Project: Gen2 JDM Integra XSi

Our TOVW DA-Integra special series continues by looking at a DA6 Integra XSi Coupe. Lyonel is a Malaysian who has settled down in New Zealand. A friend of Tamati, (whose stock DA8 Integra XSi was the focus of our first article in this DA-Integra series) Lyonel drives a 1991 3-door DA6 Coupe. As the main photo above shows, Lyonel keeps his DA6 in very pristine condition ! But unlike Tamati, Lyonel has done quite a bit to his DA6. In this second article of our DA-Integra series, we study Lyonel's car to see how far bolt-on modifications can take the performance of the DA6 (and DA8) Integra XSi. However Lyonel frequents the race-track so his mods approach leans towards race-usage.

Bolt-on Power

At the moment, all of Lyonel's mods are concentrated on "bolt-ons", i.e. modifications that can be installed by simply removing the existing stock component and replacing the aftermarket one in. Bolt-on ideally also means no need for hacking, sawing, welding, etc. If there are any mounting and fitting, the original stock points and items will be used. The most popular bolt-on items for engine power are the open element air-filter, exhaust and headers, and air-fuel controllers. For handling & ride, bolt-on items entails replacing the stock shocks & springs as well as the re-sizing the wheels. Lyonel's mods are focussed on these items, but because of his leaning towards track-usage, he also did mods which sacrifices certain conveniences for street usage in return for a bit more power.

As described above, modifications to the engine for power increase has gone via the popular route of bolt-on mods. Favoured for their simplicity in installation, bolt-on mods exploits the restriction in air-flow that certain stock components has (in return for practicality and domesticity like noise level, etc) and enhances air-flow into the engine. The ideal complementary mod would be to use an air-fuel controller to adjust the air-fuel ratio for more power. Nevertheless, the stock Honda ECU is able to compensate for this increase in air-flow reasonably well so we will see some power increase via this method even without an air-fuel controller. The mods Lyonel has on his car includes :

• - Custom cold air intake with open element filter (short-stack for winter)
• - original JDM 98 Spec ITR 4-1 headers
• - custom 2.5" exhaust with an N1 type muffler
• - PCV ventilation filter (mini K&N type filter)

TOVW readers are probably well aware of the superior air-flow of the open element filter. A 'cold air intake' is typically used to refer to a system of providing cooler outside air to the air-filter. A cold-air intake will use an extra long intake pipe that places the air-filter into the space originally occupied by the resonator. This placement keeps the filter away from the hot air inside the engine bay, thereby allowing it to ingest the cooler outside air. However, during winter where rain is likely, such an arrangement do incur slight risks of water being ingested into the engine so a short-stack is used. A short stake is really just another name for the standard metal-pipe/open-element-filter that is popularly used. A well-designed 'short-stake' will put the air-filter back into the original position occupied by the stock air-filter box just like Lyonel's car. For the DA6/DA8 (and in fact also for the corresponding EF8/EF9 CRX/Civic SiRs), this original position also benefits from the placement of the battery which actually helps to form a sort of heat shield between the filter and the hot engine. This preferable placement between the air-filter, battery, and engine can be clearly seen from the photo of the engine bay above.

The JDM 98 Spec Integra Type-R 4-1 headers are stainless steel items made of individual runner tubes for each cylinder. Indeed the stock item is quite comparable to expensive aftermarket versions ! However after the initial 160ps generation, B16As and B18Cs (including the Spec-Rs) uses a double wired O2 sensor instead of two individual single-wire O2 sensors. Furthermore, the block design for a B18C is different from that of the B16A (the B18C block itself is actually taller). So fitting the 98-Spec ITR headers required some customization work making it not a fully bolt-on item but it did work well.

An N1 type muffler is usually used to refer to a straight-through design. The muffler itself has a straight pipe running through, wrapped in noise damping materials. Nevertheless the exhaust gases flows right through the muffler so this type of exhaust system gives practically no exhaust flow restriction with consequent benefits in power gain. The downside however is noise; with no baffling or materials to directly dampen the noise, N1 type exhausts are very loud, 'extreme' models frequently loud enough to be heard across several blocks or streets ! For domestic requirements, such exhausts are strictly speaking not streetable. Go cruising with one in the car and conversation will be impossible not to mention anti-social too. But for track-use, N1 exhausts are the only way to go because they are able to squeeze every last bit of power from the engine.

Because of his fondness for track-racing and the good weather conditions in New Zealand, Lyonel also removed the entire air-conditioning system from his car. This includes removing the air-cond compressor, the condenser plus all pipings, etc. This not only allows some saving in vehicle weight, the parasitic power loss due to the air-cond compressor, irregardless of whether the air cond is in use or not, also contributes to a power 'gain' (or more accurately, a reduction in parasitic power loss due to auxiliary engine components). The particular mod works for Lyonel of course since New Zealand is famous for its clean atmosphere and year round cool weather. However, the air-cond system is a domestic requirement for street-usage so this mod really works only for race-cars or cars biased towards track-use.

Wong KN
February 2002
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