Buick Excelle Tuning

"All you need to know about tuning the Buick Excelle engine!"

As many of our forum members and readers have asked about the Excelle and tips on how to modify one, so this how to guide has been assembled to go over what we feel are the primary areas which make for improvement and tuning success on this great car.

This car is sold as the Lacetti under the Daewoo brand and the XT was essentially a rebadged Astra.

Herein we provide a guide to Excelle tuning and point out the ultimate mods that work. Buick Excelle make awesome project engines and with carefully picked modifications like ECU maps, turbo kits and camshafts you will dramatically maximize your driving fun.

History of the Excelle Engine

First generation (2009)

There were two 1.6-litre engines a turbocharged four-cylinder gasoline engine that delivers 135kW which is quite a nice unit for a tuning project, and a NASP one with a two-stage variable intake manifold that was produced to provide fuel economy offering a paltry 85kW. The large 1.8-litre delivers 103kW and feels slower probably due to it's weight.

• 1.6 L Family 1 I4 (gasoline)
• 1.6 L Family 1 I4 (turbo gasoline)
• 1.8 L Family 1 I4 (gasoline)Excelle GT (sedan)
• 1.6 L Family 1 I4 (gasoline)
• 1.6 L Family 1 I4 (turbo gasoline)
• 1.8 L Family 1 I4 (gasoline)

Second generation (2015)

• 1.0 L LJI I3 (turbo gasoline)
• 1.3 L LI6 I3 (turbo gasoline)
• 1.4 L LFF I4 (turbo gasoline)
• 1.5 L L2B I4 (gasoline)

Tuning the Buick Excelle and best Excelle performance parts.

Best Excelle tuning parts

The best Excelle parts on an engine are sensibly the ones that give the best value for money.

We won't be swayed by popular Excelle parts, they need to be cost effective.

Please watch our video which covers the 5 principles of tuning your Excelle. Be sure to keep up with our latest YouTube content and subscribe.

Best mods for your Excelle

1. Braking Mods - Enhancing your stopping power ought to be listed in your priority list.
2. Remaps - A Remapped Excelle ECU provides the most power for the money, replacement ECUs, and inline Tuning boxes are all alternatives.
3. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
4. Fast road Camshafts are generally the biggest mechanical mod upgrade, but they must be fitted by someone who knows what they are doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
5. Excelle Handling Mods (suspension) - Replacing worn bushings and shocks greatly enhances your Excelle road holding and cornering. Coilovers and Bushings are the usual go to mods
6. Intake and Exhaust Upgrades - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
7. Forced induction upgrades - A New Turbo is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.

Excelle Tuning Stages

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

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

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

Fast road cams raise the top end power which makes it a best mod for NASP and turbo petrol engines, but not so much on diesels. Most cars will see peak power increases through performance camshafts on most engines

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.

Fast road camshafts tend to raise the bhp and torque over the rev band, you may lose a little low down bhp but higher rpm power will be better.

Competition camshafts, 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 typical daily driver you need to optimize your power band to your typical driving style.

I'd be shocked if you'd think that a Excelle Competition camshaft is a pleasure to live with when driving in heavy traffic.

This is because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

Different Excelle engines respond better to more aggressive cam durations than others.

The map and fuel pump and injectors also have a large bearing on the torque gains you'll achieve.

Extending exhaust or intake durations can alter the torque 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.

Remaps will help unlock the full potential of all the upgrades you've done to your Excelle.

(Sometimes flashing the ECU 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 around 30% more power on turbocharged vehicles and you can expect to see around 15% on NA (naturally aspirated) engines, but your mileage usually vary depending on the upgrades you've applied and the condition of your engine.

Intake improvements on the Excelle

Forcing more air and fuel into your Excelle is the aim to any engine upgrade job.

Intake flow the air from the filter and allow it to be drawn into the engine cylinders.

The shape and flow rate of the Air Intake manifolds can make a substantial change to fuel mixing and power on the Excelle.

It's not uncommon that air intake manifolds are needing aftermarket parts, although a few manufacturers provide reasonably well designed air intake manifolds.

Larger Excelle valves, carrying out port work and head flowing will also raise performance, & importantly will raise potential for an improved performance increase on other upgrades.

Excelle 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 Excelle

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

If the engine is turbocharged, tuning parts are going to make more power and most turbo charged engines are made using strengthened components, hence why we see these as a better base for a tuning project.

There are tuning limits for every engine, with some being over specified and some just sufficiently able to handle stock power.

See where you'll find these limits and upgrade to better pistons and crank to survive the power.

We see many mechanics spending a a stack of money on turbo upgrades on the Excelle only to have the whole thing throw a rod on it's first outing after it's been finished.

Bigger upgraded turbochargers will usually suffer a bottom end lag, and small turbochargers spool up really quickly but won't have the top end torque gains.

Over the last 20 years the range of turbos is always evolving and we now see variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbos divert the exhaust gases into 2 channels and direct these at differently designed vanes in the turbo. They also improve the scavenging effect of the engine.

It is not unusual that there's a limit in the air flow sensor AFM/MAP on the Excelle when considerably more air is being drawn into the engine.

We see 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor limited bhp at a much lower level.

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

Excelle Fuelling

You will need to ensure that the engine is not starved of fuel so will need to increase the fuelling when you start exceeding 20% of a bhp and torque increase.

It makes sense to be generous with your flow rate on the injectors.

The accepted safe increase is to add 20% capacity when fitting an injector, helps cope with injector deterioration and gives a bit of 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. From the chart below see how the fuel requirements dramatically shoot up with power levels.

4 Cylinder turbocharged engines

1. 1. • 58 PSI 340cc/min 200hp
      • 58 PSI 511cc/min 300hp

4 Cylinder NA (naturally aspirated) engines

1. 1. • 58 PSI 285cc/min 200hp
      • 58 PSI 426cc/min 300hp

4 Cylinder supercharged engines

1. 1. • 58 PSI 312cc/min 200hp
      • 58 PSI 468cc/min 300hp

Excelle Performance Exhausts

You only need to to uprate your exhaust if your current exhaust is actually creating a restriction.

On most factory exhausts you'll see the flow rate is good 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 get you'll reduce the exhaust flow rate - the best exhausts 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 in the catalyst and filters installed, so adding a higher flowing race aftermarket version removes the restriction, and rather than doing an illegal catless mod, will keep the car road legal.

We should explain that performance catalyst perform similarly to test pipe mod and will effectively raise the performance to levels you would expect without having a catalyst installed.

This keeps the car road legal and will better flow due to it's higher internal surface area and design.

The alternative test pipe mod or cat removal should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars (and in some you can't even replace a working catalyst).

Weak spots, Issues & problem areas on the Excelle

The Excelle engines are reasonably reliable and solid as long as they are regularly serviced and maintained.

Early models (2012 2013, in particular, had many issues)

Electrical problems were rife with faulty sensors, causing engine warning lights to come on or the engine to cut out and stall.

High oil consumption has also been reported on these models, so keep an eye on your oil levels regularly.

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

If you want to know more, or just get some friendly advice on Tuning your Excelle engine please join us in our friendly forum where you can discuss Excelle tuning options in more detail with our Excelle owners. It would also be worth reading our unbiased Buick 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 mods work best for them on each model of car. We use your comments and feedback to improve the accuracy of these Excelle tuning guides which get regular updates and revisions.

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