Modern Hemi Tuning


After more than four years and many failed attempts to unlock the Chrysler Hemi and other V6 Chrysler factory ECU’s, we are very happy to report that we can now correctly tune the 5.7, 6.2 and 6.4 Litre engines, as well as many of the Jeep and Dodge Chrysler V6 engines in 2003 to 2015 Challengers, Chargers, Jeeps, Chrysler 300, SRT8. See this list of supported vehicles to determine if your engine is supported. 

We can now correctly tune these engines for improved HP, Torque, and fixing issues caused by modifications owners have done to their cars. Using 11 custom math Histograms to measure and compare the stock tune to what is actually being delivered by the PCM, both on the factory calibrated narrow-band sensors and our Dynojet test gas certified wide band LC-2 sensor, we are able to see that we have eliminated knock at the low end, and increased fuel injector pulse width, while not changing the demanded PE or the ignition timing. More fuel pulse width with the same delivered AFR and no timing pull will equal more HP at the wheels. Surprisingly there are a number of features in the stock PCM not utilized in the original stock tune on this year of the 6.1 Hemi engine.

In the last two weeks, we have made dramatic improvements to our test Charger SRT8. We have data-logged many hours of real road data to look at where the stock tune fell short of what an owner of one of these motors would want from this car. We have already improved throttle response, idle, and max power as well as shift feel on NAG1 Trans Cars, on manual 6 speed Challenger we have also turned off the annoying skip shift mode. The stock tune in this car introduces knock immediately, which is of course hard to get rid of after it’s introduced. Over our many years of tuning engines we know it’s better never to let the motor pull timing due to knock, as once knock in introduced its hard to get rid of it later without pulling spark and increasing fuel, causing loss of power, as demonstrated by this dyno run from our stock Charger taken three years ago, shown below. 

In the Dyno run base-line we did on our factory stock 2006 Charger SRT8 a few years ago on Shell V Power 91 octane premium fuel, we can see that the jagged tuning in the dyno run was in fact due to the knock and timing retard in the stock tune. By measuring and logging what the stock tune is doing, its very easy for us to see what’s going on with the more or less terrible base-line run. Using our HP Tuners software Beta for Dodge, along with our Histograms, we can see that the engine would knock as soon as the throttle was opened up part throttle and into wide open throttle, see the photos below with the base-line run as well as data logged from the ecu showing how knock is pulling timing, causing the saw blade jagged dyno result. That being said, the stock tune did deliver the rated 425 HP for this engine.

I will be posting final dyno runs soon to show how we have corrected this tune issue, and optimized the AFR and Spark to improve the overall tune. Note: This 2006 SRT8 Charger is absolutely dead stock, with no modifications. It even has a stock paper air filter. By cleaning up the tune we have not changed any of the steady state or emissions of the engine so this is a win win as there is no need to make your car not road legal when having it tuned. For cars that are off road or race cars where emissions hardware is not required we can supply custom tuning via the Internet. Or the car can come to our shop.

Finally we are able to Correctly Tune the Modern Chrysler Hemi

Dyno Base Line stock 2006 Charger SRT8 6.1 Hemi

Example of the knock you see at wide open throttle

Example of error in VE causing knock and bad emissions and output

Example of custom math histograms, not actual

One of the jagged maps from the stock tune