07/08/2026
今日は夜明け前からNAGIでスタート。
まずは月例の静電気除去抑制コーティングのメンテナンスへ出掛けました。
AM5:00、日の出前の外気温は28℃。
洗車場へ向かう途中、先日行ったPCVバルブ／グロメット交換と、2年振りになってしまったFORTEによる吸気系内面・エアフロセンサー処理後の状態も確認。
これまでNAGIでは、アイドリング時の吸気圧表示が－0.38付近、走行時は最大0.5～0.65付近でした。
メンテナンスを終えて帰宅するAM7:30頃には快晴、外気温31℃。しかも帰路はエアコン使用。
ところが吸気圧表示は、アイドリングで－0.43、走行時には0.99まで確認しました。
走行条件が完全に同一ではないので単純比較はできませんが、気温も高く、エアコンも使用している条件でこの変化。体感でもスロットル入力に対するトルクレスポンスが明らかに軽くなっています。
急激な不調ではなく、2年間かけて少しずつ変化していたため、こちらもその状態に慣れてしまっていたのでしょうね。
そして帰宅後はSHINO。
これまで行ってきたアンダーフロアのタフトテストから得た内容をもとに、床下の流れに対する新しい整流対策を一つ施工しました。
具体的な施工内容や位置については非公開としますが、施工後の初期走行では、以前NAGIの床下対策を行った際に感じたものとよく似た変化が出ています。
「おお！効いた！」という派手なものではなく、車体後半が穏やかに落ち着き、速度感が薄くなったような感覚。
さらに、通常モードのCVT制御にも若干変化を感じています。
発進直後は以前より高い変速比を選んでいるように感じる一方、そこからアクセルを踏み増すとキックダウンが非常に速く、その後はかなり強く回転を引っ張って加速します。
まだ初期確認の段階ですので、この変化を床下整流対策だけの効果とは断定しません。
ただ、NAGIでも最初は「静かで穏やかになった」程度だったものが、その後走り込むうちに冷却や車体姿勢など、別の部分への影響が見えてきました。
今回のSHINOも、これから少しずつ確認していきます。
静電気対策も大切です。
吸気系の状態も大切です。
床下の空気の流れも大切です。
でも、一つのアイテムだけが本丸ではありません。
空気、熱、圧力、車体姿勢、電気信号、そして電子制御。
それぞれの条件を少しずつ整えていった時、車両全体がどんな答えを返してくるのか。
そこを見ていくのが、やはり一番面白いですね。
Today started before sunrise with NAGI.
First, I went out for the monthly maintenance of the electrostatic-charge reduction coating.
At 5:00 AM, before sunrise, the ambient temperature was 28°C.
On the way to the wash area, I also checked the condition of the intake system after the recent PCV valve and grommet replacement, together with the FORTE treatment of the intake passages and MAF sensor — which, as I discovered, had actually been two years since the previous treatment.
Previously, NAGI’s intake pressure display was around -0.38 at idle, with a maximum of approximately 0.5–0.65 while driving.
By the time I returned home at around 7:30 AM, the weather was clear and the ambient temperature had risen to 31°C. The air conditioner was also running on the return trip.
Even under those conditions, the display showed -0.43 at idle and reached 0.99 while driving.
The driving conditions were not perfectly identical, so this cannot be treated as a strict comparison. However, despite the higher temperature and A/C load, both the displayed values and the throttle-to-torque response were clearly different.
Rather than a sudden deterioration, the previous condition had probably changed gradually over the past two years — slowly enough that I had simply adapted to it.
After returning home, it was SHINO’s turn.
Based on what I have learned from previous underfloor tuft testing, I carried out a new airflow-control measure on part of the underbody.
The exact location and details will remain private, but the initial driving impression is very similar to what I experienced when I first introduced underfloor airflow control on NAGI.
There is no dramatic “Wow, this is working!” sensation.
Instead, the rear of the vehicle feels calmer and more settled, and the sense of speed itself seems slightly reduced.
I also noticed a subtle change in the normal-mode CVT behavior.
Immediately after moving off, the CVT seems to select a relatively taller ratio than before. However, when more throttle is requested, the downshift response is very quick, followed by surprisingly strong acceleration and sustained engine speed — even without using Sport mode.
This is still only an initial observation, so I am not attributing all of these changes solely to the new underfloor treatment.
With NAGI, the first impression was also simply “quieter and calmer.” Only after further driving did I begin to notice changes in cooling behavior and vehicle posture in more complex situations.
I expect SHINO may reveal its answers in much the same way.
Electrostatic-charge control matters.
Intake condition matters.
Underfloor airflow matters.
But none of these single items is the whole answer.
Airflow, heat, pressure, vehicle posture, electrical signals and electronic control are all connected.
What interests me most is seeing how the entire vehicle responds when each of those conditions is gradually brought into better balance.
That is still the most fascinating part of vehicle development for me.
