So this is the design we have settled on and we are going to produce this sill
So first we draw up the sill on its own using the CAD system
Then we make the mould on the computer as well
Then we make the actual physical mould
Next we produce our master profiles
the finished prototype
Perhaps unusually this time I am doing this article "from the workshop floor" so I make no bones about it, this is all about ME! As you may know we were allowed by Alfa to purchase one of the early 4C coupe's and after a winter's thinking about what we wanted to do with the car, earlier this year we decided it was time to bite the bullet and get on with it. In order to approach this in a logical manner we divided the task into areas; power, handling, sound and weight. Then we looked at how we could effectively get the most bang for your buck and decided this on a simple formula which is either cost per bhp increase, or per kilo reduced, on a roughly 1-4 basis. So if a modification gives us either a 1 bhp increase or reduces the weight by 4kg we were willing to pay £xx.xx amount. Anything performance wise that was less than this figure we had to justify on either esthetic grounds, practical grounds or not do it. The 1-4 ratio comes from the 4C's present power to weight ratio.
Next we had to decide on areas where the 4C could be modified in order to get an increase in performance, this is always an area where I struggle, as I have said before many many times Alfa Romeo spent millions developing the car and they have extensively tested the car, the car they deliver is exactly as they want it to be and no Fred in a shed is going to improve on the product. Having said that in car design everything is a compromise, stiffer springs will give better road holding but will rattle the teeth out of the occupants, more power corresponds with more strain on the drive train and then there is the cost. The 4C is built to a budget and it would surprise me if Alfa Romeo were making any money on the 4C, in fact I suspect that they loose money on every car they make so there is always the opportunity to use more expensive components. Knowing my own limitations it was time to call in some specialist help, now round here being on the edge of motorsport valley there is no end of very professional help. So it was time to call in some favors and you would be surprised how many guys in motorsport own Alfas and have used the workshop in one way or another.
The two things that were at the top of the list were more power and less weight. Power was simple, being a turbo charged engine there is always the opportunity to increase the boost pressure, which gets more air into the engine, and once you have more air it is a relatively easy job to add more fuel (up to a point). The car first has to go on a rolling road to get a bench mark power figure, once that has been done it is time to change some parameters. Along time ago I used to tune in house on our own rolling road, but it was particularly antisocial and our neighbours did have to put up with a lot so when we moved premises I sold it. Anyway back in the day we used to be able to unplug the chip and plug in a lead from a laptop with a program that would run the car. We could then run the car and change parameters in real time to tune the car up. Unfortunately times change and sometimes that is not always for the better; with a modern engine management system manufacturers can download a program to the engine management system through the diagnostic port, something I think VW may well wish they had done a couple of weeks ago.
The engine management system will not allow you to upload the program from it so you have no starting point to work from. This presents a problem in that all the computers are programmed differently so a generic program can’t be used. So ….. the control unit has to be taken apart to download the program directly from the chip, then the engine maps can be modified within the program on another computer and the new program uploaded to the chip, then the power output can be checked by running the car up on the rolling road and then if we are not satisfied or there is an issue we have to go through the whole process again which as you can imagine is a very time consuming process. But bang for buck it works out relatively inexpensive with a gain of 40 bhp for the sake of a day's work.
Next the bodywork comes in for attention, as you know the chassis is made from carbon fibre however all the panels are made from the same plastic that modern car bumpers are made of. This presents the opportunity to change the material the panels are made of, and naturally the material of choice is carbon fibre. Once upon a time you would have had the panel removed, taken a mould from it, changed the panel as you saw fit using filler and fiberglass, make another mould and then produce the new panel. However once again times change but this time for the better, so the first job is to scan the car to produce a CAD three dimensional drawing on a computer, this takes about 4 hours, once this is done you can then manipulate the design on the computer while keeping the original mounting points, once you are happy with this the computer can machine the new design into a mould and a new panel can be produced in carbon fibre; simple! So at this moment somewhere in deepest darkest Wales there is a Welshman (surprisingly) by the name of Paul Sparrow busy producing carbon fibre panels for the 4C. They should be back with us in the next week or so and with luck and a following wind this should shave 17-18 kg off the car and should look cool with the entire carbon weave showing.
Finally the suspension and wheels are also in for a makeover, the 4C has come in for some particularly unwarranted criticism from the press over its handling and while it was not to everyones taste, I always enjoyed the handling as every trip was an event which always brought a smile to my face. However to make the car really fast some of that exuberance needed to be dialed out, the main issue wasn’t the handling on a circuit where with everything loaded up it was in my eyes perfect. The issue was that before all the bushes had loaded up the car felt slightly nervous, almost like it was oversteering and after a lot of investigation, fiddling and faffing, it turned out that it was in fact oversteering, but the oversteer had been engineered into the chassis by Alfa Romeo. To dial this out we have changed a bush in a wishbone transforming the handling, so now when you go into a corner you can feel the rear wheels loading up and feel confident enough to feed a lot more power in through a corner which has in turn made it a bit of a road missile.
I find myself trying corners again and again to see how much faster it will go, right up to the point I suddenly realise I am exiting corners at double the speed of other cars and get nervous of other road users not realising exactly how fast I am going and pulling out on me; it really has reached the point where nothing much will keep with the 4C. The shock absorbers have been removed and sent to Ohlins for dynoing to find out what the present settings are and Ohlins are working with Eibach to produce some suspension struts that will further improve the road holding. This is one of the upgrades I am most looking forward to as I find road holding gives me more of a buzz than outright speed, mainly because her majesty's constabulary can’t do much about how fast you go round a corner while they get most excited if you do double the speed limit! We do have a bit of a problem with the wheels in that you can’t buy any really sticky tyres in 205/40-18, which are the really nice option wheels, and in order to get some track day tyres you need to use the 17 inch wheel on the front. Not what I would like in an ideal world, but it does mean we can buy some superlight wheels which will help to reduce the unsprung weight by over 10 kg which in turn will help with ride quality without detracting from the road holding.
We have a deadline on all this work and we hope to have it all done and painted in time for Christmas so it is all hands to the wheel here!