Guest jjohart Posted June 25, 2004 Share Posted June 25, 2004 Hi, I've got an 83 280ZXT, with a NPR large intercooler, a Greddy Profec B boost controller, a modified pop off valve (supposedly set to open at 15psi), a open air K and N type filter, and a DSM blow off valve, all presumably working and installed properly at this time. I noticed last night (with the driver's T top removed and windows down that there is a fairly consistent raspy fluttery sound when I press the throttle at or very near full wide open throttle in boost range (i.e above 3,000rpms). This sound is almost exactly like a piece of writing paper taped or held up to the grille of yer standard indoor fan on high speed! Uh, I should say it is a bit louder than that indoor mechanical analogue........"BPPPFFFFTTHHHTTTPPP"!!! If I modulate the pedal a bit more away from the floor (in other words, less gas, but not immediately lower revs at 30-70mph), it will cease immediately, but alas, pressing the throttle back down to the floor brings it right back. I don't hear any of this in revving in a stopped position (this is a 5 speed), so I don't think it's an exhaust leak. The first question, apart from the obvious "whatheF&*@ is that?!" is whether this could be pinging. I wish someone would give me a soundfile, for I've no idea what pinging sounds like. IF this is, what do I do? If it isn't, what else could it be, and how to cure..unless this is "normal"...I don't think so, but sorry for the usual baseline level of this inquiry! Thanks John Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 13, 2004 Share Posted July 13, 2004 I was gonna say too much fuel or a Catylitic Converter...but your engine is turbo charged, so all bets are off. Since this is the "General" Engine Forum you might try posing your question in the Turbo-Supercharger Forum for a better response. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 13, 2004 Share Posted July 13, 2004 Sounds like pinging to me. My best description of the noise is that it sounds like a marble trapped and rolling around in the front bumper. Kind of metallic tapping noise. Not a turbo guy but I would expect to see some fuel mods in your list and I don't. If you're upping the boost you need to increase the fuel too! Jon Quote Link to comment Share on other sites More sharing options...
Sean73 Posted July 13, 2004 Share Posted July 13, 2004 I had a boost leak that sounded like that once. Turned out to be a loose IC hose connection that was leaking/flapping under high boost. Since you've probably already ruled out hoses, your BOV or POV could be malfunctioning. Try turning down the boost 1-2 psi at a time, and see if it goes away. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted July 13, 2004 Share Posted July 13, 2004 Sounds like the pop-off valve venting. Mine went in the trash about a week after I got the car running. Sure - its a disaster-preventer, but some things are sacrificed in the quest for more performance. Remove it - plug the hole with a pipe plug and take the car out for a ride. Then you'll know. Good luck - Doug Quote Link to comment Share on other sites More sharing options...
Guest znow white Posted July 14, 2004 Share Posted July 14, 2004 could be you have something leaking in your ic plumbing or blow off because you had allot of previous incidents. I also agree with some others you should increase your fuel when boosting more.... Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted July 14, 2004 Share Posted July 14, 2004 Hi, I have come to realize that adding fuel management items will probably raise as many problems as it might solve. I definitely am not investing 5-7 grand in a JWT chip and intake system at this point, and I have heard nothing but mixed blessings about use of fuel computers and other outboard items (i.e this site's particular bias against progressive rate fuel set ups, which I already bought and sold, convinced accordingly that it was of no use in my fuel injected system). Indeed, before I even went to intercooling, most respondents on this site were telling me that the stock fuel management system would be adequate for pressures under 16psi. I just spent $200 for a stupid boost gauge (anyone's guess if the Nissan stock dash unit overestimates by 2psi or the aftermarket underestimates by same!!), and all I know is I was running upwards of 17psi and creating a hell of a lot of backpressure. The simplest solution for me is simply keeping the hi boost setting at 14, the low at no more than 11. That paper-flipping sound doesn't seem to be pinging at all to me...not like a marble in a metal bumper, more like the BBC Boo-Bah kids characters when they release gas/air and blast off into psychedelia. Perhaps I'll get a show of my own if my engine blows up, but I don't think fuel mods are the answer....the answer for me seems to be not pushing the design tolerances of the Nissan/Datsun too far beyond stock pressures. Anything else is bound to cost $1,000's of dollars for me, and I notice, cringing, that all the fuelie advocates are thousands of miles away from me (i.e no competent local mechanics to keep the tweeks going!). Thanks though John Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted July 14, 2004 Share Posted July 14, 2004 5-7 grand in a JWT chip I think thats a little high of an estimate of the price of the set-up. I bought mine used and payed 800 for it. Worth every penny. A new one is in the 2000.00 range I believe. No dought it wouldn't fix your current proublem but, it would help in the drivability and overall power output would be much greater than the stock set-up can muster. No, it's not the best compter on the market but, most of us can have it installed in under an hour and it'll get 95% of the power out of your setup. Changes such as turbos and exhaust don't require retuning. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted July 14, 2004 Share Posted July 14, 2004 Well - If you were running 17 psi and the pop-off was modded to hold 15, chances are it is blowing off. It does sound somewhat like you are describing. BTW- 17psi manifold is likely 19ish psi at the turbo, you are running on the ragged edge of destruction of the stock turbo - no joke! That is seriously overspeeding the turbo. One could get the stock compressor map and work out by how much, but I don't think one would want to. This is also probably why the recirc line keeps blowing off of your BOV, the air temp coming out of the turbo is probably around 275-300 deg. The Nissan L28ET sure is one tough engine...... Doug Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 14, 2004 Share Posted July 14, 2004 19psi at the turbo, stock turbo... I wonder if the blade tips are supersonic or how close they are? Instead of a jim wolf setup, why not just buy an SDS for less, and then you can modify your maps as you like, and as you make future engine mods? Quote Link to comment Share on other sites More sharing options...
Guest znow white Posted July 15, 2004 Share Posted July 15, 2004 are you running 17 psi of boost on stock fuel pump? i would recomend you get a walbro , rrfpr, bigger injectors and adjust from afm it wont cost thousands i think $ 400 would cover but you are seriously hurting your engine if your running all stock Quote Link to comment Share on other sites More sharing options...
Sean73 Posted July 16, 2004 Share Posted July 16, 2004 Who told you that the stock fuel system can handle 16 psi? Basic math dictates that the stock injectors at stock fuel pressure are only safe to 12 psi. The ECU probably limits it even more. Most of the guys here running over 12 psi routinely have fuel mods. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 17, 2004 Share Posted July 17, 2004 Back to the fluttering sound.....Mine did it in a big way PHUTPHATTTFLUTT in rapid succession when I let off the throttle after building some boost. I had no BOV and thats why it made the noise (described by someone as the sound of choking a goose). Once I put in the TurboXS Race Type blow off valve, the sound dissapeared. So....maybe your BOV is not BOV'ing enough. Quote Link to comment Share on other sites More sharing options...
aaronp Posted June 27, 2010 Share Posted June 27, 2010 i agree with Doug77zt, my car did that very same thing until I did a little experimenting with the POV, which verified that it was indeed the problem. The remedy was removing it and replacing it with a one inch pipe cap. Now I have the boost set at eleven psi with no problems, of course I bumped the fuel pressure a couple lbs. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 27, 2010 Share Posted June 27, 2010 holy necroposts batman! I think this was solved 6 years ago! someone wants to post something up for sale in the classifieds in a big way if they're responding to this now... Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted June 28, 2010 Administrators Share Posted June 28, 2010 Tony, You forgot the pic, mang... Quote Link to comment Share on other sites More sharing options...
aaronp Posted July 1, 2010 Share Posted July 1, 2010 I don't believe it clearly stated "that the problem is the POV blowing off the excess boost", so I just wanted to post my findings for the next guy looking for answers to this problem. Quote Link to comment Share on other sites More sharing options...
luvmy280zxt Posted July 29, 2010 Share Posted July 29, 2010 LOL choking a goose....I just spit OJ all over my keyboard. Too funny! Quote Link to comment Share on other sites More sharing options...
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