Northampton Motorsports - Rolling Road and Geo Setup

The weather forecast wasn't looking too good, so I put the 1/2 hood on and set off for Northampton at 05:30.  Just after passing Thruxton I stopped for fuel at Buck Services on the A303 then headed up the A34, on to the M40 for a couple of miles before turning off onto the A43 and the final 30 miles or so to Northampton, going past Silverstone and the back of our old house at Towcester.  I arrived at NMS at just after 08:00 and then went and refilled with fuel at the garage just down the road.

The first job was Corner Weighting and my first decision to make was 1) driver only or 2) driver and passenger?  After a brief discussion on the pros and cons I decided to do driver only on the basis that Corner Weighting was over kill for a road car so mainly for track days, so better to accept any compromise on the road.  Chris disconnect the front ARB, checked the tyre pressures and each of the wheels - n/s rear had play in the wishbone bushes which he tightened (need to watch them) then onto the scales - car, full tank of fuel and me - 725 kgs ouch! 

At the IVA they recorded 675 kgs which included a 75kgs allowance for the driver and perhaps only 3/4 of a tank of fuel (last minute leak and dodgy gauge) so the inboard ARB is heavy! The car was reasonably well balance already and Chris made the final adjustments to the rear shock absorbers and confirmed the ride height was 35 mm nose down which was in the middle of the 25 - 45mm range that he recommended for a fast road/track set up.

Next came the Tracking and again nothing drastically wrong especially given that the ballasting for the driver first time was  a tad underestimated and I'd swapped out the steering rack a couple of weeks ago using tape on the garage floor to transfer the distance between the track rod ends.  Second decision was to keep with the fast road/track day setup so slightly more camber on the front and not so much toe-in. 



 
 




The final thing was reconnecting the front ARB, this took a reasonable amount of time as Chris wanted to ensure that it had free movement throughout the full wishbone articulation to minimise the chassis issues that have been experienced by some. 

His final advice was to fit the cross chassis brace that Westfield now make to help with the chassis issues and a rear ARB to complement the front - the brace was in stock at WF so now ordered at a cost ~£27+P&P.

After a very lightweight - diet started already - lunch the car was strapped to the rolling road, lambda sensor replaced with the rolling road one and Troy started to work his magic.  First was a check of the throttle and the pedal stop needed adjusting to allow a full WOT to be achieved.  Then the TB balance and he was happy that, after my numerous attempts, they were balanced.  Once the oil and coolant had been checked, Troy confirmed I was happy to use the full engine rev range and then he was off.

After a run with the original map he saved it and loaded his own base line map.  The first few runs established the full throttle performance and after some adjustment of both the fuel and ignition maps the power runs were completed 166.7 bhp @ 6,700 rpm and 143 ftlb @ 5,400 rpm.  Slightly lower bhp than I'd hoped for but the torque was smooth and above 125 ftlb from 2,700 to 7,000 which should make for very driveable.


Troy then moved on to the full mapping adjusting both the fuel and ignition maps plus a whole series of other adjustments.  Once he'd done the individuals stop points he then used the 3D graphs to make final adjustments - the speed at which this was done and attention to detail was amazing to watch.  After some final test runs Troy declared that he was happy and the final map was saved and the ECU updated.

It was now 14:30 and I discovered that it was now raining.  After paying the bill and getting some stickers for the car I head off in the rain back to Yeovil.

I immediately spotted that the speedo wasn't working a remembered that Chris had found and fixed some play in the o/s steering arm so I pulled into a layby on the A43, quickly adjusted the sensor and  re-tightened up the caphead screw then got back on the road.  By now the rain had stopped but the roads were still greasy so I took it very easy.  My initial impressions on the mapping were wow - the car was so torquey and smooth.  The flat spots in the low to mid rev ranges were non-existent and the engine even seemed to rev much more quickly.  On the ride the benefits weren't so clear but as the journey progressed the roads began to dry out and I began to push a little harder (although never above the speed limit, honestly officer) by the time I got to Yeovil I was convinced that I could feel the difference and it was that the ride somehow smoother and the steering more precise.

After a bite to eat at home I headed off to the WSCC meeting just outside Dorchester armed with my pack of printouts and had a very enjoyable evening comparing notes on the visit to NMS and enduring the banter "only 166 bhp on TBs got more from my 1800 on Webbers" etc etc - on the drive home I was now convinced that the car was transformed - but I was now very tired and needed my bed!