turbo can't pass 10 psi colt.

[SvarO]

hi guys,

I need some help with this, my friend have a mitsubishi colt turbo, the issue is he can't boot after 10 psi, even with the wastegate disconnected.

we did:

leak test at 20 psi and pass.
replace the 14b with evo 16g, try another 16g still the same problem
check vacuum
check the intercooler.
test 2 hks bov
put evo 3 cam


a nothing, the max boost is 10 psi.

I can't understand why the boost stay at 10, spool fine and everything is just not building boost after 10 psi :S

any extra tips or support we will appreciated.

 

[SvarO]

anyone?

 

[rlacasse1]

Did you disconnect the waste gate actuator rod. Or does it have a different aftermarket wastegate.

 

[SvarO]

Did you disconnect the waste gate actuator rod. Or does it have a different aftermarket wastegate.

we used 3 different turbo with different wastegate. they are internal. the last one is one from oem mitsubishi new.

 

[livedsm4g63]

correct me if im wrong but if its internal and you disconnect the wastegate rod, wouldn't you not boost? because then the flapper would be open all the time due to the exhaust pushing it.
to get more boost wouldn't you have to either "bend" or get a shorter wastegate rod?
what if you were to disconnect the vacuum to the wastegate? Flapper wouldnt open.

Im sort of confused on how you disconnected it. Any kind of boost controller?

 

[SvarO]

correct me if im wrong but if its internal and you disconnect the wastegate rod, wouldn't you not boost? because then the flapper would be open all the time due to the exhaust pushing it.
to get more boost wouldn't you have to either "bend" or get a shorter wastegate rod?
what if you were to disconnect the vacuum to the wastegate? Flapper wouldnt open.

Im sort of confused on how you disconnected it. Any kind of boost controller?

we disconnect the wastegate vacuum (open boost) and didn't pass 10 psi.

 

[rlacasse1]

I'm confused.

F**k it. Unhook the actuator rod and hold the waste gate closed with pliers or something and see if it will boost over ten that way.

 

[SvarO]

I'm confused.

F**k it. Unhook the actuator rod and hold the waste gate closed with pliers or something and see if it will boost over ten that way.

even if this is the third turbo we test with different wastegate also??


is there any other thing that can cause this problem, believe me, this problem doenst make sense, but is happening :S.

 

[rlacasse1]

Do you have a massive boost leak anywhere?

And what size engine does the Colt have in it?

 

[SvarO]

Do you have a massive boost leak anywhere?

And what size engine does the Colt have in it?

we did leak test at 20 psi.



the engine now is 2.0.

 

[rlacasse1]

have you put a MBC on it yet to see if you can up the boost that way. The 14b stock boost is 10 PSI range so it would make sense that it won't boost over that without a MBC on it.

 

[SvarO]

have you put a MBC on it yet to see if you can up the boost that way. The 14b stock boost is 10 PSI range so it would make sense that it won't boost over that without a MBC on it.

that was the firts turbo, after that we test two evo 3 16g still the same problem, right now the colt have a e316g. we haven't test any mbc since we are running open boost disconnecting the wastegate vacuum line.

 

[FactoryChrome]

Exhaust leak preturbo somewhere??

 

[falcon8r]

Is it possible that the exhaust is plugged at higher exhaust flow? It is posssible to unscrew O2 sensor and install a pressure gauge. The car will run poor for the test but the engine should rev fine with some throttle. Should be less than 3psi. You have done lots already with the upriver stuff. So.... Tres.....

 

[SvarO]

Is it possible that the exhaust is plugged at higher exhaust flow? It is posssible to unscrew O2 sensor and install a pressure gauge. The car will run poor for the test but the engine should rev fine with some throttle. Should be less than 3psi. You have done lots already with the upriver stuff. So.... Tres.....

what should I see with this? I do not understand this test.

 

[falcon8r]

what should I see with this? I do not understand this test.

Are you running a full exhaust? If so it is possible for a baffled muffler of cat. converter to restrict flow and decrease cfm. when the flow is needed most. The test is lumb a pressure gauge into the exhaust somewhere in the downtube. If using a secondary bung in the down p. for egt or uego etc., obtain a pressure reading instead by hooking up a gauge. You should idealy have just above no "0" psi. If its' 3psi or more with the loud pedal matted, the cat or muffler is bad. Tres

 

[94awdcoupe]

if line in BOV has a leak boost will not go over 7-10psi no matter what turbo is on car.

 

[SvarO]

Are you running a full exhaust? If so it is possible for a baffled muffler of cat. converter to restrict flow and decrease cfm. when the flow is needed most. The test is lumb a pressure gauge into the exhaust somewhere in the downtube. If using a secondary bung in the down p. for egt or uego etc., obtain a pressure reading instead by hooking up a gauge. You should idealy have just above no "0" psi. If its' 3psi or more with the loud pedal matted, the cat or muffler is bad. Tres

this is good, the car is running straight pipe with muffler, not cat. is 2".

we can cut the pipe before the muffler to check.

I let you know.

if line in BOV has a leak boost will not go over 7-10psi no matter what turbo is on car.

even with the leak test at 20 psi for a few seconds?

well we cut the exaust on the middle of the car, sound like racing car and still won't pass 10 psi...

this is the most weird thing I haven seeing....

 

[livedsm4g63]

seems so weird that having the vac line disconnected to the bov it still only runs 10psi. normally you'd see crazy boost levels. any update?

 

[SvarO]

seems so weird that having the vac line disconnected to the bov it still only runs 10psi. normally you'd see crazy boost levels. any update?

no updates, the car is running catless/ just straigh pipe on the middle, with the wastegate vacum line disconnected at 10 psi on WOT.

I don't know what else I can do to text, I will test 2g ported manifold, right now he have evo 3 manifold.

any other tip?

 

[falcon8r]

It is unlikely it is the ex manifolds. save some work. They will change the boost response but not your 10psi problem. It really is weird that it will produce only 10psi. Is the gauge working ??? If the turbo-turbos will produce 10psi, there is only the wastegate that would consistenty break at that psi. Any leak I think you would have found with the leak test. It would seem that any MBC installed in the wastegate line would give an inclease. WTF Tres....

 

[Sp1kE]

shitty spark plugs?
is your flapper fully closed?

 

[robbo185]

too much back pressure from too small diameter exhaust?

 

[SvarO]

shitty spark plugs?
is your flapper fully closed?

I can check the spark plugs.

the flapper is different since we test 3 different turbos with housing and everything.

too much back pressure from too small diameter exhaust?

we cut the exhaust on the middle of the car, he is running open exhaust right now, he will upgrading to 3" straigh pipe, not cat, not muffle.

bu i think the problem is not there since we cut it.

It is unlikely it is the ex manifolds. save some work. They will change the boost response but not your 10psi problem. It really is weird that it will produce only 10psi. Is the gauge working ??? If the turbo-turbos will produce 10psi, there is only the wastegate that would consistenty break at that psi. Any leak I think you would have found with the leak test. It would seem that any MBC installed in the wastegate line would give an inclease. WTF Tres....

before we disconnect the wastegate line to run open boost, theres was a MBC fully closed. I can test another one to see what happen.

for the gauge he said he test another one and same issue. when we did the leak test 20, the gauge work fine.

 

[robbo185]

you may have cut the muffler but a 2 inch straight pipe is really small. stock was like 2.25inch