Locost: Snetterton Damage Report

We made it to Snetterton; its official. I’m going to leave it until later to give you a run down of what it took to make my little red car trackday-ready. However, its fair to say the six weeks leading up to Snetterton left me feeling both physically and mentally achy.

Having just performed a two day fabrication marathon on Saturday and Sunday (Feburary the 11th/12th; for posterity), the car was sat on the trailer ready to go at 7pm. After a quick batch of takeaway pizza and beer we were ready for bed; we had a 5am start the next day to get to the track. “We” was myself and my younger brother Alex, who is now the official truckie for OgilvieRacingTM and second mechanic (he fit the passenger seat in the car the day before).

The two hour drive to Snetterton went without a hitch and we rolled in at about 7:40am, giving us 50 minutes to unload and sound check the car.

Sound Check

Every circuit has a different static noise level which your car must pass to be allowed on track. Snetterton’s static noise level sits at a deafening 105dB, which mean’t I was quietly confident the car would sneak in under the volume radar. While sitting in the cue waiting to be tested we both got quite giddy, as it dawned on us we were actually at a race track track and it was really happening. Hence the following terrifying selfie.

We were surrounded by Sevens of many shapes and sizes, Subarus, RGBs, Hatchbacks and a multitude of MX5s. The atmosphere was quietly buzzing as everyone was excited to be there and not taking themselves too seriously.

When our turn came around the operator asked us what type of engine we were running, I said “A 1300”, and he explained that we should bring the car up to 5000rpm and hold it there for the test. This was based on the car being at ~3/4 of its peak RPM, which was a fair guess as I was  planning to shift between 6500 and  7000rpm. Fortunately we breezed through with a reading of 100dB; even though I was running a weedy little motorbike exhaust can. This was our first achievement of the day.

Run 0 – Sighting Run
Data: None

Following the drivers briefing we were required to perform three sighting laps in a group of approximately 20 cars, to get a feel for the layout of circuit and any slippery bits. Given that it had snowed all weekend the track was very greasy and gave me a few surprises even at low speed. I was following a Porsche 911 , which was both gorgeous and  incredibly hard to keep up with at full chat! I took these laps to get used to the gearbox and pedal layout, having never driven the car for this period of time before. That said, it took to the track rather well and had a lot of front end grip.

Having completed my three laps I returned to the pits,.

Run 1 – A trip in the mud
Data: LOG022.TXT

Feeling confident, my brother and I jumped in and went for the first official
drive of the Locost at Snetterton; this didn’t last long. We did a slow out lap to
get a feel for the grip level and then started to push a little. The car felt good,
the gauges looked happy.

Coming into T6 (Oggies) on our first flying lap I over cooked it on the brakes, expecting
there to be a lot more grip than there was; doh! With a little steering angle the
rear would start to step out, and with less steering angle the front would plow on, giving me two options. Go off front-first, or off rear-first. I chose front.

Fortunately the car kept turning as it went into the mud and we were almost back on
track once we came to a stop. I slowly got the car back to the pits, thankfully without having to be rescued, and we were surprised to find that the car was not damaged at all. Just slightly sad looking. With an old towel in hand we were able to clean the car to an acceptable level and get ready for another crack at it.

About thirty seconds after we got into the garage my far-more-trackday-experienced-friend Dan rolled in covered in mud. He had also gone off at Oggies, which made me feel a lot better about my driving!

Run 2 – Before Lunch
Data: LOG023.TXT

Given how slippy the track was I made some setup adjustments before heading out again. I raised the Front Ride Height by 3mm at the front dampers (1.5 Turns, ~1.6 Wheel/Damper Motion Ratio giving +4.8mm Front Ride Height), which also happened to reduce the Front Static Camber (due to the camber change in bump) and raise the Front Roll Centre; each of these helping to stabilise the car. I also increased the front damping by two clicks to slow down the initial turn in response. The car was a little two reactive for me at this time of the day.

The car felt great following the changes I had made and gave just a touch of understeer, with on throttle rotation on exit thanks to the open differential.

I only managed four laps, including my in and out laps, as I could see a big drop in oil pressure on the gauge in T7 going onto the back straight and I wanted to make sure the car was okay. That said, I drove the car as fast as I could while I was on track; it appears all mechanical sympathy goes out of the window once your at speed!

Having checked the data over lunch it appeared that the engine temperatures were safe and the oil pressure never dropped below 20psi. That said the oil pressure was dropping off in right hand corners, from 40/50psi to 20psi, but never going to zero.

It was likely the engine was sucking some slightly thinner aerated oil in these corners. To be safe we topped up the sump to the maximum amount I’d designed for. In fast right hand corners the oil pressure stayed rock solid; Turn 3 (Palmer), Turn 4 (Hamilton) and Turn 8 (Brundle).

Run 3 – PM Brake Bias Forward
Data: LOG024.TXT

Before lunch I was struggling to trail braking into the T2 hairpin (Montreal) without some rear inside locking; especially as I released the clutch. I decided to move the brake bias 2% forward to help with this, which was ~2mm at the balance bar.

I went out again with Alex in the passenger seat, so setup wise it wasn’t going to be too representative, but it is plenty of fun with a passenger on board.

Unfortunately I had forgotten to put my helmet strap on! Being smart I did an Out/In lap and fixed my helmet in the pit-lane. This coincided with a red flag on track so we ended up sitting in the pit lane for a little while looking at a red flag (the data suggests almost 6 minutes). We noticed the engine getting properly hot at this point, and blowing a little steam, so we took it back into the garage to cool down.

I didn’t notice it at this point in the day, as I already had enough to think about , but the fan had failed; maybe even when we towed the car to the track on the trailer. The data showed very high pit lane engine temperatures all day, however the car had not sat still for long enough for this to be an issue; until this red flag.

Run 4/5 – Overheating!
Data: LOG025.TXT / LOG026.TXT

We went out for two short runs (two timed laps, three timed laps) but clearly the car wasn’t running right. Once we brought it back in and it was finally clear to me that it was overheating.

Once it had cooled down I opened the water cap and topped up the system, a lot; too much . Following the pit-lane incident in Run 3 the engine had spilled a lot of its water onto the pavement (I have no expansion tank) and was now running sub-optimally. There was still water in the head but the top pipe and the top of the radiator were completely empty. Flow across the thermostat would have been very slow indeed.

Fortunately I had dodged a bullet. The water was running clean and the oil was also clean; so no blown head gasket.

These runs did show an improvement in oil pressure in right hand corners, which was a relief. Topping up the sump had at least made a measurable difference.

Run 6 – Short Lived Glory
Data: LOG027.TXT

With the track having fully dried out, and my car back in tip top health, I went out for what would be my final run of the day; riding solo and at race weight with a little less than half a tank of fuel.

This fifteen minutes was what the day was all about. The track had gripped up nicely and the car was running the best it had all day. I kept pushing the braking points until I was starting to under rotate the front inside wheel and felt I had quickly found my limit.

The Nankang NS2R’s actually came in quite quickly, which was a surprise for a Medium compound tyre, and gave really good feedback. My lines were pretty lame and I was only pushing the kerbs on corner exit, but I was having a lot of fun and going faster each time around.

Coming into T4 (Agostini) on my fifth lap I felt a large front end vibration which suddenly disappeared. This was accompanied by some mid-corner understeer/weirdness and a general feeling of confusion. Once I limped around to T10 (Bomb Hole) I was flagged by the marshals to return to the pits. Upon my arrival the man in orange explained to me that I had broken my front splitter and it was waggling all over the place; fair enough!

At this point I parked the car and basked in my own smugness. I had experienced a small glimpse of all the fun that could be had doing track days and was relieved that I had made it this far. Of all things to break the splitter was the easiest to fix, but it would have to wait until the car was at home. This felt like the right time to pack up and call it a victory.

Final Thoughts

On paper, we didn’t have a hugely successful day. The car didn’t turn that many laps and suffered a few engine teething problems along way. However, that was never what this was about. The Locost has been the accumulation of almost ten years work, and started life in my young teenage mind going on fifteen years ago.

On Monday the 13th of February 2017 I achieved a life goal: I built and trackdayed my own little racecar; and I’m still buzzing about it! I have definitely caught the trackday bug it. A car like this, driven in a track environment  is a massive endorphin hit.

What really surprised me was how well the chassis handled on track. In the tight car park events that I am used too, it lacks rotation at a high steering angles and tends to plow on if you push it too hard. On track it eats up kerbs, rotates on demand on corner entry and, if your willing enough to use it, has great peak grip in the mid-corner. The small adjustments I made at the beginning of the day gave me a measurable change in handling, and the engineering knowledge I had learn’t in motorsport was both applicable and effective.

The Locost has always held a special place in my heart. Uncountable hours have been poured into it, however it hasn’t always been that usable. Now that I can drive it on track, I think I have fallen in love with it all over again.

Time for more trackdays, lots of development, and endless fun. Success.

 

Engineering Notes

Just a few bullet points about the car, which I will likely elaborate on in the future:

  • The engine was definitely down on power compared to where it could have been and is in need of a dyno session in the very near future. This was also reflected in poor drivability out of corners.
  • I am getting spikes in RPM from the ECU which suggests the ignition system needs more filtering/shielding. This tended to happen at the same engine speed each time, supporting my electrical noise theory. These could be felt as flat spots while driving and were obvious in the data.
  • The fan is dead, long live the fan; replace the fan.
  • The splitter needs supports back to the chassis at the forward edge; clearly.
  • Having to add so much front ride height to balance the car suggests the mechanical balance is too far rearward, and I need to get softer rear springs, stiffer front springs OR add a front anti-roll bar.
  • The GPS was broken on my datalogger all day and it needs to be torn down and investigated. This was also the case when I drove the car in the week, but I didn’t have time to fix it. It has been tested and known to work, so it was rather odd.
  • The car needs a water expansion tank. Badly.

Locost: Desperate Trackday Preperation

Life has got the better of me over the last few months and progress on the Locost has been slow. I had hoped to be doing a Trackday this December, but the car simply wasn’t ready, and there weren’t enough hours in the day to make it so. Subsequently, when my mate Dan messaged me about a Trackday he was organizing at Snetterton in February I was all ears. This is just far enough away to give me enough time to get the car prepared, but at a push. Fortunately, I work well under pressure.

So for my benefit, here is my Locost-work-list that needs to be completed before February the 13th:

  • Fibreglass Rear Arches – By now you have read my article about the Locosts rear light pods. These are still being fettled into the arches so the lights can be fitted. I’m hoping to get these into primer over the Christmas break and bolted to the car.
  • Finish Lighting Loom – With the arches in place I can finish the loom for the rear indicators and brake lights. I ordered connectors for this job, and have built an unfinished rear-end loom, so this should be fairly straightforward.
  • Mount Front Arches – This is one of the more complicated tasks. I have some M8 threaded standoffs that I can weld to the front uprights to make mounting easier, but really I need to bend some 3/4inch tube to make the frames for these. If I can measure these up before I head back home for Christmas I should be able to get this done.
  • Finish Mounting Drivers Seat – This is a straightforward task as it is already bolted in place, the 8mm holes simply needed to be taken out to 9mm. I would also like to re-paint the floor pans while the seat is out; just in case it rains.
  • Fix Leaky Sump – Remember that awesome wet sump I made? Yeah it leaks. I’ve been struggling to get it to seal to the block. I always used to use the standard Suzuki cork gasket but this time have been trying to go purely Silicone; this is clearly a terrible idea. The sump needs to come off one more time and get sealed properly. I have a spare gasket so all I need is time.
  • Mount Rear Panel – I have a sneaking feeling that I need have a rear panel to cover the fuel tank for Trackdays. It would make sense that the driver would not be allowed straight line of sight to a flammable tank of gasoline. So for my safety I need to sort this out. I have a carbon rear panel molding, so I just need to get measuring and cutting before Snetterton.
  • Shakedown – I need time to drive the car and check it has no issues. It has been dried stored for over twelve months now, so with a little luck it should be fine.
  • New Tyres – My old Yokohama A539s are almost as old as the car and have seen far better days. While they have heaps of tread on and I’m tempted to give them a final send off, they need to go. Given I’m not going to be racing anyone I may just get a fresh set of A539s or the Toyo equivalent. Cheapish tyres, but at-least new tyres.

Optional:

  • Paint Front/Rear Arches – It would be nice for the car to look good while on track, but my priority is actually being there. However, if I get the time it would be nice make things pretty.
  • Wire In Datalogger – This is a project I am yet to write up, however over the last couple of months of dark evening I have created a datalogger for the Locost. I would quite like to run this at Snetterton as the data will tell me a lot about the car and help me progress my driving. This is almost not optional in my eyes, but I guess its low priority.
  • Cover Gearbox Opening – I ran a pneumatic paddleshift system for a while, which is now on the back burner until I can track the car. This required opening  up the tunnel around the gear-stick to fit. With the normal gear-stick mounted now the driver has line of sight to the engine bay. For safety reasons this is bad, and although I don’t think it will cause any issues, when I get the time I hope to cover this up.

What do you think? I don’t have anywhere near as much free time as I used to and could do with some spending some time with friends over the Christmas break. So realistically, other than the rear arches, everything has to get done in six Sundays. Fingers crossed.

(Featured imagine taken from here)

Locost: Baffled and Gated Sump

This is the first part in a series I like to call “What’s wrong with the Locost?” or WWWTL for short. I promised myself I would do a Trackday this year and as things are starting to slow down for the summer I now have time to prepare the car.

Firstly, the Locost is not perfect; I can easily stand and point my finger at a million things “wrong” with it and there are a few things I can’t really live with that I feel I need to amend before it starts turning laps.

You see, as you fix the fundamental setup issues on your home built race car, and attach a set of half decent sticky tyres, you’ll start to go around corners much faster. This has a big effect on the longevity of the car, increasing the loads through the suspension and engine, and you will definitely find some design flaws if you are lucky enough to have any. If you applied good engineering when designing/building said race car you will hopefully have no issues. You would have considered all loading conditions, and you will suffer no tears/breakdowns/failures.

Something I feel I did not consider enough many moons ago, and potentially completely overlooked, was oil starvation.

 

The Oiling System

I’ll do a short run through of the oil system in a combustion engine to give you a basic idea of what we are dealing with.

Firstly, oil lives in the sump pan. This is essentially a bucket of oil at the bottom of the engine which stores a supply of oil for the engine; this is directly under the rotating crank. Oil is sucked out of the sump by a crack driven pump and forced through an oil filter, which removes all the small particulates which might potentially cause damage upstream.

From the oil filter it feeds the main oil gallery which gives oil to the main bearings and crank, ensuring there is adequate lubrication and load support for the connecting rods. The main gallery also has a vertical feed going vertically towards the head. This lubricates the cam bearing surfaces and pressurizes the hydraulic lifters.

Oil slowly leaks out of the bearing surfaces, and flows back to the sump thanks to gravity. The restriction between the pump and atmosphere (the effective hole size in which the oil leaks out of) leads to a pressure build up in the oiling system. Once a given oil pressure is reached a blow-off valve allows oil to flow straight back into the sump, restricting how much oil pressure will be achieved. Therefore the less wear on an engine, the greater the restriction and the greater the running oil pressure (until the blow-off valve pressure, which is usually 60-70psi).

As an aside, when an engine is cold the oil is thick and viscous, and therefore the oil pressure is higher.

G13B Oil System

So, if for some reason the engine is starved of oil it will pump air and the oil density will drop, flowing easily through the gap in the bearings and reducing the oil pressure. Air does not lubricate or bear load very well, leading to excess wear and potential engine failure.

In short, oil pressure is an effective measure of engine health.

 

The Sump

So how does oil starvation occur? Well usually its one of three things, a lack of oil in the sump (check your dip-stick!), aerated oil or oil slosh away from the pickup. Keeping the sump full is easy, and really there is no excuse for having a low oil level, however the other two are not so obvious.

Oil aeration occurs when the crank stirs up the oil in the pan and fully/partially turns it into foam. This can be designed out with use of a Windage Tray; more on that later.

Oil slosh occurs due to the accelerations that are applied to the oil volume. If you achieve a lateral acceleration of 1g (at the apex of a corner for example), there will be a force pushing the oil against the side of the sump equal to gravity and it will set in triangular shape; as illustrated below:

Oil Slosh

In this case the pick-up is partially open to the air and pumps that as opposed to oil. This leads to bearing on bearing interaction, friction, wear and potential engine failure. The secret to good sump design is to reduce the chance of the pick-up being exposed to free air.

You can do this by using a tall deep sump, or by baffling and gating the sump. As the Locost is a small tightly packaged race car its nearly impossible to package a tall sump without running an impractically high ride height, so the sump needed to be baffled and gated, with an inbuilt windage tray.

 

Old/Poor Sump Design

My old sump was built from the flange of a standard front wheel drive sump, with custom sheet metal work underneath. The pickup was at the front and approximately central. It had longitudinal and lateral baffles with liberal drainage holes between each (making them almost useless) and a bolt in windage tray. It looked a whole lot like this:

Old Sump with Windage Tray

With the windage tray removed the baffles were accessible:

Old Sump Baffles

In hard right hand corners I think it was possible for the oil to slosh to the left hand side of the sump and expose the pick-up; as you can see there is no baffle in the central section where the pickup was located. The only saving grace of this design was its large capacity, giving minimal oil depth change when oil is trapped in the top end of the engine. Fortunately when I put slicks on the car it had terminal understeer and I don’t think I did any serious damage.

Given that the sump was off the engine, it was a great opportunity to inspect the oil/sump for particulates. The oil was clear of shiny aluminium bearing material, but there were some small bits of the cork gasket in the bottom; nothing scary but also suboptimal.

Blergh

I was happy to move on from this design…

 

New Sump Design

The new design was going to be wider and shorter than the original, positioning the pickup in the middle of four separate oil chambers, each giving the pickup instantaneous oil in the case of hard cornering. Also, the windage tray would bias towards the pickups central volume, to flood it and reduce the chance of oil starvation.

New Sump Flange

Fabrication started by cutting out the main flange to mount to the block. This was bolted to an old junk fitment engine I had lying around (I use this for making engine mounts, brackets etc).

New Sump

New Sump

New Sump Windage Tray

New Sump Pickup

Then the windage tray was cut to match the sump and measurements taken from the chassis.

New Sump Central Chamber

The sides of the sump were then cut and tacked to the windage tray. The central chamber around the pickup was mocked in place.

New Sump Gates

Sump Baffles

Welded Baffles

Then the baffles were put in place to create the four separate chambers. Four gates were added to the central chamber to avoid oil moving away from the central chamber in hard cornering; these were made from steel door hinges! Note that they have limiting tabs to stop the gates going over-centre and killing the engine. The baffles were welded into the bottom plate to stiffen the sump and ensure oil does not escape the central chamber.

Sump Drain

I almost forgot to add a sump drain plug (uh oh!), so I welded in an M12 nut. It turns out M12 course thread is not a standard sump plug size (arg!) so I had to use an M12 bolt with a magnet epoxied too it; could be worse.

Oil Leak Down Test

Once the whole thing was welded together it was tested for leaks using some old oil and left to sit for a few evenings.

Painted Sump

After this it got a snazzy coat of Racing Red!

Closing Comments

The sump is now bolted onto the car and we will see if it causes me any issues. On paper it should be a great improvement over my previous sump and I’m hoping it will give the confidence and peace of mind its designed too.

Before Christmas I will have gathered some track data, covering a large span of lateral/longitudinal accelerations and engine oil pressures. In a perfect world there would be no drop off in pressure over the full span of achieved accelerations; but realistically I’ll  be happy with just very low drop off and a healthy engine.

There is still plenty to do before hitting the track- front wheel arches, rear lights, blah, blah blah… I will get there eventually!