Boost Help


DV8

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Having a boost issue and i've run out of ideas of what could be causing it.

Basically the car will only reach 11 PSI of boost no matter what i've tried. Please note all turbo kit parts are brand new.

So far i've:

- Eliminated the wastegate being the issue (ran boost to the top port of the wastegate to keep it shut and still only achieved 11 PSI - should have spiked out of control - also done on dyno with visual of wastegate to verify it isn't opening).

- Checked for any boost leaks using a tester.

- Examined Intercooler & piping for any restrictions.

- Checked for any exhaust leaks from head to turbo - fitted brand new gaskets and bolts to make sure of a good fit

Turbo is a T3/TO4B Turbonetics and should be able to easily achieve more boost.

On saturday we are going to take off the exhaust system and see if its that but causing a restriction but i'm doubtful as its a 5zigen 2.5" system and should be spot on.

After that i'm stumped. :(
 
Sounds strange, first thing that comes to mind is boost leaks or wastage not sealing as you say

Has your turbo got an adjustable actuator? it would be worth tightening it up and preloading the wastegate spring as it might not be strong enough to hold good pressure

Are you using an electronic boost controller, have you got it on the correct setting for either external or internal wastegate? Is it plumbed in correctly? Have you tried adjusting the gain on the boost controller?
 
Dump valve opening?
What's the pressure supposed to be?
Broken gauge?
What map sensor you got?
 
^^ Yes forgot to mention dump valve

The boost started to drop off in my EVO 8 and it turned out the standard dump valve was leaking, replaced that with a new EVOX dump valve and it was right back up where it should have been
 
He'll have a brand new TIAL valve in there if it's the same kit as mine so doubt it's that but it's a possibility I suppose
 
What wastegate is it? If it is a tial MVR then are the rest of the holes blanked up around the outside of the gate? Also what size spring is in the gate?
How did you test for leaks? If its just a basic smoke test then you might need more pressure to find a leak.
The exhaust will be fine.

Murray
 
Sounds strange, first thing that comes to mind is boost leaks or wastage not sealing as you say

Has your turbo got an adjustable actuator? it would be worth tightening it up and preloading the wastegate spring as it might not be strong enough to hold good pressure

Are you using an electronic boost controller, have you got it on the correct setting for either external or internal wastegate? Is it plumbed in correctly? Have you tried adjusting the gain on the boost controller?

It's def not the Wastegate (external Tial WG by the way), we had boost pressure going to the top of the WG (holding it shut) and had the dump tube off so we could see the valve itself and it stayed totally shut but still didnt go above 10-11 PSI.

No internal WG and the internal WG port is blocked shut (we thought it might be leaking past but tested and fitted a new gasket so its not that either).

Boost controller doesn't even come into it at this stage.

Dump valve opening?
What's the pressure supposed to be?
Broken gauge?
What map sensor you got?

Might look at the DV but I doubt thats the cause...
I should be able to reach 20 PSI+.
Gauge and MAP sensor read the same (both brand new) - MAP sensor is a Hondata 4Bar

^^ Yes forgot to mention dump valve

The boost started to drop off in my EVO 8 and it turned out the standard dump valve was leaking, replaced that with a new EVOX dump valve and it was right back up where it should have been

Brand new Tial BOV so as above i have my doubts - might try a block off.

What wastegate is it? If it is a tial MVR then are the rest of the holes blanked up around the outside of the gate? Also what size spring is in the gate?
How did you test for leaks? If its just a basic smoke test then you might need more pressure to find a leak.
The exhaust will be fine.

Murray

As said above its def not the WG - yes all holes are blocked apart from one at the top and one at the bottom which have the nipples on them.

Tried everything from a 7 PSI - 14 PSI spring combo - with the 14 PSI spring combo the valve stayed shut (doing its job) but the car still wouldnt create more than 10-11 PSI of boost.

We tested for leaks using a turbo system leak tester and compressor - the system held very good pressure.
 
Where is your vacuum source coming from for the BOV?
 
Is it holding a steady 11 psi? Did you try put a boost gauge on port off compressor housing and measure boost there?
 
Is it holding a steady 11 psi? Did you try put a boost gauge on port off compressor housing and measure boost there?

Yeh the max it will hold is 11 which it holds quite well in the data log.

Not tried a boost gauge at the compressor housing but I can, what would this tell me - if theres a restriction in the system?
 
Yeh the max it will hold is 11 which it holds quite well in the data log.

Not tried a boost gauge at the compressor housing but I can, what would this tell me - if theres a restriction in the system?

If you log boost off compressor housing and it is considerably higher than what your seeing at the intake manifold then you more than likely have a leak somewhere. Did you pressure check the intercooler and pipe work? Some times leaks don't show until X psi so you need to pressurise the boost pipes to check correctly. If that all checks out id suggest maybe your exhaust housing on turbo has a crack.
 
Yeh we had the system up the the Throttle body right up to 1.7 bar (and the BOV pressurised too to make sure that was staying shut.

Turbo has been off and examined - its brand new, no signs of blowing or a crack. :(
 
How have you got your boost solenoid hooked up ? Are you 100% sure the settings and the vacuum lines correct ?? It sound like something to do with this to me. Recheck everything and take a look on the Hondata forum as well.
 
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