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Gen V Dyno Pulls with Nitrous!

Discussion in 'Generation V Discussions / SRT Coupe, GTS, GTC, AC' started by Tom Welch, Oct 16, 2013.

  1. Tom Welch

    Tom Welch Enthusiast

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    Hello All,

    Got to the dyno this morning (maybe raining by Friday) and made a few pulls with the nitrous system on my 2013 GTS. First let me say that the car LOVES IT! I was satisfied with the Wheel Torque of 771 Ft/Lbs which equates to 887 Engine Torque.

    The horsepower is not coming up to where it should when the car is on the dyno and I have concluded that this is because the ABS/Stability Control system is interacting by pulling timing and other measures at about the 5000 RPM mark. You can see this clearly on the graphs. Here are some facts....

    1. The first pull of the session is always smooth with a positive and predictable climb in horsepower.

    2. By the time the car slows on the dyno after the first pull, the ABS/Stability Control/ECS System has sensed a failure due to the back wheels going fast but the front wheels not moving and therefore all of the associated idiot lights come on and the traction control button is rendered useless.

    3. Every run after the first pull, whether with or without nitrous then shows the sharp reduction in power at about 5000 RPM along with continued enrichment that is evidenced by the air/fuel ratios shown on the graphs.

    4. NOTE: The torque is NOT affected as peak torque takes place at or before 4000 rpm on all pulls.

    5. I tried different jetting giving a leaner mixture which helped a small amount as evidenced by the 664 hp pull over the 640 hp pull.

    6. I tried also starting the pulls at a higher rpm (this lowered peak torque as expected) in hopes of moving the 5000 RPM anomaly up in rpm also, but this did not seem to help as again at @ 5000 rpm the power went flat.

    7. When this occurs on the dyno I can actually see it in the movement of the tach and hear it in the exhaust tone.

    The GOOD News...on the street (when the stability control/ecs/abs is working normally) the car pulls solidly through every gear. The spark plugs look great and i cannot sense any abnormalities from nitrous use at this point.

    Take a look at the graphs below and feel free to share your thoughts......these are OUR cars and if WE can figure out how to get around some of the tuning issues, at least when using dyno's, we can all benefit from them.

    I hope to go back to the dyno on Friday. My plan will be to NOT use nitrous, but instead make pulls while pulling fuses for the affected systems in hopes of taking these systems out of play. If I can find the correct fuse or system and eliminate it during dyno tuning, the horsepower should return to a more normal and linear output and display as such on the dyno graph.

    Finally, if you have not seen the video of the 13' Viper at Livernois Shop on the dyno, please watch it. Here is a link. What is important to note is during their set up you can see clearly that they pull 1 or 2 of the 4 plugs off of the ECU! I tried this but only got immediate shut off or inability to start the engine. Take a look, you will see them pull these in the beginning of the video. I have tried to reach out to Erich and Dick with no response.

    http://www.youtube.com/watch?v=ZrTyJXIyeEY

    WELL......I AM UNABLE TO UPLOAD THE DYNO GRAPHS......SYSTEM SAYS I HAVE EXCEEDED MY QUOTA?? WHAT DOES THIS MEAN?
     
  2. ACRucrazy

    ACRucrazy Enthusiast

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    Enthusiast limits?
     
  3. TrackAire

    TrackAire Viper Owner

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    Congrats on breaking new ground!!

    Is there such a thing as a 4 wheel dyno that works on a RWD car so the fronts are spinning the same mph as the rears? Too bad the stability control fuse can't be pulled for these dyno runs. Keep up the good work, can't wait to see what you end up with.

    Cheers,
    George
     
  4. Tom Welch

    Tom Welch Enthusiast

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    Enthusiast? Check my join date......

    I have been a member and supporter and Dodge Viper owner since before this website was in existence. Useless banter and heckling is why I refrain from posting here, but after thousands of dollars and countless hours of my personal time invested in trying to help the Gen V community realize some possibility of gains, and working together towards a common goal of overcoming dyno tuning issues, it remains apparent that a nickel continues to hold up a dollar. No wonder this club is failing!

    Yes, there is such a thing as a 4WD dyno but the 2nd drum will not turn without being driven by the vehicle wheels to the best of my knowledge.

    Anyone interested in reviewing the dyno sheets feel free to PM me.

    Thanks,

    Tom
     
  5. Nine Ball

    Nine Ball Enthusiast

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    email a copy to me at Tony(at)DV8motoring.com and I'll host/post it for you.
     
  6. ACRucrazy

    ACRucrazy Enthusiast

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    I knew your join date. I was not heckling or posting useless banter. I don't have your answer, but rather trying to offer a helpful suggestion to your question of maybe why you were getting that error?
    You are an "Enthusiast" according to VCA. If you don't like it, bring it up with them, not me.
    "Enthusiasts" have different limits than "Members" for whatever reason..
     
  7. Tom Welch

    Tom Welch Enthusiast

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    Tony,

    Thanks, I emailed them to you.

    ACR...Thanks for your reply. Your post was ambiguous which led to my reply, which of course was not...LOL....I apologize.

    Has anyone dynoed a Gen V Viper that wishes to share their pulls? Did anyone have this same experience whereas the first pull was clean and linear, followed by
    stability control/ECS/ABS failure lights and subsequent horsepower fluctuations?

    I had wondered if in the video that the engineers made on the dyno, they unplugged and replugged those ECU plugs in an effort to "reset" the stability control and ABS/ECS between pulls, but I still can't get an answer. One thing for sure, once I figure out how to disable or reset those systems (without unloading the car from the dyno and driving it forward 50 feet), this car will make well over 700 Rear Wheel Horsepower on the dyno.
     
  8. Nine Ball

    Nine Ball Enthusiast

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    Here ya go:

    [​IMG]

    [​IMG]

    [​IMG]
     
  9. Tom Welch

    Tom Welch Enthusiast

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    Thank you very much, Tony.

    If we look at the middle sheet it is a comparison of the very first pull of the session and a subsequent pull. On the first pull (RED COLOR) the computer has NOT sensed any abnormalities and the graph looks clean and linear (in this case the 539 RWHP pull), but after the first pull the computer has recognized that the back wheels moving and the front wheels not...LOL so it lights up the ABS/ECS/Stability and TPMS lights and deactivates the ECS button on the steering wheel. I feel certain that this is the reason why all subsequent pulls (BLUE COLOR on middle pictured graph) have the abnormal, flattened horsepower curve, and therefore the peak horsepower is reduced by means of computer interaction (as evidenced in all subsequent pulls shown).

    The good news is that it is easy to see if the computer did not interfere, every pull on nitrous would be well over 700 RWHP as a linear horsepower graph similar to the first pull (RED COLOR 539 RWHP) would be predictable.
     
  10. FLL-B/W-GTS

    FLL-B/W-GTS Viper Owner

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    Get that car to the drag strip......
     
  11. ViperSmith

    ViperSmith Enthusiast

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    that torque is just staggering
     
  12. Getnlwr

    Getnlwr Viper Owner

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    Holy crap. That's just insane. Mind numbingly insane.
     
  13. eucharistos

    eucharistos Viper Owner

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    man-o-man :omg:

    outstanding :2tu:

    thanks
     
  14. Jack B

    Jack B Enthusiast

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    Tom

    did you run the car with the ESC totally off?
     
  15. 345s-bspinnin

    345s-bspinnin Viper Owner

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    Was the wide band after the catalytic converts? On the N/A run, I am surprised that the A/F dips well into low 12's and high 11s A/F on anything past 5k rpm. Besides that, that shot of nitrous is certainly fattening those hp/tq curves.
     
  16. Tom Welch

    Tom Welch Enthusiast

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    Jack,

    Yes, I turned it all the way off (held 5 seconds) before the first pull and then could not do anything with it after that.

    Yes, the wide band was after the cats. That is the problem. At @ 5000 RPM something is taking charge in the computer and probably pulling timing and adding fuel and who knows what else in an attempt to reduce power for some reason......then after a few hundred rpms of this, the power comes back on....but it's too late and the fuel enrichment can't compensate quick enough before the pull is finished. On the street the car behaves normally, pulling hard all the way through each gear. I am confident that the ECS/ABS system is causing this anomaly after the first dyno pull as the first dyno pull is the only clean and linear pull with no idiot lights glaring from the dash.
     
  17. Jack B

    Jack B Enthusiast

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    Tom

    Take your scan tool along and read the code and remove it.
     
  18. Tom Welch

    Tom Welch Enthusiast

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    now thats an interesting point! If this rain quits, I will bring that with me when I go back tomorrow.

    Thanks Jack.
     
  19. mnc2886

    mnc2886 Enthusiast

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    Please video!!!!
     
  20. Tom Welch

    Tom Welch Enthusiast

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    I have a short video of one of the nitrous pulls from yesterday....but will have to send to someone to post for me.

    Will take more tomorrow if all goes well.
     
  21. KB Viper

    KB Viper Viper Owner

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    amazing gains. i'm tuned in!
     
  22. Jack B

    Jack B Enthusiast

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    Tom

    They pulled them and waited a few seconds, then, reconnected them. That is pretty common on gm cars to get rid of the limp mode. Keep im mind you will not see these protective codes in the dashboard diagnostics screen, you need a scan tool.

    What was your bottle pressure?
     
  23. ROCKET62

    ROCKET62 Has Left the Room!

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    Nice! It does seem odd that no one else has has the same problem with the Dyno though???
     
  24. Jack B

    Jack B Enthusiast

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    When Tom uses the scan tool we will learn what code was set, it may not be ESC. If you watch the SRT dyno pull that was posted, SRT definitely pulled two PCM connecters, they either having problems or were trying to avoid them.


     
  25. Fatboy 18

    Fatboy 18 Viper Owner

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    I just wanted to say that I'm in ore of you guys that purchase a new Viper then start modding them straight away, you guys are on a whole different level.

    Well done :hail: :hail: :hail: :hail:

    So I guess your dealership warranty's go straight out the window?
     
  26. Tom Welch

    Tom Welch Enthusiast

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    Rocket....

    I think other tuners ARE having the same problems on the dyno...they are just not coming forward with it. My BONE STOCK Viper does the same wacky dyno curve even without nitrous.....but ONLY after the first pull because after the first pull all the ECS/ABS idiot lights come on.

    I wish there wasn't such a veil of secrecy on this....I have taken the high road here and stepped forward to discuss these issues in an effort to solve this simple problem.....but I have a feeling some folks just don't want to see a $ 1200.00 nitrous kit make as much horsepower as a $ 40000.00 forced air kit.....but I could be wrong and hope that I am!

    Jack,

    Its raining today so I could not make it back down to the dyno shop and tomorrow morning I leave for Hong Kong for 2 weeks. I will get back on the dyno when I return but i am thinking that those particular events do NOT set codes....but I will check with the scan tool that I have.....and i will also UNPLUG and then PLUG back in again all (4) of the PCM Plugs immediately after the first pull when the ABS lights come on.....will see if that works.

    Further, I have a photo of them actually unplugging the terminals from the ECU.....but of course I cannot post it here.....so here is a link for anyone who wishes to see it for themselves. This photo is part of the video that SRT made of a Viper on the Livernois Dyno in Michigan.

    https://www.google.com/search?q=2013+viper+on+dyno&source=lnms&tbm=isch&sa=X&ei=H0ZhUvzXJ4TW9ATI2YCgDA&ved=0CAcQ_AUoAQ&biw=1362&bih=778#facrc=_&imgdii=_&imgrc=THv8LN3yKmhGzM%3A%3BdmfAnOJ37h27kM%3Bhttp%3A%2F%2Fwww.drivesrt.com%2Fnews%2Fwp-content%2Fuploads%2F2013%2F06%2FDyno-Test-3.jpg%3Bhttp%3A%2F%2Fwww.drivesrt.com%2Fnews%2F2013%2F06%2Ftesting-the-limits-2013-srt-viper-power-output-is-tested-on-a-chassis-dyno.html%3B1717%3B967


     
    Last edited: Oct 18, 2013
  27. TrackAire

    TrackAire Viper Owner

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    Tom,

    What effect do you think this has at the drag strip when the driver heats up the rear tires buy locking up the fronts and spinning the rears to get heat into them?....does the PCM (or some stability sensor) sense the same thing you are experiencing on the dyno and goes into that " timing limp" mode for the first part of the run until the computer figures out both axles are turning at the same speed?

    Last question, do you think the front axle has to spin at the same mph as the rear as to not go into the "timing limp" mode? It might be interesting to see if spinning the fronts at 10 mph is enough to fool the computer into thinking all is good even though the rears are going over 100 mph. If a slow front rpm is all that is needed, it might be easy to rig up some sort of electric motor with a friction roller to spin the fronts slowly on a 4 wheel dyno. I wonder if the computer is reading both front tires or just one of them? Just a thought. It sure would be nice to have some SRT engineering support regarding this so you can eliminate wasted time.

    Cheers,
    George
     
  28. Jack B

    Jack B Enthusiast

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    Good question, here is one more, why is this happening with ESC turned off.

    Due to rear brake bias the burn-out is no longer as easy as the earlier cars.

     
    Last edited: Oct 18, 2013
  29. TrackAire

    TrackAire Viper Owner

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    Tom,

    Don't know if this helps, but on the Gen 4 if you try to left foot brake while trying to accelerate (like on a road course) the car goes into a limp mode power-wise. Makes me wonder if the issue is not actual front/rear speed differential but if the computer is seeing the front tires not moving and puts out a code that the front brakes are on causing the power reduction.

    Instead of the ecs being the issue, I wonder if it is possible to start pulling abs fuses, etc and see what happens.

    Good luck,
    George
     
  30. Tom Welch

    Tom Welch Enthusiast

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    Hi George,

    Based only upon my trial and error, i think that the ABS/ECS/Stability control issue is defaulted to a higher speed as just running the car momentarily on the dyno to check for truing and strap adjustment in 1st or 2nd gear isnt enough to trigger a fault in one of those systems. Certainly though as the car spins down after the first full throttle 4th gear pull, the issue arises and causes the lights to come on in the dash and then the ECS button is deactivated. I have not had this car to the track yet to try a water burnout...but even then I would only do that in 1st gear as the tires dont need to get hot.

    An interesting note also, if you lift the hood and look carefully at the right front spindle you will see a sprocket (maybe on the left front wheel also) and surely that is driving sensors that are tied to the above referenced systems. The car performs flawlessly driving down the road so Im sure it will do fine on the track. It's only the system trying to be smart and kill power or at a minimum disrupt power based upon the back wheels moving at some MPH or RPM while the front wheels are stationary. If I was an ABS computer, it would fool the hell out of me also...LOL. There must be a way to disable this, and i hope to find it the next time i go to the dyno. That will be my only mission on the next trip....disable the culprit before making any further pulls on Nitrous or Stock for that matter.

    One other note, the rear brake rotors have a second caliper which is also part of the ABS/ECS/Stability system and that could also be pulling power during these pulls by engaging braking.....what ever happened to the days of go fast without all the "big brother" computer gadgetry working against us?

    Heck next thing to happen will be the U-Connect voice command putting the car in limp mode if it hears the "N" Word, or the engine won't start if a bottle of Vodka is noticed in the cabin from the liquor store, or even it goes into the "limp" mode and the computer finds the word "limp" to be offensive and derogatory towards such a manly automobile and just blows the car up in the parking lot......LOL....wholy ****e!!!
     
    Last edited: Oct 18, 2013

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