The morning session went pretty well, we found a problem in the way I was trying to control boost that meant the control logic was never going to be able to react quickly enough, but after some minor re-configuration an alternative method was shown to be working well. After that we moved on to testing a another new throttle response control strategy, don’t want to say much about this (or the other methods we are using) yet, but it got rave reviews from the test driver so I think that’s a keeper as well.

The afternoon was less productive with the trackday crowd getting  in the way a lot by not yielding position for overtakes. Can’t say I blame them, I used to be the same once I thought I knew the track well enough. What they can’t hear while they are “speeding” down the straight in their 20-year-old overweight knackered Porsche is the foul language coming from my mouth while my foot barely touches the throttle and I wonder if the engine is about to stall because we are going too slow… Don’t think we will be going back to Blyton anytime soon, for a trackday anyway.

I made some other changes to the cooling system by adding a splitter to encourage better flow through the radiator, this worked pretty well, roughly running 10C cooler than it had before. What did not appear to improve much was flow through the intercooler. Think we have reached the limit of what I can get from this setup, so time for new ideas on further cooling to the inlet temperatures. The temps aren’t bad, but we can do better which will mean more bhp (and probably a little more weight).

From the Blyton data logs I think I may have found a weakness in the engine fueling that has been causing problems forever. Can’t say for sure just yet, but it’s now top of my list to checkout on another run. If we can nail that and make some more progress on inlet temps in the next run then think I will be happy to start a winter rebuild with some confidence about next year.

I worked on a couple of major products at Intel over six years, the first was a spin-off of XML library work I did at Sarvega (acquired by Intel in 2005). This product ran into difficulties really on all fronts, its business positioning, its value proposition and its technical merit. I was heavily invested (several years or work) in the technology behind this, but good technology (arguably the best XML libraries available anywhere) is rarely enough to ensure success and the development was eventually scaled back substantially.

The XML development group was reformed closer to its roots as part of what is now termed “Application Security & Identity Products”, I took on a more central role for the identity side, managing the engineering team rather than only being a standalone architect. The result of this was the release earlier this year of Expressway Cloud Access 360 (yes, it’s rather a mouthful).

Everyone keeps asking me where will you go next, well the short version is I am taking a break before deciding anything. I learned a lot of great lessons at Intel but I need to be somewhere where I can use those to better effect, that is where I expect I will be in a few months time. For the moment I am happy to take some time out, catch up on where the broader tech world is and regain a better life/work balance; maybe I can even stop speaking in Intel-isms if I try very hard

Sunday was much brighter, we only got three runs in due to a combination of slow turnaround of cars and an impending rain storm. On the first two we were trying out a new control mechanism for boost, I had seen signs of this working ok during practice but something was wrong on Sunday leaving us with very low boost. For the final run we reverted to a less sophisticated strategy to get back the boost knowing this would compromise throttle response, but it was the quickest option to try to salvage some better times.

I ran first and promptly spun after the third corner ruining my run. In hindsight I was just trying to hard, by the time I had got to that point I had already had four “moments” where I had spun up the rear tyres way beyond their ability to keep traction. Kind of inevitable that I was not going to manage to keep the car straight with that much aggression. My long-suffering double drive ran better, getting ~3 sec improvement leaving him ~2 sec off class pace.

Overall, the weather sucked again, we needed the Saturday for testing, but we did learn a few more things, just less than I would have liked. That’s it for this year in competitive runs, but looks like I need continue with winter testing again if we are ever to get this car competitive. So far, 2 yrs effort has taken us stuttering towards better times but it’s not good enough yet.

• In May I got the engine rebuilt by at Extreme Engines. Karl was great, spending loads of time walking through the options and making sure I was clear on costs. Not a cheap thing to do, but I had to take the plunge.
• In June we ran at Curbourough on very low boost to make sure all was well. We were a bit off the pace but a lot of the difference was due to being fairly slow down the finish straight, our terminal speed was ~104mph vs 112-115mph for the rest of the class. Even better, was that I was not far off the time of my double drive which I have never got close to at Curbourough before.
• In August we ran at MIRA, we have only visited here once before, it did not end well, so a lot of the day was spent learning it again. Time wise I was about the same amount off the pace, but on a longer run with some fairly obvious areas we could improve. Felt like we made progress again.

Next and last outing this year is at the Ty Croes circuit on Anglesey this weekend, I have made another bunch of improvements so looking forward to possibly having a chance at being competitive.

Time to take some advise on engine rebuilds I think.

I think at this point I should be tempted to just throw in the towel, but I am staying optimistic since I did get to run the car at full pace during the practice run and it was rather good to say the least, the engine was pulling like the proverbial train and the car felt very planted and responsive. You see, like some poor addicted junkie I only need one good hit to remind why I still put effort into this pastime, I am addicted to the shock and awe that comes from releasing a lot of bhp in a light weight package.

The failure details are rather unexciting (that is a good thing), sometime during the day a bracket the holds the plenum down broke. This resulted in the throttle bodies lifting off the engine and throwing the fueling out. The net result was I stalled on the first timed run and on the second I got away but the engine was misfiring. I might have had a chance to find & fix but the rather unhelpful start marshal refused to let me recover the car between the 1st and 2nd runs so it was stuck in the pit lane for most of the afternoon.

During the practice run I hit a flexible bollard at the second chicane damaging the front left wing (pic thanks to blatman). The tyre only just survived, it will need replacing before the car is run again. This track was really too big for the gearing on the car, I hit the rev limiter (~125mph) many times in practice. I don’t have many options to fix that, some bigger profile tyres will probably make most sense for later in the year if we make it that far.

Previously you could see on the data logs two problems coming out of a slow corner, both cases you would say are lag. The first was a delay from throttle opening to really seeing any boost appear. This I would estimate as 1/3 sec and second was the rate of boost increase was poor, perhaps taking a further 1 to 1.5 secs to build up, so worse case 2 secs to reach full torque. That sounds a lot but of course the car is still accelerating in that 2 seconds, it’s just not accelerating as quick as you know it can and want it to.

With just the timing change on everything was a bit slicker, I would estimate worst case fell to more like 1 second to reach full torque. Better, but not enough for our needs. With the anti-lag turned on things felt much better when it worked. The logs show cases of instant boost, i.e. torque available as soon as you press the loud pedal. This was such a great feeling given all the struggles we have had with the engine setup, finally a properly responsive engine package.

The problem with the anti-lag was that it didn’t always work, some post analysis of the logs showed an interesting behaviour, when the anti-lag should be operating the rpm would die like the engine was going to stall. This would trigger the anti-lag to turn off and the revs would instantly rise, sometimes high enough to start the cycle all over again sometimes not.

The theory I have about this is that I programmed in too much timing retard into the anti-lag settings. The system I am using involves an electronically controlled throttle blipper and custom fuel and ignition maps. When the anti-lag is active the throttle is effectively opened a small amount, say 10% by the blipper to let air into the engine. This would normally cause the car to surge forward so at the same time the ignition is retarded very significantly, in this case to 25deg after top dead center.

With these setting the combustion should not really be pushing the piston down much but more chasing it, and so the engine makes less power. The energy in the combustion gases actually exits more via the exhaust valve port and so it is used to drive the turbo and not the engine. So with too much retard I suspect there is not enough energy being used to drive the piston and so the engine rpm goes into free fall. The solution of course should be simple, use less retard so the revs don’t drop off a cliff when anti-lag is on. Something to test on the next outing.

We did test a few other changes, notably paddle gear changes, but it was getting close to an effective anti-lag setup that I was most happy with. Without that I don’t think we would have looked at running this car this year.

The long term concern here is going to be burning the turbo out or the exhaust valves, they don’t particular like anti-lag setups. I am trying to mitigate that by only running a very mild system where we don’t add an extra fuel to really heat things up. That felt quite nice to drive on, frankly full power on the exit of a slow corner is not something I want to experience, that’s for the straights only.

The turbo was/is already showing signs it needs a re-build via blue smoke, maybe I will need to take that on before the competition season starts to make sure we in the best possible position to enjoy the car. Next & last testing session is at the end of the month so time is running out to get this spot on.

Update: I have since discovered that during some re-wiring the throttle blipper was disconnected. This would have been having a big effect on how the anti-lag setup was working, I thought it was rather quiet in operation from what I was expecting after testing the garage. Also spotted a interesting article on how an anti-lag like setup is being used on F1 cars to “blow diffusers”, certainly worth a read.

The problem at the last event turned out to be a simple boost leak, but what it did pin point was that in the transition range from normal to boosted running we had an engine management issue of some type. The engine was very stuttery during the transition although fine before it & fairly fine after it. The boost leak just meant we were spending more time in this transition. The stutter was not a new problem, the engine has always been like this but each time we have traced a different issue that could be the cause and clearly none of them had been.

The good news it turned out was I had a lot of good logging from the running with the lambda sensor turned on. What I didn’t have though was a decent way to analyse the data. The DTA ECU software does not really have a log analysis package although there is a third-party application called E-Race that is OK, but not ideal. So, I broke out GWT and knocked up my own analysis code to plot the air-fuel ratio readings from the lambda sensor against the RPM and manifold pressures at a pretty fine granularity.

This showed the problem pretty directly, the fuel map was good but it wasn’t granular enough. In the transition between on & off boost (between 90kpa and say 125kpa, where 100kpa=atomospheric) the fuel needs rise very quickly, so fueling was good at 90kpa, good at 100kpa, and even good a 125kpa, but poor at 105,110 & 115kpa. The issue here is that the ECU interpolates between the fuel columns that are each at a fixed kpa value, but of course it does that linearly, and linear is not at all what the engine needs in this area.

The fix for this is fairly straight forward once you know it is there, you adjust the position of the fuel columns so there are more in the non-linear areas and fewer in the linear ones to improve the accuracy. Of course I had set the map up in a non-linear way already based on others advise of how to do for turbo engines, but the column positioning clearly wasn’t right for what this engine needed. We should have caught this doing dyno testing but you skip over this area very quickly in a straight power run so don’t notice the fueling going bad, it only shows itself on slow corners (and of course when you have a boost leak). Anyway, some spreadsheet calculations later I now had a new fuel map for the ECU ready for testing and so took the car off for a day at Barkston Heath.

The engine was now running so much better you would not have believed it was the same setup as before. On a couple of runs I thought the stutter might be back, each run was when running low on fuel and the stutter didn’t return after a top up. So problem #2 found, there is a minor starvation issue somewhere in the fuel system. I haven’t fixed this yet but its easy to avoid so it can wait.

Snow, and other distractions stopped me taking the car out for more testing but problem #3 was gifted via an email conversation about possible upgrades for the turbo with Holeshot (the original engine builders). The dyno shows the engine making ~270bhp at near full boost, but the claim is it should be making ~300bhp at this level, I had dismissed that as marketing BS but it was suggested I double checked the timing, so armed with a new timing gun I did and found the DTA running a few degrees retarded. This is a setting inherited from the default Hayabusa map for the DTA, I should have checked this sooner, not the first DTA default map setting that has caused problems, mea culpa.

Next test day is 30th Jan back at Barkston Heath. The first day there had shown that turbo lag (a delay between opening the throttle and making boost caused by the turbo needing to spin up) is maybe going to be an issue. With the odd engine running I had not really felt this much before but Barkston has a couple of very tight corners that really highlighted the issue now the fueling was much better. The retarded timing issue may well have been making this worse, but we will have to see on that one. In case this really turns into a problem I have configured things to allow testing a mild anti-lag (or bang-bang) setup. This is a fairly complex setup, the long and short is we can get the turbo generating boost when running round slow corners so that there is no lag when you open the throttle again. The downside is reduced turbo life, but maybe I can live with that on a competition car.

That’s been my winter of fettling, as always I would have liked to have done more but time is always more limited than you would like. Plans for this year I think are going to depend rather a lot on how things go at Barkston next time out …

We went to Anglesey this weekend for the Ty Croes sprint rather hopeful of at least an average performance. We had found some missing boost (a weak spring in the CBV was limiting us to 8psi or so, after replacing with external BOV we had 14psi) which meant 50bhp extra to play with, a cage had arrived and been fitted and we now had four wheel sensors meaning traction control could be turned on.

Saturday morning didn’t start to well, the car stalled on Paul on the first gear change off the line. Logs indicated this may well be just when traction control should be coming in so we turned it off and tried again. I didn’t get a clear practice run due to catching the car in front but Paul got an OK second run, about equal on times to last year although top speed was clearly much higher.I had to skip the second runs due to the car running too hot when Paul returned it to the pits.

That was the complete highlight of the weekend. The rains came in and we were stood around wondering if we should take it out on slicks (we didn’t have any decent sized wets with us) with no TC to help. We decided to play with the TC settings to see if we could find out what was wrong, the short answer was probably nothing was and the stall is still rather a mystery. We did go out for the final run of the day and tippy-toed around without TC, turned out its wasn’t too bad for a scenic drive, although I don’t think either of us were trying at all having so wanted a dry day so we could learn some more about how to drive the slicks.

Sunday morning started dry … and it then rained before the first run. I was starting to think it was time to go home, but we stayed, turned on TC and went out. The car felt very docile and rather hard to drive, but safe. After an early lunch it looked like we might have a chance of dry run later. So we turned down the TC to get back some drivability, but Paul reported it was just the same. He got a re-run due to another Westfield going off, so we had to take the car back to the paddock to re-fuel for me which pushed me virtually to the end of the run. When I eventually got out the car was hopeless in comparison to the grip available on the drying track. I don’t recall ever been so ****** off as after this run.

This is when the weekend really fell apart, because I ran late in order we had little time to look for faults. I tried downloading the ECU data logs but it was taking forever so abandoned this and we went for the quickest possible fix we could think off, turn off the electronic shift cutter in case that was causing the issues. Paul went out for the last run but it was obvious it was no better, end of day.

That was it, a weekend of waiting for a dry run completely ruined by a stupid fault occurring just at the wrong time and being masked by the wet. The kicker of course is that after getting back home it took me all of 30 mins to locate the issue as a simple boost leak. We had initially lost boost on the run just prior to turning on TC but obviously we didn’t know it as messing with TC had initially hid the issue. Of course we were only messing with TC in the first place because of a mystery stall. I am struggling to belive the luck we have had this year. Faults on a new-ish package I can deal with, but this feels like a ******* conspiracy now.

That’s this year over for us, four rather unsatisfying outings, arguably where our relative performance has got worse at each one. Not sure what the future holds really, I have put too much time/energy/money into this car to really want to walk away from it, but I can’t continue having such a bad time with it for my own sanity. We still have last years car so that gives us some other options. Either way I am going to stop writing about this for a while, other things in life have to take priority for a bit.