boost cut?

bryan767

New Member
Jul 27, 2009
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Maryland
i just wanted to confirm what im having is boost cut.

when i first got my car, sc300 stock auto soarer 1jzgte i would notice a little back fire/miss if i went to WOT at a stop. it wouldnt really do much more then 2 misses. but now i have a good size front mount and a 3" cat back straight pipe to a hks hi power muffler iv been having what to i initially thought was ignition breakup. so i changed my oil, filter and spark plugs which i gaped to 0 .027 it runs a little smoother but the backfiring/missing is still really bad. for instance:

ill be at wot, accelerating, it starts to back fire and miss, then all of a sudden i take off like rocket and my friend said he saw 14psi on my digital boost gauge. so OBVIOUSLY i am hitting boost cut. but does this sound like normal boost cut? this is my first turbo charged engine so i dont know what it feels like (i learned what 120 speed cut feels like though :p)

if this is my problem, it just so happens my buddy has a sw20 greddy bcc that hell sell me for $20 bucks (he ownes one hell of a mr2) which i know i can use for my car. but a different friend is telling me ill also need a boost controller since im removing the boost cut. i dont understand if im internally wastegated, and since its just spiking to 14psi i wouldnt imagine it would be anything really higher since i only have a catback and a front mount on a completly stock engine.


edit: id also like to mention the plugs are ngk copper and that i had one my charge pipes blow off the other day. i put it back on and got the car out of limp mode.. perhaps i still have a boost leak??
 
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bryan767

New Member
Jul 27, 2009
48
0
0
Maryland
i ran up to my local performance place and got a new coupler since one of my couplers was from a intake setup and it kept falling off. got the new one on and it seems to have helped alot with the sputtering. so its either boost cut or my wastegate actuator has gone bad. any idea on if i can replace this part for cheap or should i just not bother and put the money toward a single :)
 

bryan767

New Member
Jul 27, 2009
48
0
0
Maryland
isnt it a maf? but ill check. i dont have any vacuum leaks anymore. im nearly positive its the wastegates not opening/closing correctly because if i break boost to 11 psi ill backfire.
 

bryan767

New Member
Jul 27, 2009
48
0
0
Maryland
im dumb. its a map idk why i thought it was a maf.

i installed the greddy bcc and i still backfire at WOT when its around 14ish psi. now im not on a boost controller it should be stock boost. however it doesnt really lag when i hit the 14psi as it used to (i was hitting boost cut) but i believe my wastegate actuator is sticking open or closed. i was thinking about putting a spring on it so it stays closed longer. i hear alot of guys have done it to other cars because it allows for max boost.