What you see below is the Mitsubishi drivetrain (engine and transaxle) removed from the car, complete with subframe, suspension, struts and discs etc. What I had not expected when this was finally on my garage floor was that the driveshaft would be approximately 40mm lower than the crankshaft. It was a surprise, mostly because you struggle to get a feel for such things in a modern, completely filled engine bay. This means that the centre of gravity of the drivetrain could be considered higher by about 30-40mm than that originally expected, although in reality this simply reflected my ignorance of the specific details of the 380’s layout. With a little thinking, three ‘solutions’ immediately came to mind.
The first is to tilt the engine forward by 25 degrees or so, thus raising the driveshafts which are behind the engine (i.e. towards the back of Godiva). This ‘solution’ is both simple and requires little initial engineering/expenditure. The very real downside is obvious: it may create significant oiling problems in both the engine and gearbox. The engine is not designed to be run in such a manner and the sump, oil pump and oil return (particularly from the cylinder heads) may be adversely affected and lead to significant oil starvation.
The other aspect is that the gearbox is also not designed to be run at an angle and this would require attention to ensure that the gears get the appropriate lubrication. This could be as simple as checking the oil levels with respect to the gears (with splash lubrication) and ensuring the oil level is maintained at the same level with the additional angle. It may not be necessary to do so if the gearbox has an internal pump, although if this is the case then attention must be given to the oil pickup for the pump; either again raising the oil level if required or by moving the oil pickup. I will find out when I get a good look at a service manual. Of course if there is not a pump in situ, then an external belt driven oil-pump could be added if required, though again this is added work for a problem that may not exist.
The next ‘solution’ that sprang to mind was to cut the bellhousing at the engine mounting plate and then rotate this 20 degrees and re-weld it to the rest of the bellhousing. This meant that the engine/sump and oil circuit would remain as per standard, but that the gearbox/driveshafts would be raised by the ‘required’ amount, although attention would also have to be paid to the very substantial bearing that holds the long shaft that runs beside the block to the drive cup. This modification would require substantial care and astute engineering, though I have been told that it is straight forward enough and would not be that expensive. The gearbox oiling issues are exactly as per the first ‘solution’.
As the plan was to transplant a complete driveline without modification, the last solution is simply to leave it all as it is. The package is very well engineered after all and the driveshaft height may not be a problem at all, but it will all be checked very carefully when it is placed on the build plate. To coin an old cliché from my childhood, “Why is it so?”. Well, I believe that in the majority of FWD cars, the manufacturers need to be mindful of a great number of factors, one of which is the ‘approach angle’ clearance (my terminology). This is where the car needs to be able to clear a sharp increase in road angle, such as driving from the road into a steeply inclined driveway. In such a situation there needs to be sufficient clearance under the sump to ensure that it does not hit the ground. Thus the engine is higher than it would otherwise be if only centre of gravity was considered. Of such compromises are all cars made!
The gear shift mechanism is a delight. The plastic moulded setup is very light, securely mounts the cables and also mounts to the tunnel via four bolts, which looks like it will be very easy to adapt to Godiva. In short, I could not come up with a better design, so I will try very hard to keep it as is, although the very heavy gear knob will have to go, though it was pointed out to me that this weighty item may be a mass damper. Even if it were, the vibration range that it was designed to combat will most likely not be a part of Godiva as it will be a different car in almost every way!
The pedals are as you see them in the image below. The accelerator pedal is a Bosch product and is part of the drive by wire throttle. There is no throttle cable, but instead there is a sensor in the pedal assembly that controls the throttle plate via a small electric motor (naturally as part of the engine management system). This electronic integration also allows traction control etc, though it was not fitted to the donor 380. The electronic pedal is very light and very compact and this will be retained as it is part of the full engine management system and this is required for ADR purposes. The brake and clutch pedals are mounted in their break away assemblies, which are quite compact. However these may not be used as I am sorely tempted to fit a bias pedal box, such as is made by Formula Motorsport, one of Race Magazine’s supporters. This would allow in cabin adjustment of the brake force front to rear, which is an advantage in most motorsport, but it will not be ADR compliant if adjustable from within the cabin. There are numerous solutions to this, but no decision is required for some time of this, as there is much else to do.
The steering column is as you see it above. The bottom section of the column with the two universal joints has a collapsible section it, which would be especially desirable in any ICV given the lack of impact testing they have! The column also has the height adjustment, steering wheel and switchgear attached as you can see, though I am not sure if the cruise control etc is really desirable! The most important part of this column is the ignition key and transponder/receiver unit, as the whole engine management system will not function without it and they are very expensive to replace. Should you ever look at getting a late model engine and ECU, make sure you research this aspect very carefully. The downside to the column is that it is quite heavy. A lighter steering column will be on the cards if one can be found.
An instrument panel is part of the wiring package for the engine and it is light, compact and easy to read. There is a simple plug into the back of it and it will meet the ADR requirements, so it will be used.
One of the things to do was to have the build plate made up. This is the ladder frame that will be covered by 20mm MDF and will be used to build the wooden mock-up of the chassis. Originally I had planned a simple two box arrangement with some cross bracing (see picture D), which would have the build surface approximately 400mm off the ground. After some extensive discussions with Laurie Bongailis, this design was scrapped for the following. Laurie has a very extensive history of making Cobra replicas, having delivered over 70 cars to his customers over the past fifteen years. In discussion with Laurie, the following build plate was designed. This will still have the MDF attached to the top as for the mock-up stage, but it has the additional benefit of providing a much stiffer and more stable build surface for the steel chassis later. The better performance for the steel construction is not only due to the build plates heavier construction, but also down to its use. Laurie advocated strongly for the individual components of each section to be tack welded to the actual surface of the build plate and the joining welds for the components then completed. The tack welds are then cut away when the component is completed. Laurie reported that he uses this method for his replicas and that it has always resulted in a very straight final chassis. He is able to do some minimal stress relieving on the build plate by reheating some joints with an oxy-acetylene torch. This build plate will be delivered by the time this issue of Race Magazine is at the printers. The castors on the bottom are from one of my local cheap tool importers and for things such as these they are a fantastic resource.
The build plate is 1500mm wide and 3000mm long. This width is narrower than the narrow track planned for the rear of the car, at 1570mm. The slightly narrower section of the build plate will allow the use of thin plywood wheels with the same diameter as the planned wheels to be used in the mock-up stage. This will allow more accurate visualisation of the build and suspension alignment and component fit. These plywood disc wheels will lie outside the build plate width and will be supported by brackets attached to the side of the build plate. Thus the top surface of the build plate will effectively be the lowest surface of the underneath of the car and then the ‘ground clearance’ can be set for mock-up purposes by moving the plywood disc wheel supporting brackets up or down the side of the build plate. This simple system means that ride height changes can be quickly reviewed and altered.
So now it seems that nearly all of the important bits are here….not so!
Now a parallel and interdependent process starts: The wooden mock-up will start almost as soon as the build plate arrives. This is to be built to dynamically test component fit and suitability and also driver fit. After all there is no point building something that I cannot fit or get into and out of easily enough. This full-size mock-up will also allow component placement to be loosely worked out for ease of build and also for the most compact and serviceable layout.
The interdependent part is that the actual chassis tube layout will need to remain flexible whilst the upright and wheel/tyre package is decided. These components will largely fix the outside suspension points within certain dimensions, less fixed for the top point on the strut conversion. From here the rest of the suspension design will occur and this suspension design will give us our inboard suspension points, which is where the intersecting chassis tubes need to be to ensure correct transfer of loads into/through the chassis.
The wooden mock-up may also allow a systematic construction check to be done, going through the attachment of panels and welding order of tubes. This will help to ensure that I am not designing myself into an unbuildable structure!
The last element of Godiva to come into review is the Roll-Over Protection System, ROPS for short. It was suggested by Russell Performance in Dandenong that the main ROPS tubes should extend through to the floor level and not attach to the top of the chassis structure as planned. It was suggested that this would alleviate a potential source of weakness in the overall ROPS structure. This poses a number of benefits as you can image. The ROPS tube is unbroken and is of very high quality, but it is also round. A round tube is potentially problematic when you want to attach a rigid panel. The excellent suggestion was to use a formed section of steel that is stitch welded (say a short 1cm long weld every 3cm) to the round tube for the length of the tube that would constitute chassis attachment points. This suggestion is unwanted from the perspective of complication, additional materials and additional cost, as the ROPS tube is considerably more expensive to purchase and form. It would also require different tooling to form the joints to the rest of the square tubes at the upper level.
The complicating factors here are not solely structural. If the ROPS main tube extends to the chassis floor where does the ROPS structure really start? In reading my CAMS manual there seems to be a few questions to sort out before a decision is made.
If the ROPS starts at the floor, because that’s where the ROPS structure extends to, then the top horizontal tube will most likely need to be changed to a round tube of similar metal for side intrusion purposes and ROPS certification. Of course a different tube could be proposed to CAMS for approval IF the engineer’s computations show that the tube exceeds that required by the standard CAMS set.
If only this were so simple! What if the ROPS regulations change? Any Godiva that was log-booked with a cage would be fine, but the design may need to be changed to adapt to a new ROPS code.
The solution is simply that I will have to meet with CAMS to discuss the issue and to get their perspective on it. However at this point in time it would appear that the simple solution is to have the ‘less perfect’ chassis/ROPS design.