Blow off valves?

Jono FD3 · August 19, 2006, 09:30:54 PM

Mine has just split the diaphram and has stopped working as a result!! I\'m trying to get one like my bro had on his sunny GTiR (never saw it, only heard it), it was a multy staige chattering sound to it......... would that be the HKS Super sequential?

?

Please help as I want a cool sounding blow off valve and I need one prety fast as I\'ve got a show to do a a week!!!

Thanks for your help,

Jono

Bobfish · August 20, 2006, 11:01:46 AM

that sound is compressor stall, if it has a cha cha cha cha psscch sound to it then its just a stiffly adjusted adjustable dump valve. The HKS SSQV is adjustable, but be aware that sound is not good for a turbo. Wont blow it up in seconds like, but its not good for them.

McCARTHY · August 20, 2006, 11:26:00 AM

if its a cherp type noise then yes i would says it probibly was an HKS jobbie, if i was more of a flutter could have jusy been wastegate chatter, or something like the Greddy Type R BOV they have a much more airy sound (if thats the wayto put it???)

Jono FD3 · August 20, 2006, 03:00:34 PM

Cheers guys...... im getting turbo stall at the moment due to the diaphram being shagged, which is why I\'m looking at getting another one!!

Jono

ianelvar · August 20, 2006, 05:50:33 PM

Quote from: Bobfishthat sound is compressor stall, if it has a cha cha cha cha psscch sound to it then its just a stiffly adjusted adjustable dump valve. The HKS SSQV is adjustable, but be aware that sound is not good for a turbo. Wont blow it up in seconds like, but its not good for them.

I agree, be carful Jono. If the turbo compressor is stalling then it unloads the turbine, which is then free to spin the turbo up to terrific speeds. Can lead to bearing failure, or at worst fracture of the turbine. The dump valve is there to stop that happening.
I\'ve seen a turbo get knackered from compressor stall, it\'s nasty. Was being used as a jet engine at the time, but even so!

Jono FD3 · August 20, 2006, 06:11:07 PM

Yea I know it nakers things up, thats why I\'m not useing the car till I get another BOV fitted!!!
Jono

G@NDY · August 20, 2006, 06:13:58 PM

Jono dont you have the standard dump valve that you took off to put the hks one on, that might keep you going for a while?

Jono FD3 · August 20, 2006, 08:03:39 PM

finding it is the problem mate!!!!
Jono

Grizzly · August 21, 2006, 02:00:05 AM

Quote from: ianelvarI agree, be carful Jono. If the turbo compressor is stalling then it unloads the turbine, which is then free to spin the turbo up to terrific speeds. Can lead to bearing failure, or at worst fracture of the turbine. The dump valve is there to stop that happening.
I\'ve seen a turbo get knackered from compressor stall, it\'s nasty. Was being used as a jet engine at the time, but even so!

Depends on what Turbo you are Running with no BOV and what sort of Boost.

If its a tame set up you won\'t have any problems its only when you run Big hp you\'ll run into Problems if you are using the wrong Turbo.

From experiance there does\'nt feel any diffrence when your Driving hard with with or without BOV, Its only Prelonged On Off load that could cause the Turbo Drive Shaft to fracture, but it won\'t happen over night.

CraigN · August 21, 2006, 02:03:01 AM

Quote from: ianelvarI agree, be carful Jono. If the turbo compressor is stalling then it unloads the turbine, which is then free to spin the turbo up to terrific speeds. Can lead to bearing failure, or at worst fracture of the turbine. The dump valve is there to stop that happening.
I\'ve seen a turbo get knackered from compressor stall, it\'s nasty. Was being used as a jet engine at the time, but even so!

What complete tosh

compressor stall does the oposite it slows down he shaft speed.

what you are describing is the result of a faulty BOV and a loss of pressure in the charge system, resulting in the turbo overspooling to try and reach pressure.

for your info i do not run a BOV

the car is much more responsive without running the BOV

Grizzly · August 21, 2006, 02:35:04 AM

Basically Turbo Stall is where the Throttle Snaps shut in say a gear change whilst the Turbo is producing its peak boost, the air in the system has no where to go so it over pressurizes until ether the Throttles open or the Turbo\'s wheel stops, its the speed it goes from 10,000 rpm - 0 repetitively that does the damage! but a Turbo will take this for quite along time before the Drive shaft Fatigues and Fractures, the effects are reduced when you have a Big Ic and big ic Pipes so there is lots of Volume of air to Compress before the stall giving it more of a Cushion.

Think about it to over rev a Turbo you have to increase the Volume/Speed of Exhaust gasses going through it or Reduce the Resistance of the Air coming out.

Bobfish · August 21, 2006, 10:20:22 PM

Grizzly knows the dance. As i said in my post, It wont blow up in seconds - but its not good for them.

prince_of_tokyo · September 27, 2006, 12:39:26 AM

when and how does turbo stall occur, because i just fitted a second blitz blow off valve and when i rip it in 1st and harshly put it in 2 second it makes a wierd noise and dont really go nowhere?

prince_of_tokyo · September 27, 2006, 12:43:03 AM

so i guess to stop turbo stall you should put the original recirculating blow-off valve back on yeh?

probedb · September 27, 2006, 10:26:37 AM

If you read Grizzly\'s post he explains it all.

Blow off valves?

Bobfish

Bobfish

probedb