Matt Lane

Trouble is, a track day means different things to different people.

At a DE with 4 runs of 20 minutes each (then accounting for warmup and cooldown laps, and any interruptions to sessions) you are probably only looking at an hour of 'track' use per day. An open track day - I'll drive 3 times as much easily.

As a rule of thumb, I change my oil at 12 hours give or take. UOA from Blackstone confirmed this was more than good with my 993. I will need to verify how the GT3 with thinner oil is performing. But it's probably a decent starting point for a DE car that's not racing.

My $0.02:

- you may be doing less 'track' than you think
- unless you keep track of your usage and do a periodic analysis, the rest is speculation
- yes, changing oil is cheaper than wearing your engine unnecessarily, but overdoing it is just wasteful - so test based on your usage and know for sure

Cheers

Matt


Cheers

Matt

mark kibort

food for thought.

The take aways here are that oxidation high temps, high presures and contaminates, wear out an oil. racing will shorten the life of the oil for those reasons i mentioned and those listed below.

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Like just about everything else, motor oil has a lifespan. Even the best oils eventually require you to change them. Historically, many motorists like the convenience of changing oil with the seasons, visiting the quick lube or pulling the ramps out of their garage each spring and fall.Motor oil can deteriorate by becoming contaminated, the additives depleting over time or both.

How oil becomes contaminatedBase oils are the backbone of the finished lubricant that ends up in your engine. They can be conventional, synthetic or a combination thereof. They’re responsible for lubricating components, which reduces friction and protects against wear.Base oils can lose their effectiveness over time due to a few different factors.Oxidation – The interaction between oxygen molecules and motor oil molecules naturally leads to chemical breakdown. Just as oxygen causes a cut apple to brown or exposed metal to rust, it breaks down base oils and reduces motor oil’s effectiveness. Oxidation can lead to increased oil viscosity, which negatively affects energy efficiency. It also causes the formation of harmful deposits and sludge.High heat – Today’s engines run hotter than ever before, with temperatures up to 235°F, and even higher if towing or hauling. The rate of oxidation for oil doubles for every 18°F increase in temperature.Moisture – Your vehicle is also subjected to temperature swings, even when it is parked in the garage. Those temperature swings cause condensation to form inside your engine, leading to water contamination. Leaving a vehicle parked for extended periods or taking short trips that don’t allow the engine to fully warm up allow water to remain in the oil rather than evaporating and exiting through the tailpipe. Water can lead to formation of sludge.Viscosity loss – A lubricant’s viscosity is its most important property. Viscosity has a direct bearing on wear protection, and your engine is designed to operate best using a motor oil of a specific viscosity (e.g. 5W-30). The intense pressure the oil bears as it’s squeezed between moving parts, like the piston ring/cylinder wall interface, can tear apart, or shear, its molecular structure, leading to viscosity loss. Suddenly, the 5W-30 motor oil your engine was designed to use is now essentially a 5W-20 oil, and wear protection may be compromised.Fuel dilution – Fuel can wash past the piston rings and contaminate the motor oil, causing it to lose viscosity. Frequent short trips that don’t allow the oil to reach normal operating temperature can be especially problematic because the fuel won’t volatilize and exit through the PCV system. Excessive fuel dilution leads to sludge and varnish, requiring the oil to be changed more often.Additive are designed to depleteAdditives are added to base oils to reduce destructive processes and enhance beneficial properties. For example, antioxidant additives help slow the rate of oxidation. Detergency additives help prevent deposits and sludge while cleaning pre-existing deposits. Anti-wear additives are added to some lubricants to form a sacrificial barrier on metal components and help prevent wear.Since they’re sacrificial in nature, additive depletion is one of the primary reasons motor oil loses its effectiveness and must be changed.Though all motor oils eventually deteriorate, synthetic oils last longer than conventional oils and deliver improved protection against wear and deposits. They’re formulated with base oils that are more resilient to oxidation and heat, while their additives also typically offer improved performance.

BillNye

You are correct.
There's many ways that an oil can break down. Sustained high-rpm use has a drastic effect on the properties of the oil.

That said, oil should be a pretty small proportion of your operating expenses for a car driven on the track. Change it as often as it seems cheap. i.e. If you track your car 10-12x per year consuming 1 set of tires and brake pads in the process, the cost difference between changing your oil 2x or 3x is trivial compared to the amount you're otherwise spending.

joshdunn87

If your only running 4 days or less a year total I would stay with a yearly oil change. Although If you run 2 events back to back, you might consider changing it sooner. I also error on the side of changing the oil more frequently if I am pushing the car to the limits.

Glyndellis

Let's try to rationalize this

- if you DIY, 8 liters of oil = $50ish. Oil filter kit about $30.
- It doesn't hurt anything to change the oil early.
- If changing it three times a year makes me happy, it's a good investment.
- It's my hobby.
- it's still cheaper than turning good bourbon into urine (my other hobby).

djbooya

So... I got a free blackstone test as a raffle prize. Got a sample from my wife's 996.. Unfortunately, I have no idea how to interpret the results. Is there a guide somewhere that tells me what that numbers mean?

bml376

I don't mean for this to get side tracked into an oil thread. But this thread got me curious about what others who track or race their cars use in terms of oil? I'm using Mobil 1 5W-50. Is there anything better than this available for a car that sees little street usage, mostly about 12-14 track days a year?

BFT3.2

"better", who knows?.. For the past two DE seasons (10+ days per season) I've rotated between Motul 8100 5w-40 and M1 5w-50 changing oil about every 5 track days or 3,000 miles which ever comes first, did Blackstone reports on both and came back good, apparently. In a couple weeks Im going to give the new Motul 5w-50 Sport a shot and see what those #'s say. Supposedly it bridges the gap between the 8100 5w-40 and the full race 300V stuff. Being a M96 engine Im probably a little paranoid and like to keep a eye on that magnetic drain plug. So I do 2-3 changes a summer, not the biggest expense of a DE season by far.

mark kibort

ive seen serious viscosity break down at track temps for mobil 1. it seems to be a non issue with 911s, or other cars other than the porsche 928, where we saw the engine oil pressure light come on on track days.... changing to redline, amsoil, and a few others.....and the light didnt come on oil pressures were near double levels.

Cacciatore

There a small paragraph at the top of the page noting blackstone's comments for your car and anything that you should particularly pay attention to. In addition, the columns down below have universal averages and your values. If you have any questions about what you are seeing, you can reply to the email that the analysis came in and they are usually pretty good at explaining it in laymans terms.

jdistefa

It only took 22 posts to get to the magic question.

Blue Chip

If you ask some well known engine builders - Joe Gibbs only and change it after every weekend.

bgiere

I've been using Motul 300V and Miller's in the engines...Both are ester based, both can do 12-15 hours easily in my motors. They are hard to shear and they hold up to high temps. Take yer pick, both are really high quality...both are very expensive relative to other oils. . Confirmed and it works for us. You may see a lesser quality oil deteriorate and not make it past a few weekends.. Gearbox I am using Miller's 75w110 this season.

T10Chris

I 2nd 300V... Good stuff!

mark kibort

That's because racing temps, pressures, blowby, etc, doesnt hurt the oil......