「An Ultralight 810kg AE86 with 220hp!」A Powerful Lightweight N2 Circuit-spec Hachiroku!

Published : 2020/02/18 17:34 Modified : 2020/02/18 17:34

KOIZUMI SHOKAI Lightweight AE86

Hit the circuit hard with a carbed 5A-G that has insane mid-range torque!

 

Dropped 100kg in weight with lightening of bolts

 

This Levin has the 3 key elements of a true N2 racer; N2 fenders, GT wing and racing slick tires. It can be seen rampaging Maze and Tsukuba circuits. Interior comforts such as air conditioning and power steering have been omitted and the vehicle weight reduced by 100kg to a total 810kg.

 

KOIZUMI SHOKAI Lightweight AE86

Powered by a 5-AG with 82φ forged pistons and an 83mm stroke HKS crank. Total displacement is 1750cc.

 

The engine that fits inside such a lightweight body has an expanded bore and stroke by combining 82φ forged pistons with a no-longer-in-production HKS crank. It has a “5A-G” specification with a displacement of 1750cc. Rare TRD high cam and FCR carburator are incorporated, gaining 200ps at 8000rpm. Rather than setting for high-rotation and high-power, emphasis has been placed on the mid-range torque to improve durability and recoverability while driving.

 

KOIZUMI SHOKAI Lightweight AE86

The exhaust manifold is made by Nagisa Auto. The muffler is an original by Koizumi Shokai.

 

The head is from a late-model AE92, which has a small intake port diameter and can increase flow rate. The head itself has been port processed and 1.5mm surface polished. Valve seat cutting is applied and the valve periphery is reinforced with genuine processing valves, Ogawa Engineering valve springs and Vitz genuine valve lifters. The ignition system uses a crank advance kit to set the ignition timing to a fixed advance type and also realizes a stable spark by MSD.

 

KOIZUMI SHOKAI Lightweight AE86

Front springs are 9kg/mm, made by Swift.

 

Koizumi Shokai’s original suspension kit is installed. It supresses change in damping due to heat sag by increasing piston capacity over the cartridge type which are often used in AE86 dampers. The rear incorporates isometric links. Front calipers and rotors are from an FC3S.

 

KOIZUMI SHOKAI Lightweight AE86

Since the rear links are equal in length, movement of the hosing is flexible.

 

Front and rear balance in braking is controlled by rear brake rotors from an S13. Brake balancer is also equipped.

 

KOIZUMI SHOKAI Lightweight AE86

Arms are by Cusco.

 
By changing from a genuine arm to a pipe-shaped one, rigidity is increased while shaving off weight. Bushings are converted to pillowball type to produce smooth movement and excellent handling response.
 

KOIZUMI SHOKAI Lightweight AE86

An 8-point Cusco roll cage is installed. Instruments are simple with only a tachometer, oil temp gauge, oil pressure gauge and water temp gauge.

 
Because it is strictly set up for circuit runs, the inside of the car is a single seater. Panels that don’t affect strength are cut cleanly and removed. Bolts used to attach each part are kept to a minimum, and weight has been saved drastically.
 

KOIZUMI SHOKAI Lightweight AE86

The removal of the factory dashboard is also a big contribution to weight savings.

 

The factory dashboard has been replaced with a carbon panel. This saves weight but adds a touch of sporty visual appeal.

 

KOIZUMI SHOKAI Lightweight AE86

The overfenders were produced by TRD for the “Group N” classification of N2 races.

 

N2 fenders add 50mm in width to each side and house SSR Formula Mesh in F8.5J R9.5J -21. Tires are 15-inch radial slicks (225/585-15) which are used rather than 14-inch bias slick tires that were standard on N2 cars. This 86 lapped Tsukuba in 59.7 seconds, Maze Circuit in 1 minute 3.3 seconds and Okayama International Circuit in 1 minute 40.8 seconds.

 

KOIZUMI SHOKAI Lightweight AE86

Glass has been replaced by Car Factory Ai acrylic throughout for ultimate weight reduction.

 
In addition to the TRD N2 overfenders, the exterior has a one-off front under panel, rear diffuser and CBY side skirts. Parts like these are getting harder and harder to find. Although tuning of this kind for the AE86 used to have been widely established, unfortunately its evolution is likely to come to an end.
 

●Special Thanks:Koizumi Shokai 759-5 Shinnonoi Onbegawa, Nagano, Nagano Prefecture  TEL:026-292-9860

 

Koizumi Shokai

http://koizumi86.com/