Tuning the Honda B18

"Comprehensive guide to tuning and performance parts on the Honda B18 engine!"

The Honda B18 make awesome project engines and with the best performance tuning mods like a remap, turbo upgrades and camshafts you will positively maximize your driving opportunities.

Here we review B18 tuning and provide tips on the greatest modifications.

Just because particular upgrades are are common on B18 it doesn't mean you should fit it, instead we'll greatest upgrades that will give your B18 the best power gain for you money.

The cam profile plays a big part in the engines power output so cam upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen cam profile, so large bhp gains are on offer for cam upgrades.

NB: Fast road camshafts tend to push up the bhp across the rpm range, you may lose a little low down torque but the top end will be higher.

Race camshafts, push up the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Race camshaft is not great in heavy traffic.

You should ideally optimize your engines power to your cars usage so for a car driven daily stick with a fast road B18 camshaft

Different B18 engines respond better to less aggressive camshaft durations so view each engine as unique.

The ECU mapping and fuel pump and injectors also will make differences on the bhp gains you'll hit.

Extending exhaust or intake durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

Stage 1 modifications: Remaps/piggy back ECU, Intake headers, Fast road camshaft, Panel air filters, Sports exhaust manifold, Drilled & smoothed airbox.

Stage 2 modifications: Ported and polished head, high flow fuel injectors, fuel pump upgrades, Sports catalyst & performance exhaust, induction kit, Fast road cam.

Stage 3 modifications: Engine balancing & blueprinting, Internal engine upgrades (head flowing porting/bigger valves), Crank and Piston upgrades to alter compression, Twin charging conversions, Competition cam, Adding or Upgrading forced induction (turbo/supercharger).

A remap should help to release the full potential of all the modifications you've fitted to your B18.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but your mileage usually rely on the modifications you've carried out and the condition of your engine.

Pulling air and fuel into the B18 engine is vital to any performance tuning project.

Air Intake manifolds flow the air during the suck phase from the filter and allow it to be drawn into the engine and mixed with fuel.

Shape and flow characteristics of the Headers can make a noticeable difference to to fuel mixing and power on the B18.

We often see intake are in desperate need of an upgrade, although some OEM provide decently flowing intake.

Fitting big valve kits, getting port matching and head flowing will also improve power, & importantly will afford you a greater power increase on other modifications.

Turbo upgrades

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your B18

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.

When an engine is turbo charged modifications are simpler to install and most turbocharged engines use more solid components.

There are weak spots for every engine, with some being over specified and some only able to handle stock power

Research these limitations and install better quality components to survive the power.

It's not unheard of mechanics spending a loads of money on turbo charger upgrades on the B18 only to suffer the indignity of watching the engine block throw a rod on it's first outing after it's finished.

Bigger capacity turbo chargers tend to experience low end lag, and little turbo chargers spool up really quickly but do not have the top end bhp gains.

We are pleased that the world of turbos is always increasing and we now see variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbos divert the exhaust flow into a couple of channels and push these at differently angled vanes in the turbo. They also boost the scavenging effect of the engine.

It is not unusual that there is a restriction in the air flow sensor MAP/MAF/AFM on the B18 when considerably more air is being pulled into the engine.

Going up you'll find 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited power at a much lower level.

Adding a supercharger or additional turbo will make large performance gains, although more difficult to get working. We have this guide to twinchargers if you want to read more.

Fuelling upgrades and mods

When you raise the torque you will need to pay attention to to the fuel system.

More torque needs more fuel. We strongly recommend you to over specify your injector capacity.

The accepted safe increase is to add 20% capacity when fitting an injector, which takes into account injector deterioration and gives some spare capacity should the engine need more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Exhaust upgrades and mods

You may need to uprate your exhaust if your exhaust is creating a flow problem.

On most factory exhausts you should find that the flow rate is still ok even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Sports exhausts can usually air flow from the engine but do not go too large or you could will reduce the flow rate. Stick to 1.5 to 2.5 inches for best results.

Usual exhaust restrictions can be traced to the filters installed, so adding a higher flowing race alternative will help avoid this restriction.

Weak spots, Issues & common problem areas on the B18

The B18 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the B18, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

History of the B18 Engine

The B18 was the most popular B series engine produced by Honda, and was deployed in family cars and performance cars alike with various states of tune.

VTEC and compression ratio played a large part in the power figures on offer.

B18A1

• 1990–1991 Acura Integra USDM "RS/LS/LS Special Edition/GS" (DA9 Liftback/Hatchback, DB1 Sedan)
  Power: 130 bhp (97 kW; 132 PS) at 6000 rpm & 121 lbft (164 Nm) at 5000 rpm

 B18A shares much with the B20A engine.

• 1986–1989 Accord Aerodeck LXR-S/LX-S (Japan)
• 1986–1989 Accord EXL-S/EX-S (Japan)
• 1986–1989 Vigor MXL-S (Japan)
  Power: 100 hp (75 kW; 101 PS) at 6100 rpm & 128 lbft (174 Nm) at 4700 rpm

B18A1

• 1992-1993 Acura Integra USDM "GS/LS/LS Special Edition/RS" (DA9 Liftback/Hatchback, DB1 Sedan)
  Power: 140 bhp (104 kW; 142 PS) at 6300 rpm & 126 lbft (171 Nm) at 5000 rpm

B18A2

• 1990-1993 Honda Integra LS DB1 Sedan (Made in India)
• Power: 140 hp (104 kW; 142 PS) at 6300 rpm & 126 lbft (171 Nm) at 5000 rpm

B18B1

• 94-01 Integra RS/LS/SE/GS - DB7/DC4/DC3
• 1994–2000 Honda Integra "RS/LS/GS/SE/(GSI Australia)" (DC4/DB7)
• 1992–1996 JDM Honda Domani (MA5)
• 1993–1994 JDM Honda Integra (DB7)
• 1996–1999 JDM Honda Orthia (EL1)
  Power: 140 bhp (104 kW; 142 PS) at 6300 rpm & 127 lbft (172 Nm) at 5200 rpm

B18B2

• 94-01 Integra RS/LS/SE/GS - DB7/DC4/DC3
• 1994–2001Honda Integra "RS/LS/GS/SE/(GSI Australia)" (DC4/DB7)
  Power: 143 bhp (107 kW; 145 PS) at 6300 rpm & 127 lbft (172 Nm) at 5200 rpm

B18B3

• 1992–1995 Honda Civic – Middle East & South Africa Ballade (SR4)
  Power: 143 hp (107 kW; 145 PS) at 6000 rpm & 123 lbft (167 Nm) at 5000 rpm

B18B4

• 1996–2000 Honda Civic – Middle East & South Africa Ballade (SO4)
  Power: 103 kW (140 PS; 138 hp) at 6200 rpm & 126 lbft (171 Nm) at 4900 rpm

JDM B18C Type R  Honda Integra (JDM) DOHC VTEC

• 96-01 Honda Integra JDM Type R (DC2 & DB8)
  Power: 197 hp (147 kW; 200 PS) at 8000 rpm & 180 Nm (133 lbft) at 7200 rpm (96 spec) ; 200 hp (149 kW; 203 PS) at 8000 rpm & 186 Nm (137 lbft) at 6200 rpm (98 spec)

JDM B18C VTEC

• 95-98 Honda Integra JDM SiR/SiR II (DB8, DC2)
• 98-99 Honda Integra JDM SiR-G (DB8, DC2)
  Power: 132.5 kW (180 PS; 178 bhp) at 7200 rpm & 126 lbft (171 Nm) at 6200 rpm

B18C1 DOHC VTEC

• 1994–2001 Acura Integra USDM GS-R (DC2 & DB8)
  Power: 170 hp (127 kW; 172 PS) at 7600 rpm

B18C2 DOHC VTEC

• 1994-2001 Honda Integra AUDM/NZDM VTi-R
  Power: 170 hp (127 kW; 172 PS) at 7300 rpm

B18C3 DOHC VTEC

• Honda Integra Asian market
  Power: 187 hp (139 kW; 190 PS) at 7600 rpm & 174 Nm (128 lbft) at 7500 rpm

B18C4 VTEC

• 1996–2000 UK Civic VTi 5-door Hatch (MB6)
• 1996–2000 UK Civic 1.8i VTi-S (Limited Edition) 5-door Hatch (MB6)
• 1996–2001 UK Civic Aerodeck 1.8i VTi 5-door Wagon (MC2)
• 1998–1999 EU Civic Aerodeck 1.8i VTi 5-door Wagon (MC2)
• 1998–1999 EU Civic 1.8i VTi 5-door Hatch (MB6)
  Power: 169 hp (126 kW; 171 PS) at 7600 rpm & 128 lbft (174 Nm) at 6200 rpm

B18C5 (Type R) DOHC VTEC

• 1997-1998,1999 CDM, 2000-2001 Acura Integra USDM/CDM Type R
  Power: 195 hp (145 kW; 198 PS) at 7800 rpm & 130 lbft (176 Nm) at 7500 rpm

B18C6 (Type R) DOHC VTEC

• 1998–2001 Honda Integra UKDM/EUDM Type R
  Power: 190 PS (140 kW; 187 hp) at 7900 rpm & 131 lbft (178 Nm) at 7300 rpm

B18C7 (Type R) DOHC VTEC

• 1999-2001 Honda Integra AUDM/NZDM Type R
  Power: 189 hp (141 kW; 192 PS) at 8200 rpm & 172 Nm (127 lbft) at 7500 rpm

For more information on Tuning your Honda engine please join us in our friendly forum where you can discuss B18 tuning options in more detail with our B18 owners. It would also be worth reading our unbiased Honda tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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