sc400 boosted and over boosting issues - Club Lexus Forums

Log In 

sc400 boosted and over boosting issues

Reply
 
 
 
Thread Tools Search this Thread
Old 05-15-14, 11:24 PM   #1
kolessc400
Pole Position
Thread Starter
 
Join Date: Feb 2012
Location: colorado
Posts: 205
Default sc400 boosted and over boosting issues

So I have an sc400 1uz v8 with a t3 t4 turbo a 38mm wastegate 8 psi spring and hks bov... I creep from 8 psi and it fludders from 10 14 psi... I have swaped the turbo bov and wastegates 3 times and it still does it... but it works great for about a day everytime I swap the waste gate there is no cracks in the lines I have checked and checked but still cant figure it out
kolessc400 is offline   Reply With Quote
Old 05-15-14, 11:33 PM   #2
ArkLaTexSC
Pole Position
 
Join Date: Feb 2014
Location: LA
Posts: 310
Default

Boost controller?
ArkLaTexSC is offline   Reply With Quote
Old 05-15-14, 11:43 PM   #3
kolessc400
Pole Position
Thread Starter
 
Join Date: Feb 2012
Location: colorado
Posts: 205
Default

None I never put one in yet
kolessc400 is offline   Reply With Quote
Old 05-16-14, 01:48 AM   #4
ArkLaTexSC
Pole Position
 
Join Date: Feb 2014
Location: LA
Posts: 310
Default

Yeah that would help
ArkLaTexSC is offline   Reply With Quote
Old 05-16-14, 08:44 AM   #5
Ali SC3
Lexus Fanatic
iTrader: (10)
 
Ali SC3's Avatar
 
Join Date: Oct 2007
Location: CO
Posts: 9,205
Default

If the wastegate isn't letting the extra pressure out a boost controller is not going to help.
maybe your turbo is too small or your wastegate is too small.
The bov shouldn't have anything to do with it.
Ali SC3 is offline   Reply With Quote
Old 05-16-14, 10:30 AM   #6
mecheng10
Lead Lap
 
Join Date: Aug 2013
Location: ohio
Posts: 476
Default

you could just have bad wastegate placement... that causes tons of creep issues.
orrrr
your wastegate is too small.
go up to a 44mm wastegate
(just get the old wastegate flanged chopped off and weld on a new one)
mecheng10 is offline   Reply With Quote
Old 05-16-14, 11:38 AM   #7
Ali SC3
Lexus Fanatic
iTrader: (10)
 
Ali SC3's Avatar
 
Join Date: Oct 2007
Location: CO
Posts: 9,205
Default

^^ Yes that is correct. going to a larger waste gate will help even if the placement is still bad. if that wont fix it then check placement or just raise the boost to where it creeps via a boost controller and run the 14 psi.
Ali SC3 is offline   Reply With Quote
Old 05-17-14, 04:30 PM   #8
kolessc400
Pole Position
Thread Starter
 
Join Date: Feb 2012
Location: colorado
Posts: 205
Default

Well it worked on the first for about 6 mos... then blew the wastegate diaphram... got a new one with bov too and it worked great then started doing it the other day after about a year... then put the new every thing just because... worked for a day and did it again and the last 2 waste gates had no leaks and both are still good but its still doing it and when I did the tutbo I went with a 65 trim and I had a 50 trim originally... im alo just going to replace the lines today too just incase I have a leak I cant see
kolessc400 is offline   Reply With Quote
Old 05-21-14, 12:10 PM   #9
mecheng10
Lead Lap
 
Join Date: Aug 2013
Location: ohio
Posts: 476
Default

bigger turbo +low boost=bigger wastegate needed.
go up to a 44mm wastegate
mecheng10 is offline   Reply With Quote
Old 05-26-14, 09:14 PM   #10
Abelo
Driver
 
Abelo's Avatar
 
Join Date: Mar 2011
Location: Canada, Alberta, Calgary
Posts: 162
Default

I used to have slag from my manifold getting stuck in my wastegate and keeping it stuck open. I had to take it off and clean it out and on the 3rd time it started working fine.

Another thing is that if your turbo was originally internally gated then I know like the holsets you need to weld the internal gate port shut or else you get boost creep or fluctuations.
Abelo is offline   Reply With Quote
Old 06-01-14, 01:36 PM   #11
kolessc400
Pole Position
Thread Starter
 
Join Date: Feb 2012
Location: colorado
Posts: 205
Default

So I figured it out the vaccine lines were the wrong size... now I got out fixed its great...o and now I'm working on installing the fic8 again and got the boost controller in
kolessc400 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Having issues with USDM OBDII TT ECU mod myLEXsc400 Performance & Maintenance 103 03-24-16 06:05 PM
Boost leak/ Turbo failure? sc3757 Performance & Maintenance 4 08-20-14 04:00 PM
Vortech Supercharger wastegate idea KC95SC400 Performance & Maintenance 0 06-21-14 03:03 AM
wastegate spring question SCereal Performance & Maintenance 5 02-11-14 06:06 PM
2jzgte Single turbo boost issue... Lowlexus Performance & Maintenance 5 09-23-13 10:39 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -7. The time now is 12:09 AM.


Copyright © 2000-2016 Internet Brands, Inc. All Rights Reserved