GM Family 1 Tuning

"All you need to know about tuning the GM Family 1 engine!"

The GM Family 1 great bases for a tuning project and with the optimum modified mods like remapping, turbo upgrades and camshafts you will positively improve your driving fun.

Let us look at Family 1 tuning and outline the premier modifications.

History, Power & Specs of the Engine

1.0 X10YFH

  • 78–80 bhp) at 6400 rpm  69–71 lbft) at 5200 rpm
  • Chevrolet Celta
  • Chevrolet Prisma
  • Chevrolet Corsa/Classic

1.2 Opel Corsa A Vauxhall Astra A

  • 12NV
    52hp 39 kW @ 800 rpm 63 lbft @ 2600 rpm
  • 12ST
    54hp 40 kW @ 600 rpm 90 Nm (66 lbft @ 2200 rpm
  • A12ST
    50hp 37 kW @ 600 rpm 88 Nm (65 lbft @ 2200 rpm
  • C12NZ
    45hp 34 kW @ 000 rpm 88 Nm (65 lbft @ 2400 rpm
  • S12ST
    54hp 40 kW @ 600 rpm 90 Nm (66 lbft @ 2200 rpm

1.3 Opel Ascona C  Opel Kadett D Opel Manta B Astra

  • 13N
    60hp 45 kW @ 800 rpm 69–71 lbft @ 3800 rpm
  • 13Nb
    60hp 45 kW @ 800 rpm 71 lbft @ 3200 rpm
  • 13S
    68–75hp 51–56 kW @ 800 rpm 71–74 lbft @ 3800–4600 rpm
  • 13SB
    70hp 52 kW @ 800 rpm 74 lbft @ 3800–4200 rpm
  • 13SH
    83hp 62 kW @ 800 rpm 80 lbft @ 4200 rpm


  • 14NV
    74hp 55 kW @ 600 rpm 80 lbft @ 3000 rpm
  • C14NZ
    60hp 45 kW @ 600 rpm 76 lbft @ 2600 rpm
  • C14SE
    82hp 61 kW @ 200 rpm 86 lbft @ 3400 rpm
  • X14YFL
    89–97hp 66–72 kW) at 6200 rpm 90–94 lbft
  • X14YFH
    99–105hp 74–78 kW) at 6000 rpm 95–97 lbft
  • N14YF
    97–102hp 72–76 kW) at 6000 rpm 93–97 lbft at 3200 rpm


  • C16NZ
    72–75hp 54–56 kW @ 200 rpm 92 lbft @ 2800 rpm
  • C16SE
    100hp 75 kW @ 800 rpm 100 lbft @ 3400 rpm
  • C16SEI
    98hp 73 kW @ 600 rpm 97 lbft @ 3400 rpm
  • E16SE
    100hp 75 kW @ 800 rpm 100 lbft @ 3400 rpm
  • L73
    74hp 55 kW @ 600 rpm 90 lbft @ 2800 rpm
  • G16SF
    92 hp (68 kW @ 600 rpm
  • Z16SE
    64 kW (86 hp) at 5400 rpm 98 lbft @ 2600 rpm
  • X16SZ
    52 kW (72 hp) at 5000 rpm at 2800 rpm
    82 bhp@5400  (96 lbft) @ 2600 rpm

1.8 N18XFH

  • N18XFH
    106–108 hp at 5600 rpm 119–124 lbft @ 3200 rpm

Tuning the GM Family 1 and best Family 1 performance parts.

Best Family 1 tuning parts

Just because particular upgrades are are common on Family 1 it doesn't mean its worth having, instead we'll best upgrades that will give your Family 1 the biggest power gain return for your cash.

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

Fast road cams usually increase the torque across the rev range, you may lose a little low down power but your high end rpm power will be lifted.

Race cams, increase the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Motorsport cam is not great driving in heavy traffic.

You should ideally match your engines power to your preferences so for a road car stick with a fast road Family 1 cam

Each engine responds better to extreme cam durations so view each engine as unique.

The ecu map and fuel pump and injectors also will say much on the power gains you'll hit.

A longer valve duration can alter the power 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.

Typical stage 1 mods often include: Fast road camshaft, Sports exhaust manifold, Panel air filters, Intake headers, drilled & smoothed airbox, Remaps/piggy back ECU.

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

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

Carefully think through your options and then source your tuning parts and set yourself a power target to save yourself from expensive mistakes.

Remaps helps fully realize the full potential of all the modifications you've fitted to your Family 1.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved will vary depending on the modifications you've fitted and the condition of your engine.

Pulling fuel and air into the Family 1 engine is vital to any engine tuning task.

Intake transmit the air during the suck phase from the air cleaner and allow it to be fed into the engine cylinders with fuel for the squish phase.

The shape and rate of flow of the Intake can make a noticeable change to fuel atomisation and engine efficiency on the Family 1.

Many mass produced engine headers are needing performance upgrades, although a few manufacturers provide decently flowing headers.

Increasing the Family 1 valve size, doing some 3 or 5 angle valve jobs and porting and head flowing will also boost bhp and torque, this will give you a better bhp and torque increase on other upgrades.

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 Family 1

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

If the engine is turbocharged, modifications are more reliable and most turbo engines are made with harder and stronger components.

However you'll find engines will need better parts at higher power limits

Discover these limits and install more solid crank and pistons to survive the power.

We see many tuners spending a lots of money on turbo charger upgrades on the Family 1 only to have the Family 1 literally blow up soon after it's been enthusiastically driven.

Big capacity turbo units will usually experience low end lag, and smaller turbo units spool up really quickly but don't have the peak end torque gains.

Thanks to new tech the selection of turbo units is always increasing and we now see variable vane turbo units, permitting the vane angle is altered according to speed to lower lag and increase top end power.

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

It is common that there's a limitation in the air flow sensor AFM/MAF on the Family 1 when loads more air is being drawn into the engine.

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

Adding a supercharger or additional turbo will make large bhp gains, although more challenging to configure. We have this feature on twinchargers if you want to read more.


When you improve the power you will need to look at to the fuel system.

More power needs more fuel. We would recommend you to over specify your injectors flow rate.

As a rule of thumb add 20% capacity when specifying an injector, this allows for injector deterioration and affords a little 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.

All the following flywheel power targets will assume an injector duty cycle of 80% and a base of 58psi of fuel pressure at idle.

4 Cylinder turbocharged engines

  • 58 PSI 340cc/min 200hp
  • 58 PSI 511cc/min 300hp

4 Cylinder NASP engines

  • 58 PSI 285cc/min 200hp
  • 58 PSI 426cc/min 300hp

4 Cylinder supercharged engines

  • 58 PSI 312cc/min 200hp
  • 58 PSI 468cc/min 300hp


Only look to increase your exhaust if the existing exhaust is creating a flow problem.

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

Do not go with the largest exhaust you can find you'll slow up the exhaust flow rate - the best for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Common exhaust restrictions come around the filters installed, so adding a faster flowing race alternative such as a sports catalyst pretty much removes this restriction, thanks to it's larger size and surface area, and will effectively raise the performance to levels you would expect without having a catalyst installed, but keeps the car road legal.

Weak spots, Issues & problem areas on the Family 1

The Family 1 engines are generally reliable and solid units, as long as you follow the manufacturers service schedules, and use a good quality oilthey are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the Family 1, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your Family 1 engine please join us in our friendly forum where you can discuss tuning options in more detail with our Family 1 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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

We love to hear what our visitors have got up to and which modifications work best for them on each model of car. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these Family 1 articles which are continually updated.

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