Zraced... Posted February 8, 2006 Share Posted February 8, 2006 I am new to the boost game as I have just done a turbo swap, but was wondering if you guys know what the problem might be. As my motor boosts up around 10psi-15psi the motor bucks and then the blowoff valve goes off. It feels like maybe one of my vaccum lines to the wastegate collapses and then releases. The wastegate has an 8 psi spring and I am using silicone tubing...maybe I need thicker walled stuff. I have a garrett GT35RBB Turbo, external wastegate, standalone ecu etc... any ideas? Quote Link to comment Share on other sites More sharing options...
Silent Posted February 9, 2006 Share Posted February 9, 2006 surging, or you need to either tinker with the timing map, or add fuel Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 9, 2006 Author Share Posted February 9, 2006 if it was surging than to much flow to the intake? Maybe add more fuel at the higher RPMs. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 9, 2006 Share Posted February 9, 2006 A 2.8L shouldn't surge before 20psi with the GT3582R compressor. And even then it shouldn't buck the engine and cause the BOV to go off. Collapsing intake tract after the BOV is the only thing that will cause the BOV to go off that I can think of? Dave Quote Link to comment Share on other sites More sharing options...
The Revelation Posted February 9, 2006 Share Posted February 9, 2006 i know you said its an rbb but do you know which model? there are 4 models in the 35 family by garrett and all but one of them has an extremely large A/R, making your spool not very adequete, im not saying thats the problem but i think its a good place to start. ps: the gt35 with an adequete sized A/R is the GT3582R Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 9, 2006 Share Posted February 9, 2006 i know you said its an rbb but do you know which model? there are 4 models in the 35 family by garrett and all but one of them has an extremely large A/R' date=' making your spool not very adequete, im not saying thats the problem but i think its a good place to start. ps: the gt35 with an adequete sized A/R is the GT3582R[/quote'] Err.. they're ALL GT3582Rs mate. The 35 indicates the series, the 82 indicates the compressor exducer size (mm) and the R indicates dual ball bearing core. As indicated on the garret website the PN's for the GT35R is `714568'. The suffixes are `1' for the 1.06 turbine a/r, `2' for the 0.82 and `3' for the 0.63. These suffixes actually appear on the turbo's tag as `-500X', as opposed to just `-X'. Do you consider 0.82 upwards as extremely large A/R? Dave Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 9, 2006 Author Share Posted February 9, 2006 A 2.8L shouldn't surge before 20psi with the GT3582R compressor. And even then it shouldn't buck the engine and cause the BOV to go off. Collapsing intake tract after the BOV is the only thing that will cause the BOV to go off that I can think of? Dave You mean a collasping vaccum line might be my problem? My main intake pipes are pretty solid. Would a low amount of fuel at high RPM's cause this phenomenon? Quote Link to comment Share on other sites More sharing options...
Silent Posted February 9, 2006 Share Posted February 9, 2006 You mean a collasping vaccum line might be my problem? My main intake pipes are pretty solid. Would a low amount of fuel at high RPM's cause this phenomenon? yulp butt dyno tuning is not a way to do it. what are the a/f's through out idle to max rpm? Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 9, 2006 Author Share Posted February 9, 2006 At idle I am at 13-14 then under load it is 9-10, but when the popping/coughing happened I didn't get to see the AFR numbers, it probably was starved for fuel. Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted February 9, 2006 Share Posted February 9, 2006 9 to 10 at wot is PIG rich.. i bet its getting to much fuel... but if u didnt see the afr's at the time of the problem then i dont really know. mike Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 9, 2006 Author Share Posted February 9, 2006 Yeah and my laptop broke it's connection so I have no log of it. I was using Matrix mode on the Microtech my friend with hi RX-7 said to use normal mode. I'll try that and keep an eye on the AFR...I had to much excitement feeling the power of the Z under boost for the first time, and didn't watch my AFR...for shame Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 9, 2006 Share Posted February 9, 2006 Ya get that. I just realised you are exceptionally unlikely to get collapsing intake tract when its pressurised. Hehe.. The BOV going off thing threw me. Fix the mixtures, change the plugs (you've probably fouled those) and for gods sake, make a $10 detonation detector. Dave Quote Link to comment Share on other sites More sharing options...
AnTmanS130T Posted February 9, 2006 Share Posted February 9, 2006 I was looking into doing an audible detonation setup with the headunit through AUX input. Just out of curiousity, what type of detonation setup do you use? Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 10, 2006 Author Share Posted February 10, 2006 Ya get that. I just realised you are exceptionally unlikely to get collapsing intake tract when its pressurised. Hehe.. The BOV going off thing threw me. Fix the mixtures' date=' change the plugs (you've probably fouled those) and for gods sake, make a $10 detonation detector. Dave[/quote'] How do you make one of those if you don't mind humouring me. Quote Link to comment Share on other sites More sharing options...
Silent Posted February 10, 2006 Share Posted February 10, 2006 How do you make one of those if you don't mind humouring me. id really love to put a knock sensor on my L series. especially after some more of the extreme hp mods im going to be doing Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted February 10, 2006 Share Posted February 10, 2006 What TheHelix is describing is basically a piece of metal tubing bolted to the block going into some rubber tubing which splits off into two sections and connects to a set of ear muffs so you can listen for pinging. Helix, sorry if I oversimplified the description of your design. I'm thinking of making one myself. It's so simple and cheap, there's not much to lose by trying it. Quote Link to comment Share on other sites More sharing options...
ngrimm Posted February 10, 2006 Share Posted February 10, 2006 How about spark blowout due to overly wide plug gap? It's happened to me many times in my Mustang. Norm Quote Link to comment Share on other sites More sharing options...
Zraced... Posted February 10, 2006 Author Share Posted February 10, 2006 I put in new plugs and gapped them to within spec...I must have a fuel problem on my curve...either too much/little. The motor would cough and then the blow off valve could be heard. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 10, 2006 Share Posted February 10, 2006 neinberg, Nup thats about it. I was given the idea by a track racing mate. Works a treat, but you'll see(hear). Coughing at boost could definitely be spark break down. What heat range plugs are in it? I still don't get why the BOV would go, that only happens when the pressure on the manifold side of the T/B is greater than what the BOV is seeing on the face of its valve (assuming you have it hooked up that way). Dave Quote Link to comment Share on other sites More sharing options...
iaconsultants Posted February 10, 2006 Share Posted February 10, 2006 There is another possibility which I hope it is not for you. Please check each cylinder with a compression gauge if you find one that is a little lower you broke a ring or piston land. You will really only notice the bucking under good boost and not at light boost unless you have really borken the pistons where pieces are in the pan. If the piston lands are floating in position they will still run and under higher boost you will get that bucking because the lands move around and allow the air to blow bye easier and you will hear some poping on the oil pan from the cylinder being fired off. Once again I hope this is not it. Also open your oil cap and see if your engine is puffing air then it has gotten bad. I wish you lots of luck Quote Link to comment Share on other sites More sharing options...
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