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With a mass airflow system, the computer will retune the car itself with performance mods. Our motors air speed density (surprizingly old school techno) and performance gains from aftermarket parts will give increases, but before and after dynoes done on the same day will probably offer no performance gains, as seen by testing several CAI back to back and seeing no results on the dyno. Speed density works off of baseline preprograms, and are slow to adjust to changes. Just like when I used to do performance mods on my 88 mustang, which was the last year mustangs used speed density, it was limited to how much you can add power before the computer could not compensate any more, and results from cai, catback, headers was about the limit, and it would take an honest week of driving for the car to compensate. I have done a few dynoes in the past to show the differences. About 25 to 35 hp was the limit on a stock computer.

Custom done chips were the norm, and required to do any real modifications on those systems. For 89 and above, MAF was the ford way to go, and could handle all modificaitions done, up to 398hp on the computer, before custom tunning was done. This was a big selling point for the mustang, cause they were at the time easier to mod and get good gains then the main competition could offer(CHEVY). I have dynoed my car and saw 300 hp at the rears with just a cai, and catback, and Jet chip, my car feels faster from me and every friend that has driven it, especially after the chip! I see stock dynoes in the 260 to 270hp range, so either I got a good motor, or my mods made a difference.

I was surprized to see that no comments were made about the speed density before when they did that back to back CAI tests with like 6 systems. Just like Jet has a chip for stock, then a stage 2 chip for CAI, and Catback mods. Custom tuning or chips are absolutely going to be the required solution for our cars in the future, if Chrysler does not choose to use MAF again. Look at all the supercharger companies that have given a pass on the new Hemi, cause they really needed a company that could crack the computer and work with the old style of speed density programming to keep from blowing up the motors. This is why GSmotorsports is the only supercharger company to offer this, they have been working on chrysler trucks and cars for years and is probably the only company that has the skill to do the required computer tunning, hell even in Hot Rod magazine this month on page 138, they stated that Paxton gave up and handed the project over to GS, to see if they could crack the programming problem, with a exclusivity claim if they could.

Our cars will be limited to what can be done before the computer will trip and start dropping codes, cause there is only a small parameter in there to allow for variations of motors, climates, altitudes, that all these different cars will have to work through. You guys know they test the hell out of products, and drive in all different environments to get the cars to run great out the box, but they always leave room for improvements, it's just that we are limited in our mods without tunning for each application. It is almost like a step back for Chrysler to choose to use this older system, compared to MAF that has been out for 20 years in common use.

So don't fret, buy your mods, you will get gains, maybe not as much as you would like, and maybe not immediate, but there will be gains.

More effecient, IS more effecient!

I use my Wrangler Jeep to compare cause this is a speed density system also, and I have run into the same questions from that crowd. There are a lot of mods out there for the 4.0 motor, but a lot of people complain that there is little gain with the modifications, and a lot of guys trip the computer when they move to headers. If you research wrangler modifications you will see a lot of package deals, like intake, throttle body and new computer! These guys are getting great gains from just an intake and larger throttle body, cause it comes with reprogrammed parameters for the new performance parts. Kind of expensive but pretty much necesarry!

Contacting and talking to tech support from Jet, they are going to make a hand held programmer for our cars also, that will ask what mods you have done for the best programms for your vehicle. Headers will require the Jet Stage 3 chip, if you do not want the ability to program the tranny and play with the torque managment. This pretty much all leads to just longer times for performance mods, but with such a strong package like our cars, we will see plenty of mods to come and go for our cars!
 

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Nice write-up.

There was a lot of discussion about Speed Density before the CAI test. That was a major factor in the test and one of the reasons for resetting the computer between each test (which I think turned out to further confuse the results)
I did my own intake test. Before the CAI Basically 2 runs with the stock filter and 2 runs with no filter or airbox, just the elbow hose unhooked from the air box.
I got solid gains.
my dyno results

Here was my theory on the cold air intake test. I still contend that the test did prove what intake was less restrictive.
My theory
A commonly referenced article link

Here is an interesting read from a little over a year ago.
old thread

I am planning to repeat my Magnum dyno test with my Charger. But with the twist of the GSM torque management delete On/Off. I also will have results after I install the header I ordered. My brother will hopfully have his Charger at the dyno shop on the same day.
We shall see.
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why is everyone dynoing in 3rd gear?

this was a big problem with the 2005 mustangs with the 5 speed auto, unless 3rd gear is 1:1 ratio in the transmission, you are getting tainted results, 3rd gear pulls in 4 speeds auto were done because 3rd gear was 1:1.


gains posted with 3rd gear pulls are essentially worthless, when 3rd gear isnt 1:1

these pulls need to be made in 4th gear in the chargers.


:twocents:
 

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bstowers said:
I believe 4th gear is our 1:1 ratio, isn't it?



yup, and 4th gear would be the gear that the dyno's need to be run in, if your gonna dyno in 3rd instead of 4th, might as well dyno in first and make 7000ftlbs lol
 

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But this car might have some cool mods not possible with other cars as well...

Since the throttle and shifting is computer controlled imagine having a pre-programmed sequence for 1/4 mile runs. Once we get consumable devices that can speak on the CAN bus or the proprietary PCM/TCM bus, then WOT could effectively be "take of the best known, tested, tire traction and accelleration". That would be cool... and illegal at some track events ;-)

Crack the stability program communications and drift or donut in ANY way you see fit...not just by raw mechanics of an out of control rear end, but using the brakes and throttle to CREATE instability... All preprogrammed.

Sounds cool to me.
 

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HEMIRT said:
why is everyone dynoing in 3rd gear?

this was a big problem with the 2005 mustangs with the 5 speed auto, unless 3rd gear is 1:1 ratio in the transmission, you are getting tainted results, 3rd gear pulls in 4 speeds auto were done because 3rd gear was 1:1.


gains posted with 3rd gear pulls are essentially worthless, when 3rd gear isnt 1:1

these pulls need to be made in 4th gear in the chargers.


:twocents:
The 2005 models would not stay in 4th gear if you are under 3500 rpm, and you will hit the speed limiter before you get to 5000rpm.
Now luck us that ordered the performance group, we should be able to hold 4th gear to it's shift point. That's why I will be Dynoing my charger in 4th.
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Discussion Starter #8
A few of the dynoes adapt to this also, you just have to tell the computer that it is running in 3rd gear when peforming the test. The dyno takes the numbers into account. A lot of vehicles are speed limited in 4th gear!
 

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As far as the Dyno is concerned, it doesn't matter what gear you?re in.
Why would it?
Do you have to enter rear-end ratio's when dynoing?

Third will most likely cause the trans to scavenge more power than forth, only because of the extra rotating mass.
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