Troubling Dyno results for Stock 2006???

[Fast Too]

Originally Posted by Roadrunner

Ouch... if the pressure was 26.5" Hg.... that's only 670torr... sea level would be 760torr. You were lacking nearly 13.4% of available air due to low density. Power should have fallen similarly. Don't know what correction factor was being used at your dyno though.

Looked like SAE on the graph axis headers

[MuscleJunkie]

Here are the files from the two runs the dyno operator sent. If something else is needed - let me know and I'll ask him for it.

Thanks everyone for the help!

[pteam]

ouch that big dip on hp and tq at 4500 seems very concerning. I think something is wrong with the car.

[MuscleJunkie]

Well if you look at the A/F there is a big dump in fuel at that point. I was told there was some knock for some reason at that point and the computer did that in reaction? Not too sure what that means.

Thanks!

[pteam]

Its an 06 so should be still under warranty, I would take it in.

[MuscleJunkie]

Funny you should say that as I took it in to the dealership today and they looked at it and really didn't know of much to say. They said I should talk to some other local Viper owners and get their opinions. They felt that Chrysler wouldn't do anything but that was just an initial thought. They said they could pull the plugs and take a look but that was it for the moment......

[pteam]

Funny how often the board will know more than a dealership

[Fast Too]

Here is another view of your graphs and a text file of the data. It looks like the operator started getting off the car at 5,600 rpm to me, or it peaked there rather than 6,000. I don't have an answer for the torque. Cat going bad maybe looking at the a/f? The humidity was around 20%. I also used STD correction instead of SAE.

[MuscleJunkie]

Originally Posted by Fast Too

Here is another view of your graphs and a text file of the data. It looks like the operator started getting off the car at 5,600 rpm to me, or it peaked there rather than 6,000. I don't have an answer for the torque. Cat going bad maybe looking at the a/f? The humidity was around 20%. I also used STD correction instead of SAE.

Thank You VERY MUCH for taking the time to do this. I am not sure all what I am looking at completely but I appreciate your explanation. I have forwarded the info to the dyno operator and will consult with the dealership and others to see if I might be able to get to the bottom of this and perhaps a find a resolution.

Thank You again!

[MuscleJunkie]

Ok, I sent this info over to the dyno operator and this is what came back.

That feedback really doesn't make any sense.

I don't even know who pulled the car, but trust me, foot was on the floor unless they said something about it. No one uses STD correction anymore. And cat going bad on a new car that's stock? Maybe, I guess. Never seen that happen on any GM vehicle.

Here's what I see: a car that shows quite rich WOT, could be that the computer has added some fuel due to a sensor malfunction, I see that all the time, there's variations in the stock sensors. Also, the appears that the timing is being pulled back in the computer, could be (if it were a GM) a false knock sensor event, a cat overtemp protection event, even torque management (which I know the Dodge trucks have BAD)

What I don't see is any indication that someone lifted their foot (do you know how hard it is to only lift your foot that much, it's hard!) and I find it hard to believe that a cat is going bad. I see the standard stuff that tuning takes care of on these cars.

Crazy. Lifted foot at the same time on 2 runs so that the car peaks early. I've never heard that in 6 years of doing this. And the 03/04's I've dynoed peak a little earlier 5400/5500 than yours at 5600/5700, not later as suggested. Even checked a couple of SRT10 trucks. :-)

So, are the numbers ok? The 03/04 cars seemed to all be a good bit higher, maybe the 06 is supposed to be weaker??

Keep me posted, I'm just buying lifting throttle and bad cat.....

FYI - I was the one who was in the car and I kept my foot in it all the way to redline

[Roadrunner]

If it's the knock system.... run the tank down and get some better fuel. The 2005 and 2006 cars have an active knock system, and will pull up to 8 degrees to prevent knock and engine damage if the fuel is less than real 91 octane.

[Fast Too]

Originally Posted by MuscleJunkie

Ok, I sent this info over to the dyno operator and this is what came back.



FYI - I was the one who was in the car and I kept my foot in it all the way to redline

okay good you kept in it up to red line, but if you look at the data in the text file the car peaks at 5600 and drops off. No matter, something is wrong. You might want to send a pm to Joe Dell (a member here) or Dan Cragin (DC Performance) and send the dyno files in the zip file from your tuner which you posted up for us and get their opinions. They have forgotten more about tuning these cars than we will ever know. Your tuner knows GM cars, but what is his experience with Vipers? Also thought it was funny he didn't know who's foot was on the pedal since it was yours. Anyway good luck. I hope you get it worked out before something bad happens to the car.

[Fast Too]

MuscleJunkie - one other thing, and perhaps this an apple to orange comparison since I am modified but my HP peaks at 6,100 rpm not in the mid 5K's and TQ peaks around 5,300. My car is an 06 coupe.

[adamlotus]

on my 06 above 5000 rpms it felt like it was loosing power like it was it at 5000 rpms.where my 08 just keeps going above 5000 rpms

[MuscleJunkie]

Thanks everyone. I'll send a message to both Joe and Dan and see if they might be able to give some input here.

Thanks again and if anyone else can add anything it is much appreciated.!