Go Back   AstinaGT Forums > Performance & Technical > Performance & General Maintenance

Reply
 
Thread Tools Display Modes
Old 10-08-2012, 05:52 AM   #1
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
boost still spiking

So I ported my wastegate heaps and I mean heaps.....check the wastegate actuator arm etc its all working sweet and yesterday was holding a nice 8psi to 10psi in all gears at load....then I go out last night and the boost is still spiking. Could there be a possible boost leak somewhere? Likr would a leak in manifold from exhaust to turbo do this?
rogerstrampoline is offline   Reply With Quote
Sponsored Links
Old 10-08-2012, 06:58 AM   #2
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Just realised it only started hitting boost cut since I put the boost gauge on....might check there for a leak hahaha
rogerstrampoline is offline   Reply With Quote
Old 10-08-2012, 07:06 AM   #3
derb
Senior Member
 
derb's Avatar
 
Join Date: Oct 2008
Location: Brisbane
Car: 1993 BG Astina GT-X
Posts: 1,822
That makes sense with the gauge. Try just disconnecting it from the vac source and if that's sweet replace the line.
__________________
derb is offline   Reply With Quote
Old 10-08-2012, 07:43 AM   #4
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
The T piece has been installed yes?
project.r.racing is offline   Reply With Quote
Old 10-08-2012, 07:53 AM   #5
mikey_something
Senior Member
 
mikey_something's Avatar
 
Join Date: Oct 2009
Location: NSW
Car: 1998 Toyota Supra 3.0L Twin Turbo
Posts: 1,413
Could have been the cold air causing a spike too.
mikey_something is offline   Reply With Quote
Old 10-08-2012, 08:56 AM   #6
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Yeah t piece installed....i just cut and retightened the line and threads. I'll test her tonight cux it only really spikes when cold. If that doesnt work I'll disconnect the guage and replace the bov line i tapped into and see if no gauge fixes it
rogerstrampoline is offline   Reply With Quote
Old 10-08-2012, 09:00 AM   #7
TheMAN
Senior Member
 
Join Date: Feb 2010
Location: USA
Car: .
Posts: 2,623
you should never have the boost signal line spliced into anything or anything spliced from it! It needs to have the most direct source... having stuff tied to it reduces the pressure and will cause the wastegate to move slower!

if you want to connect your boost gauge, find a different vacuum source... if you're out of vacuum ports, you need a vacuum block which is what you should've done long ago
__________________
Protege FAQ, the best 323/Protege/Mazda3 resource enjoyed worldwide for 10 years
TheMAN is offline   Reply With Quote
Old 10-08-2012, 09:04 AM   #8
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
How does it effect wastegate? My wastegate has its own line separate and figured running the bov and boost gauge off the same line from back of intake manifold would be fine?
rogerstrampoline is offline   Reply With Quote
Old 10-08-2012, 09:30 AM   #9
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
So the T piece on on the vaccuum line from the manifold and air bypass valve?
project.r.racing is offline   Reply With Quote
Old 10-08-2012, 09:40 AM   #10
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Don't have a bypass valve It's an atmo bov...I have custom 2.5" piping to fmic etc so It's custom. And yes I have the line t into the manifold and the bov line
rogerstrampoline is offline   Reply With Quote
Old 10-08-2012, 09:55 AM   #11
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
whatever. doesn't matter what type of valve it is. it is a valve controlled by the pressure in the intake manifold. it you tap this vacum line and reduce the pressure/vacuum inside it, then the valves function will be reduced.

dunno if this will work. but try the gauge on the vacuum line port on the intake manifold for the purge control solenoid. block off your T piece.

to be honest, i got no idea if removing the purge control will send the engine into hissy fit mode or not. but as least you should be able to run the other air control functions at 100%.

just had an after thought also. having issues with the valve would only result in a spike after you took you foot off the gas as the pressure between the turbo and intake manifold wouldn't decrease.

so next question is, how is the pressure spiking? on gas, off gas, at high rpm, at low rpm etc?

Last edited by project.r.racing; 10-08-2012 at 10:09 AM.
project.r.racing is offline   Reply With Quote
Old 10-08-2012, 11:55 AM   #12
TheMAN
Senior Member
 
Join Date: Feb 2010
Location: USA
Car: .
Posts: 2,623
disconnecting the purge control solenoid will not cause any driveability issues, it is an emissions control part and you might fail rego in the future... but at the meantime, it is worth a try

honestly, you are better off with a vacuum block (all of which attach themselves to the large brake booster line for very good vacuum) because you have so many connections needed
__________________
Protege FAQ, the best 323/Protege/Mazda3 resource enjoyed worldwide for 10 years
TheMAN is offline   Reply With Quote
Old 10-08-2012, 12:01 PM   #13
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Sweet thanks for the ideas. It doesn't spike through the street generally but from 100km/h back to third or fourth and flat foot it spikes so i generally have to take it to 10psi and hold my foot there to stop it from cutting. Thing is when I had to boost gauge off to start with I could flat foot
rogerstrampoline is offline   Reply With Quote
Old 12-08-2012, 03:24 PM   #14
DavoAust
Senior Member
 
DavoAust's Avatar
 
Join Date: Mar 2007
Location: Brisbane
Car: Red '93 3000GT / Black '08 Ninja 250R
Posts: 2,930
Send a message via MSN to DavoAust
Quote:
Originally Posted by project.r.racing View Post
just had an after thought also. having issues with the valve would only result in a spike after you took you foot off the gas as the pressure between the turbo and intake manifold wouldn't decrease.
It'd do the opposite, you'd get compressor stall not a boost spike. You'd hear it too, its a very unpleasant sound at high boost.

If you're free and in the inner city I can drop round and take a look at the vacuum setup for you?

Why are you running atmo? Unless you're at ridiculously high boost all it does is increase lag and make the engine spaz everytime it vents. MAF systems don't like running atmo at all.
__________________
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall, torque is how far you take the wall with you.

'97 1.8L Hardtop
'93 3.0L TT 3000GT
DavoAust is offline   Reply With Quote
Old 12-08-2012, 04:02 PM   #15
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
Quote:
Originally Posted by DavoAust View Post
It'd do the opposite, you'd get compressor stall not a boost spike. You'd hear it too, its a very unpleasant sound at high boost.
It would spike very quickly for a moment before becoming compressor surge.

And I'm reading the word spike, ie a increase for a quick moment. I'm not reading high boost or over boost. Can only give advice on the description given.

Is nothing wrong with the sound of compressor surge. Try to find a rally video from the 80s with a car fitted with a turbo, before bypass valves become the norm. The flutter noise is damn sexy. Although mine guessing the blades on the turbo would be rooted over time.
project.r.racing is offline   Reply With Quote
Old 12-08-2012, 04:10 PM   #16
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Ok the full thing....ill be sitting at 100km and put it back to third then flat foot and the boost just keeps rising until it hits boost cut. And it happens within about 15-20km increase so I can't go from 100-120 flat foot without it hitting the 14.4psi boost cut
rogerstrampoline is offline   Reply With Quote
Old 12-08-2012, 04:12 PM   #17
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Furthermore my car runs 10psi in first and around 12psi in secojd which it shouldnt because of the ported wastegate and factory setting which should be 8psi. but i have 2.5"piping, 2.5"dump to a 2" exhaust and a fmic
rogerstrampoline is offline   Reply With Quote
Old 12-08-2012, 04:13 PM   #18
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
okay, thats not spiking, thats overboosting. although many may have a different word/s for it again.

don't look at the bypass valve then. go back to the actuator or wastegate then.

you actually revved the balls off it and had someone watch the actuator shaft for movement?

if it turns out to be one of the lines, or a solenoid, i have those here if you need them.

Last edited by project.r.racing; 12-08-2012 at 04:18 PM.
project.r.racing is offline   Reply With Quote
Old 12-08-2012, 04:29 PM   #19
rogerstrampoline
AstinaGT Regular
 
Join Date: Apr 2012
Location: south brisbane
Car: 1993 BG Astina SP
Posts: 365
Sorry for the misused phrase then, im new to turbos haha. I'll rev it and get a mate to check it but when I had it off and tested it with the compressor lines it worked fine and opened and the wastegate is ported probably another 8-9mm in diameter. I'll try the rev and then try my lines again cant hurt to triple check everything
rogerstrampoline is offline   Reply With Quote
Old 12-08-2012, 04:51 PM   #20
project.r.racing
Senior Member
 
project.r.racing's Avatar
 
Join Date: Sep 2004
Location: n/a
Car: n/a
Posts: 10,929
got something you can test, and it is a 5 minute job. switch the wastegate solenoid with the fuel regulator solenoid.

if after that, it start to have fuel issues, then you know it is the solenoid. and if nothing new happens, you've wasted 5 minutes and rule out the solenoid.

p.s.

Quote:
Originally Posted by rogerstrampoline View Post
Sorry for the misused phrase then, im new to turbos haha.
Dont worry about that. We are all noobs at one stage. Better to ask than to blow up.

Last edited by project.r.racing; 12-08-2012 at 04:56 PM.
project.r.racing is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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

Forum Jump


All times are GMT +10. The time now is 12:25 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
2001- 2010 AstinaGT