Questions about boost leak and new boost guage.

[95EclipseGST]

I have a new 6bolt evo3 turbo setup that i just got running and im pretty sure it has a boost leak. Okay for starters i have a question about the boost leak test. I put 20 psi through the turbo inlet and it leaks out pretty fast " 10 seconds" My first question is: DO the pistons have to be at a certain position ? #1 @TDC or anything? Does it matter? Im asking cause i can hear air around the intake manifold but sounds like its inside it and cant pinpoint a leak.So im thinking maybe the pistons had to be in a certain position.Does this matter ? or just put 20 psi in there and listen.

Today my boost gause was installed and runs -20 vac right on the nose.So i go boosting at 17psi. The boost climbs very slowly.In a second gear roll i floor it at 2000 rpm and at 4500,its still at only 10 psi then rockets from there to 17 psi and hold steady.Leaving me with very little margin for good boost. Well im doing another leak test tonight and wanted some inputs before i try it again. Does this sound like a leak with my vac holding steady and then boost holding at 17psi but not until 4700 rpm? Im trying to take it to the races this weekend so i really need some inputs and now that i have more accurate info with my boost gause hooked up.Thanks for your inputs.

 

[Dieselboy]

Usually a loud and high pitched "squeel" will happen when your under boost if there is a boost leak (usually hard to miss). Your pistons do not have to be in a certain position and you should hear no air leaking. If your hearing air rushing around the manifold, try checking around the UICP/TB elbow/TB area. Check the lines of the IM and any vacuum source where you may have tapped for a boost gauge or whatnot.

 

[realhp=turbo]

I think you are gonna have to take the intake piping loose at the manifold and cap it. then run your test. I dont think that you are going to get it to hold pressure otherwise. try that and tell me how it works out.

 

[95EclipseGST]

So are you saying to pressure cap the throttle body elbow and fill it with air at the elbow also? Or cap the IC piping where it meets the TB elbow and pressure it up at the turbo still.


Man i was just out and this guy has a 560hp supra out tonight and there was a Z28 with a vette motor.Anyways we were hanging out then went for a spin.The z28 wanted to race the supra so i was right behind them to see how much i had on the z28. I hung right with the Z28 BUT that supra's ass end jogged to the right and was gone! I have this boost leak until 4500 then my 17 psi kicks in ,so i just wanted to see if i could hang with the Z and i did. I HAVE to fix this boost leak by the weekend so i can hand the Z28 his ass.I have a fully built 6 bolt with an evo setup and just got this thing running around on the streets to where its drivable except the boost leak.My car feels fast as shi* and i know its not even the beginning once i get the boost leak fixed and my 680 injectors etc.The whole summer was spent on this swap and now im just getting a glimpse of what it can do.It sucks cause im putting it in the paint shop on Monday so i will be without it again.I had the engine bay painted 350z blue while the whole engine was out and now the rest of the car is getting done.


Anyway sorry to get off topic. Please help me clarify what you meant by cap off the intake pipe at the throtle body and where to be putting the air in from etc.Thanks guys, Travis

 

[realhp=turbo]

That sounds great! I took a Vortech 350 chev 4 speed auto with my stock set up and still crunched his ass too. To answer your question, yes disconnect the ic pipe from the elbow and cap it. Then run the test from the begining. Good luck!