Prelude Type S Technical Highlights


Disclaimer - The original information about the Type S used to be in Honda of Japan's homepage but has since been removed. Kaz Mori, our japanese articles editor translated it as best as he could.

Overview

Prelude Type S
The Prelude Type S is a car which Honda put much effort in making it sporty, yet elegant. Honda dubs this, "Intelligent Sport". (or sportiness) The Type S boasts an impressive 100hp/liter engine, producing 220ps from 2.2 liters (2,156cc) utilizing its VTEC technology. It also comes with the new Prelude's signature ATTS (Active Torque Transfer System) already found on the Prelude SH, and the Type S is treated to an active-control ABS that improves braking through turns.


The Prelude must be a very smooth car to drive. That has been its signature mark as a specialty car in the Honda lineup, and has proven itself by its annual Best Ten ranking by Car & Driver magazine. The great handling is matched to a plentiful, yet quick and even-responding NA engine. With its smooth torque curve, lower intake resistance, higher compression, and secondary balancers on the engine, Honda was able to create a masterpiece.
Engine Output Graph


Tech Specs


H22A SpecS
In order to produce more naturally aspirated power from an already powerful engine, Honda realized that it must improve on such things as intake resistance and heat dissipation. The H22A engine received yet another dosage of Honda's racing technology and custom engine work. Though not as widely known, the Type S engine, like the Type R engine, receives a port-&-polish job from Honda.

Engine

Improving on its already sky-high 10.6 compression ratio, Honda created a new pistonhead that increased the compression ratio to 11.0. By doing so, the burn-off response increased, helping heat dissipation, as well as improving torque throughout the powerband. The VTEC valve timing, lift, and duration were also adjusted as well. The valve lift on the intake reaches 12.2mm, while the exhaust end reaches 11.2mm. As far as production engines go, these are really high numbers.
SiR Piston

Type S Piston

Intake


New Intake

Port & Polish
Honda felt that it would need to improve on the intake path to compliment the increased high-end performance. The air intake box was made into a funnel shape -- utilizing what Honda calls "dynamic chambers." The throttle body was also bored out from 60mm to 62mm. Even the material used in the inlet manifold was changed to a more fine, granular one in order to make it more smooth. The valve seat was re-adjusted from 60 to 45 degrees. Finally, the cylinder head and intake port was treated to a manual port-&-polish job by Honda technicians. Honda is making these engines as if they were meant for the track.

Exhaust

By lowering the intake resistance and making an engine that burns efficiently, Honda needed to finish its tuning job by allowing for the exhaust to get out smoothly. The exhaust manifold, while retaining its outer diameter, had its opening size increased. The dual-pipe design to follow was made truly cylindrical, (as opposed to oval) and the wall lining was made to 15mm -- decreasing exhaust interference. The catalytic converter was also increased in size, and the exhaust piping increased from 50.8mm to 57mm. The silencer efficiency was increased from 97 liters/second to 113 liters/second. This completes the improvements made on the air flow efficiency of the Prelude Type S.
New A-pipe


May 1999
Translation by Kaz Mori, Temple of VTEC Asia
Information Source : Honda Japan's homepage (original japanese article no longer available)