Tuning the GM Family II

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

TorqueCars will look into Family 2 tuning and show the optimum modifications for your car. GM Family 2 are good project engines and with the right sports upgrades like a remap, turbo upgrades and camshafts you will certainly maximise your driving experience.

Best Family 2 modifications

Just because particular tuning mods are popular with Family 2 owners it doesn't mean it is good, so we'll best tuning mods that will give your Family 2 the best power gain for you spend.

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 power band gains are on offer for cam upgrades.

Fast road cams commonly push up the power through the rpm range, you might lose a little low down torque but high end rpm power will be lifted.

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

For a car driven daily one should, ideally, try to match your power band to your cars usage.

I'd be surprised if you have ever thought a Family 2 Motorsport and race cam is a pleasure to live with when in heavy traffic.

Some Family 2 engines respond better to less aggressive cam durations check your engine on a rolling road.

The ECU mapping and fuel pump and injectors also have a large bearing on the bhp gains you'll hit.

A longer valve duration 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: Intake headers, Remaps/piggy back ECU, Drilled & smoothed airbox, Sports exhaust manifold, Panel air filters, Fast road camshaft.

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

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

A remap will help unlock the full potential of all the modifications you've fitted to your Family 2.

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 differs on the modifications you've done and the condition of your engine.

Forcing more air into the Family 2 engine is the main goal to any engine tuning job.

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

Design and rate of flow of the Plenum can make a substantial difference to to fuel atomisation and engine efficiency on the Family 2.

On popular production engines headers are in dire need of performance upgrades, although a few car makers provide reasonably good headers.

Big valve conversions on the Family 2, getting port work and head flowing will also improve power, and importantly will give you raising the power increase on other parts.

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 2

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

When a car has a turbo already fitted upgrades are going to make more power and we find turbocharged engines are built using more solid components.

However every engines will have power limits

Discover these limitations and upgrade to better quality crank and pistons to utilize the power.

We've seen mechanics spending a loads of money on turbocharger upgrades on the Family 2 only to suffer the indignity of watching the engine explode just after it's been finished.

Bigger capacity turbos will usually suffer no power at low rpm, and low capacity turbos spool up more quickly but don't have the top end engines power gains.

Thanks to progress the choice of turbo units is always developing and we commonly find variable vane turbo units, permitting the vane profile is altered according to speed to lower lag and increase top end performance.

Twin scroll turbo units divert the exhaust gases into 2 channels and direct these at differently angled vanes in the turbo charger. They also help the scavenging effect of the engine.

You'll commonly see there is a restriction in the air flow sensor AFM/MAP on the Family 2 when a lot more air is being drawn into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting performance at a much lower level.

Adding a supercharger or additional turbo will make large bhp and torque gains, although more difficult to install. We have this article on twincharging if you want to read more.

Fuelling

When you lift the bhp you will need to pay attention to to the fuel delivery.

More bhp needs more fuel. It makes sense to be generous with your injector capacity.

As a rule of thumb add 20% to the flow rate when fitting an injector, this allows for injector deterioration and gives some spare capacity should the engine require 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.

Exhaust

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

On most factory exhausts you'll find the flow rate is still fine 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 equal out the flow of gases through the engine.

But if your exhaust pipe is too big, ie: over 2.5 inches bore, you will lose much of the flow rate and end up lacking power and torque.

Usual exhaust restrictions can be traced to the catalyst installed, so adding a freer flowing sports alternative will help avoid this restriction.

History of the Engine

1.6

• 16LF
  72 hp (53 kW ) @5200 rpm (Ethanol) 73 hp (54 kW) @5400 rpm (Petrol)
• 16SH
  66 kW (90 PS; 89 hp) @5800 rpm
• 16D
  40 kW (54 PS; 54 hp) @4600 rpm
• C16NZ2
  55 kW (75 PS; 74 hp) @5200 rpm

1.7

• 17D
  42 kW (57 PS; 56 hp) 105 Nm (77 lbft) @2400 rpm
• 17DR
  44 kW (60 PS; 59 hp) 105 Nm (77 lbft) @2650 rpm
• X17DTL
  51 kW (69 PS; 68 hp) 132 Nm (97 lbft) @2400 rpm

1.8

• 18E
  85 kW (115 PS) @5800 rpm 151 Nm (111 lbft) @4800 rpm
• C18LE
  70KW (95HP)
• 18N
  62 kW (84 PS) @5400 rpm 143 Nm (105 lbft) @2600 rpm
• 18S
  66 kW (90 PS) @5400 rpm 143 Nm (105 lbft) @3000–3400 rpm
• C18NV
  74 kW (100 PS) @5800 rpm
• C18NZ
  66 kW (90 PS; 89 hp) @5400 rpm 145 Nm (107 lbft) @3000 rpm
• LH8
  63 kW (84 hp)
• LA5
  112 kW (150 hp)

2.0

• 20NE
  115 PS (85 kW) @5200 rpm 175 Nm (129 lbft) @2600 rpm
• 20SE
  122 PS (90 kW) @5400 rpm 175 Nm (129 lbft) @2600 rpm
• 20SEH
  127–130 PS (93–96 kW) @5600 rpm 180 Nm (130 lbft) @4600 rpm
• C20NE
  115 PS (85 kW) @5200 rpm 170 Nm (130 lbft) @2600 rpm
• LT2
  96 hp (72 kW) 160 Nm (118 lbft)
• LE4
  110 hp (82 kW) @5200 rpm 167 Nm (123 lbft) @3600 rpm
• LT3
  165 hp (123 kW) @5600 rpm 175 lbft (237 Nm) @4000 rpm
• C20XE
  115 kW (156 PS) 203Nm(150 lbft)
• C20XE
  110 kW (150 PS) at 6000 rpm 196Nm(145 lbft) at 4600 rpm
• C20LET
  150 kW (204 PS) at 5600 rpm 280Nm(207 lbft) at 2400 rpm

ECOTEC 2.0

• X20XEV 136 PS; 134 hp (100 kW) 185 Nm at 4000 rpm
• X20XER 160 PS (118 kW) 188 Nm at 4300 rpm
• Z20LET 147 kW (200 PS) 197 lbft (267 Nm)
• Z20LEL 125 kW (170 PS) 193 lbft (262 Nm)
• Z20LER 147 kW (200 PS) 193 lbft (262 Nm)
• Z20LEH 177 kW (241 PS) 236 lbft (320 Nm)
• X20SED
• U20SED (L34) 119–132 hp (89–98 kW) at 5400 rpm 126 lbft (171 Nm)

2.2

• C22NE 123 hp
• C22LE 116 hp
• X22XE
  100 kW (130 hp) @ 5200 rpm, 104 kW (139 hp) @ 5400 rpm
• Y22xe
  106 kW (142 hp) @ 5400 rpm Torque: 205Nm(151 lbft) @ 4000 rpm
• Z22xe

2.4

• C24SE – 2.4 L SOHC
• X24XF— 2.4 L
• X24SFD 150 hp @5200 rpm 228 Nm @4000 rpm
• Z24XE FlexPower (134–138 hp) @5200 rpm 160 lbft @2200 rpm

Weak spots, Issues & problem areas on the Family 2

The Family 2 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the Family 2, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your Family 2 engine please join us in our friendly forum where you can discuss tuning options in more detail with our Family 2 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help improving this article, so please send us your feedback in the comments box below and pass on any tips, points or facts we have wrong or have not covered.

We really like hearing from our readers, and hearing about which tuning parts were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our Family 2 guides and tips are kept up to date.

METAS! below

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

Click to accept YouTube Cookies & Play.

This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under GM. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.