nr.metalguitar Posted April 28, 2017 Share Posted April 28, 2017 Note for people outside of Australia: 'Dose' refers to the turbo chatter when off throttle boost. Hey all, Have an 04 liberty with custom intake and blow off valve that's on really tight. The car has the factory VF38 turbo, and doses well except for one admittedly unessesary issue. It's sorta low pitched. Not really a SUTUTUTU sound but more like a low pitch shoo-shoo-shoo. Running an aluminium intake pipe with a pod filter too, wondering if theres any tricks to get a higher pitch dose Thanks! Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
xtea Posted April 28, 2017 Share Posted April 28, 2017 Are you talking about purposefully generating compressor surge, a.k.a. "Turbo flutter". If so you I doubt you'll get help here as thats not a good thing. Link to comment Share on other sites More sharing options...
Andy_Mac Posted April 28, 2017 Share Posted April 28, 2017 Even less wise on a VF38 since they love to wreck themselves even when looked after reasonably well. 2000 Legacy B4 RSK - SOLD 2006 Legacy BP5 GT Spec B wagon - Garage Thread 2011 VW T5 van 2.0L of turbo diesel awesomeness Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 28, 2017 Author Share Posted April 28, 2017 Compressor surge is when the boost pressure 'surges' past what the engine is capable of using (only ON throttle). I'm referring to flutter off throttle, where boost pressure just exits from the turbo compressor Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 28, 2017 Author Share Posted April 28, 2017 Even less wise on a VF38 since they love to wreck themselves even when looked after reasonably well. Ah damn, never knew. Just got into Subies so getting used to the complicated pros and cons of each turbo they decide to put into whatever iteration of a certain engine. Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 28, 2017 Author Share Posted April 28, 2017 After some playing around, I believe that there is a high pitch sound but just for an extremely short amount of time. As the flutter is fast and short, maybe a front mount intercooler will increase the volume of air going back in. I'll record the intake with some of my studio equipment and slow it down to kind of simulate the effect of a front mount. Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
The 2Fiver Posted April 28, 2017 Share Posted April 28, 2017 Sell your Subaru and buy a Toyota Supra. Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 28, 2017 Author Share Posted April 28, 2017 Ahaha no thanks mate, I'm in love with the general quality of Subarus now Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
gkinslow Posted April 28, 2017 Share Posted April 28, 2017 Is your BOV adjustable? If so is it set to 100% VTA? (full ricer mode) Link to comment Share on other sites More sharing options...
Phate Posted April 28, 2017 Share Posted April 28, 2017 Is your BOV adjustable? If so is it set to 100% VTA? (full ricer mode) I bought a GFB specifically so I can do this. I generally run it somewhere around 90% recirc/10% VTA, which is just enough PSSHHH to make my inner ricer happy. Link to comment Share on other sites More sharing options...
gkinslow Posted April 28, 2017 Share Posted April 28, 2017 I definitely understand the novelty. Don't you have to tune for that as well?? I prefer the sleeper status. Around my neck of the woods I'd get harassed by every Mustang boy racer in the county, and I'm getting a little old for constant shenanigans. Link to comment Share on other sites More sharing options...
Phate Posted April 28, 2017 Share Posted April 28, 2017 I definitely understand the novelty. Don't you have to tune for that as well?? I prefer the sleeper status. Around my neck of the woods I'd get harassed by every Mustang boy racer in the county, and I'm getting a little old for constant shenanigans. It shouldn't effect the tune. On full recirc it behaves exactly like the stock bov, maybe reacting slightly quicker. With any amount of vent to atmosphere, it will go rich for about as much time as it takes to shift to the next gear. I can probably adjust the tune to be slightly happier about it, but at my current setting I don't really notice any problems from it. I don't mind it dumping a bit of extra fuel into the exhaust, it tends to crackle nicely on upshifts, keeping my inner ricer happy. Obviously venting more means it goes rich for longer, but I didn't notice too much of a stumble even when I briefly drove around with it cranked all the way open just to see how loud it was. Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 29, 2017 Author Share Posted April 29, 2017 I have a GFB too, but 99% of the time it's kept to full recirc. God bless you if a police car hears a blow off valve in Sydney Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 29, 2017 Author Share Posted April 29, 2017 Alright, hooked up a good mic to my audio interface and ran it in front of the intake. Here's the un-edited clip: https://drive.google.com/file/d/0B6q-u4tYLUQ4eTVoTWU2aDBKWm8/view I used audacity to slow it down (Extremely high sample rate recording so not too much quality loss), and applied some EQ to cut off some background drone. Obviously this clip is cut up to save time. https://drive.google.com/file/d/0B6q-u4tYLUQ4ZWlIVmdEWWZWVG8/view Need a second opinion if a front mount will give me that higher pitch, slow chatter off throttle. Not sure if its just me, but especially in the last rev of the slowmo clip, that high pitch whistle from the turbo can be heard. Open to all opinions. Thanks. Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
ATLspeed Posted April 29, 2017 Share Posted April 29, 2017 Remove/block off BOV and it's louder if you have an aluminum intake with pod filter. That's all you need to do. I generally ran no bov on any of my turbo cars (t25, t28, hx40, he351, ct26) without a problem. Only time I would use one is if the turbo has ceramic blades. As you said before it's called turbo flutter and no compressor surge (that majority of people confuse it with...even confused with wastegate chatter) Link to comment Share on other sites More sharing options...
xt2005bonbon Posted April 29, 2017 Share Posted April 29, 2017 God bless you if a police car hears a blow off valve in Sydney Sent from my SM-N910G using Tapatalk What will they do if they hear it? Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 29, 2017 Author Share Posted April 29, 2017 Remove/block off BOV and it's louder if you have an aluminum intake with pod filter. That's all you need to do. I generally ran no bov on any of my turbo cars (t25, t28, hx40, he351, ct26) without a problem. Only time I would use one is if the turbo has ceramic blades. As you said before it's called turbo flutter and no compressor surge (that majority of people confuse it with...even confused with wastegate chatter) Exactly what I already have, the BOV spring is tight so it pretty much doesn't open. Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
nr.metalguitar Posted April 29, 2017 Author Share Posted April 29, 2017 What will they do if they hear it? Pretty much put down your car as undrivable temporarily, because the car is seen as unroadworthy. Sent from my SM-N910G using Tapatalk Link to comment Share on other sites More sharing options...
1-3-2-4 Posted April 30, 2017 Share Posted April 30, 2017 It drove me nuts on my car when it was running.. I suspect it's something larger than 16G or 18G.. I can't find much info on the turbo the blade design was the double blades for the intake side.. but that's all I have to go off of. Boy my wheel bearing sounded bad in this video I remember getting on the ramp from my house and I went to shift and get back on the throttle I let a nice large cloud of black smoke behind me.. but it was not something that always happened.. I'm going to go full recirculation Link to comment Share on other sites More sharing options...
nr.metalguitar Posted December 19, 2017 Author Share Posted December 19, 2017 Whoops, Late reply much. After some experimentation with boost levels and volume with piping, A VF38 (Standard turbo on JDM and AUDM Legacy GT's 04-06) will get a really nice resonant flutter. Not very high pitched, but very noticeable and airey. I got this using an aluminum cut plate to block the diverter valve, along with a pod air filter using a 3 inch stainless steel pipe with a housing for the MAF sensor replacing the stock plastic intake piping. Sent from my SM-G950N using Tapatalk Link to comment Share on other sites More sharing options...
bigleben Posted December 19, 2017 Share Posted December 19, 2017 Running without a BPV/BOW will get you the high pitched sound you're after sooner or later... A failling turbo. Link to comment Share on other sites More sharing options...
nr.metalguitar Posted December 19, 2017 Author Share Posted December 19, 2017 Running without a BPV/BOW will get you the high pitched sound you're after sooner or later... A failling turbo.VF38 is still going strong, just upgraded to an aftermarket turbo and getting a much better sound than compressor blades scraping Sent from my SM-G950N using Tapatalk Link to comment Share on other sites More sharing options...
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