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Thread: Very dissapointing dyno on a gt42/supra :(

  1. #1
    NSW supra club Member
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    Very dissapointing dyno on a gt42/supra :(

    Hey guys,
    just had a dyno tune and honestly, all i can say is im very dissapointed in the power readings
    Its a jza80 supra, converted to a single turbo, garrett gt42(74mm), has all the fuel(850cc inj) /pump/fmic ect and running e11 haltech.
    Engine is totaly stock.
    Now, being that i run a haltech, i thought i would use Matt/hitman to tune it.
    Well, the results are:
    at 19psi = 306KW/410hp.
    at 25psi = 324KW/434hp (spraying meth/water on that run.
    as you might be able to see, there looks to be something wrong! as far as i know, people with such a turbo are making a lot more power then me, and some are making more power with less boost as well as smaller turbo's(like gt35/40 or to4z).Matt showed me some graph's of similar supras with teh smaller turbos making over 500hp+ on less boost.
    AFR was around the 12.0:1 and there was no obvious problems that we could see/tell!
    i was expecting to see close to 400kw without spraying meth/water

    Can anyone see a reason for such a low power? motor pulls strong/compression is fine.
    Matt was saying that the cams are not allowing it to breath! but i for one know of another supra owner from teh club that has ran over 400kw on stock cams, and on teh smaller t72 turbo, and a few other members with a to4z on stock cams making around 350kw, again, on lower boost.

    Ive added a dyno sheet of the ~25psi run
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  2. #2
    weirdo F|sh's Avatar
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    headwork different cams? different dyno fudge packing rating?
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  3. #3
    Registered User Dansedgli's Avatar
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    Thats very strange.

    Hows your exhaust? Blocked cat?

    Auto vs manual figures? Hows your spark?

  4. #4
    Registered User Rz's Avatar
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    yes very poor numbers.
    i noticed you have a pretty small downpipe for a turbo that size.
    whats the rest of your exhaust comprise of ?

  5. #5
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    Maybe the smaller turbos work OK with the stock cams, and the large turbo is sort of incompatible because it comes on strong at high RPM where the stock cams are out of their efficiency?
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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  6. #6
    Registered User Rz's Avatar
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    his camshafts would be taxing it bigtime , but it should still do better than that on stockers.
    272 that bitch as soon as your onto this problem mazman , stick the limiter at 8k and happy days

  7. #7
    NSW supra club Member
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    to answer some of the questions...

    1.The exhaust is 3" completely all the way, from turbo to back. Has a custom made 3" dump, then a blitz nur spec r cat back all the way, wich has a resonator and 1 muffler at rear.
    2.The cat is not restrictive, as there isnt any.
    3.there was no issues with the spark either, nothing showing up and not braking up. Using new coils and have hks dli. plugs gaped at .7mm
    4. car is a 6sp manual, so should show even better numbers.
    5. mates that i know of with more power, dont have headwork or cams, and like mentioned, have even smaller turbos.
    6.2jzr31, that is exactly what the tuner/matt was going on about, but i find it very hard to believe! it still shoudl be pulling much better then teh smaller turbos i would of thought!

    Next on my list would be to put a 4" dump and see what it does.
    If you remember, i had an issue with the cat, where i couldnt go beyond 15psi and boost would apply after 6K rpm, and solved the issue by removing the cat, so maybe the exhuast is restrictive? but i still dont see why i would of had less power even with the smaller exh!
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  8. #8
    Now with more ebay parts. 2JZR31's Avatar
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    6.2jzr31, that is exactly what the tuner/matt was going on about, but i find it very hard to believe! it still shoudl be pulling much better then teh smaller turbos i would of thought!
    What RPM are the guys with smaller turbos making peak power? What RPM did you make peak power? Maybe the smaller turbos allow a good hit of boost lower in the RPM range where the cams are still efficient and yours is only generating boost way after the cams loose efficiency. This is my crackpot theory. And in actual fact there is probably just a minor prob like a boost leak

    Is 8K ok for a stock 2JZ? Or is yours built MAZMAN?
    Last edited by 2JZR31; 12-07-06 at 08:43 PM.
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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  9. #9
    Registered User Rz's Avatar
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    8k is accepted as safe on a stock motor.
    mine has gone 20,000 kms so far without issue , with plenty of excursions to redline.

  10. #10
    Registered User Emre's Avatar
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    Something is definitely choking it up the top end.
    Could be the exhaust or the intake. I'd say 3 inch should be taxing but sufficient.
    A mate had a problem with the rubber intake pipe collapsing at similar power, another one had an issue with restrictive pods, but at a higher power level.
    Last edited by Emre; 13-07-06 at 01:36 AM.

  11. #11
    Registered User out_in_front's Avatar
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    Have you got any pics of the setup? How is the intake setup? maybe boost leak somwhere?

    How does it feel to drive and have you taken it down the quater yet? would be interesting to see if some of it was just due to dyno settings (doubt much of it would be though, due to the top end of that graph)

  12. #12
    2jz crank bolt ftl pH@tTm@N's Avatar
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    as a comparo

    haltech e11 on my supra, similar but I have hks 264 cams, to4r but with 70mm comp wheel, results 411hp @ 15psi

    But there is a story too, at 20psi it only made another 30hp or so - IE - it stopped making relatively easy power. Now I have a fairly cheapo cat - havent ruled that out yet. But it was suggested that the old valve springs might be allowing valve float with increased cylinder pressures.

    EDIT: Also according to some, the supra factory ecu typically runs lots of ignition advance - but I think hitman would have covered that for you. Also remember, US spec inlet cam is bigger than jap spec if you are comparing to them, meaning also that Jap spec cams become the bottleneck VERY quickly.
    Last edited by pH@tTm@N; 13-07-06 at 12:06 PM.

  13. #13
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    Was it ran with the airfiler off? Some filters suck themselves in and block off slightly on high boost.

    Best way to check exhaust is drop it completely, if it makes a huge improvement you know you wont be wasting money on a new one. This is of course if the noise isn't going to be a problem.

  14. #14
    Nay sayer Mr Ed's Avatar
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    Yeah I would have thought uber-retarded ignition timing, but if youve got a Haltect and a good tuner this shouldnt be happening.

    Silly question: Was he in the right gear?? (4th)
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    Registered User 260BC's Avatar
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    What hp does yours do Rz?

    Cam timing for the problem, a tooth out????
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    Brobdingnagian Member Mighty Mouse's Avatar
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    Quote Originally Posted by 260DET
    What hp does yours do Rz?

    Cam timing for the problem, a tooth out????
    Problem is the power band is quite nice until the top end, where as you can see on the graph, it just flattens right out.

    2nd call for check air filter and or ducting to the turbo.
    It looks like it is seriously hitting a brick wall in terms of air flow somewhere.

  17. #17
    Registered User Rz's Avatar
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    ive done 702 rwhp at 27.5 psi , mazman's setup should do at least that on 25 ... once those girly stock cams get das-boot

  18. #18
    Now with more ebay parts. 2JZR31's Avatar
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    8k is accepted as safe on a stock motor.
    mine has gone 20,000 kms so far without issue , with plenty of excursions to redline.
    ive done 702 rwhp at 27.5 psi
    Am I reading this wrong or do you have you made 702 rwhp on a stock bottom end?
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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  19. #19
    Registered User Rz's Avatar
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    yes.
    a testament to how good these motors are.

  20. #20
    Now with more ebay parts. 2JZR31's Avatar
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    FUCK ME DEAD! SWEET! I knew I picked a 2JZ for good reason over the RB's, but that is amazing. I have heard most people say the 2J will do 8K but its pretty dangerous and its a bit of a time bomb at those RPM. Even to complete one run at that power level without blowing up is amazing for a stock 3 liter engine bottom end. How much power do you run on what you consider to be a safe street tune on pump fuel?

    Sorry for the hijack MAZMAN.
    10.83 @ 125

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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  21. #21
    BLING BLING PLAYA's Avatar
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    definatly check cam timing my rb26 dropped power top end exhaust cam was keeping all the gasses in, also drop the exhaust just to check its not that.
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  22. #22
    Registered User Rz's Avatar
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    i stopped using straight pump fuel at 500 rwhp , or thereabouts.
    i use ultimate and toluene , 70/30 % , with some oil mixed in.
    a 2j under 8k is as safe as houses , dont believe what your average joe tells you , most the time they have NFI
    the americans/japs have been thrashing these motors to within inches of their lives for 10 years now , theres nothing that hasnt been tried

  23. #23
    NSW supra club Member
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    thanks for all the idea's and some suggestions, i will be taking them into consideration and checking it out this coming weekend.

    some questions to answer to some of you :
    1). i have attached a picture of my setup, so have a look and im sure you will see that there should not be any resrictions in that.
    2). I have ran it with the filter ON. it is a K&N pod inside a cold air box. If there was a air flow restriction, wouldnt teh fuel mixture sky rocket towards rich??? no air = way too much fuel!
    3). car feels very good on teh street, wich is what suprises me that i have such low power! just by driving it i cannot tell that there is any problems evident.
    4). boost stays steady throughout the whole rev range, usually with boost leak, i will see a drop or it wont even reach high boost levels. I have previously checked for boost leaks when i made another thread about my problems, wich was the cat. and it does not have any leaks.
    5). I will check my cam timing on the weekend, but surely my idle and cruise would suffer?.. ill let you know how i go with that on teh weekend. I have changed the timing belt about 30k-40k ago, and back then it was spot on.
    6). I havent check what kind of ignition timing hitman/matt has put into the ecu yet! i will do this as well on teh weekend just to double check and see if he has not retarded the thing too much, i doubt he has as im pretty sure he should know what he is doing!
    7). i dont know if ill be able to drop the whole exhaust in my area, the attention would be way too much and there is nowhere near my area i could sneak out and test it out i however might try making a 4" dump pipe as this will cost me the least amount of $$$ and see if i notice improvement.

    RZ- have you had your setup ever run on the stock jdm cams? if so, was it also this restrictive?
    i somehow cannot see how a set of 272 cams would allow me an extra 300hp+ at the rear wheels, that sounds way too much, i could understand if i gained 50-80hp or so... but 300hp?! if this is the culprit, then i will have no problems in putting in a set of 272's...

    I really had high hopes from this turbo i hope that i can still gain that hope.
    Last edited by MAZMAN; 13-07-06 at 07:43 PM.
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  24. #24
    NSW supra club Member
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    Quote Originally Posted by Sir_2jza70
    Silly question: Was he in the right gear?? (4th)
    Buddy, this question got me thinking...

    what if he(matt) was in 6th gear thinking he was in 4th, as the 6th gear is also downwards...
    now, a 6th gear on a dyno.. ive heard dyno's have a speed limiter of some kind? if this is true, could it be that teh speed limiter was reached in 6th gear, and thats when the flat curve started happening? and dyno didnt let it go any higher...and thast why the flat curve on such a low RPM!!!
    just a thought? any dyno operators in here, can anyone answer regarding dyno speeds/limiter? ect...
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  25. #25
    Now with more ebay parts. 2JZR31's Avatar
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    Dont stress. Check this out. The GT42 owns all... well it beat the T74 by 1rwkw and shit all over the other turbos you said might beat yours. Both on 25 psi, both with 272 cams the T74 was on a 1.5JZ. The GT42 seems to have a meatier powerband too. I am pretty sure these were all done on a dyno day so are a good comparison (same dyno same conditions etc)

    Last edited by 2JZR31; 13-07-06 at 08:25 PM.
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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  26. #26
    Registered User Rz's Avatar
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    431 fuy happens to be my car.
    i have a gt42r , with the 67mm wheel.
    mazman , what are your exact turbo specs ?

  27. #27
    Now with more ebay parts. 2JZR31's Avatar
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    Sweet What is your name on the Supra forum? Hows the lag on that big mofo?
    10.83 @ 125

    Quickest stock exhaust manifold stud 2JZ in Aus.


    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  28. #28
    Registered User Rz's Avatar
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    i dont frequent supra forums , it hurts my brain.
    im old , and all i see there are tossers.
    lag , well no real action to 5k , but you quickly get used to it.

  29. #29
    Now with more ebay parts. 2JZR31's Avatar
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    dont frequent supra forums , it hurts my brain.
    im old , and all i see there are tossers.
    Man I totally hear you. I started going there for 2JZ specific info and the amount of bullshit you have to wade through to get real answers is close to intolerable. Most of my time there is spent answering questions, then arguing with other people with no idea who will give the wrong answers to some poor sod that will then waste more money on shit he doesn't need to, or blows something up. Sometimes I don't know why I bother....

    5K isn't too bad if you have a 8K redline. I'm sure its worth the wait.
    Last edited by 2JZR31; 13-07-06 at 08:50 PM.
    10.83 @ 125

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    Quote Originally Posted by cracka View Post
    Some conclusions empirically were that a large protruding ridge like a prolapsed arsehole around the runner was largely beneficial.

  30. #30
    NSW supra club Member
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    RZ- mine is the bigger garrett gt4202 spec turbo, wich is the ~74mm wheel inducer and 102mm exducer.
    1.05 a/r ta45 housing modded.

    when i see those two graphs from teh gt42 and teh t74... all i can say is, i cant wait for mine to do similar
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