Synapse BOV surges when recirculated, ideas and advice please!

[teedoff00]

Hey I have had this BOV installed on my 87 Supra for about two weeks now. I ran it vented to atmosphere for a few days until I could get the recirculation figured out. It worked great and no surge was noticed. I did notice that my car wasn't loving the loss of metered air and it was showing in my AFRs. So I recirculated the BOV into my intake pipe (between turbo and AFM). But now I am getting compressor surge! Bad! This turbo is brand new and I don't want to run this thing when it is causing surge. I disconnected the recirculation train from my intake pipe and ran the BOV vented to atmosphere with with recirculation train still attached, the surge is still present. So I took the recirc. fitting (recirculation and hoses/couplers) off and the surge is gone again, but my AFRs are all over the place, depending on throttle and vacuum levels.

I am assuming it is something to do with my recirculation setup. Because of the large 1.25" fitting I got a 1.25" inch to 7/8" inch coupler and took that to a 90 degree elbow (probably not ideal) to a 3/4" hose to my fitting on my intake pipe (all of the fittings I have on the intake pipe are 3/4" fittings).

My question is this: What can I do to eliminate the surge with this setup? I don't see how I can connect a line much bigger than 3/4" and I am starting with 1.25"! There is about 3 inches of space to the intake pipe from the outlet of the BOV. Does Synapse offer anything that can help? I know they make a 1" fitting, but I hate to order it if it is going to only reduce the surge, I need it eliminated! Has anyone else had this issue? You can't all have 1.25" bungs on your intakes... maybe?

I have toyed around with moving the BOV further down the line to give myself a longer run at the accordion hose, but I don't know if eliminating the 90 will solve it. Any advice, experience or ideas would be great!

I included some pictures for reference of the setup.

Thanks!

 

[Poodles]

My guess is the elbow...

 

[IJ.]

My guess is the elbow...

Mine is the reducer....

 

[supraguy@aol]

Mine is the headgasket.

...oh- sorry...my standard answer.
I would see if you can get an adapter that goes from the accordian hose's inlet size to the same diameter as the output for the BOV.
Basically- an all-metal reducer that will fit the nipple off the intake, and allow you to run a full-size elbow hose of 1.25" diameter.

 

[Flateric]

Wait a second.......didn't the Synapse guy say that their BOV NEVER surges? Oh wait thats another conversation entirely.....LOL.

 

[RazoE]

Mine is the reducer....

really..?

my BOV has a 25mm hose that reduces to 19mm right near the accordian hose, do you think that's bad..? (haven't run her yet)

 

[hvyman]

Venting only effects when you let off the throttle.

 

[IJ.]

really..?

my BOV has a 25mm hose that reduces to 19mm right near the accordian hose, do you think that's bad..? (haven't run her yet)

You're trying to release as MUCH air as possible as quickly as possible to prevent surge, if you restrict the BOV in any way it can't do this and if you're running a big enough compressor section on the turbo it's going to be an issue.

As an example my 7M with the T04z (a known surge monster) with 2x 32mm type 3 turbosmart BOV's was fine at 10psi but surged it's brains out at 15 if you got on/off the throttle say on a twisty road due to the fact the stock springs were far too stiff and couldn't react fast enough or open wide enough.

The Synapse doesn't have the spring issue so "should" be surge free, the fix for my car was to removed 1/3 of each spring and to run a large bore hose to help keep them closed while on boost.

 

[teedoff00]

Thanks for the input guys. I am currently waiting on a new silicone elbow to redo a piece of my current intercooler setup so I can move the BOV further down stream and get a longer run at the accordion pipe. I still don't know how I am going to get 1.25" all the way to the accordion hose, but maybe the Supra Gods will turn their graces my way... So I will probably be posting in a few days telling you all that it still doesn't work. Ha ha, but not really.

So which should I try: Reduce to the fitting on the accordion without the elbow? or Cut my accordion bung (silicone) off and jam 1.25" fitting in and silicone around it? I would prefer the first if it will work, but I am doubtful...

Once again, thanks for all the ideas.

Oh I am not sure if you are talking about the Synapse in this case but...

Venting only effects when you let off the throttle.

I guess the Synapse design leaves the valve partially open at vacuum and at idle (also vacuum, but stated on their website) and then when it sees boost pressure it slams shut and that's why they can hold "over 100 psi". So pretty much it leaves me with a huge maf leak all the time. Yeah its pretty awesome driving my car right now...

 

[hvyman]

<--Does not like the synapse.

 

[IJ.]

Thanks for the input guys. I am currently waiting on a new silicone elbow to redo a piece of my current intercooler setup so I can move the BOV further down stream and get a longer run at the accordion pipe. I still don't know how I am going to get 1.25" all the way to the accordion hose, but maybe the Supra Gods will turn their graces my way... So I will probably be posting in a few days telling you all that it still doesn't work. Ha ha, but not really.

So which should I try: Reduce to the fitting on the accordion without the elbow? or Cut my accordion bung (silicone) off and jam 1.25" fitting in and silicone around it? I would prefer the first if it will work, but I am doubtful...

Once again, thanks for all the ideas.

Oh I am not sure if you are talking about the Synapse in this case but...
I guess the Synapse design leaves the valve partially open at vacuum and at idle (also vacuum, but stated on their website) and then when it sees boost pressure it slams shut and that's why they can hold "over 100 psi". So pretty much it leaves me with a huge maf leak all the time. Yeah its pretty awesome driving my car right now...

Did this on a buds car awhile back, machined up a fitting with a flange on it then we cut a hole in his accordian slightly smaller than the fitting's od and siliconed it in, let it set then slide the connector hose right down to the rubber before clamping and it's 100% leak free.

If the Synapse is open off boost I hope you guys put a filter on them when running unrecirculated.

 

[MA70_Powa]

I have the same problem (same setup too but 1" - 19mm reducer hose, 90 degree bend into accordian hose) but with an SSQV, so I'm keen to see how you fix this!

 

[Poodles]

Yep, open off boost, and listen to the BS reasons they say. Their vids like this are why I wouldn't run their products...
[video=youtube;B_RWZASfE3M]http://www.youtube.com/watch?v=B_RWZASfE3M[/video]

 

[RazoE]

so they're saying their BOV's are supposed to blow air out even at idle? It's just one big ass boost leak in that case..

 

[teedoff00]

Yeah, in retrospect, I am feeling I should have gone with a different brand, maybe even just upgraded to the Bosch Diverter Valve since I rarely run high boost. I am thinking I am going to have to go the route of cutting into the accordion hose (so thanks for the experience IJ). I am not really sure on the effects of having the BOV open during idle and vacuum (other than the non-filtered air if not filtered), but I do know that under boost, it is completely sealed shut. (infact, from what I can tell this "sealing" happens around -1 mmHg vacuum.

Thanks again for the replies guys.

 

[Flateric]

Yep, open off boost, and listen to the BS reasons they say. Their vids like this are why I wouldn't run their products...
[video=youtube;B_RWZASfE3M]http://www.youtube.com/watch?v=B_RWZASfE3M[/video]

Yup, BINGO, thats the video I was referring to and I commented about it there too and then a few days later I got this private message from them explaining that the GT4088r is a roots type forced induction.......ummmm noooo, anyways here is the message I got verbatum.


mkrv4jtta

Reply to your comment on: Filtering a Blow-Off Valve (BOV)
Reply to your comment on: Filtering a Blow-Off Valve (BOV)
im not saying its making boost at idle. im saying there is a lot of pressure in the "boost pipes" at idle. the turbos are spinning, pushing air to a closed throttle body, the air cant pass the throttle body nor can it go back to the turbo thats why the bov is open,oh and your gt40,it has boost pipes? right, its a roots blower, and most roots blowers now adays have a "bypass valve" anyways,go check out some vortech and procharged setups or any centrifugal for that matter and see how their dv work


So there ya go, he's not saying that there is boost at idle, but in the video he is saying that the pipes want to explode, and he is not saying its making boost at idle, but he is saying there is alot of pressure in the "boost pipes" at idle........HUH? How does this make any sense at all in anyway shape or form. I've said it before and I'll say it again, it may be a great product, it may not be a great product, but anyone that needs to sell their product by completely misrepresenting other products, spouting completely contradicting and outright wrong info about forced induction of all types, is obviously not letting the product stand on it's own or feel they need to confuse others to buy said product.

Just my opinion though. I've also got some super special snake oil here that when added to your 7m's oil will 100% eliminate the possibility of ever getting a BHG again. How? Well, it's specialized polimer fibro flange electrovibing technology eliminated all possible cylinder pressures normally created and instead cause a vacum to form sucking the headgasket down onto the block hard than any bolt set ever could. The tramorgifying the efficiency of the engine to always be in a vacum state even on the power stroke inversly causing the oil to not-unpressurize and sealing the head to the block. Actually there is no need to even bolt the head down at all anymore with this supra special snake oil. In direct propriatary secret nonidependant testing with leading synthetic cooking oils like pam, it outperformed by a factor of 10 to 1 on the unobtanium flteric idex which we invented to measure just such things so precisly.

 

[gottadiesel]

Oh perfect :icon_cry: I wish I had seen this thread before spending $200 on this very BOV, what research I had done... obviously not enough... thought it to be a great idea not having any surge of course... but yeah guess being held open sure doesn't seem like a great idea and if you filter it, would that not slow down the release of air that is supposed to avoid the compressor surge... gonna have to think over this one for awhile and figure out what direction I will go... running out of time, motor should be going back in next week I hope :x:

I am anxious to see how your issue pans out after the mods you are going to make to your current setup for bo return.

 

[Flateric]

Oh perfect :icon_cry: I wish I had seen this thread before spending $200 on this very BOV, what research I had done... obviously not enough... thought it to be a great idea not having any surge of course... but yeah guess being held open sure doesn't seem like a great idea and if you filter it, would that not slow down the release of air that is supposed to avoid the compressor surge... gonna have to think over this one for awhile and figure out what direction I will go... running out of time, motor should be going back in next week I hope :x:

I am anxious to see how your issue pans out after the mods you are going to make to your current setup for bo return.

Hey man, seriously don't let my critical attitude towards them throw you off here. Seriously, as I said it may be a great product. But I strongly dislike the way of presenting it when compared to other and their constant misinformation they spread. It may be a great or good product. I seriously meant that part.

If I were in your shoes ATM I would try running the thing. Let us know your unbiased opinion of how you like or dislike it. Not many run them, but this doesn't mean they are totally crap either. I am aiming my harsh attitude at the people and presentation, not nessecarily the product. Your not gonna hurt anything (I don't see how anyways, correct me if I am wrong please someone) by running it and seeing how she performs.

Seriously run it, give us some feedback on your feel of it. I'm willing to bet regardless of your tech knowledge level, you'll be more accurate than their sales team.

 

[redhot91gt]

Ok, I have this BOV in just about the same location as the OP. I am currently venting it to atmosphere and have no issues with driveability really, but I am also running a map based system. For afm cars I dont think this is the bov you want. I also tested mine and it stays open at anything over 7" of vacuum. So even at part throttle situations (right when you start building some boost pressures) It can still let air that the turbo is making out which does equate to a boost leak. It is adjustable but theres no way I will be able to get it to open at around 20" of vac like I would want it to. The bov works great as far as opening quick after a hard boost/close throttle run.

Another problem I have with it is filtering. They do show that (if your turbo is efficient enough) it will blow air through the bov at idle. I dont really know about that... But I am worried that at certain times its pulling in air and would rather it be filtered or recirculated. I tried recirculating this bov simular to the OP but I had it reduced right before it got to the accordian. This resulted in surge when I let off hard after full boost. My next option is puting a aux filter on it (which wont help people with afm's) If I were to do it all over again, I would probably buy something else.

 

[MarkIII4Me]

You have got to be shitting me. I just ordered one of these last week (still hasn't come in). I'm thinking of cancelling now.