Slow Spool and bad boost recovery

Posted by 19BLACKGST98, Jun 2, 2011
Turbo System Tech - 4G63 turbos, Intercooling, Boost Control, Wastegates, etc.

  1. 19BLACKGST98

    19BLACKGST98 Proven Member

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    First off, I have read every thread that has anything to do with slow spool/boost recovery. I think in one of the threads the guy had the same issue as me but he gave up after about 4 pages and I think he just sold the car.

    I have an FP3082HTA and I don't hit full boost till around 4,700 RPM when I should be hitting full boost in the 3,700 RPM range. As much as I hate the late spool I hate the boost recovery even more. When I'm doing a pull I will hit full boost (I have it set to like 21psi right now but normally around 30) and when I shift the boost gauge drops into vacuum real quick then when I hit the gas it will jump up to 10 psi then it will take a 1 1/2 sec to get back up into boost. I have been having this problem for a long time.

    My mod list is current, however I do have ECMlink V3 but I wont be hooking it up at all until tomorrow.

    List of things that have been done and that I know about the issue:
    There are NO BOOST LEAKS.
    Compression is good @ 145, 145, 145, 150
    Leak down test was good.
    I have taken apart the tail 44v wast gate. The valve seat was there and there was no rips in the diaphram.
    We installed a MBC in place of the EBC and it did nothing.
    We have ran WG pressure and the problem is still there.
    We have verified base timing numerous times and even pulled plug one to verify it with true TDC.
    We removed the adj cam gears and replaced them with stock gears because the marks on the adj ones were a little weird.
    We completely removed the exhaust and did a pull like that and it didn't help the problem.
    We blocked off the HKS SSBOV and it didn't fix the problem.
    We checked PSI from the lower intercooler pipe against PSI from the JMF SMIM and it only showed a 2 psi drop during spool up and no difference when in full boost.


    I think that is it but we may have tried more. Any help would be appreciated. I am at the end of the line with this car and this problem. I'm going to try everything in my power to figure this out until July first, after that im tearing it apart and crushing the cursed shell.
    #1
  2. simple jake

    simple jake Proven Member

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    Sounds like a pre-turbo exhaust leak. Check to make sure your exhaust manifold gasket is good, and your manifold to turbo gasket is good. I'm having the same problem with my 16g and i doesn't hit full boost til about 4100 rpm. So I started up the car and ran my hand around the mating surface of the manifold and turbo, and sure enough I could feel a huge leak in the back. Hope this helps.
    #2
  3. 19BLACKGST98

    19BLACKGST98 Proven Member

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    I will give it a try first thing in the morning (if my car wasn't so loud I would go outside right now and try it). I have suggested that to my mechanic once but he said that we would be able to hear a leak if it was bad enough to cause this issue.

    Thanks for the help. Keep the ideas coming :)
    #3
  4. BoostFrenzy

    BoostFrenzy Proven Member

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    Just a question here. Why do you say that you should be spooling 1k rpms earlier? From previous experience where you were spooling there?

    From your mod list, a lot of them slow down spool. From the "large" FMIC with the 3" UICP to the mustang TB that leads into your JMF manifold that is bolted to your ported head with larger cams. Not to mention you are running a GT30 turbine wheel on a 2.0L engine.

    With that aside though....first educated guess goes to pre turbo exhaust leak. Which means you'll have to check quite a few mating surfaces. (Head-manifold, manifold-turbine inlet, where the 44mm WG connects to the turbine and also the wastegate itself). And since the Tial is a modulated exhaust leak, that is where I'd check first. Possibly even swapping it out with another one to see if it makes a difference. And even though you've taken it apart, it still could be the culprit. They all leak anyway, Yours might have just gotten worse.

    Next, I'd say look into the adjustable cam gears. If they were not setup correctly the first time, you could have some bad cam timing.
    #4
  5. Maverick4g63

    Maverick4g63 Proven Member

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    You must have nerve damage or rhino skin! My 16g spools late too and I just replaced my mani/turbo gasket with no improvement. I will be watching this thread closely for more ideas.
    #5
  6. 19BLACKGST98

    19BLACKGST98 Proven Member

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    It seemed easier to answer your questions this way. The responses are in red above.

    Edit: We took the cheepo adj cam gears off because the marks on both sides of the gears were on the peaks (instead of one in the valley one in the peak). When he redid the timing he matched up the marks on the cams together and it lined up with TDC... are you saying that the cams can still be off? If so how and what do we need to do to fix it?
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  7. BoostFrenzy

    BoostFrenzy Proven Member

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    No, if you took the adjustable ones off then they shouldn't be an issue with cams at all now. The FP2's are actually pretty close to dialed in right out of the box from what I remember.

    By chance, do you know the PSI rating on the spring you have in the wastegate? (What PSI was being run while on wastegate pressure only?). I had a similar issue with re-spooling my GT30 because the spring in the wastegate was too soft. I had bought the gate second hand and it turned out to have only a 8lb spring in it which was getting pushed open while trying to achieve my 20PSI setting.
    #7
  8. 19BLACKGST98

    19BLACKGST98 Proven Member

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    Well tonight I dialed in ECMLink V3 and when I was only running WG pressure I was in the 14 - 15psi range. I turned my Greddy profec B II up to 41% which has me running at 22psi.

    I will post a log tomorrow. My car takes 2.4 sec to get from 80 to 100 MPH :(

    Ok Maybe this log will shine some light on my problems. In the 5,500ish RPM range there is a spike in maf raw, boostest and AirFlowPerRev....I'm not sure what its from but my guess is the EBC not being set up 100% correct (like the gain and start boost %'s). Because this didn't happen when using just WG pressure.

    Also why does it take my car so long to gain MPH when it show's that its making power just fine?

    Here is a link with a shift between 2nd gear and 3rd while WOT. 2011.06.3.10


    ***NONE OF THESE PULLS HAD THE METH INJECTION ON***

    Attached Files:

    Last edited by a moderator: Jul 10, 2014
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  9. MY1GDSM

    MY1GDSM Supporting Member

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    Im not on a computer or I'd look at the logs...

    Just guessing but I'd say part of your problem is the weak Wg spring... I had a similar problem years ago running a small spring swapped it out for the strongest spring I could get my hands on an never looked back...
    That's why I asked what spring you had in the other thread.
    #9
  10. 19BLACKGST98

    19BLACKGST98 Proven Member

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    The thing with the wg spring is that I have had 2 springs in the wg that equaled 19psi and I still had this problem.

    Also I would like to add that I plugged up the tail pipe today with the car idleing and couldnt find any pre turbo exhaust leaks.
    #10
  11. MY1GDSM

    MY1GDSM Supporting Member

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    Your Not shifting WOT An Not With Nlts you can clearly see where your off the throttle an the Idle switch is triggered an your off the throttle for almost a full second... in the second log during that same 2-3 shift your also pig rich.

    I would be curious to see how the spool would be In a log with A map sensor logging an Nlts on an Really shifting WOT...
    #11
  12. 19BLACKGST98

    19BLACKGST98 Proven Member

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    I cant use nlts with link yet because I havnt been able to find my soldering pen to instal the clutch cut wire.

    I have my foot to the floor then im letting it off to shift then putting it to the floor. Do you have any idea why it takes so long to get from 80 to 100?

    The 2nd log was earlier in the day so we were still tuning. All of this was done after 2pm yesterday...link was never on the car before this and these were the first to logs ive ever posted. The post me log was the last log we did and it was after midnight.

    I guess I misunder stood the term wot shifting.
    #12
  13. dawid4444

    dawid4444 Proven Member

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    I think your compresion is too low ;/

    It should be 178 psi across the board.
    Thats why your spoll is lil late.
    Just my opinion
    #13
  14. mitsu-luver

    mitsu-luver Proven Member

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    your using a cast manifold with very short runners compared to tubular style manifolds for one (this is not a problem but...) your also running up to 30 psi which is going to take quite a bit of exhaust pressure for the cold side to reach 20-30 psi. your wast gate is probably cracking open on the way to reaching your desired boost pressure. think about how much space there is for the exhaust pulses from head to turbine! theres alot of pressure building up very fast and those pulses want to take the very least path of resistance, thus cracking the waste gate open early slowing down the turbine wheel making your turbo spool up slower. This is the problem with the modern day waste-gate but no one seems to believe me....
    #14
  15. 19BLACKGST98

    19BLACKGST98 Proven Member

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    Ill swap it out with a diffrent one just to be sure. I was going to do that today but family was in town.
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  16. mitsu-luver

    mitsu-luver Proven Member

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    what the manifold? probably could try that see what happens. I wanna know the out come so reply back when you get it done.
    #16
  17. 19BLACKGST98

    19BLACKGST98 Proven Member

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    No I ment the wastegate. I may still have the stock manifold but the tubular I had cracked in a month.
    #17
  18. doesitonall4rs

    doesitonall4rs Proven Member

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    What MBC did you try using? Did it have the tiny tiny vent hole on the line going to the wastegate?
    #18
  19. 19BLACKGST98

    19BLACKGST98 Proven Member

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    It was a hallman with the knob that leads into the car. Ive never owned a mbc so thats all I know.
    #19
  20. PieEyedPiper

    PieEyedPiper DSM Wiseman

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    Do you know how much oil pressure your turbo is seeing?
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  21. 19BLACKGST98

    19BLACKGST98 Proven Member

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    I don't remember off of the top of my head but its what ever amount the black Forced performance oil filter (restricter) allows. I already considered that but it was ruled out when I told about the FP filter inline to the turbo oil feed line. I read many threads about that where someone thought that they were getting to much oil causing there turbo to spool late. Out of all of the ones I read it never actually turned out to be the problem (I was hoping it was mine...but I hope that every problem I read about is mine so I can finally fix it).

    Thanks for the reply. I'm shocked anyone even reads this thread any more.

    This coming Saturday me and a few friends are installing the FP beehive/retainer set and a stock set of 1g cams and seeing how that works out for me. We are also putting the adj cam gears back on.
    Ill update the thread with the results.
    #21
  22. BoostFrenzy

    BoostFrenzy Proven Member

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    I believe you because this happens with ALL wastegates. I've only heard of the Synapse gate not doing this.



    OP: Fix spool problem first. Then add parts to car.
    #22
  23. 19BLACKGST98

    19BLACKGST98 Proven Member

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    Those parts are another attempt to fix the problem. Im in the "throw parts at it till its fixed" phase right now. After this month the car will either run correctly or be parted out...so its now or never. (also its not the WG. Thanks for the reply though)
    #23
  24. Black-Out

    Black-Out Proven Member

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    Your hot housing is a .82 correct? If your hot housing is that big or bigger,on a larger T4 style flange then your housing may be a little too relaxed to promote response....and just geared toward top end flow.....I would think you would need a .63 or .78 to get your spool to drop down 1000 rpm lower....especially if you have an 8.0:1 compression ratio or lower (which with compression numbers under 150 it sounds like you do).......I would'nt strip it just yet...LOL but what I would do is contact your friend with the quicker responding set up thats similar to yours and find out what that hot housing size is because if everything else is good and your not finding restrictions in front of or behind the turbo then it'll more than likely be something directly with the system specification......especially if your getting the power you want....your just not getting it when you want it....

    Hope this helps...I want to keep you in your DSM!
    #24
  25. 19BLACKGST98

    19BLACKGST98 Proven Member

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    Im not sure exactly what size the hotside of the turbo is....its an FP30 turbo (Forced Performance GT30 style turbo FP3052 - FP3065 Forced Performance Turbochargers: DSM FP3052 Ball Bearing Turbocharger ) which to my knowledge all have the same hot side...also I was having this same problem before the turbo was upgrading and it was actually 200 rpm's slower spooling before the upgrade to the 82 HTA wheel.

    These are the differences in mine and his car:
    Mines FWD his is AWD
    Mine has a 75mm Throttle body and his has a 1g Throttle body
    Im sure we have different FMIC
    Mine has a 3" UICP his has a 2.5" UICP
    I have a built bottom end and his is stock
    I have FP2 Cams and he has F4R cams
    I think that's it

    Also my pistons are 8.5:1 and I think the compression is low also (we are changing the cam's/degreeing them, installing the beehive and retainer kit because my friend and others think that they are the reason the compressions low...like having valves open at the wrong times and things like that)

    Just to make sure though I will call the guy with the same turbo and I'll call Forced Performance (or stop by they are 8 miles down the road) and make sure we have the same exhaust side of our turbos.

    Thanks for the help and I hope I get to keep it also.
    #25

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