Tuning the GM LS1 and best performance parts.

"All you need to know about performance parts and tuning the GM LS1 engine!"

We review and look at LS1 tuning and highlight the ultimate mods that work. GM LS1 make awesome project cars and with the right modified upgrades like a remap, turbo upgrades and camshafts you will noticeably increase your driving opportunities.

The LS1 or Generation III as it's known was very solidly built and with the right mods can make a significant amount of power.

It is a big lazy V8 and if you tighten up the fuelling and timing you can make some significant power from this popular block.

Most tuners make larger power gains on the LS1 than they do on the LS2 or LS3 primarily because it was built and designed for solidity and reliability rather than performance.

History, Power & Specs of the Engine

The Generation III V8 was an all new from the ground up design, which replaced the Gen I and Gen II engine families in 2002 and 1995 respectively. The coil was relocated to the plug, and the aluminum engines were as strong as iron blocks making it an ideal base for your tuning project.

  • 345 hp (257 kW) at 5,600 rpm and 350 lbft (475 Nm) at 4,400 rpm
  • 350 hp (261 kW) at 5,600 rpm and 365 lbft (495 Nm) at 4,400 rpm
  • Engine versions included VT,VX, VU,WH, VY, WK, VZ
  • OHV 2 valves per cylinder with a 90° V8 layout
    With the following displacements offered
  • 4,806 cc (293.3 cu in)
  • 5,327 cc (325.1 cu in)
  • 5,665 cc (345.7 cu in)
  • 5,967 cc (364.1 cu in)

 

Best LS1 modifications

Just because a modifications is popular with LS1 owners it doesn't mean it is good, instead we'll focus our attention and tuning advice on the specific modifications and upgrades that will give your LS1 the best power gain for you money.

Altering your LS1 cam will make a dramatic difference to the engine torque. Choosing a higher performance cam profile raises the torque accordingly.

Fast road cams normally push up the bhp across the rev band, you may sacrifice a little low down bhp but the top end will be better.

Motorsport and race cams, push up the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a road car must carefully try to optimize your power band to your preferences.

You will never have found a Race cam is a pleasure to live with when driving in heavy traffic. The low end idle will be very lumpy and irregular, so something you would 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 lamenting their decision to add an extreme competition cam profile to their engine.

Don't forget to uprate the valve springs and and rockers when changing cam as these can wear quickly, especially under load and you won't get the lift or end up with leaking valves.

Some LS1 engines respond better to mild cam durations check your engine on a rolling road.

The engine timing and fuel pump and injectors also will say much on the power gains you'll get.

Longer valve durations 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, Remaps/piggy back ECU, Panel air filters, Intake headers, drilled & smoothed airbox, Sports exhaust manifold.

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

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

The LS1 engines are great to work on and we're pleased to see that there are plenty of mods and performance parts around.

You'll typically need to hit around 600hp before you need to strengthen the pistons and rods and we've heard of 1000hp engines running the stock crank. It makes a lot of sense to uprate the oil pump when running higher power tunes on the LS1 as loss of oil pressure is one of the big engine killers.

Remaps helps to establish the full potential of all the tuning parts you've fitted to your LS1.

(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 15% on NASP engines, but you mileage will vary depending on the tuning parts you've done and the condition of your engine.

It is the whole point to any engine tuning task to feed more air into each cylinder

Air Intake manifolds carry the air 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 Air Intake manifolds and head can make a large improvement to fuel engine efficiency on the LS1 with a ported head boosting your power gains from any other mods you do.

A 383 stroker kit works well on the LS1 and we see people adding LS6 heads, with larger ports making a "Frankentune" version.

A word of warning on reboring as the 1997-1998 LS1 engines hit a maximum oversized hone of 0.005". The 1999 to 2000 blocks are the best in our opinion for modification, as they are stronger and have better oil flow.

I usually find intake manifold are in desperate need of motorsport parts, although a few manufacturers provide reasonably well designed intake manifold.

Larger LS1 valves, doing some port work and head flowing will also boost bhp and torque, and more importantly will permit raising the bhp and torque 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 LS1 but a low boost turbo or supercharger can work quite well, and for larger power gains you should drop the compression ratio.

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

Intake mods are popular and can make good power, we have some members using an LS2 throttle body

If your car has a turbocharger upgrades are relatively easy and turbo engines are built with more solid components.

However you'll find engines have weakspots

Research these restrictions and upgrade to more solid crank and pistons to utilize the power.

We see many tuners spending a lots of money on turbocharger upgrades on the LS1 only to suffer the indignity of watching the LS1 go up in smoke when it's finished.

Larger turbo units tend to suffer low end lag, and low capacity turbo units spool up really quickly but don't have the peak rpm engines power gains.

the selection of turbos is always moving on and we now see variable vane turbos, permitting the vane profile is altered according to speed to lower lag and increase top end bhp and torque.

Twin scroll turbos divert the exhaust gases into a couple of channels and flow these at differently profiled vanes in the turbocharger. They also improve the scavenging effect of the engine.

You'll commonly see there's a limitation in the air flow sensor MAP/MAF/AFM on these engines when loads more air is being drawn into the engine.

The factory air flow metering and fuelling maps are probably one of the first places a tuner will look to improve the LS1.

We see 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 performance gains, although more complex to configure. We have a twincharger performance adding guide if you want to read more.

Fuelling

When you boost the bhp you will need to uprate to the fuel delivery.

More bhp needs more fuel. Most tuners we speak with say to over specify your injector capacity.

The accepted safe increase is to add 20% when specifying an injector, this allows for injector deterioration and provides 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.

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

8 Cylinder NASP engines

  • 58 PSI 285cc/min 400hp
  • 58 PSI 426cc/min 600hp
  • 58 PSI 568cc/min 800hp
  • 58 PSI 853cc/min 1200hp

Exhaust

Only look to upgrade your exhaust if your current exhaust is actually causing a flow problem.

On most factory exhausts you should find that 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 can help equal out the flow of air through the engine.

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

Common exhaust restrictions can be located the catalysts installed, so adding a higher flowing sports alternative is the answer. This keeps the car road legal and will flow much better due to it's higher internal surface area and design, so has the added benefit of keeping your car road legal. The alternative decat should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars..

Weak spots Issues & problem areas on the

The engines are generally reliable and solid as long as they 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 , especially when tuned and will help extend the life and reliability of the engine.

Valve springs can weaken over time, especially with high RPM driving or where a fast road cam is fitted. Replace valve springs at the first sign of valve rattle or when you add a performance camshaft. It's also worth checking the rocker arms, and upgrading to fill roller rockers.

Check the oil pump is in good condition and the fuel pump also, this is not necessarily a weak spot but is the most common fault you'll find on higher mileage LS1 engines.

1999 to 2001 suffered from weak rod bolts that were prone to fail.

If you would like to know more, or just get some friendly advice on Tuning your engine please join us in our friendly forum where you can discuss tuning options in more detail with our 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 articles which are continually updated.

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