Page 1 of 4 1234 LastLast
Results 1 to 20 of 77

Thread: Car slow to build boost, won't go past 10 pounds

  1. #1
    boostaholic
    Join Date
    Dec 2005
    Location
    South Side Indy
    Posts
    1,221

    Car slow to build boost, won't go past 10 pounds

    Was making 20 pounds....then started going down to around 14, then won't go over 10. Maxed out the boost controller and managed to get around 12 and went back down to around 10.....then removed the boost controller and left the wastegate disconnected...only 10 pounds. No obvious boost leaks...no loud wooshing or anything. When you floor it, it takes a while for boost to come on. No obvious intercooler pipes off...all couplers are tight and look good. I'd think that a large enough of a boost leak to only give me 10 pounds when the can is disconnected would have a pretty obvious culprit.
    Car is a 2.5 with Buick GN turbo and 3 core FMIC.

  2. #2
    turbo addict
    Join Date
    Aug 2009
    Location
    Myrtle Beach, SC
    Posts
    2,133

    Re: Car slow to build boost, won't go past 10 pounds

    Curious what you find because my buddy built a turbo 5.0 mustang and his car wont build any meaningful boost either. I tested the wastegate using regulated air and it opened when it was supposed to. Our next step was to block off the BOV to make sure it's not leaking.

  3. #3
    turbo addict
    Join Date
    Dec 2005
    Location
    Mesa, AZ
    Posts
    7,351

    Re: Car slow to build boost, won't go past 10 pounds

    Leaking BOV/CBV, damage compressor wheel, c-clip came off at the wastegate lever, etc

  4. #4
    turbo addict
    Join Date
    Dec 2011
    Location
    Hemet,CA
    Posts
    1,636

    Re: Car slow to build boost, won't go past 10 pounds


  5. #5
    turbo addict
    Join Date
    Dec 2005
    Location
    WI
    Posts
    1,565

    Re: Car slow to build boost, won't go past 10 pounds

    Homebrew IC? Might be a PITA but pressure test in a water tank.

  6. #6
    Hybrid booster
    Join Date
    Jul 2006
    Location
    Notre-Dame de L'Ile Perrot, QC
    Posts
    716

    Re: Car slow to build boost, won't go past 10 pounds

    I would also verify crank/cam timing.

  7. #7
    Garrett booster
    Join Date
    Dec 2010
    Location
    jerzy
    Posts
    202

    Re: Car slow to build boost, won't go past 10 pounds

    i'd start with a boost leak test.. http://www.ebay.com/itm/Torque-Solut...41ec2e&vxp=mtr .. pretty simple to make your own.. plugged 2" pvc pipe, coupler and a couple hose clamps..

    basically plug/cap turbo input, pull a vac line (short piece of fuel line hose with a couple of clamps) and add compressed air to intake manifold (i.e. 20lbs) and listen for a leak, feel around each of the silicon couplers etc.. good luck

  8. #8
    turbo addict
    Join Date
    Dec 2011
    Location
    Hemet,CA
    Posts
    1,636

    Re: Car slow to build boost, won't go past 10 pounds

    if its a boost leak causing the issue it will have to be massive, i.e. intercooler hose popped off. the turbo can keep up with the engine at WOT at 25+psi most likely which is around 300+ CFM, so a smalll leak wont cause this issue I dont think

  9. #9
    Garrett booster
    Join Date
    Dec 2010
    Location
    jerzy
    Posts
    202

    Re: Car slow to build boost, won't go past 10 pounds

    this was a problem for me
    [IMG][/IMG]

  10. #10
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
    Join Date
    Nov 2010
    Location
    Raleigh Area, NC
    Posts
    4,809

    Re: Car slow to build boost, won't go past 10 pounds

    I'd check the wastegate actuator first, could be a broken spring. It could be as Harry said no c-clip and arm came off the valve.

    Check intercooler hoses and clamps.

    Easier stuff first. That's the best advice.
    Wayne H.

    '91 Dodge Spirit ES 2.5L turbo 5spd
    '05 PT GT 2.4T HO autostick (RIP)
    '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 11.699 @ 114.43 mph! - Oct 15th, 2022 Cecil County Dragway, MD)
    MeanMini dragracing videos: https://www.youtube.com/playlist?lis...URZLB1RxGYF6vw
    and other cars, trucks and motorcycles
    https://www.youtube.com/user/SlugmobileMeanMini

  11. #11
    boostaholic
    Join Date
    Dec 2005
    Location
    South Side Indy
    Posts
    1,221

    Re: Car slow to build boost, won't go past 10 pounds

    Checked all the IC pipes and couplings and there's no obvious rips or holes.....the BOV is a 50MM with a Vband....not sure the brand...the intercooler appears to be OK...no obvious holes there...I'll check the wategate arm once the car cools off on my lunch break. I know that I said it's slow to build boost, however since I have the wastegate can unplugged...half throttle or less gets me almost instant boost at low RPMs until 10 pounds when it flattens out...it's when I floor it from a lower RPM, boost builds slow.

  12. #12
    boostaholic
    Join Date
    Dec 2005
    Location
    South Side Indy
    Posts
    1,221

    Re: Car slow to build boost, won't go past 10 pounds

    I'll definitely be making a boost leak tester...I don't have access to an air compressor at the moment though.

  13. #13
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
    Join Date
    Dec 2005
    Location
    Greenville/Spartanburg SC area
    Posts
    7,557

    Re: Car slow to build boost, won't go past 10 pounds

    Could be the puck is stuck ----ed at an angle and not sealing the wg hole fully...
    Rob M.
    '89 Turbo GTC

    2.5 TIII stroker, 568 w/ OBX and 3.77 FD

  14. #14
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
    Join Date
    Nov 2010
    Location
    Raleigh Area, NC
    Posts
    4,809

    Re: Car slow to build boost, won't go past 10 pounds

    Another thing and hopefully its not, but a cracked turbine housing.
    Click image for larger version. 

Name:	uploadfromtaptalk1438796117056.jpg 
Views:	255 
Size:	50.3 KB 
ID:	55810
    This isn't the worst one i've seen like this, but it did effect boost.
    Wayne H.

    '91 Dodge Spirit ES 2.5L turbo 5spd
    '05 PT GT 2.4T HO autostick (RIP)
    '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 11.699 @ 114.43 mph! - Oct 15th, 2022 Cecil County Dragway, MD)
    MeanMini dragracing videos: https://www.youtube.com/playlist?lis...URZLB1RxGYF6vw
    and other cars, trucks and motorcycles
    https://www.youtube.com/user/SlugmobileMeanMini

  15. #15

    Re: Car slow to build boost, won't go past 10 pounds

    I'm with Gaboon. If timing jumped a tooth or two, you'll have that lag on spool up. But a cracked exhaust housing would do it too. That's a tough one. If you don't hear any exhaust noise when at idle or driving (as it spools), I would check timing. You can turn it manually and get the cam, crank and distributor at TDC and see if everything is lined up. Start with the crank and the flywheel at 0, then confirm the cam and ignition are where they should be.
    [SIZE="3"] [B]Jon Trotter[/B][/SIZE] [B]1985[/B] Dodge Shelby Charger, Currently decommissioned [B]1987[/B] Shelby GLHS, #937 [B]1987[/B] Shelby Lancer, #628 [QUOTE=Reeves;587010]I can be ready. Please send pics of wife. _____DodgeZ add comments here______[/QUOTE]

  16. #16
    turbo addict
    Join Date
    Dec 2011
    Location
    Hemet,CA
    Posts
    1,636

    Re: Car slow to build boost, won't go past 10 pounds

    checking the throttle cable is easy..sit in the drivers seat and floor the gas..then have someone go under the hood and see if they can still move the throttle blade further WOT

  17. #17
    boostaholic
    Join Date
    Dec 2005
    Location
    South Side Indy
    Posts
    1,221

    Re: Car slow to build boost, won't go past 10 pounds

    I'll check the throttle cable when I get home after work. I hope it's not a cracked turbine housing or O2 housing. I hear no extra noises under throttle, the exhaust is the same. Timing would keep boost at 10 pounds? I'll have to check that. I checked out the wastegate arm and it's attached and I couldn't move it with my fingers.... I have a 2 piece intake with a box upper and a Buick GN turbo so there's not much room there to check....perhaps the gasket between the intake halves blew out? I'd hear noise tho, right? I'm gonna remove the BOV and see if the piston is weak when I get home.

  18. #18

    Re: Car slow to build boost, won't go past 10 pounds

    Timing can keep it from building boost, yes. If the timing is off, then the ability for the motor to build pressure can reduce. The car can still run, idle, accelerate, but it will be slower.
    [SIZE="3"] [B]Jon Trotter[/B][/SIZE] [B]1985[/B] Dodge Shelby Charger, Currently decommissioned [B]1987[/B] Shelby GLHS, #937 [B]1987[/B] Shelby Lancer, #628 [QUOTE=Reeves;587010]I can be ready. Please send pics of wife. _____DodgeZ add comments here______[/QUOTE]

  19. #19
    turbo addict
    Join Date
    Dec 2011
    Location
    Hemet,CA
    Posts
    1,636

    Re: Car slow to build boost, won't go past 10 pounds

    in regards to timing (ignition), if that distributor hold down clamp bolt wasnt tightened then the distributor could rotate freely and everything goes wonky..this happened to me once but I forgot the resulting symptoms

  20. #20
    boostaholic
    Join Date
    Dec 2005
    Location
    South Side Indy
    Posts
    1,221

    Re: Car slow to build boost, won't go past 10 pounds

    Quote Originally Posted by minigts View Post
    Timing can keep it from building boost, yes. If the timing is off, then the ability for the motor to build pressure can reduce. The car can still run, idle, accelerate, but it will be slower.
    Thanks! I'll check it for sure this evening.

Page 1 of 4 1234 LastLast

Similar Threads

  1. fast throttle input means low boost, slow throttle gets higher boost
    By going4speed in forum Turbos & Intercoolers!
    Replies: 14
    Last Post: 01-05-2015, 05:20 PM
  2. slow boost build in 1st gear
    By islandglh in forum Turbos & Intercoolers!
    Replies: 3
    Last Post: 05-25-2011, 04:11 PM
  3. engine rpm reluctant to build past 3,500rpm.
    By Wizard in forum Transmission
    Replies: 5
    Last Post: 04-14-2010, 07:59 PM
  4. No boost past 11psi
    By rosie in forum Maintenance & General Tech
    Replies: 28
    Last Post: 09-23-2008, 07:50 PM
  5. Slow boost
    By Jasmeleg08 in forum "I need help!"
    Replies: 3
    Last Post: 04-24-2007, 11:49 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •