Apr 2018

1st or maybe 2nd in class at the Aintree Sprint

On Friday the replacement mk2 front wing bracket arrived, courtesy of DJ Cars and Plays-Kool Motorsport. Nick and Luke Algar had CNC machined the parts for me, and so I built the front wing up on Friday afternoon, and the design certainly looked promising. On arriving at Aintree at 7am (2 1/4hrs towing) I nabbed the space next to Steve Miles' Van Diemen, and unloaded the car. Steve was changing his gear ratios, and was stuck trying to get the end case back on the gearbox. So I spent 20 mins with Steve, getting him sorted and the issue was simply one of misalignment. All the right gears, not necessarily in the right order. Steve Wilkinson used that on his commentary, descrbing his sequential gearbox as having the Eric Morecambe setup. Anyway, scrutineering went through very quickly, I received a free MSA sticker on my Simpson Hybrid FHR (thank you Chris) and first practice was soon on us. A beautiful sunny day at Aintree, despite rain all over the rest of the country. As I built the speed up, there was no front wing wobble, however when I pushed the car on the final straight, the wobble returned. Albeit at a much higher top speed.

In the paddock, I raised the front wing up, 10mm, as the mounts that DJ designed, gave me that option. On to the 2nd practice run, and again the wobble returned, but at an even higher top speed. Which was encouraging. So for the first timed run before lunch, I added further packing spacers to the front dampers to reduce the drop in ride height, and again, this improved things. And I ran a 42.90s, which was just 3/10ths off my PB from 2017. But I had little suspension travel left, so on the long lunch break, I raised the front suspension two turns of the turnbuckle on both sides, to give the car another 6mm of ride height.

The second timed run I ran a 42.91s, one hundredth slower, but, no wobble and with some suspension travel restored, I had nothing to lose for the third timed run. I lined up, and setting off recorded the quickest 64ft time all day with a 2.13s on cold tyres. I really pushed the car, took a little more speed in to the corners, and as I crossed the line at 146mph, no wobble, and I'd run a 42.61s lap, which was just 0.02s off my PB. And I was just 1s behind Steve Miles so that was also very pleasing. I was 1st in class too, as FTD winner John Graham took FTD in the Gould.

So it looks like we've found the cause and the solution to the front wing wobbles. The car is still too softly sprung at the front, and the front wing is being driven down in to the road. And to maintain its gap to the road, I shall have to fit 950lb/in springs to the front, and fit the 1150's to the rear. I'll do that before the next event which is at Pembrey in June, so plenty of time.

The stiffer front wing mount definitely contributed to solving the problem, so a big thank you to DJ Cars and to Plays-Kool for the machining. With the stiffer front springs, I'll be able to run some flap angle, because all of the above was experienced with zero flap, therefore in order to actually run front downforce, the car needed far stiffer springs than standard, and opportunities to go testing, which unfortunatly, in Feb and March, the reliable British weather prevented. At least we had a sunny day at Aintree, and time to try a few things out until we cured the problem. A big thank you to Liverpool Motorclub for putting on such a well organised event. I'm going back this year, with front downforce, where I'll have another go at beating my PB.

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Ready for Aintree

All the jobs are complete, and I'm ready and raring to go to Aintree. 42.59s is my PB I need to beat, and I'll try my best with the new wings, and chassis setup. I've entered the Abingdon Carnival Sprint on June 9th, and the Snetterton weekend sprint on the 23rd/24th of June, which is another two rounds of the BSC.

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Diff refitted

I refitted the differential last night, and filled the box with 3L of Royal Purple gearbox oil. It wasnt easy to get the diff back in with the offside drive shaft in situ, so I ended up removing that, then when the diff was securely back inside the box, both driveshafts were refitted, and everything tightened up and checked over. With both rear wheels off the ground, now when I spin one wheel the opposite wheel turns in the same direction, which shows the preload is correct.

Next job is to drain and refill the fuel tank, so I know I've 5L in the tank for Aintree, and have a go at sitting in the car wearing the Simpson Hybrid FHR, to make sure that I can still do my belts up.

Pete took FTD at the Borough 19 Hethel Sprint on Sunday, in sunny conditions. He's recorded peak lateral G's of -2.76 and + 2.66 for the first time, which is impressive. The aero package on his car is clearly working well.

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New Pi project begins

I've started the next Pi project, which is a G-Meter with visual indicator for the race car. The page can be found here

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Diff done

The diff is back from MBR, it needed a shim 2 thou thicker to bring the pre-load back, and it cost me £80 for the labour, so not bad really for the expertise that Mark has. So nearly ready for Aintree on the 28th, where I'll be car #98 up against John Graham #99, and I've also put my entry in for the Pembrey Summer Sprint in June, no time to relax. The side and doors inside the van are now fully soundproofed and insulated, so the next trip out that requires a sleep inside, it should be more comfortable.

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Diff maintenance

The diff is removed from the gearbox. It was really only a 10 minute job, but it took an hour to suck all the gearbox oil out of the box, to avoid it leaking when I removed the diff cover. The oil came out very clean, with no metal fragments inside the bottom of the box, and there is little wear on the CWP, so I'm sure the gearbox will take more torque than the 261ft/lb I've been putting through it for the past 12 months.

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Diff maintenance

The Hewland limited slip diff needs to be sent away for a service, as it no longer has the same pre-load as it did when it was first fitted. The way to test for pre-load is to raise the rear wheels off the ground, and rotating one wheel should make the opposite wheel turn in the same direction. My diff doesnt do that, so its going to be removed and sent down to Mark Bailey for him to check. The latest DJ design for the Mygale front wing bracket is also currently being CNC machined, and I should have it back in time for Aintree on the 28th April. As I didnt get above 100MPH at Croft, I'm still not sure if the modified wing bracket cured the problem, so I'm wholly relying on the CNC bracket to cure the oscillations.

I'm three events in to the 2018 season, and even though I managed to scrape 2 British Sprint points at Castle Combe, I didnt enjoy the day, nor Rockingham the day after, and Croft was a complete waste of time due to the weather, and I'm not where I wanted to be pace wise, due to the testing in Feb and March having been snowed off, so all in all its quite a disappointing start to the year. At Aintree I will be winding the downforce on, gradually, until I'm more comfortable with the feel of the car, and at the very least I need to set a new PB. My target is to get under the 40 second barrier, closer to John Graham's Gould which easily circulates in the low 37's. But front downforce is what's still lacking, and I know the wings will totally transform the car once I've ironed out the annoying niggles.

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Van mods

The VW Kombi van I've bought to tow the trailer, and to live in on the weekends away, is receiving some Silent Coat 40 sound deadening. Once its all done inside, the light grey panels will be treated to some Veltrim, and additional insulation will be added to the cavities to make the van a bit warmer on the colder nights. I'm just getting all the parts together for the hookup kit, so I'll have mains electricity inside the van when there is a hookup point available. I used the van for the first time to drive up to Croft, and its a very capable vehicle, certainly made for an easy journey, and sleeping inside the van was more comfortable than trying to sleep inside the trailer.

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Pi Data logger results

The datalogger worked really well on Monday, I used it for both practice runs, and the GPS coordinates that it recorded are very accurate. I use Excel to import the data that the Pi creates, and I have written Visual Basic macros to analyse the data and produce the trackmaps. The hardware costs around £130, and that gives GPS logging at 10Hz, and 8 ADC channels, of which I'm just recording 4 channels for the time being, for the four potentiometers.

Once the data is analysed, Excel can export the data in CSV format, and the CSV file can them be imported in to LifeView alongside the data captured by the ECU, to display the four potentiometer traces.

British Sprint Round 2 Croft Easter Sprint abandoned

The weather beat everyone at Croft Circuit yesterday, with forecase of sleet, snow and heavy rain, not many of us thought that the event would run its course, and after the 2nd practice, in very dangerous conditions, the organisers took the correct decision in my view, to abandon the meeting. I couldnt see where I was driving, I couldnt avoid the puddles and rivers running across the track, and I didnt have the appetite to bin it in practice just to show everyone how brave I was. The conditions were almost as bad as that sprint at Barkston Heath in 2006 in the Fiesta, where we were literally skating around on the surface water.

Besides that, the car felt really great on the new springs, and the front wing didnt oscillate at up to 96mph, its just a shame it wasnt dry so I could try and go even quicker. The Raspberry Pi datalogger was installed for this event and it worked perfectly. I'll publish the results later this week.

So no points awarded, 300 mile round trip completed, two more laps driving in the rain under my belt, the Michelin wets were very grippy, it was just a shame the rain didnt stop to allow the track to drain. My next event is the Aintree Sprint on April 28th.

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