Im currently running a stock tub on my fc3s with boost running around 0.8 bar with the dump valve spring set to soft preload.
On low boost gear changes you get this turbo chatter coming through and the dump valve isn\'t opening.
Some info ive read on the net suggests that turbo chatter is bad as it eventually wrecks the seals in the tub \'\'even though it sounds cool\'\'
Should i switch to softer spring in the dumpvalve?? Would putting a harder spring in the dumpvalve increase theturbo chatter??
I personally wouldnt worry about it, for every 10 posts saying it causes increased wear there are another 10 posts saying it causes none of the sort. If you like it that way mate leave it otherwise change for the softer spring.
Ah okay il go for that then.Is the sound created from air rushing back to the turbine blades??
Yeah its the air stalling the turbo, it wrecked my OEM turbo, just make sure the vac line is connected to a good vac source and it should be ok. does the vac line going to the BOV have any other T pieces on it? Also what is the vac line made of? I changed my vac line for thicker walled stuff and my chatter stopped - my vac line was collapsing and cutting the bov off lol
+1 on what mitch said about vac lines - I had thin walled stuff on my bov and it wasn\'t always acting - thick walled now and the BOV can be heard wheezing off even after a low (3-4 psi) boost let off.
As to the turbo chatter - the air is trying to stall the turbo, the are pro and contra arguments about this - it certainly will slow down the turbine, which means it will take time to respool it, but a BOV will leak boost off, meaning the turbo has to re charge the inlet piping to recover the boost. Either way it\'s a trade off - the thing to find out is which takes longer - since that will impact performance the most.
All I really need to say on the matter is that I had turbo chatter from when the last owner disconnected some vac lines and the vacuum in the system wasn\'t enough to open the bov 100% of the time, result was that the turbo went in for £75 of porting work and ending with a full turbo rebuild costing £500ish, thicker vac line is worth the investment :)
Turbo chatter does sound cool, but imo is not worth the risk of lunching the blades. For something spinning at close to 100000rpm, it does not take a lot of unbalanced forces to cause something to wobble a bit, then after that it\'s good night.
I\'ve seen the aftermath a few times on industrial compressors where it occurs from a phenomonon called \'surge\'. The noise and vibration caused can (and has been) enough to shake a brand new £6mn turbine assembly to bits!!!
just my two cents though
Compressor stall isn\'t as bad as some people make out, especially on a turbo with a proted shroud.
Don\'t forget, soem cars came from the factory without a BOV of any kind.
From what I understand this problem is really turbo dependent some are very sensitive to it (sounds like the FC stock turbo may fit in to this catergory) some are very resistant to this type of damage.
Turbos with strong bearings like the Greddy TD06/07\'s are run without a BOV completely in some cars in Japan as their thick bearings and rugged construction allow it, my old car a MK3 Supra it\'s Hitachi CT26 really didn\'t mind it at all for a good 20k miles of abuse. Though you hear of some other turbo\'s packing up quite quickly, though it\'s undetermined whether they were on their way out or not already.
I think it\'s more a solid construction, big bearing, \'laggy\' turbo that\'s OK with it from what I\'ve read seen on the web.I\'m not sure how modern ball bearing turbos fare though.
At the end of the day WRC cars get away with it because they have anti lag too which fries their turbos anyway. As a general rule I\'d say make sure your BOV works for road and non-works cars.
Quote from: Lil-Steve;691450From what I understand this problem is really turbo dependent some are very sensitive to it (sounds like the FC stock turbo may fit in to this catergory) some are very resistant to this type of damage.
Turbos with strong bearings like the Greddy TD06/07\'s are run without a BOV completely in some cars in Japan as their thick bearings and rugged construction allow it, my old car a MK3 Supra it\'s Hitachi CT26 really didn\'t mind it at all for a good 20k miles of abuse. Though you hear of some other turbo\'s packing up quite quickly, though it\'s undetermined whether they were on their way out or not already.
I think it\'s more a solid construction, big bearing, \'laggy\' turbo that\'s OK with it from what I\'ve read seen on the web.I\'m not sure how modern ball bearing turbos fare though.
At the end of the day WRC cars get away with it because they have anti lag too which fries their turbos anyway. As a general rule I\'d say make sure your BOV works for road and non-works cars.
^^this.
If you have a fairly robust turbo then there shouldn\'t really be any issues.
As I said, the damage comes from air suddenly forcing its way \'the wrong way\' through the blades. As the turbine blades are only aerofoiled (if thats even a word! :P) this action tries to force the impeller in the opposite direction to the one in which it\'s spinning. The centrifugal forces involved are massive, and the energy imparted by the reverse flow of air puts huge stresses on the load bearing parts (blades & bearings usually).
So if you have a fairly tough tubby then you\'ll be ok, but if not then something will give sooner or later. To use my example again, industrial turbines are massively sensitive, and 99 times out of 100 will have a recycle line from the discharge side to the suction side with an \'anti-surge\' valve in it. As soon as vibration sensors detect surge occuring the valve opens immediately to recylce compressed gas to the suction side and keep the gas flowing \'the right way\' through the machine.
Again, just my (biased I may add) engineer\'s take on this!! :P
graeme
Well there\'s certainly allot of good info there! I\'m using some fairly thick silicone lines for my bov and I have my boost gauge and pressure sensor t into the same source.
I\'m not getting the chatter at higher boost levels just at lower boost, when I put a large load on the engine at low revs and let off that\'s when the chatter occurs.I\'d happily sacrifice performance to preserve the life of my tub.
Cheers chaps! :)
Quote from: Adam fc;692577Well there\'s certainly allot of good info there! I\'m using some fairly thick silicone lines for my bov and I have my boost gauge and pressure sensor t into the same source.
I\'m not getting the chatter at higher boost levels just at lower boost, when I put a large load on the engine at low revs and let off that\'s when the chatter occurs.I\'d happily sacrifice performance to preserve the life of my tub.
Cheers chaps! :)
Although you can always \'accidently\' unplug the bov and damage then turbo, then you will \'have to\' get a larger one to replace it with :rollin
Then you can get a turbo with a ported shroud, and not even have to worry :cool:
You could also unplug your bov intentionally run it for 18months without any issue except better throttle response, then plump it back in cause the chatter got annoying and run it for another few year all without any issues whatsoever.
Just because some had bad experiences doest make it so.
Sorry just another viewpoint