The 500 Horsepower Naturally Aspirated K24 Engine by 4Piston
http://blog.wiseco.com/the-500-horsepower-naturally-aspirated-k24-engine-by-4piston
There have always been two big hurtles – the high water marks of 500 hp and 10,000 rpm. Wilson and his gang at 4Piston have been building the K24 Honda engine platform for multiple years, aiming at that goal. 4Piston actually offers a K440 engine, a 2.5L drag race engine at 15:1 compression on alcohol that can push the wheel horsepower numbers above 400 as a turn-key package.

With that in mind, 4Piston decided to build an enhanced version of that package to eclipse the 500 mark at the flywheel. This would come to fruition with help from another long-time member of the team Matt Monday. The plan had to revolve around a production Honda K24 block, cylinder head, and 16:1 compression just to push it a little further. But the ultimate goal was a horsepower number that started with the number five.


To truly appreciate this power curve, take a look at that nice flat torque curve where this motor delivers no less than 280 lb-ft of torque from 6,800 rpm to horsepower peak at 9,600. That’s an impressive 2,800 rpm power band. Wilson commented 'That is a big header, and the engine can make a broader power band with a smaller header and an additional inch or so with a little 2.5-inch collector. For our application, we are pulling power out in 1st gear, then the rest of the track is 8,300-10,600 rpm. We are okay giving up some low end in favor of carrying the top another hundred or more rpm.'

Honda K24A1 from a CRV
Production block with LA Sleeve Ductile Iron liners
Bore - 90mm = 3.543 inches
Stroke 106mm = 4.173
164ci, 2687cc or 2.7L
Winberg crankshaft
GRP splayed beam aluminum connecting rod, 6.125-inch long, 340 grams
Wiseco 90mm bore, 265 grams, 2 ring billet pistons with hard anodizing
Top Ring: 0.043-inch, Oil Ring: 0.143-inch
DLC coated wrist pin
ACL Race Bearings
4 Piston Peacemaker cylinder head
Ferrea 1.510” Titanium intake valves
Ferrea 1.181” Titanium exhaust valves
4 Piston PSI Pro Stock single valve spring kit
Ferrea valve locks
Ferrea 4P RR8000 rocker arms
Skunk2 BMFx custom Camshafts
Dailey Engineering dry sump
Kinsler 71.5mm (2.81-inches) individual throttle bores
Myers Competition header, 2.00-2.125-2.250-inch, 18-inch primaries
Moroso oil pan
ECU is a Motec M130
VP M5 methanol fuel

2.5Lで圧縮15：1の400馬力オーバーのエンジンをベースに、2.7L圧縮16：1の発展型を構築して、目標である500馬力を達成したようです。
正確には、9,400回転時に518馬力。
4連スロットルの口径は、Φ71.5（笑）

NAなのに、アルミコンロッドを採用している点が興味深い。軽量化だろうか？
2本リングでアルミコンロッドなので、完全な競技用、耐久性は無さそうですが、NAで500馬力、1万回転回るエンジンは魅力的であった。


We stopped by 4 Piston racing and talk to co-owner Luke Wilson about how you can make 500+ horsepower while spinning over 10,000 rpm.


Building a 500hp Naturally Aspirated K24 Engine with 4 Piston Racing
https://www.youtube.com/watch?v=YRFrFudg7eM
Inside a 500+ HP Naturally Aspirated K24
https://www.youtube.com/watch?v=SXVMk49BGIg


K1社製H断面 コンロッド　ホンダ HONDA　S2000 K24 コンバージョン用
http://matsulix.com/?pid=58978026
※ K1 Technologies社製　H断面コネクティングロッド　4本セット
※ この商品はホンダ S2000 K24 コンバージョン用です。
※ 大端部中心から小端部中心の距離：5.646"
※ 大端部径：2.008"
※ ピン径：22mm
※ 重量：526g
※ ボルトはARP 2000 3/8"が付属します。
※ 小端部はフル・フロー用ブッシュが入っていますので、圧入式のピストンピンではご使用頂けません。
※ 商品写真は見本であり、実際に受け取る商品とは多少外観が違う場合がございますので、ご了承ください。
※ 予告無く仕様が変更される場合がございます。