🔴💊 Engine Oil Red Pill Thread: Only Post If You Have UOA - Official Honda Civic Type R K20C1 Engine Oil Analysis

[johnloov]

That’s great information. Very curious what these next oil samples will show.

Sponsored

 

[johnloov]

Planning a controlled oil A/B at COTA — looking for data-driven feedback

I’m mapping out a simple two-day experiment to quantify oil-grade effects on the FL5 under HPDE load.

Test plan (baseline car in stock mechanical trim):

• Day 1 (COTA): Pennzoil Ultra Platinum 0W-20
• Day 2 (COTA): Pennzoil Ultra Platinum 5W-30
• Method: hot drains with mid-stream samples to Blackstone both days; identical filter, fill level, fuel load, tires/pressures, and pace targets.
• Logging (Honda LogR/CAN): coolant temp (ECT), oil temp, and hot oil pressure (front straight, ≥5k rpm). I’ll compare stabilized values over the last three hot laps each session and post the UOAs.

What I’m hoping the community can weigh in on (with data if possible):

1. Race precedent: Type R TCR and HPD F4 K20C1 packages specify 0W-20 with short OCIs. Beyond logistics, what technical drivers (flow/heat rejection/pressure targets) led to that choice for this engine family?
2. Overheat reports on 5W-30: Many owners report ~240–250 °F coolant and elevated oil temps after moving to 5W-30—even with auxiliary coolers. For a stock, unmodified engine, are clearances/pump and the oil-to-coolant exchanger fundamentally optimized for a low-vis grade?
3. Short-interval tradeoff: For 1–2 track days per fill (not 5,000-mile drains), if 0W-20 already meets hot-oil pressure targets, does a 5W-30 that runs 10–20 °F hotter deliver any net protection benefit—or does the added heat negate the on-label viscosity advantage?

Context:

I completely understand the case for 5W-30 with long street OCIs or on built/looser engines. My use case is different: short HPDE intervals, stock clearances, and a focus on maintaining hot-oil pressure while keeping temperatures and lap-to-lap consistency in check. There are also long-mileage anecdotes on 0W-20 (200k+), which makes me want to measure rather than assume.

If you have same-day A/B logs (ECT, oil temp, hot oil pressure) and/or UOAs comparing 0W-20 vs 5W-30 on this platform—or similar—please share your files and conditions (ambient, pace, car setup). The more apples-to-apples the better. As an engineer, I’m happiest when data—even when it challenges my priors—drives the conclusion.

Zygrene's car running PUP 5W-30 242.4 Max Water temps - no dual oil coolers

Gears and Gasoline Type R - Ben, He's running actually 0W-20 on his type R and has a Cobb tune 50Hp+

Jason's WOT Type R - Running PUP 5W-30 264 actual oil temp ( Type R estimate is 285 - confirmed Log R Estimator shows ~20F higher ) and 226F water temp is accurate. Heavily cooled radiator, dual interocoolers -- Jason also confirms anyone seeing 240F+ water temp's should pit " call it "

 

[joshinthecity]

I've learnt more in this thread, than any other.
Would the below 0W-20 full synth be considered suitable for street driving, hot climate (Australia) plus 1 x track day (moderate) between changes (5,000klm intervals) ?

 

[AspecR]

Did my oil change over the wweekend moving from Honda Ultimate 0W-20 to Redline High Performance 5W-30. Took 2 oil samples that will be sent off to Blackstone labs. I'm very late to the oil analysis game since this will be the first test done on my car and it has 28,519 miles on the chassis. Honda Ultimate had approxiamtely 4000 miles on it. This is the 7th oil change done on my car btw. Also added a Greddy Magnetic drain plug as some cheap insurance.

I'll post the results when I get them back from Blackstone

 

[johnloov]

Fellas - check out this latest from LakeSpeed Junior.

Basically the first 10k miles your data will be unreliable as your car removes break in contaminants - when you compare 0w-20 to 5w-30 - Then they are very similar performance after 10k miles. I'm getting more details. changing more often, and keeping your engine in optimal operating temps on track - is key. Enjoy

 

[Ktrw]

Yeah I was gonna mention that I've done 3 UOAs before 10k (might end up being 4), but I knew from Lakes videos that it was somewhat pointless because there would be elevated wear until I got past that point. I just wanted to see the trend for my own car, but @AspecR at 28k miles you should be able to see some pretty low wear metals so that's awesome. I don't think it's late at all really.

 

[Rhorn]

I've learnt more in this thread, than any other.
Would the below 0W-20 full synth be considered suitable for street driving, hot climate (Australia) plus 1 x track day (moderate) between changes (5,000klm intervals) ?

Not really sure. I dont see the HTHS number which would show how a better baseline of its viscosity rating.

Also unfamiliar with API SP and ILSAC certifications but you want an oil thats low SAPS to reduce carbon buildup, blowby and fuel dilution. ACEA C1-C4 is the certification that confirms its low SAPS but thats only for European vehicles so it'll be a bit confusing. If you can try looking at the VOA Database on Bob the Oil Guy and see what the contents are

 

[Ktrw]

I've learnt more in this thread, than any other.
Would the below 0W-20 full synth be considered suitable for street driving, hot climate (Australia) plus 1 x track day (moderate) between changes (5,000klm intervals) ?

A stock K20C running 0W-20 could easily do 5km oil changes (we've seen plenty of folks on here do long OCIs with low wear metals), but I would shorten the interval if you have a track day in there, especially at high temperatures due to oil oxidation. @johnloov is changing his a bit more frequently than that because he has some California track days in there, and I would recommend doing something similar.

You can either change more often (potentially unnecessarily) or do at least one used oil analysis (UOA) that is representative of your desired driving habits. Do your normal drives and track days and send that sample out to see if your viscosity, fuel dilution, wear metals, and maybe oil oxidization (if offered) are holding up sufficiently. Ideally, you do a few UOAs to plot the trend and figure out the ideal oil change interval/viscosity. To know if those parameters, like wear metals, are acceptable or not, the lab will either note that if they have experience with that engine, or check the concentrations against our UOA reports here to see if the values are within range.

If your engine is below ~10k miles, you will only be able to judge the viscosity, fuel dilution, and oil oxidation since you will have elevated levels of everything, as mentioned by John (Lake Speed Jr. Video above).

 

[johnloov]

A stock K20C running 0W-20 could easily do 5km oil changes (we've seen plenty of folks on here do long OCIs with low wear metals), but I would shorten the interval if you have a track day in there, especially at high temperatures due to oil oxidation. @johnloov is changing his a bit more frequently than that because he has some California track days in there, and I would recommend doing something similar.

You can either change more often (potentially unnecessarily) or do at least one used oil analysis (UOA) that is representative of your desired driving habits. Do your normal drives and track days and send that sample out to see if your viscosity, fuel dilution, wear metals, and maybe oil oxidization (if offered) are holding up sufficiently. Ideally, you do a few UOAs to plot the trend and figure out the ideal oil change interval/viscosity. To know if those parameters, like wear metals, are acceptable or not, the lab will either note that if they have experience with that engine, or check the concentrations against our UOA reports here to see if the values are within range.

If your engine is below ~10k miles, you will only be able to judge the viscosity, fuel dilution, and oil oxidation since you will have elevated levels of everything, as mentioned by John (Lake Speed Jr. Video above).

I agree. The data proves so far Honda Ultimate 0w-20 change it after 1-2 track days 2500 miles max or Motul Power 8100 5w30 dual oil coolers with 5000 miles 4 track days was also good.

According to the Nissan skyline engine builder, all engine oils start to degrade due to contamination after 2000 miles. They did many engine tear downs and there was a clear difference between engines that changed oils at 2000,4000 etc.

We will go deeper into this with more data.

 

[cryptolime]

anyone see the news that Honda is releasing a new "Formula R" oil? they say it will be available at all Honda dealerships

https://hondanews.com/en-US/honda-a...red-from-racing-for-honda-and-acura-customers

 

[Ktrw]

anyone see the news that Honda is releasing a new "Formula R" oil? they say it will be available at all Honda dealerships

https://hondanews.com/en-US/honda-a...red-from-racing-for-honda-and-acura-customers

"Formula R will be distributed through Honda and Acura dealerships beginning spring 2026 and are recommended for performance models like the Civic Type R and Integra Type S. The full synthetic lineup will include six different viscosity grades to meet a wide range of driving needs. "

That's pretty cool they called out K20Cs specifically, I may have to get my hands on some to see. Was wondering if it was intended as a track only oil, but it says it will be available for street applications as well.

 

[cryptolime]

"Formula R will be distributed through Honda and Acura dealerships beginning spring 2026 and are recommended for performance models like the Civic Type R and Integra Type S. The full synthetic lineup will include six different viscosity grades to meet a wide range of driving needs. "

That's pretty cool they called out K20Cs specifically, I may have to get my hands on some to see. Was wondering if it was intended as a track only oil, but it says it will be available for street applications as well.

it has an API certification so should be good to go for daily driving. SP/GF-7A.

pretty cool since most racing/track oils aren't recommended to daily.

 

[Spart]

This is an excellent thread. Lake's videos often contradict a lot of my biases and I've learned a lot from them.

I have a decent amount of data from one of my cars that I've tracked with 5W-50. Really good wear numbers on that car.

UOA is a great tool, however it's only giving you part of the picture. If you're going to go to the trouble of doing a UOA every oil change, you really aught to be cutting open your oil filter and examining the contaminants (or wear metals) caught in the filter as well.

Something in here I want to specifically address:

2) Running a 0W-20 does let the engine run cooler. Our data—and the engine-dyno work—show that running 0W-20 reduces operating temperatures, and you get 4-5 more HP. Less friction. My track logs (water temps) and friends who switched to 5W-30 all saw immediate increases in water and oil temps—so that myth looks busted. Also Lakespeed Junior commented in his ball bearing test that higher viscosity typically increases oil consumption.

If you ever watched the excellent "Engine Masters" series from MTOD, they demonstrated that underfilling the engine by a quart could net you a decent HP gain. It's not something you should ever do for a variety of reasons, but it does increase HP. What results in the best HP is not necessarily related to what results in the best engine protection. It's not a metric I would base my oil choices on.

As far as the temperatures go - viscosity varies with temperature. One oil being ten or fifteen degrees higher than another doesn't mean the hotter oil has lower viscosity than the cooler one. Hence:

>270 °F sustained = back off or cool-down lap; watch hot oil pressure (the real safety metric)

This is indeed the real safety metric, a drop in hot oil pressure can mean many things and they all tend to be bad.

 

[johnloov]

I’ll be posting fresh lab data after a G2 Motorsports Park weekend (Dallas) on a low-cost dealership-fill 0W-20 to evaluate a recommendation from a former Nissan GT-R engine builder: prioritize frequent changes of an API SP full synthetic (~2,000 miles) over running a premium blend to 4,000–5,000 miles. It's similar to what Lake Speed Jr. also recommended - Brands don't matter.

I want to prove also what the Nissan GTR engine builder is recommending - "it's better to buy cheap oil and change it more often, than buy expensive oil and change it less often."

The rationale is to maximize lubrication while routinely removing fuel dilution, wear metals, and oxidation byproducts. My previous UOAs showed measurable degradation by ~2,000+ miles, consistent with that approach.

Reference video:

If anyone else also has the dealership default warranty oil changes lab results - please post.

Please keep the data coming—UOAs, temps, and pressure logs are especially helpful!

 

[johnloov]

Wait a sec - I just did a double take.

I misread this thinking the 5w-30 was a slight bit better in protection... but Lake said it was actually the 0W-20 ? He keeps saying - don't believe the speculation

So why after 7 years of data , 7000+ Oil Sample Data, 10k+ miles ( after break in junk is removed ) did the 0W-20 show less wear than the 5w-30, and the 5w-30 show slightly higher?

Is it the friction caused by thicker oil running through an engine with very tight tolerances?

I’m genuinely puzzled: the performance data for modern oils doesn’t support a blanket ‘go thicker’ recommendation.



---------------------
0W-20 vs 5W-30: why did Lake’s 7-year dataset show
slightly lower wear on 0W-20?

I did a double-take on Lake Speed Jr.’s slide too. In >7 years and ~7,000+ UOAs, looking only at samples >10,000 miles after break-in, the bars show no statistically significant difference between xW-20 and xW-30—and the tiny edge actually favored 0W-20.

So why might a 0W-20 show equal or slightly lower wear than a 5W-30 across a huge population?

Likely reasons (mechanics, not mythology)

• Flow & temperature balance. Modern engines are calibrated for low-vis oils. A 0W-20 delivers higher circuit flow and lower pressure drop, which improves cooling and keeps viscosity in the sweet spot. A thicker oil can raise heat (more pump work/friction), thinning itself back down in service and erasing the “on-label” advantage.
• Optimal film vs. “thicker is better.” Bearing film thickness depends on HTHS at operating temperature, not the grade on the jug. If a 5W-30 runs hotter, its in-service viscosity can converge toward the 0W-20—without the flow/temperature benefits.
• Additive chemistry is tuned for GF-6/SP 0W-20s. Friction modifiers and detergents in modern FE oils are designed to work at the loads/temps OEMs expect. The chemistry often matters more than moving one viscosity grade.
• Pump relief & cooler flow. With thicker oil, some engines hit the pressure-relief valve sooner at high rpm; that wastes pump work and can reduce flow through the cooler, nudging steady-state temps (and wear drivers) upward.
• Cold-start/short-trip penalty. Across a broad dataset, 0W-20 reduces cold-start hydrodynamic and boundary friction. Over years of mixed use, that benefit can offset any theoretical advantage of a thicker hot viscosity.

Important caveats

• Lake’s own note says the differences are not statistically significant. The effect size is small; maintenance discipline, fuel dilution, temperature control, and air filtration dominate outcomes.
• Platform matters. If hot-oil pressure is marginal on 0W-20 in your use, fix cooling/oil control first; then consider a stouter 0W-20 or 5W-30. Data > dogma.

What this means for the FL5 crowd

• Use the thinnest oil that maintains hot-oil pressure for a full stint. For most stock-cooled FL5s, that’s a robust API SP/ACEA C6 0W-20 on short HPDE intervals (2–3 days / ~2–2.5k mi).
• Log oil pressure, oil temp, and coolant. If pressure meets spec and temps are controlled, a thicker grade won’t add protection—and may add heat.

Bottom line: Lake’s large sample supports his mantra: don’t believe the speculation—believe the data. In modern, tight-clearance engines, a well-formulated 0W-20 run at controlled temperature and changed frequently can match (or slightly beat) a 5W-30 on wear.
-----------

I may end up racing at COTA with a 0W-20 again to check the baseline data again. My engine is running cool and the wear metals are very low.

The K20C1 uses a gerotor oil pump with an internal pressure-relief valve and a stock liquid-to-liquid (oil-to-coolant) heat exchanger. If viscosity is higher (e.g., 5W-30 vs 0W-20), system pressure rises faster with rpm; once the relief valve opens, a portion of flow is bypassed inside the pump instead of going through the galleries and the cooler, which cuts cooler flow/heat rejection and tends to raise steady-state oil (and often coolant) temps.

Also noticed the VOA samples of PUP 0W-20 is at 8.36cst vs 8.8 advertised and my Honda ultimate which came back from Blackstone at 7.99cst.

I think I'll just try this small change, and see the water temps and UOA.

And PUP VOA for 5W-30 was 9.15cst vs 10.3 advertised )