It went great thanks Andrew, but not without some drama
Firstly, the day started wet, standing water in the pit lane wet and elsewhere across the track too so we needed to apply caution, especially as we were running Toyo Proxy 888Rs. As the track dried we gradually upped the pace, and we started properly exploring Monty's new top end performance, but it soon became clear the engine was feeling a little flatter than I'd expected over 7,000rpm, so I came in for an early lunch and to check our ECU logs.
Sure enough Monty was dog rich over 7k at 10.5:1, a situation that got worse as the revs went higher, the reason for this is it's very hard to effectively tune the top end on the road when Monty is now screaming over 8,000rpm. Irrespective of the excellent AutoTune feature, reaching the higher engine speeds required to get sufficient samples over 7k simply isn’t safe, so I'd largely extrapolated the VE at the very top end and it turns out I'd been a bit ambitions with my numbers.
Foolishly I'd also only given the short term trim 10% authority either side of the AFR targets so the feature couldn’t offer sufficient correction to pull the fuelling leaner than 10.05:1 and even richer when really pressing on to 8k. This was easily corrected by applying 50% of the VE AutoTune suggested, then giving 20% authority to the wide band lambda short term trim correction.
Back out on the track and it soon became clear Monty was now pulling like a train above 7k, the rate of acceleration was night and day improved from earlier when the top end was rich. Now we were really flying, so I pushed the SD card into my EDL-1 and logged one very hot lap where Monty was held on the bleeding edge of grip and some form of correction was required on every single bend and curve. On a few occasions, I clearly felt the hard rev limiter come in and knowing this meant I'd taken Monty's Duratec to 8,400rpm I came in to study my hero log.
What I found shocked me, my AFRs were permanently locked at 25.5:1, despite the super strong performance something was clearly wrong! It then it dawned on me the earlier supper rich top end running must have poisoned and killed my Bosch LSU 4.9 lambda sensor. Undaunted, as I knew I'd corrected the VE table and the engine had responded brilliantly, I tossed Monty's keys to my good friend Aston so he could feel the improvement. Aston started to explore the new top end power and he couldn’t believe the difference, as his confidence grew in Monty's new found thrust over 7,000rpm he started getting faster and faster, I felt his last lap needed recording so I again pushed the SD card in and started the log.
Almost exactly at this moment I started to get the faint whiff of coolant, but it wasn’t strong enough to worry me, however 30 seconds later I glanced at the Monty's temp gauge and it was showing 140c!!!!
Hazards on Aston nursed Monty off the track and into our parking spot, I didn’t even look under bonnet, I took the SD card out and went to the cafe to study the log. Sure enough coolant temps had shot up to a true 120c, back at the car and Monty's bonnet up we soon found the issue, NO BELT! The 14 year old belt had clearly decided it didn’t like 8,000rpm plus so had made a bid for freedom and escaped it's long term home to start a new life on the Castle Combe track.
Much trying to work out what belt is fitted to a 2012 Duratec Plus 4 ensued, James my engine builder had some photos of Monty's Duratec engine numbers so did some Googling and came up with 6PK1305, in the mean time I'd phoned Brands Hatch Morgan and the super helpful parts guy there gave me three possibles, one of which was 6PK1305. So we borrowed a car from Henry Williams and made our way to an excellent local motor factors who had a Gates 6PK1305 in stock. Back at Monty but having no reference to confirm the belt run, it initially appeared the 1350mm long belt was too short, then Doug came in with 6PK1306 on my TM post which made me look closer at how the belt might run, luckily I had a photo on my phone that gave some clues and within minutes the belt was on.
By this time the track day was over, but we'd had our fun (and some scares), so we topped up Monty's coolant, nipped up every coolant hose Jubilee clip, tightened the expansion tank cap and ran the engine up to make sure it had survived the very short period at 120c, which of course it had. I checked to see if the engine oil smelt burnt but it was perfect, as was the level. So we drove the 50 miles back to Aston's house with Monty purring like a kitten, we returned Monty to his road tyres and I covered another 50 miles getting myself home to Rickmansworth, again Monty ran perfectly.
I arrived home safely an hour or so ago with the only casualties of the day being one £25.00 auxiliary drive belt, and one £70.00 Bosch LSU 4.9 lambda sensor. We got up at 6.00am this morning, so it was a very long (and eventful) day, however Monty is now properly mapped at the top end and going like a scolded cat. I will buy the lambda sensor tomorrow from the ECU Master's UK dealer Road Race & Rally and I should have it on Saturday morning, at which point I can reinstate the wide band closed loop short term trim and be on my merry way.
Thanks for listening
