Real Track Testing the Stock I4 Emira – Brakes & Gearbox Issues at Buttonwillow and Laguna Seca

[jonathanhou]

Hi everyone,

I wanted to share some of my real-world track testing experience with the stock I4 Emira (yes, completely stock – including brakes, suspension, and tires). Hopefully this helps others who are considering taking their Emira to the track.

Car Setup:

• 2024 Emira I4
• 100% stock, no mods
• Factory Michelin Pilot Sport Cup 2 tires

Track Day 1: Buttonwillow 13CW

• Ambient Temp: 28°C (82°F)
• Best Lap: 1:57.1

The car felt balanced and surprisingly capable for a factory setup. However, the most significant issue I encountered was brake fade. After a few hot laps, the brake performance dropped off dramatically. Upon inspection, I found the factory pads are Ferodo DS2500, which aligns with the fade I experienced – these pads are more suited for fast road and occasional light track use, but not sustained hot lapping.

Conclusion: If you’re planning to track the car seriously, upgrading brake pads is absolutely necessary. I’ll also be revising the alignment soon – the factory alignment felt a bit too conservative for track driving. I’ll share updated alignment specs in a future post once I’ve dialed them in.
Track Day 2: Laguna Seca

• Ambient Temp: 15°C (59°F)
• Best Lap: 1:38.50 (with traffic – I believe there’s more time in the car)

Despite the lower ambient temperature, the extended full-throttle sections at Laguna really pushed the powertrain, especially the gearbox. I noticed a consistent slowdown in shift speed lap after lap, and the shifting logic became increasingly conservative. After about 10 minutes of pushing hard, the check engine light came on, and the car entered a reduced power mode. Based on throttle response and acceleration, I estimate it was down to around 250hp.

Cool-down laps didn’t seem to resolve the issue, but a full power reset in the pits brought the power back. Unfortunately, I forgot my OBD scanner that day, so I couldn’t pull the fault code. However, based on symptoms, I strongly suspect gearbox overheating and a thermal protection trigger.

Has anyone else experienced similar gearbox issues on track with the I4? I’d love to hear your thoughts or if you’ve found any workarounds.

In future posts, I’ll be sharing my planned upgrades and real lap-time results as I continue testing and refining the car.

 

[sendmeows]

Great times. Would love to see your buttonwillow vid if you have it.

 

[gcmak]

Thanks for sharing your feedback. It's curious that the car did not have the issue at BW Circuit - it was far warmer and many long acceleration zones.
I didn't want to bother you that day because I know you were dealing with a tire situation. Also, a big congratulations if I am making the connection between the rose and a laguna paddock photo a friend shared with me this weekend .

So far I haven't experienced any error lights but both Sonoma Track Day and Alameda Autocross events had favorable temperatures and not necessarily the most demanding conditions. The thing I noticed is that there was oil that seemed to push out around the oil cap area. Not a significant amount but it was clean before the track day - the computer reads between 6.6-6.7 quarts filled.

I had been running EBC Blue pads. While they do hold up decently well, they wear fast, feel somewhat unpredictable in their friction levels, and the rear pads do not sit on the rotor face correctly - therefore I cannot recommend them.

Would be interested if your code reader can see any stored or historical codes that would give more insight into what happened.

 

[jonathanhou]

Thanks for sharing your feedback. It's curious that the car did not have the issue at BW Circuit - it was far warmer and many long acceleration zones.
I didn't want to bother you that day because I know you were dealing with a tire situation. Also, a big congratulations if I am making the connection between the rose and a laguna paddock photo a friend shared with me this weekend .

So far I haven't experienced any error lights but both Sonoma Track Day and Alameda Autocross events had favorable temperatures and not necessarily the most demanding conditions. The thing I noticed is that there was oil that seemed to push out around the oil cap area. Not a significant amount but it was clean before the track day - the computer reads between 6.6-6.7 quarts filled.

I had been running EBC Blue pads. While they do hold up decently well, they wear fast, feel somewhat unpredictable in their friction levels, and the rear pads do not sit on the rotor face correctly - therefore I cannot recommend them.

Would be interested if your code reader can see any stored or historical codes that would give more insight into what happened.

Thanks for your reply and yes you made the right connection. It was me at Laguna this weekend.
The day at buttonwillow circuit I didn’t push a lot because the tire is always slowly leaking air because a nail and that’s was my first time drive the circuit, I’ll try next time see if the same situation will came out or not. But i was run Laguna and Buttonwillow classic this weekend the same issue came out many times. I’ll try to figure that out.

 

[jonathanhou]

Great times. Would love to see your buttonwillow vid if you have it.

Yes I do I just need to upload somewhere. But you can check my lap time in draggy app.

 

[MickOpalak]

In all of my Lotus cars I’ve upgraded the pads and fluid and never had an issue. I did get an overheated gearbox at Utah Motorsports Campus, but that’s because it was doing double duty at a track day. Otherwise trouble tree.

 

[gcmak]

Thanks for your reply and yes you made the right connection. It was me at Laguna this weekend.
The day at buttonwillow circuit I didn’t push a lot because the tire is always slowly leaking air because a nail and that’s was my first time drive the circuit, I’ll try next time see if the same situation will came out or not. But i was run Laguna and Buttonwillow classic this weekend the same issue came out many times. I’ll try to figure that out.

Dang, hope you can catch the code next time if it happens again. I plan to be out at Laguna later this year and will see if I run into issues - I am also more familiar with that track.

By the way are you still using 0W20 oil?

 

[jonathanhou]

Dang, hope you can catch the code next time if it happens again. I plan to be out at Laguna later this year and will see if I run into issues - I am also more familiar with that track.

By the way are you still using 0W20 oil?

Yes, I am still use 0w-20 oil.

 

[jonathanhou]

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I received this titanium bolt and installed, fit emira no problem and it’s have good deal now.

 

[_JZ_]

Not a race issue, but Anyone happen to notice scoring at the disc edges on the rear or any scalloping of the disc?

Ordered new. Have only put 260 miles on since taking delivery last week. Was doing some cleaning and noticed what looks like scoring at the rear disc edges and also an area that appears slightly scalloped.

Any thoughts?

 

[jonathanhou]

Not a race issue, but Anyone happen to notice scoring at the disc edges on the rear or any scalloping of the disc?

Ordered new. Have only put 260 miles on since taking delivery last week. Was doing some cleaning and noticed what looks like scoring at the rear disc edges and also an area that appears slightly scalloped.

Any thoughts?

I didn’t notice this issue before. Just checked my rear brake and it looks fine for me. But I have a new brake pad on the way. I’ll install and see what going on with new pad.

 

[T6061]

Not a race issue, but Anyone happen to notice scoring at the disc edges on the rear or any scalloping of the disc?

Ordered new. Have only put 260 miles on since taking delivery last week. Was doing some cleaning and noticed what looks like scoring at the rear disc edges and also an area that appears slightly scalloped.

Any thoughts?

Asked many times, my understanding is that it is done during manufacturing to balance the discs...

 

[_JZ_]

Asked many times, my understanding is that it is done during manufacturing to balance the discs...

Interesting.
It makes sense that they would balance the discs, I just had never noticed this on any of my cars before

Thanks for the info!

 

[gcmak]

Yes, I am still use 0w-20 oil.

Thanks! I still plan to do analyses after an oil change and am wondering if you have done an oil analysis after any of these events? I don't have a reason to be concerned but sadly few Emiras (of any powertrain) get driven hard on local tracks, so any info helps!

Also look forward to your pad review. Ferodo DS1.11 is on my list.

 

[jonathanhou]

Thanks! I still plan to do analyses after an oil change and am wondering if you have done an oil analysis after any of these events? I don't have a reason to be concerned but sadly few Emiras (of any powertrain) get driven hard on local tracks, so any info helps!

Also look forward to your pad review. Ferodo DS1.11 is on my list.

My shop did a lot oil analyses with a Honda Civic type R, we compared about 10 kinds of different racing oil. And we found the best one so I’ll use that one. My front brake pad option is PFC 15, and the rear I am gonna use EBC SR11 or SR21. So both is on the way and I am gonna test it and post review here after installed and another track day. In my experience PFC and Pagid are two best options, and i also have good experience for EBC SR21. So I will try those first.

 

[sirringo]

Strongly recommend changing your brake fluid for a DOT4 racing fluid as well, eg Motul 600, Amsoil, Castrol SRF.

 

[jonathanhou]

Strongly recommend changing your brake fluid for a DOT4 racing fluid as well, eg Motul 600, Amsoil, Castrol SRF.

All those brake fluid not on my list, I always use Brembo HTC 64T for better modulation and boiling point.