Honda D15 Tuning

"All you need to know about tuning the Honda D15 engine!"

We were contacted through email for further information on tuning a customized D15, specifically which turbo improvements and engine alterations perform best. (NB: We have separate articles covering the best mods and upgrades for the D16 D17 & D12 D13 D14)

So we've put together this page that includes our go-to modifications for this engine as well as what we believe are the best value additions you may do. A D Series engine may be SOHC or DOHC, and it may have VTEC variable valve timing.

Earlier versions of this engine also employed a single port fuel injection system termed PGM-CARB by Honda, indicating that the carburetor was computer controlled.

TorqueCars will go through your D15 tuning choices and highlight the best changes. The Honda D15 has a lot of potential, and with properly selected tuned components like a remap, turbo upgrades, and camshafts, you can definitely enhance your driving experience.

As with all other Honda engines, the D15 may be upgraded to provide extra power. However, the D15 lacks an abundance of easy and practical bolt-on modifications, which might make the options appear quite restricted at times. Swaps with other Honda engines are often the best course of action for a serious tuning effort; our Civic engine swap guide should be beneficial in this regard.

Check out our video introduction to Honda Tuning, all you need to know about mods and upgrades on your Honda.

History of the D15 Engine

D15A1

  1. 1984–1987 Honda CRX
  • 76 hp@5,500 rpm 84 lbftf@3,500 rpm

D15A2

  1. 1984–1987 Honda CRX HF Grifin (USA Market and Ethiopia Market )
  • 60 hp (45 kW)@5,550 rpm 73 lbft@3,500 rpm
  1. 1984–1987 Honda CRX DX and HF (USA)
  2. 1987 Honda Civic Wagon RT4WD (Canadian Model)
  • 76 hp@5,500 rpm 84 lbft@3,500 rpm

D15A3

  1. 1984–1987 Honda CRX 1.5i (Europe)
  2. 1985–1987 Honda CRX Si and 1987 Civic Si (AU/NZ)
  3. EW3/EW4 1985-1986 before switching to D15A3  in 1987
  4. 1985–1987 Honda Civic 1.5i (Europe)
  5. 1986–1987 Honda Civic Si Hatch (US)
  • 91 hp (68 kW, 92 ps)@5500 rpm
  • 100 PS (74 kW)@5750 rpm (Europe) 93 lbft (12.9 kg/m, 126 Nm)@4500 rpm

D15A4

  • 92 hp (70 kW, 94 ps)@5500 rpm
  • 93 lbft (12.9 kg/m, 126 Nm)@4500 rpm

D15A5

  • 93 hp (70 kW, 94 ps)@5600 rpm
  • 100 PS (74 kW)@5750 rpm (Europe) 93 lbft (12.9 kg/m, 126 Nm)@4500 rpm

D15B

  1. 1988 Honda CRX 1.5X (rare)
  2. 1990 Honda Civic 25XXT Formula (JDM Only)
  3. Honda Civic Ferio MX (JDM Only) EG8
  4. 1998–2001 Honda Capa GA4 (JDM Only)
  5. 1988-2001 Honda Civic SH4 EF1
  • 103 hp (77.23 kW, 105 PS)@6800 rpm 14.1 kgm (133.4 Nm)@5200 rpm

D15B VTEC

  1. 1992–1995 Honda Civic Vti (JDM Only)
  2. 1992–1998 Honda CRX DelSol (JDM Only)
  • 130 PS (96 kW; 128 hp)@6800 rpm 14.1 kgm (138 Nm)@5200 rpm
  1. 1995–1998 Honda Civic Ferio Vi (EK3, JDM Only)
  2. 1999-2000 Honda Civic Vi-RS
  3. 2001-2005 Honda Civic JDM VTEC (JDM Only, Europe)Bore and Stroke :75,0×84,5 mm
  • 130 PS (96 kW; 128 hp)@7000 rpm 139 Nm@5300 rpm

D15B1

  1. 1988–1991 Honda Civic Hatchback
  • 70 hp (52.2 kW, 71.0 PS)@5,500 rpm 73 lbft (11.4 kgm, 112 Nm)@3,000 rpm

D15B2

  1. 1988–1991 Honda Civic GL/DX/LX/CX (CX Canadian Market)
  2. 1988–1991 Honda Civic Wagon Wagovan/DX
  3. 1988–1991 Honda CRX DX
  4. 1992–1995 Honda Civic LSi Hatch/Saloon (European Market)
  5. 1992–1995 Honda Civic DXi Hatch/Saloon (European Market)
  6. 1990–1995 Honda Concerto (European Market)
  • 92 hp (69 kW)@6,000 rpm (US)
  • 90 PS (66 kW)@6,000 rpm (Europe) 88 lbft (12.2 kg/m, 119 Nm)@4,700 rpm

D15B3

  1. 1988–1995 Honda Civic Shuttle GL
  2. 1989–1996 Honda Ballade 150-16 & 150 (South Africa)
  3. 1992–1995 Honda Civic LX (NZ model)
  4. 1988–1991 Honda Civic LX/EX (NZ model)
  5. 1992–1995 Honda Civic EX (SA model)
  • 77 kW (105 PS; 103 hp)@6000 rpm 89 lbft (13.55 kg/m, 121 Nm)@4500 rpm

D15B4

  1. 1989–1993 Honda Civic GL (Australian Market)
  • 74 kW (99 hp; 101 PS)@5,200 rpm 122 Nm (90 lbft)@3,800 rpm

D15B5 VTEC-E

  1. 1992–1995 Honda Civic

D15B6

  1. 1988–1991 Honda Crx HF
  2. '88-'89 62 bhp (46.2 kW, 62.9 PS)@4400 rpm
  3. '90-'91 72 bhp (53.7 kW, 73.0 PS)@4500 rpm 83 lbft (11.5 kg/m, 113 Nm)@2200 rpm

D15B7

  1. 1992–1995 Honda Civic GLi (Australian model)
  2. 1992–1995 Honda Civic DX/LX
  3. 1992–1995 Honda Civic LSi Coupé (European Market)
  4. 1993–1995 Honda Civic Del Sol S
  5. 1998-2000 Honda City SX8
  • 102 hp (76.1 kW, 103 PS)@5900 rpm 98 lbft (13.5 kg/m, 133 Nm)@5000 rpm

D15B8

  1. 1992–1995 Honda Civic CX (U.S. model)Displacement : 1,493 cc (91.1 cu in)
  • 70 hp (52.2 kW, 71.0 PS)@4500 rpm 83 lbft (11.5 kg/m, 113 Nm)@2800 rpm

D15Y3

  1. 2001–2006 Civic EXi (Africa, Dubai, Pakistan)
  • 120 hp (89 kW; 122 PS)@6300 rpm) 149 Nm (14.9 kgm) (110 lbft)@4,800 rpm

D15Y4

  1. 2001–2006 Civic VTI (ES8) (VTEC) (Japan, Singapore, Malaysia, Sri Lanka)
  2. 2001–2006 Civic EXi (ES8) (non-VTEC) (Japan, Singapore, Malaysia, Sri Lanka)
  • VTEC version 130 PS (96 kW; 128 hp)@6200 rpm) 155 Nm @4500 rpm
  • non VTEC version 122 PS (90 kW; 120 hp)@6300 rpm) 149 Nm @4800 rpm

D15Z1 VTEC-E

  1. 1992–1995 Honda Civic VX
  2. 1992–1995 Honda Civic VEi (European Market)
  • 90 hp (67.1 kW, 91.3 ps)@5,600 rpm (92 hp@5,500 rpm; USDM) 98 lbft (13.5 kg/m, 133 Nm)@4,800 rpm (97 lbft@3,000 rpm; USDM)

 D15Z2

  1. 1993–1995 Honda Civic Breeze (AUDM)
  • 89.8 hp (67 kW, 91.1 ps)@6,000 rpm 98 lbft (13.5 kg/m, 119 Nm)@4,000 rpm

D15Z3 VTEC-E

  1. 1995–1997 Honda Civic MA9 (European Market)
  • 90 hp (67.1 kW, 91.3 PS)@5500 rpm 98 lbft (13.5 kg/m, 133 Nm)@4500 rpm

D15Z4

  1. 1996–2000 Honda Ballade/Civic in South Africa & Venezuela
  2. 1996–2000 Honda Civic LXi/EXi in the Philippines/Middle East/Trinidad & Tobago
  • 90 hp (67 kW) or 105 hp (78 kW)@5,800 rpm 99–103 lbft (134–140 Nm) :at 4,200 rpm

D15Z6 SOHC VTEC-E

  1. 1995–2000 Honda Civic 1.5i LS (European Market)
  • 114 PS (84 kW)@6,500 rpm 99 lbft (134 Nm)@5,400 rpm

D15Z7 3-stage VTEC

  1. 1996–1999 Honda Civic VTi EK3 and Ferio Vi
  • 128 hp (95.4 kW, 130 ps)@7000 rpm 102 lbft (14.2 kg/m, 139 Nm)@5300 rpm

D15Z8 VTEC-E

  1. 1997–2000 Honda Civic LS (MB3, MB9), (European Market)
  • 114 hp (85.0 kW, 116 ps)@6500 rpm 95–99 lbft (13–14 kg/m, 128-134 Nm)@4500 rpm

Tuning the Honda D15 and best D15 performance parts.

Best D15 modifications

Talking about the best modifications for your D15 engine, we are going to focus on the parts that releases the best value for your outlay.

 

Tuning tips and articles
 

Engine tuning Transmission tuning Care care Intake & Exhaust mods Improve handling Forums

Please watch our video which covers the 5 principles of tuning your D15. Be sure to subscribe and support our new channel.

Best mods for your D15

  • Low mass flywheel - a lower weight flywheel will noticeably improve the engines ability to rev freely. But not always beneficial for all D15 engines.
  • Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
  • Sporty Profile Camshafts are generally the biggest mechanical mod upgrade, but we strongly suggest they be applied to your engine by someone who can fine tune the cam timing and you might struggle to find one but we are sure you'l; find a local firm to regrind a stock camshaft for you.
  • Forced induction upgrades - A New Turbo is the most significant way to increase air supply, ensuring you are able to use more fuel and make more power. It is one of the most technically difficult modifications you'll see massive gains.
  • Intake Modifications and high flowing exhausts - NB: on their own these mods will NOT ADD HP , but they enable you to lift power after other modifications by lessening the restrictive flow.

D15 Tuning Stages

Typical stage 1 mods often include: Sports exhaust manifold, Fast road camshaft, Drilled & smoothed airbox, Intake manifolds, Panel air filters.

Typical stage 2 mods often include: Sports catalyst & performance exhaust, induction kit, high flow fuel injectors, Ported and polished head, Fast road cam, Suspension (Sports).

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

D15 Camshaft Upgrades

Fast road cams work better at higher RPM power which makes it a best mod for NASP and turbo petrol engines, but not so much on diesels. You will usually get a peak power hikes through performance camshafts on most engines.

If you have VTEC, you can get the VTEC to cut in at lower RPM ranges, essentially giving you the sportier cam profile over more of the engine's power band.

It is simpler to get VTEC to come in sooner than it is to find and install a fast road cam, thus this is our preferred solution for individuals wishing to improve the cam profile on their D series.

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

Fast road cams usually raise the power across the rev band, you might lose a little low down power but your higher rpm power will improve.

Competition cams, raise the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a road car you should ideally to optimize your power band to your driving style.

I'd be shocked if you'd think that a D15 Race cam is at all pleasant when driving in heavy traffic.The low end idle will typically be lumpy and irregular, and this is something you'd notice on a track when you drive in the upper third of the rpm band, but on roads this is a serious issue and we've heard from lots of drivers regretting their decision to install a more extreme competition cam profile to their engine.

Different D15 engines respond differently depending on how well made they are, when camshafts are fitted depending on the camshaft being more extreme camshaft durations and cam profile as unique due to manufacturing tolerances and quality variations so check your engine on a rolling road.

The ecu map and fuelling and fuel pump and injectors also will say much on the bhp gains you'll make.

Longer valve durations can adjust the bhp band, and on most engines there are some advantages to extending the intake or exhaust durations and valve lift.

The D15 engines respond well to upgrades and we're happy to report there is a growing number of modifications and performance parts out there.

ECU Mapping Improvements for the D15

ECU mapping helps release the full potential of all the parts you've fitted to your D15. Sadly mapping is virtually impossible on the older D15 engines, so an aftermarket or replacement aftermarket ECU is your best bet.

It will usually give around 10-15% on NA (naturally aspirated) engines, but the outcome may depend much on the parts you've chosen to fit and the condition of your engine.

Air Flow improvements on the D15

It is the whole point to any engine modification job to push air and fuel into each cylinder

Your intake manifold will direct the air from the filter and allow it to be pulled into the engine and mixed with fuel.

Shape and flow rate of the Plenum can make a noticeable effect on to fuel atomisation on the D15.

Most manifolds are in dire need of an upgrade, although some manufacturers provide fairly well optimized headers.

Fitting big valve kits, carrying out D15 port enlargement and head flowing will also increase bhp and torque, & importantly will make space for increasing the bhp and torque increase on other tuning mods.

D15 Turbo upgrades

NA (naturally aspirated) 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 D15

The more air that can enter an engine, the more gasoline that can be burned, thus improving intake with a turbocharger upgrade results in good power improvements.

However, with greater power levels, engines will need better components. Determine these constraints and add hardened components to handle the power.

We've seen individuals spend a lot on turbo improvements for the D15, only to have the whole system fail shortly after installation.

Larger turbos often have bottom end latency, while tiny turbos spool up rapidly but lack the top end engine power improvements.

Fortunately, the turbocharger industry is always evolving, and we now see variable vane turbo chargers, which enable the vane angle to be adjusted based on speed to reduce latency and boost top end horsepower and torque.

Twin scroll turbochargers split exhaust flow into two channels, which are directed towards differentially profiled vanes in the turbocharger. They also improve the engine's scavenging ability.

When more air is sucked into the engine, you'll often notice a restriction in the air flow sensor AFM/MAP on the D15.

You'll notice that 4 bar air sensors can handle significant power improvements, however the OEM air sensor restricts bhp and torque at a much lower level.

Adding a supercharger or additional turbo will make large power gains, although more difficult to configure. We have this article covering twinchargers if you want to read more.

D15 Fuelling Upgrades

When you increase the bhp you will need to look at to the fuelling.

The early carbureted D series engines may be modified to dual carburetors or numerous throttle bodies for increased power.

You'd be better off upgrading to fuel injection since it's simpler to tune and set up for higher power improvements.

The fuel pressure regulator is an excellent addition for injected vehicles since it enhances throttle responsiveness.

More bhp needs more fuel. Fuel pressure boost valves raise the fuel pressure, providing a more snappy throttle response.Don't forget to over specify your injector capacity.

The rule of thumb is to add 20% capacity when specifying an injector, this takes into account injector deterioration and affords you 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.

D15 Performance Exhausts

If your present exhaust is causing a flow issue, you should consider upgrading it.

Most factory exhausts should have adequate flow rates even with minor power improvements, but once you start pushing the power levels, you will need to upgrade to a stronger flowing exhaust.

The passage of gases through the engine is balanced by sports exhausts.

However, if the exhaust is excessively large, i.e. more than 2.5 inches bore, you will lose a significant amount of flow rate and, as a result, power and torque.

For road-going vehicles, upgrades such as a sports catalyst essentially eliminate this limitation due to its bigger size and surface area, and will effectively enhance the performance to levels you would anticipate without a catalyst fitted while keeping the car road legal.

And, as a result of its larger interior surface area and design, it will flow considerably better. Because removing a catalyst is unlawful in most areas and locations for road-registered automobiles

NB:(In others, you can't even replace a functional catalyst), the alternative decat or catalyst removal should be regarded an off-road only alteration.

Weak spots, Issues & problem areas on the D15

The D15 engines are not bad as far as reliability goes as long as they are looked after and serviced.

Carbon build up in the head, particularly around the valves which will reduce power, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon By avoiding short journeys where the engine doesn't warm up and using good quality fuel you can reduce this risk.

Frequent oil changes are highly recommended on the D15, and more so when the car is modified and will help maintain the long life of the engine.

If you want to disover more, or just get some friendly advice on Tuning your D15 engine please join us in our friendly forum where you can discuss D15 tuning options in more detail with our D15 owners. It would also be worth reading our unbiased Honda tuning articles to get insights into each modification and how effective they will be.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to know what our users have got up to and which parts work best for them on each model of car. We use your comments and feedback to improve the accuracy of these D15 tuning guides which get regular updates and revisions.

Please Check out my YouTube channel, we're regularly adding new content...

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