SEiGHT

I have now completed 4 events with the new suspension. The wet has affected 2 of those which made it hard to appreciate the effect on the car, although it handled nicely in those conditions. However my last 2 events have been dry. Both events led to class wins and new personal best times - at Goodwood and the Abingdon Motorsport Carnival. At Abingdon I managed to beat the dominant Andy Silman for the first time in a number of years. The car feels really planted in high speed corners but still steers beautifully on the throttle when needed. At Abingdon the ‘Team Siltech’ cars were on target for a class 1-2-3 with all 3 cars in the overall top 10 out of 150 starters until the other V8 of Simon Besant suffered an igniton fault on the second course and was forced to retire.  In fact, on the fast and flowing Abingdon course all 3 cars were inside the course record!

I recently had my car upgraded with Siltech Widetrack front wishbones, a quick rack and a Siltech front anti-roll bar.  The geometry was reset on the car.  This included some modifications to the rear wishbones as my car could only get about 0.5 degrees negative camber on the rear before the rose joints ran out of adjustment.

I have used the car for just one event since which was the end of season event at Lydden in Kent.  Unfortunately the weather was bad so I could not make any comparisons to previous trips there.  However the car felt very easy to control, I won my class and was quickest road legal car.  I am now looking forward to next season!

See http://www.siltechracing.com

I have a few more updates to make to the website ‘performance’ pages.� Will do so next week but the figures include an 11 second Zetec Turbo�and a 10 second Hayabusa powered car.

Got back from the Nurburgring last week.� This was my third trip and, despite a few problems, it was another great trip.� Blistering weather, good company and a relatively clear track.� I now have over 30 laps of this place under my belt and every trip gets better.� Full report to come on the main website soon.� Here is a pic my friend William took at Pflanzgarten:

I just realised that I have only done one post about the SEiGHT so far!� Well, the racing season has been in full swing for a few months now.

The first event was a sprint at North Weald.� The weather was absolutely awful, torrential rain on and off all day.� I had secured a class win before conditions deteriorated so far that the final run was purely academic.� In driving rain I went out and deliberately provoked the car on every corner to play with the handling as North Weald is a pretty safe venue.� It didn’t take long until I went into a spin!� A few more half-spins and the first event of the year was over.� I packed up and got even more wet on the journey home with no windscreen or roof!

Next event was at Wiscombe Hillclimb in Devon.� I had only visited this venue once before and the day was plagued by rain and then a serious accident which lead to cancellation in the afternoon so I was hoping for a better experience this time…

The weekend didn’t get off to a good start with a fractured clutch pipe on the way there the night before.� Having replaced this we resumed the journey and then I ran over some debris on the M25 from a lorry tyre which ripped off my front left cycle wing!� From this point things could (hopefully) only get better.� We stopped at a friend’s house in Dorset and fabricated a replacement wing from a piece of plastic shower base, covered in black tank tape.�

Wiscombe is a fairly scary hill, with minimal run-off in lots of places before you hit trees, earth banks or railway sleepers.� Practice was very much a learning experience and I started at the back of the class.� Second practice was a little better�and I moved up to second in class on the first timed run.� This run felt good but there were still places where I could make up more time and I was confident of pushing for a first place as the guy holding that position had barely improved his time all day and I was less than a second down.� Unfortunately it rained very lightly for the third run and everybody in my class went slower.� Still, I was happy with second place.� You can see a video of my best run here:

�Fastest timed run

The third event, and most recent to date, was Debden sprint at a military base in Essex.� This was not a good day for me!� I had a tough class with the ultra-fast Andy Silman present and a Caterham Superlight R500 too.� In practice I wasn’t doing that well, about half way down the class of 12.� First timed run I was going much better when, turning a 90 degree left hander at about 50-60mph, the back end started to get a little too out of shape.� I thought I had it under control but then it just went round some more and, soon, I was completely out of steering lock and headed for the scenery!� Fortunately I just missed a very large bush and ended up in some flat long grass.� This did mean that the pressure was now on for the final run as I was last in class.� For the final run I played it safe and put in a mediocre time for 4th in class.� Hmm, 1st at my first event, 2nd at my second, 4th at my third.� This isn’t going to plan!!!!

This year I am doing the London to Brighton bike ride.� In fact, I’m just about to go out for a few hours as part of my final preparation for the ride!� To read all about it, and to get the chance to sponsor me, have a look here:

http://seight/com/l2b/

After fitting the Visa with some different springs to try, and following the spring rate calculations in a couple of books, the specs for the final springs went off to Faulkner Springs yesterday.� We are aiming for a similar suspension stiffness to that used successfully on my own Westfield, a Peugeot 205 that I used to sprint and a Ginetta G33 that my brother sprints.� We also sent them some samples from the car so that they can build springs to our spec at the ride height that we require.� As the car does not have adjustable platforms it is essential that the new springs are the correct length!� Faulkners have been very helpful so far unlike another company that we tried.

The hunt is now on for sources for anti-roll bars of different thickness to the standard items.� These will be used to fine-tune the handling, along with camber adjustments.

Rolling road day for Darren’s�Visa.� Although no money will be spent on parts to make more power, part of the plan is to make sure it produces all that it is capable of.� The first step was to get a baseline power reading.� We took the car to Sanspeed in Bexley Heath.� Sanspeed use a Bosch intertial dyno which is very accurate and has been used by many people from our motor club so we have plenty of data for comparison.� The car was run up in 4th gear and 5th gear and made 164bhp in 4th and 168bhp in 5th (you get slightly more in a high gear as the roller is accelerating at a slower rate so you have smaller inertial losses in all the rotating parts).

The engine has a ported head and very mild cams.� Book figure for a standard Mi16 engine is 160bhp although that was apparently a slightly optimistic claim by Peugeot.� This engine has never been tuned since fitting the head and cams so, once the mixture is adjusted and the timing set properly, we are hoping for a little more power.

On the way home we carried out an acceleration test between the Visa and�my Civic Type R.� Now the Visa has 190bhp/ton laden compared to 152bhp/ton laden for the Civic, so the Visa will kill it, right?� Actually the two cars were pretty evenly matched from 30mph to 100mph.� Why?� Well, for a start 25% isn’t a big difference when it comes to power to weight, and secondly power to weight ignores the issue of aerodynamics.� Even assuming the same aerodynamics for each car, at 80mph they would both be losing about 45bhp to aero drag and rolling resistance, what is left over to accelerate the car works out at 139bhp/ton for the Visa and� 118bhp/ton for the Honda which is only 17% difference.� When you then figure in the fact that the Visa has a significantly worse drag coefficient than the Honda the difference gets even smaller!

One other interesting thing was the speed measured on the rollers.� 126mph at 7200rpm in 5th is way down on the 134mph that various gear calculator programs would suggest.� This is partly because the data on the Yokohama website does not match the diameter of the tyre as fitted to the Visa’s rims, and worn to the extent that they are.� It is also because gear calculators don’t take account of the distortion of the tyre footprint that occurs when a wheel is driven - the tread gets compressed as it meets the road and, according to Goodyear engineers, this makes about 4% difference to the calculations.

So you’ve just built your SEiGHT with all new parts and you’ve spent a considerable sum of money on it.� When you take it out for the first drive it feels a bit tail-happy, however the engine is putting out about 100bhp more than the last one you drove so you put it down to that.� For the next 18 months or so you tweak the suspension settings in order to improve the handling but, at the end of the day, it’s still a bit of a beast.

Then, one day, you notice that other people’s front springs look a little different to yours.� Still, there have been so many variations in factory fitment that you soon forget about it.� Then it’s winter time and the car is sitting idle so you remove the springs to see if the rate is marked on them.� It isn’t but you measure the rate at 212lb which is what the rears�are supposed to be.� Hmm.� You remove the rear springs and, sure enough, they are identical to the ‘fronts’!

The moral of this story?� Check everything carefully when you build your car, even if they are new parts…

Have been helping out a friend, Darren,�with his sprint car this winter.� It’s a Citroen Visa GTi 16V.� Fully stripped out.� Running on list 1b tyres.� The basic package should be good, 800kg, seam-welded, Mi16 engine with ported head and mild cams that should release 170bhp.� It’s a classic example of a car that has had little or no development since first coming out.� I don’t even think the ignition timing has been set properly for the last couple of years and it has never been on a rolling road

The only real development in the last 2 years has been the fitting of some 600lb(!) rear springs.� On rough ground the back of the car just bounces about all over the place.

I had a drive of it, on the road and at a sprint, at the end of last season.� Money is limited so the main plan is to get the spring rates more suitable, improve the tyres and get some more power from the engine.

So far we have removed the springs and accurately measured the rates, fitted some softer springs as a trial, measured all the suspension settings and calculated the new springs that are required.