blow off valves

[HoleshotHolset]

I saw these little brass relief valves on someone's truck a long time ago. From what I understand... two of 'em will keep boost at bay quite easily... and you can pick 'em up at your local plumbing supply house.



This afternoon - I finally found a picture of what I have been looking for in hardware/plumbing stores on the PDR site.



I hate calling to bug Piers for little piddly stuff like this - so I was hoping that someone could lead me in the right direction by offering a brand/part #/etc.



Thanks,



Matt

 

[chrleb1]

you can get those in different sizes (1/2, 3/4, ect. ). All they are isa pressure relief valve (safety valve). You can adjust them as you see fit. These can kinda be scary though. Sure they help control boost, but the do it by releasing intake air. When this is done it can lead to over spooling your turbo and then we all know what happenes there. Thebest solution is to run a wastegate and release exhaust gases, this helps in your over all flow out of the motor.

 

[TORQUE THIS]

Matt,



Check here... www.mcmaster.com page 397



This is where I am getting mine from, however, I haven't looked for them yet, but I know there in there...

 

[Jetpilot]

Piers.....



Doug

 

[Sled Puller]

They leak.

They are a band -aid.

 

[Sled Puller]

Oh yea, I had one set for 50 psi, the other for 60 psi.

I still hit 86 psi on the pulling track.

 

[Jim Fulmer]

Matt, there watts regulator valves part no. 530a, this is what I run also, they are there for a boost spike not to be used all the time like I use them for, I have two of them in the pipe going to the intercooler set to crack at 50 psi and wide open with shop air at 60 psi and my boost is at 80, there cheap, and that is it. On the ones I have I took them apart and put locktite on the holding screw because it was viberation apart, no there not an end all, if you want that then look for a blow off valve for about 250+ bones..... so far they work fine..... it's a Hotrod... work on it!



Jim

 

[propuller]

Doug,



What are your thoughts on these opening up & causing the turbos to overspeed damaging them. I have these on my twins & i often wondered about this also. Good idea/Bad idea. I guess its better than blowing the head off.



Kurt

 

[BigBadDodge]

Mine seem to be working great in conjuction with the wastegate, I have one set to start opening at 65psi and the second to start openig at 67 psi. The most boost I have seen on the Spa guage even while sled pulling is 69psi and I plan on keeping it that way for a while.



#ad






BBD

 

[ToolManTimTaylor]

Matt .... What no BLING? LOL!

http://www.hksusa.com/FAQ/?id=1758&rsku=0



"Q: How does the diesel blowoff work?



A: The Diesel blowoff uses an electronic/mechanical throttle trigger in conjunction with the pneumatic actuation of the standard SSQV. Please refer to the link below for an image of the Diesel SSQV and all of its components.



http://www.hksusa.com/images/?id=1746



If you have any further questions, please feel free to contact us at our techline 310 491 3300



Thanks



HKS USA"





#ad

 

[Sled Puller]

Originally posted by BigBadDodge

The most boost I have seen on the Spa guage even while sled pulling is 69psi









BBD

Thats because you haven't hooked to a heavy sled on a real track yet!

 

[HoleshotHolset]

Wow... great thread!



Thanks for the info!



Mark: Thanks for the link.



Jim: Thanks for the part number, etc.



I intended these to be used in conjunction with a big external wastegate hung off the manifold and dumping in-between the chargers. I know they're not the best solution, but they're cheap and readily available.



I'm hoping not to rely on them... but they'll be installed, setup and ready to react to head gasket eating levels of boost if I can't control the boost with my Racegate.



Scott - THAT's the picture I saw... but couldn't find. The valves you are using look a little different than the valves in the picture I posted... .



Timaaaarrrgh!: HKS' stuff is insanely priced. I wonder if/how their BOV would handle 50+psi?



Matt

 

[ToolManTimTaylor]

It's all about the Bling Yo

 

[F8LDOSE]

HKS BOV's are discontinued...

 

[nickleinonen]

Originally posted by F8LDOSE

HKS BOV's are discontinued...

there is always the BD turboguard eh...

 

[Jetpilot]

Propuller,



I think that with the your PDR twins you really don't have a worry about overspeeding your turbos. Reason being your 40 is wastegate to both control boost and turbo speed. Second you will have a very hard time overspeeding the Large with our engines.



Doug

 

[propuller]

Thanks alot Doug,That coming from you makes me feel alot better about these blowoff valves.



Kurt

 

[Sled Puller]

Originally posted by propuller

Thanks alot Doug,That coming from you makes me feel a lot better



Kurt

Right.

That makes sense. Doug has broken everything he has touched. he is an expert on the topic!LOL

 

[HoleshotHolset]

Gene: Those that live in glass houses shant throw stones.



Since when do you have a midas touch? (just ribbing you, buddy... )



Matt

 

[Sled Puller]

Yea, but I broke stuff while competing, poor old Jetty never gets out of the garage!!