Topic: BNR 2871 Flutter

[elff]

Very well [and maturely handled] Josh


Miller

Without taking my setup apart, I can not get that measurement and since I just got the front of my car back together, I am not in the mood to pull it apart again.
What I can do, is contact Synapse and see what they say.

The over feeling I am getting from this whole post is what we suspected.  The 2871 puffs too much for the BOV Josh has.   I attached my Log in the one post to show what it can reach and I have since reached higher MAF Flow.

Stay tuned for my answer from Synapse

[JoshMcMadMac]

Very well [and maturely handled] Josh


Miller

Without taking my setup apart, I can not get that measurement and since I just got the front of my car back together, I am not in the mood to pull it apart again.
What I can do, is contact Synapse and see what they say.

The over feeling I am getting from this whole post is what we suspected.  The 2871 puffs too much for the BOV Josh has.   I attached my Log in the one post to show what it can reach and I have since reached higher MAF Flow.

Stay tuned for my answer from Synapse

I will (eventually) get around to removing the Hahn BOV and getting measurements.

[elff]

I sent a note to Synapse Support.
They are in California so it's before 8am their time.

FYI- Their advertisement on their webpage states

http://www.synapseengineering.com/v4/sb/
Our Patented Synchronic Technology in our Blow-off Valve has an impressive reaction time of 12 milliseconds.
Pressure tested up to 100psi to not leak boost, with no diaphram.

The 2871 is not pushing anywhere near that limit

[JoshMcMadMac]

I sent a note to Synapse Support.
They are in California so it's before 8am their time.

FYI- Their advertisement on their webpage states

http://www.synapseengineering.com/v4/sb/
Our Patented Synchronic Technology in our Blow-off Valve has an impressive reaction time of 12 milliseconds.
Pressure tested up to 100psi to not leak boost, with no diaphram.

The 2871 is not pushing anywhere near that limit

So what is the difference between their BOV and the diverter valve?

[elff]

It's pretty much a size thing.  Their DV is smaller for more compact applications.  The smaller size affects it in the fact that it is only rated to hold up to 60PSI.   
Other than that, the internal technology is the same as the SB and still should be more than enough for the 2871 Hybrid. 

I see where you are going with this and the DV might be a good size fit

[miller11386]

100 psi is impressive, but the overlooked feature is the size of the piston. That truly determines the capacity of the valve IE 100psi in a 1" tube is much less volume than 100psi in a 6" tube. Speed of evacuation is determined by the vent diameter.

Elff, you don't need to take it apart. Just measure the end of the piston where the air comes out of and you will have the critical dimension. The others are irrelevant. Heck just throw a ruler on top of the bov and take a pic. I can tell you roughly what it is. Like I said, from what I remember its going to be around ~40mm or 1.5"

[elff]

I had thought of that, but with my engine setup, I can't see into the end of the BOV to get an accurate measurement.  The hood is in my way.
But, I would have to think it is darn close to 1.25" which is the diameter of the Recirc valve. 

[Bill Hahn Jr]

Hi all,

Just got on, been consumed this morning with farm and business chores, as well as internal meetings where we've been brainstorming Technical Support processes and possible revisions in light of this dilemma from yesterday.  For clarity's sake, I'd like to address that aspect separately from the actual discussion about the BOV's.  I'll work with Joe to address the details of separating the two.

elff, to answer your most basic question from last night, it's not actually a standard parameter of a typical compressor-bypass (intake manifold signal-referenced) BOV to establish a maximum boost pressure rating.  Their essential internal construction ensures that they will always stay shut under boost.  I'll go into greater detail on this in a bit. 

Some of the BOV manufacturers do offer different springs, but they are for the purpose of accommodating different idle intake vacuum settings.  In a nutshell, engines with bigger cams and porting develop much less idle vacuum than less aggressive setups using stock cams, and thus require a different valve opening pressure and accordingly, a lighter spring.  On the other hand, if one uses a spring intended intended for such a low vacuum application on an engine with a strong vacuum signal (such as stock cams would produce), the valve will actually start opening at idle...so a stronger spring would therefore used to keep the valve closed at idle, resisting the stronger vacuum being produced.

Our Billet BOV uses a spring that's intended to accommodate street-type high vacuum/stock or mild cam applications, as that's the bulk of its application.  Highly modified cylinder heads engines with cam, valve and port upgrades will typically also be associated with a higher HP range, and thus more airflow, at which time a larger, more adjustable (via available spring options) BOV would be the logical choice.

I'd like to also put a finer point on this "flutter" issue we're examining here.  In some LNF applications, we've seen BOV's from multiple manufacturers flutter under full load, high boost, mid-high RPM, when they should not actually be opening at all.  Josh and others, is this the issue you're referring to in this thread, or are you referring instead to a flutter when the valve is intentionally opened when suddenly releasing the throttle?

Should anyone like, I'll be happy to also expound a bit further on BOV valve design and function.  I can add some detail here I think many will find useful, just let me know.

[DeepBlueGXP]

This thread has been split into two topics. 
This one plus http://www.kappaperformance.com/forum/index.php/topic,9206.0.html

If you have any questions about this thread or posts, please PM me directly. 

Regards,
Joe

[elff]

Hopefully i am posting in the proper thread due to the split

In answer to Millers question

The diameter of the largest part of the Synapse valve is approx 31mm.  The diameter of the visible surface of the valve is approx 26mm.

[JoshMcMadMac]

I too had the Hahn BOV setup on my 08 Redline equipped with the DDM 2871 turbo.
The Hahn BOV would flutter at high rpm when boost was set over 18 to 20 lbs.
It didn't matter where you had it adjusted.
Replaced it with a Synapse and problem solved.
With a little finagling I have the Synapse BOV installed in the Hahn hoses so it recirculates the blow off air.
Jerry

Anyone hear from Jerry on this?

[elff]

He kind of dropped off after that.

I need to get some recirc tubing and then I am going to try and recirculate mine just for giggles.

[JoshMcMadMac]

He kind of dropped off after that.

I need to get some recirc tubing and then I am going to try and recirculate mine just for giggles.

From the looks of things, I think I can set up a Synapse to "look" like the Hahn BOV, so it should just be a matter of arm-wrestling into the same space between the tubing.  It took a surprising amount of googling to see the different angles of the Synapse that gave me any confidence that it is indeed capable of being modified this way!

[elff]

Please take pics of your work.

[JoshMcMadMac]

Please take pics of your work.

Will do.  This has taken a back-burner, so I really need to get this at least installed before winter.  I need to get back in touch with Miller, since I think he had at least the fitting I would need.  Just to verify: NO anti-stall kit?

[elff]

I bought that fitting from Miller

Sorry!!!!!

[JoshMcMadMac]

I bought that fitting from Miller

Sorry!!!!!

Please take pics of your work.

 

[elff]

Touche!!!!

[JoshMcMadMac]

How is everyone plumbing their vacuum line?  There are two connections on the bottom of the Synapse, and the instructions give the option of connecting one, both, or neither of them to the vacuum line off the intake.

[elff]

I have both connected, and use a Y connector to reduce it to a single line which then connects to the middle port on the ByPass Solonoid
Hopefully you can see all of that in this picture

[JoshMcMadMac]

I have both connected, and use a Y connector to reduce it to a single line which then connects to the middle port on the ByPass Solonoid

Thanks!  I figured that was the best way to do it, but wanted to check before going through the effort.  I did get it to fit in place of the Hahn BOV, although the Synapse is a bit taller and getting those vacuum lines connected is going to be snug.

[elff]

Id be real curious to see a picture of your setup when you are done

[GASNGO]

My setup with the synapse BOV plumbed into the Hahn hoses works great. I had to make up a new  BOV recirculation hose to be able to install the Synapse BOV into the Hahn intake hose. I have both hose fittings on the end of the BOV connected to a Y connector and the Y connector connected to the hose fitting which faces toward the front of the car that is part of the solinoid which is on top of the intake manifold.
I would enclose pictures but I am having trouble sending them.
Jerry   

[JoshMcMadMac]

Id be real curious to see a picture of your setup when you are done

I should be able to do that when I plumb up the vacuum line.  It is pretty much the same as the pictures with the Hahn valve, I just had to wrestle all of the silicone plumbing to get it to play nice together.  I hate that there is no lip on the inlet to the turbo to help keep the intake connector from slipping off!

[GASNGO]

Here is a photo of my Synapse BOV installed in the Hahn tubes. It also shows the two hoses attached to the end of the BOV. Jerry