Modding upgrading and tuning the Chrysler 6.1 Hemi (SRT 8) engine!

Tuning guide "6.1 Hemi (SRT 8) Modifications"

How to modify and upgrade the Chrysler 6.1 Hemi (SRT 8)

"Comprehensive guide to performance parts and tuning the Chrysler 6.1 Hemi (SRT 8) engine!"

Popular tuning sites like TorqueCars are always getting messages requesting information on how to improve the 6.1 Hemi (SRT 8) from people inquiring about getting more power from the 6.1 Hemi (SRT 8) and wanting to know what are the optimum 6.1 Hemi (SRT 8) mods that work. So let us look into Chrysler 6.1 Hemi (SRT 8) tuning mods and outline the best mods that work on this great engine and point out some problems along the way.

The Chrysler 6.1 Hemi (SRT 8) make a good tuning project and with carefully chosen modified modifications like remapping, turbo upgrades and camshafts you will improve your driving experience.

In this article we examine the options for your 6.1 Hemi (SRT 8) tuning and outline the ultimate modifications for your car.

When talking about the best parts for your 6.1 Hemi (SRT 8) engine, we are going to concentrate on the parts that give the best value for money.

6.1 Hemi (SRT 8) induction kits

Improving air intake on the 6.1 Hemi (SRT 8)

You need fuel and air for an engine to work. If there is not enough fuel then it will run lean, if there is little flow of air it runs rich resulting in lost power and potentially damaging the engine. We'll pick up on fuelling later in this article but for now we shall look at air supply.

So Feeding fuel and air into your 6.1 Hemi (SRT 8) is the aim to any engine performance tuning job.

It is common that there's a limit in the air flow sensor MAP/MAF/AFM on the 6.1 Hemi (SRT 8) when loads more air is being sucked into the engine.

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

Intake manifolds take the air during the suck phase from the intake filter and allow it to be drawn into the engine cylinders.

Design and flow characteristics of the Intake headers can make a big improvement to fuel atomisation on the 6.1 Hemi (SRT 8).

Many mass produced engine intake are crying out for performance upgrades, although a few manufacturers provide well optimised intake.

Adding a 6.1 Hemi (SRT 8) larger valve kit, doing a bit of port work and head flowing will also lift power, and significantly will raise potential for an improved power increase on other mods.

6.1 Hemi (SRT 8) performance cam tips.

Different 6.1 Hemi (SRT 8) engines respond better to extreme cam durations than others.

The ecu map and injectors and fuel pump also have an effect on the bhp gains you'll hit.

Extending exhaust or intake 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.

Significant air intake, and exhaust improvements on the 6.1 Hemi (SRT 8) can be made from camshaft upgrades. Changing the camshaft profile alters the intake and exhaust durations on the engine and can dramatically change the power band and power output.

NB: Fast road cams commonly raise the bhp through the rev band, you could drop a little low end bhp but your high end rpm power will be better.

Race cams, raise 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 camshaft is not great in heavy traffic.

You should ideally optimize your bhp range to your typical driving style so for a typical daily driver stick with a fast road 6.1 Hemi (SRT 8) camshaft

Stage 1, 2 and 3 mods for the 6.1 Hemi (SRT 8)

Before we break the best tuning upgrades down into stages of tune, let's list the most effective tuning upgrades for you.

  1. Suspension Upgrades - always improve your cars handling
  2. Brake Upgrades - Even before adding power improve those brakes
  3. Intake - make sure the intake is not restricted, use filters and intake upgrades to improve this
  4. Exhaust - as with 3 ensure there is not restriction in the exhaust, cats are the usual bottleneck
  5. Tunes - remapping, piggyback ECU's and aftermarket ECU's can all make decent gains
  6. Fuelling - when you've increased power you'll need to match this with more fuel
  7. Turbo upgrades - Improving the intake with a large turbo and better flowing intercooler will be the biggest power gain you'll see (but one of the most complex).

This video guide to tuning cars is a great starting point to work from in your project.

Stage 1 6.1 Hemi (SRT 8) parts:

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

Stage 2 6.1 Hemi (SRT 8) parts:

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

Tuning tips and articles Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums

Stage 3 6.1 Hemi (SRT 8) parts:

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

The 6.1 Hemi (SRT 8) power trains respond well to upgrades and we note that there is an increase of modifications and tuning parts out there.

A remap allows a tuner to release the full potential of all the upgrades you've done to your 6.1 Hemi (SRT 8).

You will typically expect to see gains of approximately 20-30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output may depend much on the upgrades you've done and the condition of your engine.

Turbo modifications on the 6.1 Hemi (SRT 8)

To get a turbo working on a NASP engine there is a lot involved, from lowering compression ratio to improved fuel supply and mapping, so we have found a great guide to helpavoid the common pitfalls or end up with an unfinished project because you were not told what you were getting into by doing this on the 6.1 Hemi (SRT 8).

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.

When your car is fitted with a turbo tuning mods are more reliable and we find turbo charged engines are made with more solid components.

However every engines have limits

Research these limits and install better quality components to cope with the power.

There are many people spending a fortune on turbocharger upgrades on the 6.1 Hemi (SRT 8) only to have the whole thing literally blow up soon after it's completed.

Large turbo chargers often suffer a bottom end lag, and smaller turbo chargers spool up much more quickly but won't have the top end power band gains.

Over the last 20 years the range of turbos is always moving on and we commonly find variable vane turbos, allowing the vane profile is altered according to speed to lower lag and increase top end bhp.

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

Beefing up the air intake by adding a supercharger or additional turbo will help you achieve very large bhp gains, although more challenging to get working. We have this in depth look at twinchargers if you want to read more.

Tips about fuel supply on the 6.1 Hemi (SRT 8)

You will need to ensure that the engine is not starved of fuel so need to pay attention to the fuelling when you start extending past 20% of a power hike. Don't forget to be generous with your flow rate on the injectors.

The rule of thumb is to add 15% when specifying an injector, this accounts for injector deterioration and affords a little spare capacity should the engine need more fuel.

Don't forget that different fuel grades will usually require different settings, a high octane fuel will burn more efficiently than lower octane fuel for example. A car will trim fuel supply to keep within the ideal air fuel mix but at the extreme ends you may need to adjust your injector capacity, or the mapping or you'll get flat spots and potential lean or rich fuel issues..

Recommended 6.1 Hemi (SRT 8) performance exhaust upgrades

The only time you should look to replace your exhaust system with an upgraded one is if the current exhaust is actually causing a restriction.

On most factory exhausts you should find that your flow rate is still ok even on modest power gains, but on a serious tuning project with a big boost in power you will certainly need to get a better flowing exhaust.

Please dont run with the widest exhaust you can find this will reduce the exhaust flow rate - the best exhausts for power gains are usually between one and a half to two and half inches. Your exhaust design, the bend angles and construction are what have more effect on flow rates than your pipe width to a certain extent. So the exhaust design is a big factor.

Typically exhaust restrictions are in the catalysts installed, so adding a higher flowing performance alternative will help avoid this restriction.

Catalyst removal (NB:catalysts reduce harmful engine emissions) is illegal in most countries and regions.

Faults issues and things to look out for on the 6.1 Hemi (SRT 8)

Like most engines an 6.1 Hemi (SRT 8), should have few issues if it gets properly serviced and looked after.

We cannot stress enough the need for oil changes with the correct grade of oil on the 6.1 Hemi (SRT 8), failure to do this will exacerbate engine wear, on a tuned 6.1 Hemi (SRT 8) this is more important than ever and close attention should be paid to your maintenance schedule.

If you are interested in learning more or getting impartial tuning advice for your 6.1 Hemi (SRT 8) why not pop over to the forums at TorqueCars where you can chat about 6.1 Hemi (SRT 8) tuning options and read about others projects who may be planning to do similar modifications on their 6.1 Hemi (SRT 8).

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