Busy is my middle name. Our own car, the F398, is back together and has been running regularly whilst revised warm up and idle control routines have been added to the ECU, along with some analysis on the viability of fitting larger injectors to the throttle bodies – it is possible that the misfire we suffered from throughout 2010 was caused by the 
current injectors being unable to supply the additional fuel required during high rev throttle applications due to a lack of flow rate. The car now starts easily from very cold and from hot, and idles smoothly with good fuelling as the ambient and coolant temperatures increase. Until we get on the track in February (hopefully) we won’t be able to make much progress on the fuelling elsewhere, but by the end of 2010 it was pretty good. Since writing the first part of this paragraph, I have fitted larger injectors, which will give plenty of head-room with regards to injector opening times. I’ll also be lowering the fuel pressure to give the fuel pump an easier time, which will also give the battery an easier time. And I’ve fitted a fuel pressure sensor to the car, so that we can see how constant fuel pressure remains, particularly at high revs when fuel demand is high. And finally, I hope to have a ‘box of tricks’ on the car so that the ECU data (injector pulse widths, acceleration enrichment, spark advance, air temperature etc.) can be fed to the datalogger for post-race analysis. I WILL cure the misfire!!!!
Posts Tagged ‘misfire’
Comments OffThe final round of the year was held at a chilly Silverstone, utilising the National circuit configuration. It doesn’t seem that long ago that I was thinking ahead to round 1 at Brands Hatch…
Going into the event I had the luxury of an 8 point lead in the standings, which meant I could happily accept two 2nd place finishes as long as I got the fastest lap for one race. But the trouble with motorsport is that it’s difficult to go slower than you can (mistake creep in as you deviate from your usual rhythm), and virtually impossible to go faster than you are able to. Maybe I wouldn’t be able to keep up and get fastest lap. Maybe Richard Purcell would be quicker. Maybe something would break on the car. Maybe Jeremy would crash. All I could do, in my role as driver, was do my best…
Saturday was cold and wet to begin with. The smaller engined Mono cars (I playfully refer to them as the MiniMonos) were out first, and the tyre choice was divided between wets and slicks. Fortunately, by the time we were due out the track was mostly dry, and we went out with dry-weather slick tyres.
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The penultimate meeting of the 2010 Monoposto Racing Club championship was held at Croft this weekend, and it had the potential to decide the championship. I went into the meeting 12 points adrift of Jeremy Timms, having trailed him in the championship for the entire year. Jeremy could have clinched the championship here, but fortunately the outcome was rather different, and now the championship will go down to the wire at the final meeting of the year in just over two weeks time at Silverstone on the National circuit.
The whole weekend was a chilly affair, but the rain stayed away (at least during daylight hours), and the track remained in reasonably good shape throughout. Saturday morning saw a fairly uneventful qualifying session in which Timms took a fairly easy pole position from me in 2nd, with Richard Purcell in 3rd having repaired his engine. The gap between Jeremy and me was 0.3 seconds, which isn’t a lot in Monoposto terms, but I didn’t have an answer for him. The misfire had returned, this time no longer on gear changes (well, it did once), but now on full throttle; it occurred at 6300rpm or thereabouts, and the only way to maintain competitiveness was to reduce the throttle slightly (to 90%), which allowed me to accelerate through it. How much time that was costing me isn’t known, and it may have cost me pole position, but I think overall Jeremy just out drove me.
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We’re well into the 2010 season now, and the general trends are already apparent. In our case, it’s been that we have had a quick car, but one with too many reliability problems, and hence we’ve been lacking in championship points despite a fairly large proportion of fastest laps and pole positions so far.
Most of our reliability problems have been due to bad luck rather than poor preparation, and we arrived at Oulton Park hoping our luck would change a bit. At most races we’ve had one disaster, so it was slightly pleasing when that occurred before we’d even got out of Norfolk – I realised I’d forgotten the laptop, which is important for checking the datalogging as well as attempting to improve the poor mapping in the ECU. Emma and I went back for it, whilst Andrew and Martin continued in the truck to the track. As disasters go, it wasn’t a big one, but we hoped that it would count in the eyes of Lady Luck!
More Comments OffNot a good weekend really. Our problems started on Friday when the switch for the tail lift on the truck burnt out in the heavy rain, so we had to resort to touch wires together by hand to operate it. This was the first time we were going to use the truck at a race meeting, so we knew there were going to be issues related to it, but we weren’t expecting to have such fundamental failures… Oh well, you live and learn, and we can fix it in time for Oulton (which, at the time of writing, is only a few days away!).
At the circuit on the damp Sunday, I qualified in 3rd, missing out on the front row for the first time this year due mainly, I suspect, to traffic on the final two laps when the drying track was at its quickest. The ever present misfire reared its head again too, although I don’t think it’s costing much more than a tenth per lap (although that is no excuse). We are hopeful of getting the misfire problems sorted out, and we are attempting to discuss the matter with the people that made and mapped the ECU. However, a good race was still on the cards, until the throttle bodies failed for a second time in two meetings, leaving us with no throttle – the throttle shaft that links both throttle bodies together broke up. Clearly not strong enough, and a new design is in progress. Laughably, the throttle body manufacturer even tried to suggest it was the driver or the track that was causing their product to break. We’ve since offered to let them inspect the installation and the setup of the throttle cable before Oulton Park – although I’ve been triple checking the throttle cable and the pedal stops since Mallory last year.
Comments OffA brief overview of fuel by Martin, originally written for and published by Startline (Monoposto’s e-magazine) in July 2009, and now published here for all to see. It was in response to this article on the same site. Click “Read More” below to see it…
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