Subject	My 2 cents.......
Posted by	Greg D. (Specialty-Z) on May 28, 2012 at 10:06 AM
	This message has been viewed 410 times.
In Reply To	With respect, I am calling BS for two simple reasons: posted by ConVerTT on May 26, 2012 at 07:25 PM
Message	The stock system deals with the air the turbos move by allowing the stock re-circ valves to open while the engine is in vacuum. When ever the throttle plates close, the air the turbos move can travel out of the turbo and back into the front side of the turbo in a loop, this allows the turbos to spin without resistance to flow. Going to blow off valves or installing stiffer springs in the stock re-circ valves, will not deal with the air that is moving as efficiently, and will cause resistance to flow. If you run the engine at 3000 RPM without making boost, the exhaust energy is going to spin the turbo a significant amount. When you close the throttle plates, you are blocking the air from moving forward, if you do not allow that air to recirculate, you will cause the air to force back through the compressor while it is still spinning forward. This is going to cause a flutter sound that is surge, this is causing the compressor to slow and it is decreasing the effciency of the system. The sound will increase with larger pipes and larger turbos because both increase the air volume moving in the system. If you increase the amount of air that your moving in the system, but decrease, or stop the ability for the system to re-circulate the air, you are forcing the system to fight for the direction the air is moving, the flutter is simply the noise created by the fight. If you want to stop the goose honk, I have a suggestion; I believe the sound is caused from the harmonic created from the air moving across the opening of the recirc valve pipe when the recirc valve is partially open. This sound is similar to blowing across a bottle. If you have ever blown across a bottle, you know the sound occurs from blowing a certain pressure, at a certain angle. The recirc system can be improved by making the fitting on the filter side enter back into the system in the direction of flow, similar to what we have done with the design of the wastegate tube re-entering the expansion downpipes. Installing the recirc fitting at a angle back into the intake pipe will improve recirculation flow, and it should cancel the harmonic goose honk.
Follow Ups	Can someone please explain the causes, effects and the best - DVDBURN (MD) 14:09:25 05/26/12 here... - KongZTT GT28RS MD 14:12:41 05/26/12 Too little flow for the pressure ratio. In order for the - Ash's Z 14:38:19 05/26/12 Thanks for the info. (n/m) - DVDBURN (MD) 14:52:12 05/26/12 Damn... Now my new Flutter Buster product is useless - LitlElvis 17:18:48 05/26/12 lol (n/m) - ZiNnYc 18:31:04 05/26/12 False. The flutter is really annoying in a convertible - ConVerTT 19:46:31 05/26/12 An active control system would work best. - Ash's Z 04:44:15 05/27/12 What about the flutter at the beginning of the blow off? - BlackholeZ 18:11:39 05/26/12 That would only occur if the BOV were malfunctioning. - Ash's Z 16:22:58 05/27/12 Couple questions - BlackholeZ 18:57:52 05/27/12 I did simplify the situation a good bit regarding the axial - Ash's Z 19:56:47 05/27/12 With respect, I am calling BS for two simple reasons: - ConVerTT 19:25:16 05/26/12 Original post with vids here Ash in case you missed it - ConVerTT 19:38:30 05/26/12 There is a huge difference in pressure and when the valve - LitlElvis 21:59:54 05/26/12 Ok, but do you accept my proposed test as valid? - ConVerTT 23:26:15 05/26/12 Sounds like a valid test to me. (n/m) - LitlElvis 10:26:34 05/27/12 but then you would get surge? (n/m) - BlackholeZ 19:00:33 05/27/12 Im actually elated that you bring this point. =) - Ash's Z 03:26:46 05/27/12 Coles notes version: - MixManMash 09:08:33 05/27/12 =( Damn, nutshelled into two sentences. - Ash's Z 16:58:00 05/27/12 Long paragraphs and bid words don't scare me :-) - ConVerTT 09:39:07 05/27/12 You will hear surge with no recircs. (n/m) - MixManMash 09:55:52 05/27/12 Yes. I want to compare the sounds. - ConVerTT 10:50:51 05/27/12 Re: Long paragraphs and bid words don't scare me :-) - Ash's Z 15:40:10 05/27/12 Thanks Ash and ConVerTT for the comprehensive discussion - OverZealous (CT) 15:31:24 05/28/12 My 2 cents....... - Greg D. (Specialty-Z) 10:06:29 05/28/12 That picture is ridiculous! (n/m) - na300zx (OH) 11:41:13 05/28/12 What were your suspension settings for this launch? (n/m) - KongZTT GT28RS MD 14:56:09 05/28/12 Awesome explanation Greg. - MixManMash 15:18:08 05/28/12 Good suggestion Greg. Great discussion all! - OverZealous (CT) 15:20:51 05/28/12 Honestly, I think the concerns for it are overrated... - ZinnZ32 16:24:18 05/26/12 My roomie's Turbo brick doesn't have a BOV - BlackholeZ 18:19:47 05/26/12
Post a Followup	You cannot reply to this message because you are not logged in.