The nice thing about threads of this nature is that more knowledgeable people can chime in with corrections to info that was posted. I wouldn't go as far as to speak in a tone of condescension, as many people, such as myself, are relative newbies to the turbo car scene. This is how I learn. I also appreciate the efforts of those who share their technical expertise.
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will performance exhuast over rev the turbo?
- Thread starter gsrtype1
- Start date
I was actually surprised to read how the wastegate control works on this car. My previous turbo had a simple pressure connection to the intake and when a set pressure was reached the gate opened.
On the MS3, it has a mostly conventional waste gate actuator, a pressure actuated diaphragm that normally starts to open the gate when the intake reaches a relatively low 10 psi. But the waste gate solenoid valve (which is controlled by the ECU) is in line with the pressure hose from the manifold so the ECU can hold off the opening of the gate as long as it wants to. If the solenoid wires are disconnected, the valve stays open keeping a safe boost level in case of a failure. The solenoid can be cycled on and off rapidly to servo the boost level. The ECU however cannot reduce the boost level below the conventional opening method - there is no bleed solenoid.
On the MS3, it has a mostly conventional waste gate actuator, a pressure actuated diaphragm that normally starts to open the gate when the intake reaches a relatively low 10 psi. But the waste gate solenoid valve (which is controlled by the ECU) is in line with the pressure hose from the manifold so the ECU can hold off the opening of the gate as long as it wants to. If the solenoid wires are disconnected, the valve stays open keeping a safe boost level in case of a failure. The solenoid can be cycled on and off rapidly to servo the boost level. The ECU however cannot reduce the boost level below the conventional opening method - there is no bleed solenoid.
knowledge007
Banned
No No No
gsrtype1 said:so does that mean less backpressure drasticly reduces turbo life do to overreving?
Dude, it's been answered. Reread the thread.
Capt Crunch
Member
I don't know anything about the Mazdaspeed setup, but I wouldn't make this call unless it was something tested. On the STI if you get a catless turboback exhaust it is a common occurance to have boost creep.justa4banger said:THERE IS NO WAY IN HELL YOU CAN HAVE BOOST CREEP WITH THE MS3's SETUP. the turbo is too damn small besides a manufacturer wouldn't install a turbo that could possibly hurt the engine.
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just adding a cat back exhaust or even a turboback exhaust in 4" diamter or 3" won't hurt anything PERIOD...
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Long story short, Added turbo back or cat back exhaust to the tock turbo and keeping the turbo at stock levels of boost , will not hurt anything.
Capt Crunch
Member
gsrtype1 said:whats the difference and is spike a bad thing?... thanks
A spike is when the wastegate doesn't open to vent exhaust gasses quickly enough and more boost is made than you want. Boost creep is when the wastegate isn't physically big enough to vent enough of the exhaust gasses and results in prolonged increase in boost. The former is a boost control problem, the latter is a mechanical problem with the wastegate.
Both are bad for the engine. Boost creep is worse just because there is more time running increased boost, but whenever you're running more boost than you are tuned for, it's a recipe for detonation = boom.
Capt Crunch
Member
gsrtype1 said:so does that imply if you get a performance exhuast it will spike the boost thus overrev the turbo and may cuase other problems?
The danger is not over-reving the turbo, it's causing a boost increase that isn't tuned for. Your turbo won't take a dump, your engine will blow up instead.
That said, I have no idea if adding an exhaust will cause a problem. On STIs, it is a problem if you run catless, but not a problem if you have a high-flow cat in it. in WRXs it never was a problem. Only someone with an exhaust and a boost gauge can tell you if it is a problem or not. I really doubt a cat-back exhaust will cause you a problem however. You'll still have both cats so you won't be drastically be improving flow.
thanks for the feedback, the reason i was worried is becuase this guy who yoused to manage an exhuast shop said the these guys in dodge or frod deisel trucks would come in and remove the mufflers, thus overrev the turbo and in 5 to 10 thousand miles the turbo housong is toast, so im just trying to get someone to give me areason why he is wrong on the ms3 , i know its probably know big deal, i juat dont want to screw up my turbo, and my friend who cut his muffler and pipe back to the cats sais his boost spikes to 21 all the time, everyone has an opinoin .. but sometimes you run into an awnser that your like .... ok you belive that but do i? is the belif rashonal or just assumeing and byast?
like you said the danger is not overreving the turbo, he said it was , yall both think your right so how do i know without a mechanical explanation whos correct? you both are conviced , so its not really a nutreul opinion , could you give me a mechanical reason that makes sense why the danger is not over reving the turbo that will negate that guy who has said hes seen it happen over and over agin wrong?
gsrtype1 said:thanks for the feedback, the reason i was worried is becuase this guy who yoused to manage an exhuast shop said the these guys in dodge or frod deisel trucks would come in and remove the mufflers, thus overrev the turbo and in 5 to 10 thousand miles the turbo housong is toast, so im just trying to get someone to give me areason why he is wrong on the ms3 , i know its probably know big deal, i juat dont want to screw up my turbo, and my friend who cut his muffler and pipe back to the cats sais his boost spikes to 21 all the time, everyone has an opinoin .. but sometimes you run into an awnser that your like .... ok you belive that but do i? is the belif rashonal or just assumeing and byast?
lol if you want to believe the mechanic why don't you tell him to put on an exhaust brake that those ford diesels do or dodge diesel. that should help you save your brakes won't it. if you don't know what an exhaust break is lemme know i'll tell you what it is. oh yeah they should see this ford one of my frenz own. it has a 5" exhaust dp back with a bully dog chip intake, air ride suspension and a bunch of other stuff along with an exhaust brake, his turbo has not yet melted or anything, its one thing to get worried but another to compare a turbo diesel to a regular gas turbo.
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