boost spike

BRUMBI · Post by **BRUMBI** » Tue May 27, 2008 6:09 pm

i have a rx turbo all stock except WAIC, the problem is it when im going flat out and hit over 4500rpm it start to raise the boost, i have a pricol boost gauge that read just over 7psi until 4500rpm (around there) then it can creep all the way up to about 12psi but normally hits 10psi just before redline.

is this normal?, what could it be?, how to fix it?

BrennyV · Post by **BrennyV** » Tue May 27, 2008 6:14 pm

id go a ebc asap.

Gannon · Post by **Gannon** » Tue May 27, 2008 6:50 pm

How is your wastegate articulator hooked up? is it direct between the compressor outlet and the articulator? Put a T in it and hook your boost gauge up to it, have a look at what boost it is seeing.

Or...

Have you got a very free flowing exhaust?
You are probably flowing more air than your wastegate can handle. An EBC wont help if you wastegate is already all the way open.

Id suggest either port (make it bigger) your wastegate hole, restrict your exhaust or get a bigger turbo

BRUMBI · Post by **BRUMBI** » Tue May 27, 2008 6:53 pm

yeah it has got a good exhaust on it i would say free flowing but not to big and sloppy kind of free flowing

so how do i port the wastegate hole? and were is it?

Subafury · Post by **Subafury** » Tue May 27, 2008 6:58 pm

my rx turbo engine did the same thing with the stocker turbo see here- http://www.ausubaru.com.au/showthread.p ... light=dyno

BRUMBI · Post by **BRUMBI** » Tue May 27, 2008 7:08 pm

yeah it just don't make senses

BrennyV · Post by **BrennyV** » Wed May 28, 2008 10:33 am

You still haven’t said how you are controlling your boost in the 1st place? If at all.
Ebc’s WILL help to eliminate boost creep or spike when running from factory (also be sure that the wastegate actuator line and line from the turbo both have a short amount of vacuum line and the t section is central (if you have one to your boost solenoid) even if you want to run the amount of boost that the wastegate allows from factory a Ebc is essential for making sure you won’t have any spike or creep.

BrennyV · Post by **BrennyV** » Wed May 28, 2008 10:34 am

You still haven’t said how you are controlling your boost in the 1st place? If at all.
Ebc’s WILL help to eliminate boost creep or spike when running from factory (also be sure that the wastegate actuator line and line from the turbo both have a short amount of vacuum line and the t section is central (if you have one to your boost solenoid) even if you want to run the amount of boost that the wastegate allows from factory a Ebc is essential for making sure you won’t have any spike or creep.

discopotato03 · Post by **discopotato03** » Wed May 28, 2008 10:58 am

As mentioned EBC does nothing if the waste gate valve is fully open .
If your exhaust is new from the turbo back make sure no kluts has made the dump flange badly ie restricting the waste gate swing valve from fully opening .

Also BTW EBC only really keeps manifold pressure from the actuator until just before the actuators cracking setting (if its set up properly) .

A .

BrennyV · Post by **BrennyV** » Wed May 28, 2008 11:02 am

discopotato03 wrote:As mentioned EBC does nothing if the waste gate valve is fully open .
If your exhaust is new from the turbo back make sure no kluts has made the dump flange badly ie restricting the waste gate swing valve from fully opening .

Also BTW EBC only really keeps manifold pressure from the actuator until just before the actuators cracking setting (if its set up properly) .

A .

ebs's will make sure that he can keep the constant boost and stop spike! thats all he wants! it dosent sound that drastic that it is a wastegate problem.
ur all over complicating this!

Subafury · Post by **Subafury** » Wed May 28, 2008 11:13 am

is it really that much of a problem? he only said that it creeps up to 10-12 at rpm over 4500 to redline. im sure the power band has been passed at this stage, and its time to change gear. and also im running over 12psi in my rx so alittle spike wouldnt hurt much, esp with a waic- or do spikes mean its leaning out too?

BRUMBI · Post by **BRUMBI** » Wed May 28, 2008 4:30 pm

no its not leaning out, and i only know a little about turbos or the controlling of boost,the car is stock except exhaust and waic

also it dose it slowly (creeps) from 7psi to 12psi over 4500rpm to redline

i have brought a manual boost controller if i put the boost up to say 10psi will it still spike from 10psi up...

Xtreme_RX · Post by **Xtreme_RX** » Wed May 28, 2008 4:52 pm

Take the boost controller out. loop the line from the waste gate actuator to the compressor side.

This will lower your boost level.

If it still spikes you have a defective waste gate actuator. If it does not spike you have a faulty boost controller & I would throw it away & buy a new one.

BRUMBI · Post by **BRUMBI** » Wed May 28, 2008 5:22 pm

no the boost controller inst on it yet it is factory turbo setup (untouched)

discopotato03 · Post by **discopotato03** » Wed May 28, 2008 7:51 pm

Look , everything the factory connects to a turbocharger system has some intentional function because they don't waste profit margin fitting things that don't .

If you remove restrictions behind the turbocharger on an otherwise factory std car it affects the WHOLE world the engine and turbo see's .

EVERYTHING I've seen on the std EA82T system screams I am restricted everywhere and this was done DELIBERATLY .

Back in 5 .

BRUMBI · Post by **BRUMBI** » Wed May 28, 2008 8:06 pm

i dont understand how this helps me yet...

If you remove restrictions behind the turbocharger on an otherwise factory std car it affects the WHOLE world the engine and turbo see's .

is there ment to be a link after that

Gannon · Post by **Gannon** » Wed May 28, 2008 8:16 pm

Grab yourself a dremel or similar and make your wastegate hole bigger. Trust disco and myself, it will fix your problem.

The wastegate is designed to bypass exhaust gas from the turbine once 7psi is reached, thus maintaining a steady boost pressure throughout the rev range.

If the wastegate is fully open, and there is more air flowing through the turbine than is required to maintain 7psi, your boost pressure will rise because the wastegate is already bypassing as much air as it can.

BRUMBI · Post by **BRUMBI** » Wed May 28, 2008 8:24 pm

where is the wastegate hole a pic would help

thanks heaps btw im also starting to understand it a lot more

Morcs · Post by **Morcs** » Wed May 28, 2008 8:27 pm

If you have made the exhaust flow better eg less back pressure the turbo will spool up faster therefore making it have a spike. As long as it doesnt ping/ detonate it should be fine. Make sure that it isnt running lean by checking spark plug.

BRUMBI · Post by **BRUMBI** » Wed May 28, 2008 8:34 pm

yeah but i would like it to hold the right pressure and by the sounds of suparoo the way he describes sounds good then i will put the boost controller on and wind it up to 10psi with minimal spike

also its not leaning out turbo timer has A/F ration inbuilt