4znova1 Posted April 7, 2007 Share Posted April 7, 2007 hey guys i have a huge problem that i need help with.. I am not hitting full boost until 4500 rpms. I thought that it was my crappy intercooler, but i just put a j-pipe on and still had the same results. i have good vacuum at idle. 17-18 on my vacuum gauge i dont think there are any leaks anywhere. the thing i am concerned about is the 2mm head gasket which lowered the compression and probably threw off the cam timing, but i dont know if this could be it. im tired of this car being so sluggish when it shouldnt be. l28et 3inch exhaust crane cams hi-6 ignition 8psi Quote Link to comment Share on other sites More sharing options...
J Taylor Posted April 8, 2007 Share Posted April 8, 2007 Vacuum should be 20 or so with the stock cam. You need to pressurize your intake manifold and piping and make sure there are no leaks. JT Quote Link to comment Share on other sites More sharing options...
linluv84 Posted April 8, 2007 Share Posted April 8, 2007 If it isn't leaking, maybe the wastegate is stuck open... Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted April 8, 2007 Share Posted April 8, 2007 I only run 18-19 " vacuum with a stock good compression ZXT - with a 2mm head gasket, the vac would probably be a bit lower. When does boost start to build when accelerating in 2nd gear? Quote Link to comment Share on other sites More sharing options...
linluv84 Posted April 8, 2007 Share Posted April 8, 2007 I think at WOT I was going under boost around 2500ish. I dont have a boost guage yet, but I recall watching it in MT. You should definitely be under boost by 3500, if not sooner... Quote Link to comment Share on other sites More sharing options...
4znova1 Posted April 8, 2007 Author Share Posted April 8, 2007 Yah i have a 300zx also with a blown headgasket and that thing hits boost right away and you actually feel it. in my l28et zx turbo, i hear the turbo but barely feel it kick in, and it takes so long to start building boost. It starts to build boost at 3500 but doesnt hit full until about 4500-500 rpm. I live in orange county ca if if anyone would care to take a look at it. i would pay of course.. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted April 8, 2007 Share Posted April 8, 2007 your wastegate is stuck open, or your blow off valve isn't adjusted tight enough. Quote Link to comment Share on other sites More sharing options...
4znova1 Posted April 8, 2007 Author Share Posted April 8, 2007 when i take the turbo off to inspect it what should i be looking for, when i pull on the wastegate rod, it opens and closes, and the bov ajustment could cause slow spool? Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 9, 2007 Share Posted April 9, 2007 You can do it in-place. Disconnect the wastegate rod from the actuator arm, and see if you can get the arm on the turbine hot-side to move. Sometimes soaking in Kroil or PB BLaster works to free it up, otherwise further disassembly is required. It wouldn't be the first time a linnkage rod was bound up as well. Removing the actuator completely is a simple matter with two 13mm bolts and a needle nosed pliers for the clip on the hot side. That little rusty arm should flop around pretty freely once disconnected. If it does, the possibility of the flapper being broken off comes to mind, and as stated above, 'further disassembly maybe required at that point---if the popoff valve on the manifold is not leaking boost off. So there are a few things you cna check before having to remove the turbo for inspection. Worth the time to check first, doesn't hurt at least... Quote Link to comment Share on other sites More sharing options...
Thumper Posted April 9, 2007 Share Posted April 9, 2007 Also if you are running rich it will hurt spool time. Make sure you aren't pig rich during the boost building stage. Quote Link to comment Share on other sites More sharing options...
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