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General Car Related Discussion.To discuss anything that is related to cars and automotive technology that doesnt naturally fit into another forum catagory.
Ok so as far as i gather a -31 actuator is all that is needed on a T4 no matter the pressure!we all know that a -31 spring can only see 8psi of boost before it gets overcome,and that T 4 can push a lot more volume the a T34!I am fully aware how boost controlers work etc but say both cars have air injectors,
So why for a t34 to hold high pressure do the usually need a -34 which has a opening pressure of 1bar(14.5psi)when surely with the higher back pressure in a t34 exhaust housing (compared to a T4)should help keep the penny shut!thus needed a less stronger actuator,where as the T4 will have less back pressure and would surely need the stronger actuator to keep the penny shut?
I know i am seeing this all wrong!but do you see my point!
Last edited by mechanic28; 14-12-2009 at 08:14 PM.
Also the reason for requiring the different pressure actuators is down to the size of the turbos where the boost curve works the other way round. On a big turbo you want to hold the wastegate shut at low boost (to help it spool up) and then at high rpm, you will need to be bleeding off some exhaust gasses to prevent the boost exceeding your desired point (as with the wastegate shut at high rpm, a T4 can provide well over 3 bar of boost ). Therefore, you don't need a strong spring.
A T34 being an ickle turbo will make the boost low down, so this is where you will have some bleed off to retain the boost at your desired level (otherwise it will be again overboosting, but this time at a low rpm point). As it reaches high rpm, the engine will then be able to consume all the air that the turbo can give (and then some - hence the drop off in boost), so at high rpm, you want to be holding the wastegate shut to retain as much air flow as possible.....
i make a honest mistake and look how i am treated bastards all of ya!problem is i was trying to figure it out for hours in my head so its not like it was in the spur of the moment thing
some of you only know doug on here he does this all the time not just on here i have some funny ones he might want me to tell you about lol should i tell them doug
14-12-2009, 08:12 PM
T4's and -31 actuators!?
