240hoke Posted July 6, 2003 Share Posted July 6, 2003 Aight guys now that got my 370cc injectors installed i reidid my mapps and started turning up the boost. Heres what happens: I turned the boost up to 12 psi. The boost will spike to 12 and then drop back to 10 psi and i have to have my foot planted to keep it at 10 it really wants to drop. Im running a medium NPR w/ 2.5" piping. I figure this is swallowing my turbo whole and the T3 just cant flow the air. i don't know, what's you guys take? -Austin Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 6, 2003 Share Posted July 6, 2003 You might have a restriction in the exhaust somewhere, but it could be the stock turbo running out of steam too. There are some folks who have made the stock turbo boost to 17-18 psi with intercoolers though, so it may be your exhaust. Quote Link to comment Share on other sites More sharing options...
240hoke Posted July 6, 2003 Author Share Posted July 6, 2003 Wel ive got a ss 2.5" mandrel bent downpipe, with 3" mandrel bent piping from there back. i do have a single chamber flowmaster, thats the only resistion point there could be, but its possible i had the dyno guy to tell me to get that thing offa the car and go with a straight pipe or a straight through muffler. -Austin Quote Link to comment Share on other sites More sharing options...
Nigel Posted July 6, 2003 Share Posted July 6, 2003 How about a leak somewhere in your intake plumbing that's venting boost? Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted July 7, 2003 Share Posted July 7, 2003 Try ditching the muffler, have you shortened the WG actuator rod? It may not be holding the WG puck closed tight enough or it may be hanging open a bit and bypassing exhaust past the turbine Good luck - Doug Quote Link to comment Share on other sites More sharing options...
yo2001 Posted July 7, 2003 Share Posted July 7, 2003 My stock T3 used to do that. I was in the impression that the WG wasn't big enough because it stop doing it when I got my 60-1/StageIII with larger WG hole and it stop doing it. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted July 7, 2003 Share Posted July 7, 2003 My stock turbo always did that with the stock WG actuator. You could not give me one of those again. Porting out the WG hole a little would probably help. Quote Link to comment Share on other sites More sharing options...
spork Posted July 7, 2003 Share Posted July 7, 2003 I'd guess that either one of 2 things is happening. The most likely is that you've got a leak somewhere in your piping (or bov) and its venting boost. I've pushed over 20psi out of the stock turbo...running through a starion intercooler. If I had 20 psi in the intake I'm sure I was atleast 25psi coming out of the turbo because that intercooler is restrictive as hell, and my boost was always very steady with no fade or drop. The second option is you've got boost controller problems. What method of controlling boost are you using? James Quote Link to comment Share on other sites More sharing options...
240hoke Posted July 8, 2003 Author Share Posted July 8, 2003 I'm useing a hallman boost controller, the stock wastegate actuator is pretty tough to put on you have to pull it over the little pin. The BOV leaking or pipe leaking could be the culprit, what a good way to check? This is also a 20yr old turbo that has had nothing done to it so maybe it just about had it. Quote Link to comment Share on other sites More sharing options...
spork Posted July 8, 2003 Share Posted July 8, 2003 well, you can also try to check the function of the actuator if you have an air compressor w/a regulator on it. Dial the regulator down andhook it up to the vaccum line that goes to the actuator. Apply air. If the actuator moves back and forth smoothly and you don't hear any hisses then you're actuator is good. If you've got a hiss, then the diaphram in the actuator is most likely the culprit, and you'll have to get a new actuator. As far as testing your blow-off valve for leaks, it all depends on how yours is constructed. I tested a buddies 1G talon bov by hooking a hose up to the vented portand run it into the car and then hit boost. if it leaks you'll get air coming out of the hose. Be careful with this tho and make sure you have someone helping you, that hose can get out of control when you lift the throttle or if it's failing and letting boost vent. As far as checking your piping you'll want to find 2 pvc pipe plugs that will fit into the coupler from the turbo and one that fits in the coupler that hooks to the throttle body. Drill and tap one plug and thread in a air chuck and clamp the plug into place. Make sure you get the plug in tight, or it will shoot out when you apply air. Plug the other end of your pipes with the other plug and apply air w/ an air compressor and check for leaks. Let us know how it turns out. James Quote Link to comment Share on other sites More sharing options...
Afshin Posted July 10, 2003 Share Posted July 10, 2003 I agree with James (nice write up) that you may likely have a leak. I would also strongly consider shortening the WG actuator(even though it is tight) since it's a relatively common problem. I just redrilled a hole next to where the pin goes and effectively shortened the rod without any cutting. I really don't think that you exhaust is the restriction and would not mess around with that for now. COnsidering that your turbo is able to quickly build the 12 PSI boost, I think it is less likely that the turbo is the major problem. You build boost then lose it. this suggests WG failure or leak more so than a restriction or turbo failure. Another possibility is improper fuel delivery. I know you have remapped, can you calso check if fuel mixture (and timing)is correct at peak boost? Good luck and keep us posted. Quote Link to comment Share on other sites More sharing options...
240hoke Posted July 11, 2003 Author Share Posted July 11, 2003 Hey, It was the wastegate actuator. i swapped it out for one my buddy had and it holds 14 psi and doesn't drop a bit. I did notice that the actuator was a good bit harder to put on. Anyway thought id let yall know. Thanks for the suggestions!. Quote Link to comment Share on other sites More sharing options...
Afshin Posted July 11, 2003 Share Posted July 11, 2003 Great, that seemed quick and painless. You're all set for the weekend now, hopefully the cops are relatively easy going in your area Quote Link to comment Share on other sites More sharing options...
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