GM LS9 Tuning

"All you need to know about tuning the GM LS9 engine!"

The GM LS9 great bases for a tuning project and with carefully picked tuning parts like ECU maps, turbo upgrades and camshafts you will definitely enhance your driving enjoyment.

This pages aim is detail the best approach to LS9 tuning and point out the premier upgrades.

History of the Engine

The LS9 was based on the stronger LS3 block, it had a supercharger fitted and put out 639bhp.

  • 2009–2013 Chevrolet Corvette ZR1
  • 2017 HSV GTSR W1
  • Equus Bass 770

Tuning the GM LS9 and best LS9 performance parts.

Best LS9 tuning parts

When talking about the best best for your LS9 engine, we are going to concentrate on the tuning parts that give the best power gain for you spend.

Significant gains on the LS9 can be made from cam upgrades. Altering the cam profile alters the intake and exhaust durations on the engine and can dramatically change the bhp and power output.

Fast road cams usually raise the power throughout the rpm band, you may sacrifice a little low end bhp but higher rpm power will be lifted.

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

For a car used daily should ideally to match your engines power to your preferences.

You will never have ever thought a LS9 Motorsport and race cam is a pleasure to live with when in heavy traffic.

Some LS9 engines respond better to more aggressive cam durations so set your engine up on a rolling road.

The map and fuelling also will make differences on the bhp gains you'll achieve.

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

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

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

The LS9 units respond well to mods and thankfully there are quite a few choices of mods and performance parts out there.

A remap helps unlock the full potential of all the upgrades you've fitted to your LS9.

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

Forcing air into each cylinder is the aim to any performance tuning task.

Air Intake manifolds carry the air from the filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

Shape and flow rate of the Intake headers can make a noticeable change to fuel engine efficiency on the LS9.

It's not uncommon that intake are in desperate need of an upgrade, although a few makers provide well optimised intake.

Big valve conversions on the LS9, doing a bit of 3 or 5 angle valve jobs and porting and head flowing will also raise power, and as an added benefit will give you raising the power 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 LS9

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

If a car has a turbo already fitted parts are simpler to install and turbo engines are made with harder and stronger components.

There are common areas of failure for every engine, with some being over specified and some only able to handle stock power

See where you'll find these restrictions and fit forged components to cope with the power.

We see many people spending a fortune on turbocharger upgrades on the LS9 only to experience the engine block explode when it's used in anger.

Big capacity turbochargers will usually experience a bottom end lag, and little turbochargers spool up quickly but won't have the peak rpm power band gains.

We are pleased that the range of turbochargers is always improving and we now see variable vane turbochargers, allowing the vane angle is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbochargers divert the exhaust flow into 2 channels and feed these at differently angled vanes in the turbocharger. They also improve the scavenging effect of the engine.

It is common that there is a limit in the air flow sensor (AFM/MAF/MAP) on the LS9 when a lot more air is being drawn into the engine.

You'll see that 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor sapped bhp and torque 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.


Don't overlook the need to improve the fuel system when you are increasing the power - it makes the car more thirsty. We would recommend you to over specify your injector capacity.

As a rule of thumb add 20% when buying an injector, this accounts for injector deterioration and provides 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.


You should look to replace your exhaust if your current exhaust is creating a restriction.

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

Don't go with the widest exhaust you can buy this will 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.

Usual exhaust restrictions can be located the filters installed, so adding a freer flowing performance alternative will help avoid this restriction.

Weak spots, Issues & problem areas on the LS9

The LS9 engines are generally reliable and solid as long as they are regularly serviced and maintained.

Regular oil changes are vital on the LS9, especially when tuned and will help extend the life and reliability of the engine.

For more information on Tuning your LS9 engine please join us in our friendly forum where you can discuss tuning options in more detail with our LS9 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 tuning parts work best for them on each model of car. Comments are used to improve the accuracy of these LS9 articles which are continually updated.

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