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Thread: Same problem, but with dyno tape now

  1. #1

    Post Same problem, but with dyno tape now

    I am having a problem with my van falling on its face. It will rev to 7k while in park, but will consistently fall on its face while in boost.
    The first pull I made was at about 8-9 psi. As you can see in the pic (link), it laid over at about 4300-4400 RPM.
    As we cranked up the boost it revved further, but still would only rev to about 5250 RPM before it planed out. The other four (higher in the rev range) pulls were done at 25 psi.

    https://imageshack.com/a/img922/1541/54A9h8.jpg BTW, I tried to put [IMG] and [/IMG] before and after, but it didn't work.


    I have had this problem for quite some time. I remember that I thought it was weak valve springs, so I ordered a set of Mopar 061 springs and a FM 475 cam. I installed them and had the same issue. Additionally, when Mike (at FM) built my short block I sent him my head to go through. So the valve springs have been on the head twice as Mike took it apart to inspect it.
    The cam timing is correct. I verified that (again) today. Also, I had this same problem with an adjustable cam gear and a stock cam gear.
    I have had this same issue using one of Rob's cals and now on Big Stuff.
    I had my wife push the accelerator pedal to the floor to make sure it was opening all the way; it was flat as a board when pressed, so it is good.
    The TV cable is adjusted correctly. At WOT I can reach down to the TV lever and cannot move it any further.
    I may need some fresh eyes on this.

    My set-up:

    FM Enforcer II 2.5 short block

    782 cylinder head- port-matched, standard valves, ARP head studs with Cometic HG, Mopar 061 springs (with new locks and retainers), #4 coolant mod
    FM 475 cam
    750cc injectors
    FM-modified 1-piece intake manifold, 52mm TB
    TurbosUnleashed coated/ported stock Chrysler exhaust manifold
    FM Enforcer II turbo with TurbosUnleashed 3" SV.
    3" exhaust with no muffler or cat. The entire exhaust is about 40" long.

    FM Spearco FMIC
    BIG STUFF 3
    TurbosUnleashed performance a413 (RMVB, Peloquins LSD), I do not know what my final drive is.
    TurbosUnleashed Hughes race converter
    Derale external trans cooler with electric fan
    Holley Blue + Aeromotive A1000 fuel pumps with 1:1 RRR

    Any ideas?

  2. #2
    Supporting Member II Turbo Mopar Contributor tryingbe's Avatar
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    Re: Same problem, but with dyno tape now

    Do you have the actual dyno files?

    What are the torque numbers?

  3. #3

    Re: Same problem, but with dyno tape now

    Yes. I sent you a PM.

    Torque number was 285 at 25 psi.
    Hp number was 285 also at 25 psi.

  4. #4
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Same problem, but with dyno tape now

    What turbo is a FM Enforcer II? I've seen many different specs for the same name turbo over the years.

    - - - Updated - - -

    ETA: In the first file it looks to me like the turbo is spooling way too slow. There should be a lot more pronounced ramp to the boost and therefore HP/torque.

  5. #5
    Supporting Member II Turbo Mopar Contributor tryingbe's Avatar
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    Re: Same problem, but with dyno tape now

    What fuel?
    What plugs?
    What plug gap?
    Got log for boost?
    .48 or .63 turbine housing? I'm guess it is a .63? Stage II turbine wheel?
    Any chamber work done to the cylinder head?
    Why standard valves?
    Why a FM 475 cam?
    Do you have a stock roller cam/rockers?

    Last edited by tryingbe; 09-04-2018 at 11:11 PM.

  6. #6
    Supporting Member Turbo Mopar Contributor A.J.'s Avatar
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    Re: Same problem, but with dyno tape now

    Do a pull with a fuel pressure gauge hooked up. Make sure you ARE getting a 1:1 fuel pressure rise with boost.

  7. #7
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Same problem, but with dyno tape now

    Needs a larger TB maybe?
    Rob M.
    '89 Turbo GTC
    2.5 TIII swap is here!

    Project LookOwt
    '91 Daytona ES, 61k original miles, Rick Lozier's old 3.0 nitrous car
    Back to basics, then the mods go back on....

  8. #8
    boostaholic Turbo Mopar Contributor
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    Re: Same problem, but with dyno tape now

    The injectors should be more than large enough. 750cc's is about 71 lb/hr. That seems a bit excessive for the build. What is your AFR's when it falls flat? You sure it's not going pig rich?

  9. #9
    Hybrid booster
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    Re: Same problem, but with dyno tape now

    When you say it falls n its face, does it miss fire? If it does, tighten the plug gap.
    If no miss fire, verify fuel pressure as it falls off, see if it drops causing a lack of fuel?
    As mentioned, those are pretty big injectors for the set up, maybe it's over fueling after a certain RPM?

  10. #10
    Super Moderator Turbo Mopar Staff contraption22's Avatar
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    Re: Same problem, but with dyno tape now

    Can you post up your fuel and timing maps, as well as your wideband a/f readings from the dyno runs?
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
    Project Log:
    http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=

  11. #11
    turbo addict
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    Re: Same problem, but with dyno tape now

    Quote Originally Posted by contraption22 View Post
    Can you post up your fuel and timing maps, as well as your wideband a/f readings from the dyno runs?
    I concur. That's a pretty big injector.

  12. #12
    boostaholic Turbo Mopar Contributor
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    Re: Same problem, but with dyno tape now

    That's pretty much what I was getting at. A stock valved 2.5, even with port work & manifold work, shouldn't over-tax +40's(52pph), he's running +100's!!! Unless he's running E85, and he didn't mention that...

  13. #13
    boostaholic
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    Re: Same problem, but with dyno tape now

    But whats the downside? I see a lot of low power builds with huge injectors and they seems to do fine.
    MinivanRider

  14. #14
    Super Moderator Turbo Mopar Staff contraption22's Avatar
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    Re: Same problem, but with dyno tape now

    Big Stuff should easily be able to control an injector that size in this application. Even with a well-tuned SMEC I had no trouble running 82lb injectors on an 8v 2.2.
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
    Project Log:
    http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=

  15. #15
    boostaholic Turbo Mopar Contributor
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    Re: Same problem, but with dyno tape now

    Quote Originally Posted by Rrider View Post
    But whats the downside? I see a lot of low power builds with huge injectors and they seems to do fine.
    The only real issue I know you can get into is idle quality. With big injectors, your injector dwell gets so close to your idle PW, it can't open and close the injectors fast enough to have a decent idle.

    Higher RPM's usually aren't an issue. But with the size injector he's running, if he hasn't set up his curve right, he can easily flood it out, even at higher rpms, which is what I was getting at. He needs to post AFR readings when it goes South. My guess is he's going pig rich at higher rpm's. But that's just a guess without data. A good dyno operator should be tracking that, and be able to tell him that..

  16. #16
    Supporting Member II Turbo Mopar Contributor tryingbe's Avatar
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    Re: Same problem, but with dyno tape now

    Quote Originally Posted by 83scamp View Post
    The only real issue I know you can get into is idle quality. With big injectors, your injector dwell gets so close to your idle PW, it can't open and close the injectors fast enough to have a decent idle.
    People that have "idle" issue is usually the one that uses big injectors, lower than stock fuel pressure, and/or an off the shelf "computer".

    The rest of us that actually tune the car have zero idle issue. I had 83lbs injectors with 87 TII LM, idle just fine.

  17. #17
    turbo addict
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    Re: Same problem, but with dyno tape now

    Where's the torque curve? No wideband?

    I wonder if the MAP sensor or something to do with it is messed up? If it free revs up to 7k, but under boost/load it won't and it's done it with 2 different control systems and the hardware all checks out, time to look at sensors and such like that me thinks...

  18. #18
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Same problem, but with dyno tape now

    Yeah I've had 1000cc (95lb) injectors idling decently on a 2.5 before. Even with a ported head, intake, and an F4 cam, it sounded stock at idle.

    When you say "ported matched head", do you mean the port matches the gasket all the way around? Cause if so, that's a big bubble in the intake tract...
    Rob M.
    '89 Turbo GTC
    2.5 TIII swap is here!

    Project LookOwt
    '91 Daytona ES, 61k original miles, Rick Lozier's old 3.0 nitrous car
    Back to basics, then the mods go back on....

  19. #19
    Supporting Member II Turbo Mopar Contributor tryingbe's Avatar
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    Re: Same problem, but with dyno tape now

    Quote Originally Posted by fastasleep View Post
    I am having a problem with my van falling on its face. It will rev to 7k while in park, but will consistently fall on its face while in boost.
    The first pull I made was at about 8-9 psi. As you can see in the pic (link), it laid over at about 4300-4400 RPM.
    The DynoJet's graph looks funny when the X axis is RPM on car with automatic transmission due to torque converter slip. You can see it in Wayne's van too.

    Download the Power Core Software Suite if you want to see his files.
    http://www.dynojet.com/downloads/dow...tware/Firmware
    Wayne's dyno files
    https://drive.google.com/drive/folde...ELz3c4HRq_3ggk
    My dyno files, I have manual 2.2L
    http://www.thelostartof.net/tryingbe...omni248whp.drf
    http://www.thelostartof.net/tryingbe...omni352whp.drf

    RPM as X
    Dark Blue: my 2.2L
    Green: Wayne's 2.5L minivan
    Red/Orange: yours 22/24th runs


    Speed as X
    Dark Blue: my 2.2L done in 4th gear
    Green: Wayne's 2.5L minivan done in 3rd gear
    Red/Orange: yours 22/24th runs. Red in 3rd gear and Orange done in 2nd gear


    Time as X
    Dark Blue: my 2.2L
    Green: Wayne's 2.5L minivan
    Red/Orange: yours 22/24th runs


    Quote Originally Posted by fastasleep View Post
    As we cranked up the boost it revved further, but still would only rev to about 5250 RPM before it planed out.

    Any ideas?
    I think, the "planed out" feeling is due to your stockish cylinder head, especially with a 2.5L .

    782 cylinder head- port-matched, standard valves,
    Unless the engine is misfiring at high RPM, I think the cylinder head just doesn't support the flow at higher RPM.

    Here is couple 2.5L dyno.





    Not to brag, but my 2.2 engine with FM stage III 8 valve big valves head is one of the handful of turbo dodge dyno that I've seen have its peak power after 6000RPM. I searched high and low for those dynos and just can't find those dynos.
    Last edited by tryingbe; 09-06-2018 at 09:02 AM.

  20. #20
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
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    Re: Same problem, but with dyno tape now

    Sorry I've been tied up with trying to get things ready for dragweek and I'm still way behind.

    But after messaging I went back to look, and things made more sense. You have the silver van with the extended roof that just recently raced at a DSM day?
    Your dyno graph as Harry pointed out looks normal for an automatic. When you look a vs RPM, the graph looks weird but that is because of the converter. At that transition where you said it "levels out" that is when the converter is as locked as it will get. All the rpm up to that there is converter slip. (There is still some slip loss even after the "locked" rpm since it is a fluid coupling.)
    So it looks like according to the graph, you are at about a 5200 stall at max boost. I can remember my number exactly but I think it was around that same 5000ish.

    Looking at your dyno vs time will make the graph look a bit more familiar.
    Wayne H.

    '91 Dodge Spirit ES 2.5L turbo 5spd
    '05 PT GT 2.4T HO autostick
    '89 Plymouth Acclaim 2.5L turbo auto, "Slugmobile" yes, THE Slugmobile!
    '89 Dodge Caravan SE 2.5L turbo auto, "Mean Mini" yes, Gus' Mean Mini! (Current best 11.7786@113.04 mph! - Jan 15th, 2017 Fayetteville Dragway, NC)
    MeanMini dragracing videos: https://www.youtube.com/playlist?lis...URZLB1RxGYF6vw
    and other cars, trucks and motorcycles
    https://www.youtube.com/user/SlugmobileMeanMini

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