Guest wolfztech04 Posted April 10, 2004 Share Posted April 10, 2004 Hello yall, the first week in my new 83 280ZXT, was quite a mess. I soon discovered the water pump to be bad, cracked hoses, skipping ignition and plenty of potential. The engine draws great vacuum (I still think I have a vac leak) Plenty of oil pressure and a strong engine (overall). I gave the engine a tune up. New battery wires and terminals. New Cap and Rotor, plug wires, and Bosch platinum 2 plugs. I set the Ignition timing to 20 BTDC, Running 92 oct fuel, Oil and Filter change, transmission and differential fluid change. The car runs strong and I've already waxed a Toyota Supra (80's model) He didn't stand a chance; 35mph, 3rd gear, 3500rpm. Waxed! Anyway, Is the stock boost setting 5psi? How much boost can I SAFELY run with no IC, BOV, or any mods except those stated....basically stock. Any Info would be greatly appreciated. Thanks... Wolf. Quote Link to comment Share on other sites More sharing options...
GrayZee Posted April 10, 2004 Share Posted April 10, 2004 Stock psi is supposed to be 7psi, although it's been said that the stock boost gauge isn't very acurate. I've got a autometer mechanical gauge (the stock one uses a electric one from a vac/boost sensor that coverts the signal to electric from manifold pressure) My autometer gauge always reads 7psi under full boost (for now, until I raise the pressure ) I believe the general opinion around here is that 9psi is aceptable without a intercooler however watch out that you aren't simply blowing off your safefy relief valve because it'll blow off your excess pressure at about 9 or 10psi. Quote Link to comment Share on other sites More sharing options...
Guest ZmeFly Posted April 10, 2004 Share Posted April 10, 2004 It wouldnt be safe or prudent to go over 9 psi without an ic. Also you might want to back your timing down to 24 btdc. That is the spec for an 83, the 81's and maybe 82's not sure on that one were set at 20 btdc. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted April 11, 2004 Share Posted April 11, 2004 9 is good... a few of us crazier ones run 10 I run 10 with no I/C, ran it on the dyno and there was not even a hint of detonation (which even if you can't hear it, usually shows up as an extremely erratic power curve when it starts to occur). It was running a little leaner than is considered safe above 5000rpm (save on a turbo setup should be 12 or so to 1, I was running 13:1). I know Jersey used to run 10psi with no I/C at the dragstrip all day long, only once he bumped it up to 11 or 12 did he start hearing detonation. Agreed though, the 'safe' limit is 9psi. The factory pop off valve was designed to blow off at about 9, so it's a reasonable assumption that the factory ECU was programmed to handle up to that as well. You should be completely safe running 9 on 91-93 octane. Quote Link to comment Share on other sites More sharing options...
Guest wolfztech04 Posted April 11, 2004 Share Posted April 11, 2004 Thanks, This is my first turbo and I want to be sure that everything is in sound condition. Since I just recently purchased this 83, I'm still going over everything one at a time, finding new things to clean, repair, replace etc... This afternoon I did a compression test (cold) and the engine pumped up 100psi over all six cylinders. I figured that being cold it would have squeezed more at normal operating temp. The stock vac/boost gauge only reads 5psi (the needle never hits the "7" thats on the gauge). The engine draws good vac at idle and idles smooth. The timing skips around alittle bit and I'm not sure if that's normal, or a problem. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted April 11, 2004 Share Posted April 11, 2004 DEFINATELY get a real boost gauge installed before you even TOUCH the boost. You can not trust the factory boost gauge. I've noticed problems with my timing skipping around as well. Odd thing was, if I checked the timing on any other cylinder (you can check on the #6 and it should show the timing mark just like on the #1) and it ONLY did it on the #1. I know I finally got it fixed but I can't remember exactly what I did to fix it... I did a LOT of things trying to get it to stable out... everything from just replacing ignition components, to adjusting the CAS, cleaning everything off... you know, if I remember correctly, I believe it stopped when I disconnected the TPS. I drive with my TPS disconnected all the time now and my car runs smoother for it, coming off idle there used to always be this stumble but with the TPS disconnected it's gone. Heheh you guys put a little scare into me so yesterday I nudged my boost down a bit further Peak is now like 9.5psi but averages out at 9. Quote Link to comment Share on other sites More sharing options...
Guest wolfztech04 Posted April 11, 2004 Share Posted April 11, 2004 Thanks, I'll install an aftermarket gauge, recheck the timing and try the compression test warm. thanks again. Quote Link to comment Share on other sites More sharing options...
stagefumer11 Posted April 13, 2004 Share Posted April 13, 2004 ive run 15psi on my l20et. no deto. but i guess i would be leaning out majorly. just got a fmic. and ran 15psi the thing was NUTS!!!! Quote Link to comment Share on other sites More sharing options...
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