yellow LPG Vapour injectors (56hp each).
The turbo is a TD05 with 20G compressor waste gate mods and housing porting by me. Rebuilt and balanced by Glen at Munro Racing Turbochargers.
I fabricated an intercooler using a PWR core with my own custom tanks and an alloy VW Polo modified by me to suite side mounting and nozzle sizes.
I fabricated the exhaust system which consists of a custom mild steel dump ceramic coated by competition coatings the rest of the system stainless steel with Magnaflow Cat and Muffler.
The ignition system is standard with Top Gun Max 300 Leads and 2 heat range colder NGK 8s plugs to account for the increase in boost and hotter burning of LPG. I have also had to reduce the plug gap down to 0.6mm to prevent spark misfiring due to the LPG.
Engine management is handled by Microtech ECU LT10s with an INJ-8 low impedance injector driver box for the high current requirement of LPG injectors. All tuning is done on the road using a Techedge wide band O2 unit to set the AFRs and a Gtech Pro RR to tune Ignition timing.
Boost control is by a cheap but effective restrictor bleeder arrangement.
I used the wiring harness out of the GSR with all the extra wiring removed and the remaining wiring shortened to suite.
Currently using bowser LPG which is a mixture of propane and butane which is usually around 105 octane in Australia in summer but have had to start using BBQ gas which is straight propane and close to 112 octane. As much as the octane rating increase sounds good the real benefit to me is change from the near 0deg boiling point of butane to around -40deg of propane removing the need to run hot water over the converters at events when the starting temp are sub-zero plus the broad availability of 9kg BBQ bottles.
The transmission is a GSR AWD Manual 5 speed which I rebuilt using the gears from a spare VR4 gearbox to get a taller first gear. The centre differential machined to take 4 pinions by Emery Engineering and Quaife helical rear differential. The factory flywheel was lightened and heavy duty clutch with 5 puck driven plate by NPC Performance Clutches.
The original GSR two piece tail shaft rear section shortened with Commodore centre bearing and support - Driveline Services Acacia Ridge.
A one-way Cusco supplied by Carmods Australia is fitted to the now front diff.
Shocks are Protech 600 Series coil overs.
Calipers are VR4 Evo 0 Twin spot VR4 Evo 0 at the front and GSR rear both with EBC Green operated by a modified Wilwood pedal assembly with balance bar.
Front and rear wheels are Speedy Lite 9 Wheels 15X7 with R Spec 205/50/15 tyres.
Fibreglass Gel coat black finish with the chassis painted with KBS chassis coat kit brushed-on.
Knowledge is power …
And finally, thanks goes to those who earlier in my car building experiences did poor quality work or charged extortionate prices thereby forcing me to learn about and do as much of the work as I could for myself.
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