How is your bov set up?

[Flapjack]

Believe you ment tial 50mm there not 38mm thats the wg . Fluttering gate usualy means too stiff a spring for the vac you have. Which in turns means your likely also getting some compressor surge as well be it a supercharger or turbo setup.

You are right. Duh on my part. Someone else (maybe you?) said pretty much the same thing in my other thread. I'll be taking a few coils off to help it stay closed, but I'm going to ask Jim at THP to check his paperwork to see what spring I have. He'll probably end up sending a 6lb spring, which is pretty close to 1/2 my idle vac (-10hg).

I had an 11psi in my tial bov orignaly which was too stiff a for my vac (18-19) and it wasn't opening like it should so I was getting fluttering/compressor surge. Swapped to a 9psi spring (1/2 my vac) and all is well. No flutter, no surge and the bov springs fully open when letting off the gas and then shuts.

That's good to know. I've been told to not go too low on the spring. Need to find the sweet spot...

On a blower setup you need to take it a bit further than 1/2 your vac since the blower moves alot of air at idle unlike the turbo which is load based. So for a blower a good rule of thumb is 1/3 of your vac at idle.

I have turbos, so I had not heard the 1/3 rules for a blower. That would be a pretty light spring!

On a side note, why aren't the Tial 50s adjustable? Every diaphragm-type valve I've seen (and I've seen a lot in 10 years Air Force service as a Liquid Fuels Systems maintenance NCO) has an adjusting nut. You you have to know which way to turn, depending on how the seat is in relation to the disc, but they all adjust somehow.

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[BruceH]

You are right. Duh on my part. Someone else (maybe you?) said pretty much the same thing in my other thread. I'll be taking a few coils off to help it stay closed, but I'm going to ask Jim at THP to check his paperwork to see what spring I have. He'll probably end up sending a 6lb spring, which is pretty close to 1/2 my idle vac (-10hg).

That's good to know. I've been told to not go too low on the spring. Need to find the sweet spot...


I have turbos, so I had not heard the 1/3 rules for a blower. That would be a pretty light spring!

On a side note, why aren't the Tial 50s adjustable? Every diaphragm-type valve I've seen (and I've seen a lot in 10 years Air Force service as a Liquid Fuels Systems maintenance NCO) has an adjusting nut. You you have to know which way to turn, depending on how the seat is in relation to the disc, but they all adjust somehow.

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I'm pretty sure the TiAL adjusts with washers added to the spring.

 

[Flapjack]

Really? Wouldn't that make it open less?

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[555]

Speaking of signal lines, thats something often overlooked I think, I know I never really considered it before. I love the fore boost/vac block I have now. It makes sure nothing is starved for signal and I ran 8an line to it right off the back of the manifold between it and the brake booster which is a perfect spot. I run the my eboost2/boost gauge, frps and bov directly off it now. Instead all the t's off the factory frps line like I had before.

Very clean set up with the Vac/boost block

 

[JeremyH]

You are right. Duh on my part. Someone else (maybe you?) said pretty much the same thing in my other thread. I'll be taking a few coils off to help it stay closed, but I'm going to ask Jim at THP to check his paperwork to see what spring I have. He'll probably end up sending a 6lb spring, which is pretty close to 1/2 my idle vac (-10hg).

That's good to know. I've been told to not go too low on the spring. Need to find the sweet spot...


I have turbos, so I had not heard the 1/3 rules for a blower. That would be a pretty light spring!

On a side note, why aren't the Tial 50s adjustable? Every diaphragm-type valve I've seen (and I've seen a lot in 10 years Air Force service as a Liquid Fuels Systems maintenance NCO) has an adjusting nut. You you have to know which way to turn, depending on how the seat is in relation to the disc, but they all adjust somehow.

Sent from my Galaxy Nexus using Tapatalk 2

I'm pretty sure the TiAL adjusts with washers added to the spring.

Really? Wouldn't that make it open less?

Sent from my Galaxy Nexus using Tapatalk 2

The pressure in the bov is still only going to be as weak as the spring. Adjusting a set screw on top or shimming the spring internaly with a washer will only make it stiffer from where it is. In other words to get optimal life and proper operation wether its an adjustable or non-adjustable unit you still want to have it as close to the right size spring size on your setup as possible. If you have to go smaller/softer on the spring and if you unit is adjustable you can tweak it just a tad or if its non adjustable you can shim it with a washer. I wouldnt reccommend cutting a spring to make it weaker just to save money due to the potential side effects.


Here is a link to some info on spring pressure and bov operation for ya. The 6psi spring will be perfect for your setup flapjack.


http://www.tialmedia.com/documents/BOVspc.png

 

[Flapjack]

The pressure in the bov is still only going to be as weak as the spring. Adjusting a set screw on top or shimming the spring internaly with a washer will only make it stiffer from where it is. In other words to get optimal life and proper operation wether its an adjustable or non-adjustable unit you still want to have it as close to the right size spring size on your setup as possible. If you have to go smaller/softer on the spring and if you unit is adjustable you can tweak it just a tad or if its non adjustable you can shim it with a washer. I wouldnt reccommend cutting a spring to make it weaker just to save money due to the potential side effects.


Here is a link to some info on spring pressure and bov operation for ya. The 6psi spring will be perfect for your setup flapjack.


http://www.tialmedia.com/documents/BOVspc.png

Thanks for the link. Does being at a high altitude change things any? Our air pressure at our altitude (about 6800ft here in Peyton, about 6200ft in Colorado Springs) is about 11.9psi, vs 14.7psi at sea level.

**EDIT**
After looking at the pictures in that chart, I don't have a BV50... I have a "Q"

 

[JeremyH]

No altitude doesnt matter its all relative to your vac at idle. The Q is a 50mm bov they use the same springs as you can see in the link.

 

[Flapjack]

No altitude doesnt matter its all relative to your vac at idle. The Q is a 50mm bov they use the same springs as you can see in the link.

Yeah, I looked them both up later. Seems like the "BV 50" is more or a race application, rated to 80psi (yow!)

 

[BruceH]

Nice setup Jeremy.

I backed the screw out and replaced the 10psi spring with the 5psi version. Works great, doesn't shuffle.

 

[JeremyH]

Nice setup Jeremy.

I backed the screw out and replaced the 10psi spring with the 5psi version. Works great, doesn't shuffle.

 

[Flapjack]

I asked Jim to send me the 6psi spring, and cut exactly two loops off mine for now.

@Jeremy
I also bent the spring to level it out, as it was stock. Hopefully I don't have any binding issues, as you mentioned in the other thread. It's only temporary, though.

 

[JeremyH]

I asked Jim to send me the 6psi spring, and cut exactly two loops off mine for now.

@Jeremy
I also bent the spring to level it out, as it was stock. Hopefully I don't have any binding issues, as you mentioned in the other thread. It's only temporary, though.